The Falls and Balance Research Group has published many papers pertaining to the various factors influencing postural stability and falls in older people. To view our list of publications pertaining to the following topics, follow the links below. Where available, papers are provided as Adobe Acrobat Portable Document Format (PDF) files. If you would like to be sent re-prints of any of these papers, please contact Prof Stephen Lord.

To download Adobe Acrobat reader for free, click here.

Lord SR. Falls in the elderly: admissions, bed use, outcome and projections (letter). Medical Journal of Australia 1990;153:117-118.

Lord SR, Clark RD, Webster IW. Physiological factors associated with falls in an elderly population. Journal of the American Geriatrics Society 1991;39:1194-1200.

OBJECTIVE: To determine whether a battery of 13 sensorimotor, vestibular, and visual tests discriminates between elderly fallers and elderly non-fallers. DESIGN: One-year prospective study. SETTING: Conducted at a 124-bed Hostel for Aged Persons, in Sydney, Australia. PARTICIPANTS: Ninety-five persons aged between 59 and 97 years (mean age 82.7 years) took part in the study. Of the 29 non-participants, four were ill, five were absent (on holidays, etc), and 20 declined. Residents were generally independent in activities of daily living although personal care assistance was available. RESULTS: Eighty-four participants were available for follow-up. In the follow-up year, 40 subjects experienced no falls, 11 subjects fell one time only, 33 residents fell on two or more occasions. There was a total of 145 falls. Discriminant function analysis identified proprioception in the lower limbs visual contrast sensitivity, ankle dorsiflexion strength, reaction time, and sway with the eyes closed as the variables that significantly discriminated between subjects who experienced multiple falls and subjects who experienced no falls or one fall only. This procedure correctly classified 79% of subjects into multiple faller or non-multiple faller groups. Quadriceps strength was poorer in the multiple fallers compared with the non-fallers and once-only fallers, although the difference was not statistically significant. There was little difference in the mean scores for the tests of vestibular function in the non-fallers, once-only fallers, and multiple fallers. CONCLUSION: It appears that this approach highlights some key physiological factors that predispose elderly individuals to falls.

Lord SR, McLean D, Stathers G. Physiological factors associated with injurious falls in older people living in the community. Gerontology 1992;38:338-346.

Performance in six tests of sensorimotor function was measured in 50 subjects who were admitted to an acute hospital because of a fall (ICD codes E880-888), but who did not suffer a fracture of the lower limbs as a result. Performances in these tests were compared with 50 subjects of the same age and sex who had not fallen in the previous 12 months. It was found that those admitted to hospital because of a fall had decreased tactile sensation, reduced quadriceps strength and increased body sway on firm and compliant surfaces. The fallers also performed poorly in clinical tests of static and dynamic balance. Psychoactive-drug use was associated with falling and a number of test measures, including body sway, static balance, dynamic balance and quadriceps strength. Twenty-seven percent of fallers had poor outcomes, in that 1 year after testing, they had either suffered three or more additional falls, been readmitted to hospital, been transferred to nursing homes or died.

Clark RD, Lord SR, Webster IW. Clinical parameters associated with falling in an elderly population. Gerontology 1993;39:117-123.

Eighty-one elderly residents of a hostel for the aged (mean age 83.3 years) underwent clinical medical assessments to examine susceptibility to falling. The medical examination was structured and followed a clinical format with particular emphasis upon posture and gait, in addition to routine examination of the cardiovascular, respiratory, neurological, gastrointestinal, haemopoietic, genitourinary, musculoskeletal and visual systems. These subjects were then followed upfor 1 year to assess whether these clinical measures were associated with falls.  Seventy-six residents were available for follow-up.  Thirty-four subjects (44.7%) reported having no falls in the follow-up year, 10 (13.2%) fell once only, 13 (17.1%) fell on two occasions whilst 19 (25%) fell three or more times. Seventy-two percent of falls occured in the hospital building. Certain clinical factors showed high specificity (i.e. only a few fallers screened positive in the tests) but low sensitivity (i.e. there were considerable numbers of residents who scored negatively, but fell in the 12-month follow-up period). Stepwise logistic regression analysis revealed impaired cognition, abnormal reaction to any push or pressure, history of palpitations and abnormal stepping as variables that independently and significantly predicted falling. The equation predicted falls with 70.7% sensitivity and 79.4% specificity, with an overall predictive accuracy of 74.7%. It appears that a modified focussed clinical examination could provide the basis of a short assessment for predicting falls and highlight possible intervention strategies for reducing fall risk.

Lord SR, Ward JA, Williams P, Anstey K. An epidemiological study of falls in older community-dwelling women: the Randwick falls and fractures study. Australian Journal of Public Health 1993;17:240-245.

Seven hundred and four women aged between 65 and 99 years (mean age 74.6 years), who were randomly selected from the community, took part in a study to determine whether health and lifestyle factors were associated with falls. In the 12 months before the survey, 66.1 per cent of the subjects experienced no falls, 19.7 per cent fell once and 14.2 per cent fell on two or more occasions. The proportion of women who fell outside the home decreased with age, with a corresponding increase in the proportion who fell inside the home on a level surface. The most common causes of falls reported were trips, slips and loss of balance. Some (27 per cent) suffered injuries as a result of a fall, and the proportion suffering injuries increased with age. Those who rated their health and balance as impaired, those with a limitation in activities of daily living, those receiving community services, those taking psychoactive drugs, and those taking four or more drugs had significantly more falls. On the other hand, those taking part in planned exercise and those active for seven or more hours per week had fewer falls. Smoking and alcohol consumption were not significantly associated with falls. Stepwise logistic regression analysis revealed poor vision, inactivity and subjective fall risk as variables that were independently and significantly associated with falling. These findings highlight possible intervention strategies for reducing falls risk in older people.

Lord SR, Sambrook PN, Gilbert C, Kelly PJ, Nguyen T, Webster IW, Eisman JA. Postural stability, falls and fractures. Results from the Dubbo Osteoporosis Epidemiology Study. Medical Journal of Australia 1994;160:684-691.

OBJECTIVE: To assess measures of postural stability in a large population of persons aged over 60 years in order to compare performance between fallers and non-fallers and relate postural stability to fracture prevalence. METHODS: The sensorimotor, visual and balance functions were measured in 1762 ambulatory, community-dwelling patients aged between 60 and 100 years (mean age, 70.1 years) living in a large semi-urban Australian city. A history of recent falls and fractures was recorded at the time of assessment. RESULTS: The prevalence of impairment in all tests increased with age. Men performed significantly better than women in tests of muscle strength, visual field dependence, sway on the floor with eyes open and dynamic balance. In the 12 months before testing, 72.3% of the patients experienced no falls, 18.4% fell only once and 9.3% fell on two or more occasions. Multiple fallers had weaker quadriceps, poorer tactile sensitivity, greater visual field dependence and greater body sway than other patients. Test scores for once-only fallers were mostly between those for non-fallers and multiple fallers. Those who suffered recent fall-related fractures had significantly reduced tactile sensitivity and quadriceps strength and increased body sway. Postural stability was also impaired in patients taking psychoactive and/or anti-hypertensive medications. CONCLUSION: Tests of postural stability can identify, independently of age, individuals living in the community who are at risk of falls and fall-related fractures.

Salgado RI, Lord SR, Packer J, Ehrlich F. Factors associated with falling in elderly hospital patients. Gerontology 1994;40:325-331.

Forty-four patients aged 65 years and over who fell whilst in an acute hospital and 44 patients who did not fall during their hospital stay underwent structured medical examinations to identify factors associated with falling. The control subjects were matched for age (+/- 3 years), sex, patient type, and primary diagnosis. The examination was based on established assessments of posture, balance and gait, the musculoskeletal system, vision, cardiovascular status, and neurological function. Bivariate analyses revealed seven assessment measures that were significantly associated with falls: cognitive impairment, particularly impaired orientation; evidence of previous cerebrovascular accident; incoordination as measured clinically; inability to perform the 'Get-up-and-go' test, especially an inability to turn around after a 5-metre walk, and the use of psycho-active medications. Of these variables, impaired orientation, psycho-active drug use, evidence of stroke, and impaired performance in the 'Get-up-and-go' test were included in a stepwise logistic regression which correctly classified 80% of the patients into faller and non-faller groups. Falling was also related to the number of these identified risk factors. These findings suggest that a simple screening protocol, taking about 5 min to complete, can assist in the identification of patients at risk of falls whilst in hospital.

Lord SR, Ward JA, Williams P, Anstey K. Physiological factors associated with falls in older community-dwelling women. Journal of the American Geriatrics Society 1994;42:1110-1117.

OBJECTIVE: To determine the prevalence of impaired vision, peripheral sensation, lower limb muscle strength, reaction time, and balance in a large community-dwelling population of women aged 65 years and over, and to determine whether impaired performances in these tests are associated with falls. DESIGN: One-year prospective study. SETTING: Conducted as part of the Randwick Falls and Fractures Study, in Sydney, Australia. PARTICIPANTS: Four hundred fourteen women aged 65 to 99 years (mean age 73.7 years, SD = 6.3) were randomly selected from the community; 341 of these women were included in the 1-year prospective study. MAIN RESULTS: The prevalence of impairment in all tests increased with age. In the year following assessment, 207 subjects (60.7%) experienced no falls, 63 subjects (18.5%) fell one time only, and 71 subjects (20.8%) fell on two or more occasions. After controlling for age, multiple falling was associated with low contrast visual acuity and contrast sensitivity, poor vibration sense and proprioception, reduced lower limb strength, slow reaction time, and impaired balance, as indicated by four sway tests and two clinical stability measures. Discriminant function analysis identified visual contrast sensitivity, proprioception in the lower limbs, quadriceps strength, reaction time, and sway on a compliant (foam rubber) surface with the eyes open as the variables that significantly discriminated between subjects who experienced multiple falls and subjects who experienced no falls or one fall only (Wilks' lambda = 0.73 (P < 0.001), canonical correlation = 0.52). This procedure correctly classified 75% of subjects into multiple faller or nonmultiple faller groups. CONCLUSIONS: These findings support previous results conducted in retirement village and institutional setting and indicate that the test procedure aids in the identification of older community-dwelling women at risk of falls.

Lord SR, Anstey K, Williams P, Ward JA. Psychoactive medication use, sensori-motor function and falls in older women. British Journal of Clinical Pharmacology 1995;39: 227-234.

A 1 year prospective study was undertaken to identify possible mediating physiological mechanisms for the association between psychoactive medication use and falls in 414 women aged 65 to 99 years (mean age 73.7 years, s.d.=6.3) who were randomly selected from the community.  Women taking certain psychoactive medications showed impaired performance in a number of sensori-motor measures, including tactile sensitivity, lower limb muscle strength, reaction time and balance control compared with women not taking these medications. Those using psychoactive medications were also comparatively inactive - taking part in only 1.1h of planned exercise per week compared with 2.6h for non-users (F=12.44, df=1,412, P<0.01). Multiple logistic regression analysis revealed that use of long-acting benzodiazepines (OR=7.03, 95%CI=2.12-23.28) and antidepressants (OR2.84,95%CI=1.00-8.02) was significantly associated with multiple falls, whilst adjusting for age, other drug category use, frequency of alcohol use, and number of medical conditions. Use of any two psychoactive medications was also significantly associated with fallinf frequency (Chi-square=13.91, df=1, P<0.01). Path analysis revealed a significant direct association mediated via recued physiological functioning (P<0.001). Postural hypotension was not significantly associated with falls (RR=1.37, 95%CI=0.84-2.22). The findings suggest that psychoactive medication use may predispose older people to falling by impairing important sensori-motor systems that contribute to postural stability.

McLean D, Lord SR Falling in older people at home: transfer limitations and environmental risk factors. Australian Occupational Therapy Journal 1996;43:13-18.

A case control study was undertaken to examine the prevalance of transfer limitations and home risk factors for falls in 50 men aged 60 years and over who had been admitted to an acute hospital due to a fall in the previous year, and 45 age and sex matched non-fallers who were recruited from community organisations. The assessments were carried out in the homes of each subject using standardised protocols. Subjects who had fallen in the home reported significantly more difficulties with transfers than subjects who had fallen outside or non-fallers (Chi-squared=33.9, df=2, P<0.001). In contrast, no significant differences were found in the total home hazard scores among the home fallers (mean=2.8 hazards, sd=1.3), outside fallers (mean=3.4, sd=1.7), and among the home fallers compared with the non-fallers. The findings suggest that a non-specific spproach to environmental risk factors in the homes of older people may be an ineffective public health measure. Alternative strategies that include the targeting of home hazard identification and home modification for older people with physiological impairments and transfer limitations may be more effective for preventing falls. Such approaches may complement other interventions aimed at maximising balance and mobility.

Lord SR, Clark RD. Simple physiological and clinical tests for the accurate prediction of falling in older people. Gerontology 1996;42:199-203.

A 1-year prospective study was conducted in an intermediate care institution to determine whether a combined assessment of physiological and clinical measures discriminates between elderly fallers and elderly nonfallers. Seventy persons aged between 72 and 96 years (mean 85.6), who were generally independent in activities of daily living, took part in the study, and 66 were available to follow-up. In the follow-up year, 24 subjects experienced no falls, 20 subjects fell one time only and 22 residents fell on two or more occasions. Discriminant analysis identified reaction time, body sway, quadriceps strength, tactile sensitivity, gait impairment, cognitive impairment, psychoactive drug use and age as the variables that significantly discriminated between subjects who experienced falls and those who did not. This procedure correctly classified 86% of subjects into faller and nonfaller groups. These findings suggest that an assessment that combines physiological and clinical factors provides excellent discrimination between elderly fallers and nonfallers.

Lord SR, Allen GM, Williams P, Gandevia SC. Risk of falling: predictors based on reduced strength in persons previously affected by polio. Archives of Physical Medicine and Rehabilitation 2002; 83: 757-763.PDF

Objectives: To examine the contributions of sensorimotor factors to postural control and falling in people with prior polio and to determine whether these contributions differ from those found in normal populations. Design: Survey and case-control study. Setting: A falls and balance laboratory in Australia. Participants: Forty persons with prior polio (age range, 28-71y) and 38 age- and sex-matched control subjects. Interventions: Not applicable. Main Outcome Measures: Lower-limb muscle strength, sway, vision, lower-limb sensation, reaction time, foot-tapping speed, and falls. Results: Compared with the control subjects, the prior polio subjects performed similarly in sensory tests but worse in tests that involved a motor component. Within the prior polio group, lower-limb strength was strongly associated with postural sway on a compliant surface and explained more of the variance in sway than in control subjects. Prior polio subjects who fell multiple times had reduced lower-limb strength, slower reaction time, lower foot-tapping speed, and increased sway compared with those who fell less often. However, the rate of decline in lower-limb strength within the prior polio group did not exceed normal, age-related changes. Conclusions: This investigation of prior polio subjects provides an appropriate model for studying muscle weakness as a falls risk factor. Weakness was directly associated with falls, and had an indirect effect mediated through increased sway.

Heitterachi E, Lord SR, Meyerkort P, McCloskey I, Fitzpatrick R. Blood pressure changes on upright tilting predict falls in older people. Age and Ageing 2002; 31: 181-186.PDF

Background: orthostatic hypotension may be an important risk factor for falls, though this has not yet been demonstrated in prospective studies. This may be because conventional methods of measuring blood pressure changes are too imprecise and not optimally timed. Objectives: to determine whether changes in blood pressure induced by upright tilt are associated with falls in older people, and whether medication use and symptoms of dizziness are associated with blood pressure changes and falls. Methods: seventy men and women aged 62–92 years participated. We measured blood pressure with a plethysmograph monitor continuously before and after upright tilt. We recorded medication use and symptoms of dizziness in response to the tilt. Subjects were then followed up for 12 months to determine the incidence of falls. Results: subjects who fell in the follow-up period had significantly greater decreases in systolic blood pressure when tilted than those who did not fall. Furthermore, those who had unstable systolic blood pressure during the 3 minutes after tilting, in addition to large blood pressure drops, had a two-fold increased risk of falling compared with those with neither of these conditions. Symptoms of dizziness on tilting were uncommon and not associated with blood pressure or heart rate changes, medication use, or falls incidence. Antidepressant and antihypertensive medication use were associated with decreases in diastolic rather than systolic blood pressure, but were not associated with falls. Conclusions: these findings indicate that both the decrease in blood pressure and the unstable nature of the blood pressure response following upright tilt are useful predictors of falls in older people.

Lord SR, Dayhew J, Howland A. Multifocal Glasses Impair Edge-Contrast Sensitivity and Depth Perception and Increase the Risk of Falls in Older People. Journal of the American Geriatrics Society 2002;50:1760-1766.

OBJECTIVES: To determine the extent to which multifocal glasses impair contrast sensitivity and depth perception at critical distances required for detecting hazards in the environment and whether multifocal glasses use increases the risk of falls in older people. DESIGN: One-year prospective cohort study. SETTING: Falls Laboratory, Prince of Wales Medical Research Institute. PARTICIPANTS: One hundred fifty-six community-dwelling people aged 63-90. MEASUREMENTS: Contrast sensitivity, depth perception, accidental falls. RESULTS: Eighty-seven subjects (55.8%) were regular wearers of multifocal (bifocal, trifocal, or progressive lens) glasses. These subjects performed significantly worse in the distant depth perception and distant edge-contrast sensitivity tests in conditions that forced them to view test stimuli through the lower segments of their glasses. Multifocal glasses wearers were more than twice as likely to fall in the follow-up period than nonmultifocal glasses wearers (odds ratio (OR) = 2.29, 95% confidence interval (CI) = 1.06-4.92), when adjusting for age, poor vision, reduced lower limb sensation and strength, slow reaction time, and increased postural sway. Multifocal glasses wearers were also more likely to fall because of a trip (OR = 2.79, 95% CI = 1.08-7.22), when outside their homes (OR = 2.55, 95% CI = 1.14-5.70), and when walking up or down stairs (P <.01). The population attributable risks of regular multifocal glasses use were 35.2% for any falls, 40.9% for falls due to a trip, and 40.9% for falls outside the home. CONCLUSIONS: The study findings indicate that multifocal glasses impair depth perception and edge-contrast sensitivity at critical distances for detecting obstacles in the environment. Older people may benefit from wearing nonmultifocal glasses when negotiating stairs and in unfamiliar settings outside the home.

Lord SR, Menz HB, Tiedemann A. A physiological profile approach to falls risk assessment and prevention. Physical Therapy 2003;83:237-252.PDF

The purpose of this perspective article is to describe the use of a physiological profile approach to falls risk assessment and prevention that has been developed by the Falls and Balance Research Group of the Prince of Wales Medical Research Institute, Sydney, Australia. The profile's use for people with a variety of factors that put them at risk for falls is discussed. The Physiological Profile Assessment (PPA) involves a series of simple tests of vision, peripheral sensation, muscle force, reaction time, and postural sway. The tests can be administered quickly, and all equipment needed is portable. The results can be used to differentiate people who are at risk for falls ("fallers") from people who are not at risk for falls ("nonfallers"). A computer program using data from the PPA can be used to assess an individual's performance in relation to a normative database so that deficits can be targeted for intervention. The PPA provides valid and reliable measurements that can be used for assessing falls risk and evaluating the effectiveness of interventions and is suitable for use in a range of physical therapy and health care settings.

Lord SR, March LM. Cameron ID, Cumming RG, Schwarz J, Zochling J, Chen JS, Makaroff J, Sitoh YY, Lau TC, Brnabic A, Sambrook, PN (2003). Differing Risk Factors for Falls in Nursing Home and Intermediate-Care Residents Who Can and Cannot Stand Unaided. JAGS; 51 (11): 1645-50.

Objectives: To determine fall risk factors in nursing home and intermediate-care residents who can and cannot stand unaided. Design: Prospective cohort study. Setting: Residential elderly care facilities in Sydney, Australia. Participants: One thousand people aged 65 to 103 (mean age ± standard deviation: 85.0 ± 7.4). Measurements: Accidental falls. Results: Fall rates were highest in those with fair standing balance, intermediate in those with the best standing balance, and lowest in those with the worst standing balance. This nonlinear pattern was even more striking when subjects were categorized according to their standing balance and ability to rise from a chair. Using this dual classification, fall rates were highest in those who could rise from a chair but could not stand unaided (81%) and lowest in those who could neither rise from a chair nor stand unaided (48%). In residents who could stand unaided, risk factors included increased age, male sex, higher care classifications, incontinence, psychoactive medication use, previous falls, and slow reaction times. In contrast, quite different risk factors were evident in residents who could not stand unaided, with a number of known fall risk factors (previous stroke, reduced ability to rise from a chair, slow reaction times) being associated with fewer falls. In this group, risk factors were intermediate versus nursing home care, poor health status, psychoactive medication use, Parkinson's disease, previous falls, and being able to get out of a chair. Conclusion: The findings indicate that there are different risk factors for falls for people living in residential aged care facilities who can and cannot stand unaided. These findings provide important information for developing fall-prevention strategies and suggest that those who can stand unaided but have multiple falls risk factors constitute the highest priority group for such interventions.

Salgado R, Lord SR, Packer J, Janji N, Ehrlich F. Predictors of falling in elderly hospital patients. Archives of Geriatrics and Gerontology 2004;38:213-219. PDF

A prospective study was conducted to determine whether a brief clinical assessment conducted soon after admission can accurately identify older people who fall while staying in an acute hospital. Eighty-eight non-bedfast patients aged 80–99 years took part in the study. Within 3 days of admission, these patients were assessed for the following measures: impaired orientation on the MMSE, psychoactive medication use, evidence of stroke, and impaired ability on the Get-Up-and-Go-test. The major presenting condition for each patient was also recorded. Patients were then followed up to determine whether they fell while in hospital. Impaired orientation on the MMSE, evidence of previous cerebrovascular accident, and major presenting conditions of falls and confusion were significantly associated with falls while in hospital. There was also a trend indicating that psychoactive medication use was elevated in the fallers. In contrast, there was no difference in the proportion of fallers and non-fallers who had impaired ability in the Get-Up-and-Go-test. Of the 15 patients who fell, 13 had two or more risk factors, and after controlling for possible confounding factors of age, sex and length of stay, the presence of two-plus risk factors remained strongly and significantly associated with falls (adjusted OR = 13.43; 95% CI = 1.91–94.40). The findings indicate that a simple screening protocol can accurately identify patients at risk of falling while in hospital.

Sambrook PN, Chen JS, March LM, Cameron RG, Cumming RG, Lord SR, Zochling J, Sitoh YY, Lau TC, Schwarz J, Seibel MJ. Serum parathyroid hormone predicts time to fall independent of vitamin D status in a frail elderly population. J Clinical Endocrinology & Metabolism 2004; 89(4):1572-1576.PDF

Very frail older people constitute an increasing proportion of ageing populations and often have vitamin D deficiency. Falls are frequent in this population and have usually been associated with vitamin D deficiency. In this prospective study we measured serum 25-hydroxyvitamin D (25OHD), serum PTH, and falls in 637 ambulatory subjects living in institutional aged care facilities (intermediate-care hostels or nursing homes). The study sample comprised 121 men (mean age, 82.1 yr) and 516 women (mean age, 86.7 yr). Two hundred and seventy-four subjects fell one or more times over a mean duration of follow-up of 10.2 months. Vitamin D deficiency, defined as a serum 25OHD level below 39 nmol/liter was present in 73.6%. Baseline serum 25OHD and PTH were significantly associated with falls in univariate analyses. In multivariate analyses that also corrected for balance and health status, PTH remained a significant predictor of falls independent of 25OHD. Serum PTH is a predictor of time to first fall in the frail elderly independent of vitamin D status and measures of general health.

Sturnieks DL, Tiedemann A, Chapman K, Munro B, Murray SM, Lord SR. Physiological risk factors for falls in older people with lower limb arthritis. J Rheumatol. 2004;31(11):2272-9. PDF

Objective. To investigate physiological risk factors for falls in people with self-reported lower limb arthritis. Methods. Six hundred eighty-four community-dwelling men and women aged 75–98 years (mean 80.0, SD 4.4), categorized with and without lower limb arthritis, underwent quantitative tests of strength, peripheral sensation, vision, reaction time, balance, and pain. A 12-month history of falls was also obtained. Results. Subjects with self-reported lower extremity arthritis performed significantly worse in tests of knee and ankle muscular strength, lower limb proprioception, postural sway, and leaning balance than subjects without lower extremity arthritis, while being comparable in vision, tactile sensitivity, and reaction time. This pattern of specific impairments was also evident when group results for the arthritis subjects were compared with community normative values and presented as a physiological profile. The arthritis group suffered significantly more falls [relative risk (RR) 1.22, 95% CI 1.03–1.46] and injurious falls (RR 1.27, 95% CI 1.01–1.60) in the previous 12 months than the nonarthritis group. Within the arthritis group, reduced knee extension strength and increased sway were identified as significant predictors of falls. Conclusion. Older people with lower limb arthritis are at increased risk of falling due to deficits in neuromuscular systems. A physiological falls-risk profile based on mean test scores for the arthritis group highlights deficits in muscular strength, knee proprioception, and standing balance, indicating the need for targeted falls prevention interventions for this population.

Lord SR, Sturnieks DL. The physiology of falling: assessment and prevention strategies for older people. J Sci Med Sport. 2005 Mar;8(1):35-42.

Balance calls upon contributions from vision, peripheral sensation, vestibular sense, muscle strength, neuromuscular control and reaction time. With increased age, there is a progressive loss of functioning of these systems and an increased likelihood of falls. Falls can mark the beginning of a decline in function and independence and are the leading cause of injury-related hospitalisation in older people. By using simple tests of vision, leg sensation, muscle strength, reaction time and standing balance, it is possible to identify accurately older people at risk of falls and assess intervention outcomes. This approach overcomes the limitations associated with traditional methods of assessing falls risk via medical diagnoses, including varied severity between individuals. Using a physiological approach provides information at the impairment and functional capacity levels to assist in understanding falls and developing and evaluating optimal falls prevention strategies for older people.

J.S. Chen, L.M. March, J. Schwarz, J. Zochling, J. Makaroff, Y.Y. Sitoh, T.C. Lau, S.R. Lord, I.D. Cameron, R.G. Cumming, P.N. Sambrook. A multivariate regression model predicted falls in residents living in intermediate hostel care. Journal of Clinical Epidemiology. 2005; 58: 503–508. PDF

Background and Objective: To evaluate whether individual falls risk could be predicted in a frail elderly population. Study Design and Setting: We developed and tested an assessment tool and falls risk score for predicting falls based on a multivariate regression model in a prospective cohort study of intermediate care residents. Results: During the follow-up period, 1,736 falls by 1,107 subjects were recorded with an average of 170 falls per 100 person-years. Fifty percent of the study population had at least one fall within a year. Significant independent risk factors were poor balance, cognitive impairment, incontinence, higher illness severity rating, and older age. Twenty-two percent of participants with a falls risk score ≥ 7 accounted for 42% of the total falls, with a falls rate of 317 per 100 person-years. This rate was a sixfold increase from the falls rate of 52 per 100 person-years observed in participants with a score < 3. A high score (≥7) indicated almost a 2 in 3 chance of falling, while a low score (<3) indicated approximately a 1 in 7 chance of falling within 6 months. Conclusion: The assessment tool and falls risk score could identify individuals in this frail elderly population at high risk of falls.

 

Lord SR, Clark RD, Webster IW. Postural stability and associated physiological factors in a population of aged persons. Journal of Gerontology: Medical Sciences 1991;46:M69-76.

A battery of 13 visual, vestibular, sensorimotor, and balance tests was administered to 95 elderly persons (mean age 82.7 years) to examine the relationships between specific sensorimotor functions and measures of postural stability. When subjects stood on a firm surface, increased body sway was associated with poor tactile sensitivity and poor joint position sense. When subjects stood on a compliant surface (which reduced peripheral sensation) with their eyes open, increased body sway was associated with poor visual acuity and contrast sensitivity, reduced vibration sense, and decreased ankle dorsiflexion strength as well as reduced joint position sense. Increased body sway with eyes closed on the compliant surface was associated with poor tactile sensation, reduced quadriceps and ankle dorsiflexion strength, and increased reaction time. Poor performance in two clinical measures of postural stability was associated with reduced sensation in the lower limbs as measured by joint position sense, tactile sensitivity and vibration sense, reduced quadriceps and ankle dorsiflexion strength, and slow reaction times. The prevalence of vestibular impairments was high in this group, but vestibular function was not significantly associated with sway under any of the test conditions. The results suggest that reduced sensation, muscle weakness in the legs, and increased reaction time are all important factors associated with postural instability. An analysis of the percentage increases in sway under conditions where visual and peripheral sensation systems are removed or diminished, compared with sway under optimal conditions, indicated that peripheral sensation is the most important sensory system in the maintenance of static postural stability.

Fitzpatrick RC, Taylor JL, McCloskey DI. Ankle stiffness of standing humans in response to imperceptible perturbation: reflex and task-dependent components. Journal of Physiology 1992 Aug;454:533-547.

1. It has been demonstrated that subjects can alter the reflex stiffness of the elbow and wrist in response to imperceptibly slow perturbations applied through a complaint coupling. We used this technique to measure ankle stiffness in standing subjects as a means of examining reflex activity. 2. During unperturbed stance, a linear relationship between ankle torque and ankle angle is expressed as a load stiffness. The load stiffness predicted from a subject's measured physical dimensions corresponds closely with the value measured by standing the subject on a force platform. 3. Slow perturbations were applied at waist level, through a spring, to standing subjects. The perturbations caused sway similar in magnitude and rate to the sway of normal stance. Ankle stiffness was measured during the period when the perturbations were unperceived. The contribution to ankle stiffness of reflexes that use visual information was assessed by eye closure. The ability of reflexes based on sensory information from the legs to maintain upright posture was assessed when subjects balanced a load equivalent to their own body, in a situation where neither visual nor vestibular information could assist. Ankle stiffness was measured while the load was perturbed. 4. The results show that a simple mechanical model of stance predicts the torque-angle relationship at the ankle. This relationship determines the minimal ankle stiffness required to stand, and reflex muscle stiffness is a necessary component of this ankle stiffness. Visual, vestibular and lower limb sensorimotor reflexes each contribute to ankle stiffness; however, the local sensory reflexes alone are sufficient to stand. For responses to unperceived perturbations, standing subjects can alter their reflex ankle stiffness according to intentional set.

Fitzpatrick RC, Gorman RB, Burke D, Gandevia SC. Postural proprioceptive reflexes in standing human subjects: bandwidth of response and transmission characteristics. Journal of Physiology 1992;458:69-83.

1. This study investigated the reflex control of postural sway during human bipedal stance. The experiments were designed to: (i) find evidence for the operation of 'stretch reflex' pathways during quiet stance, (ii) determine the bandwidth of the reflex response, (iii) describe the reflex transmission characteristics in standing subjects, and (iv) assess the ability of subjects to make a task-dependent change in the reflex. 2. A continuous random perturbation that did not threaten stability was applied at waist level to nine standing subjects. The effects of the perturbation on ankle torque, ankle movement and soleus electromyographic activity (EMG) were identified by cross-correlation. The bandwidth of the reflex response and the transmission characteristics of reflexes that respond to ankle movement were identified by spectral analysis. Changes in these reflex responses were investigated when subjects attempted to stand as still as possible, had their eyes closed, or balanced a load equivalent to their own body in a situation in which neither visual nor vestibular reflexes would be activated. 3. When standing, a reflex response coherent with the perturbation was seen in soleus EMG at frequencies up to 5 Hz, with maximal coherence at 1.0-2.0 Hz. Reflex gain increased with frequency, and there was a frequency-dependent phase advance of soleus EMG on ankle movement reaching 135 deg at 3 Hz. When attempting to minimize sway, subjects produced a more coherent reflex response and significantly increased reflex gain. 4. The response and transmission characteristics of the lower limb proprioceptive reflex in freely standing subjects were similar to those in subjects balancing a load at the ankle, a situation in which vestibular and visual inputs could not contribute. 5. It is concluded that reflex feedback related to ankle movement contributes significantly to maintaining stance, and that much of the reflex response originates from lower limb mechanoreceptors stimulated by ankle rotation. Although reflex gain may be relatively low during quiet stance it can be increased when necessary to maintain stability.

Lord SR, Caplan G, Colagiuri R, Colagiuri S. Ward JA. Sensori-motor function in older persons with diabetes. Diabetic Medicine 1993;10:614-618.

Twenty-five persons with diabetes (aged 55-83 years) who were living independently in the community, and 40 age- and sex-matched non-diabetic controls were assessed for tactile sensitivity, vibration sense, proprioception, quadriceps strength and body sway. In both men and women, those with diabetes performed significantly worse in tests of body sway on firm and compliant surfaces compared with the control subjects after controlling for weight and body mass index. The female diabetic subjects also performed significantly worse in tests of peripheral sensation and strength compared with controls. Age-related declines in sensori-motor function were greater in the diabetic group (r = 0.55-0.75) than in the controls (r < 0.44), while within the diabetic group, duration of diabetes and vibration sense were significantly correlated with sway on a compliant (foam rubber) surface with the eyes open (partial r = 0.52, p < 0.01 and r = 0.55, p < 0.01, respectively). The study findings provide evidence that older people with diabetes have problems with stability and related sensori-motor factors which may place them at increased risk of falls.

Lord SR, Ward JA. Age-associated differences in sensori-motor function and balance in community dwelling women. Age and Ageing 1994;23:452-460.

Tests of visual, vestibular, sensori-motor and balance function were administered to 550 women, aged between 20 and 99 years at a Balance and Gait Laboratory. All of the sensory, motor and balance system measures showed significant age-associated differences. Multiple regression analyses revealed that the measures of lower limb sensation were the consistent sensori-motor factors contributing to balance under normal conditions (standing on a firm surface with eyes open or closed). Under more challenging conditions (standing on foam with eyes open) vision, strength and reaction time played significant roles, whilst when standing on foam with eyes closed, vestibular function also made a significant contribution. Analysis of percentage increases in sway under conditions where visual and peripheral sensation systems were removed or diminished, compared with sway under optimal conditions, indicated that up until age 65 there was an increased reliance on vision for balance control. Beyond this age, the contribution made by vision declined, so that in the oldest age-groups reduced vision was less able to supplement peripheral input, resulting in increased sway areas. Peripheral sensation however was the most important sensory system in the maintenance of static postural stability at all ages.

Fitzpatrick R, Rogers DK, McCloskey DI. Stable human standing with lower-limb muscle afferents providing the only sensory input. Journal of Physiology 1994;480:395-403.

1. This study investigated the sources of sensory information upon which normal subjects' ability to stand depends. 2. An 'equivalent body' was used to simulate the physical properties of each subject's body during standing. The modulation of ankle torque required to support the equivalent body in an upright position was similar to that required to support the subject's own body when standing. However, when balancing the equivalent body, vestibular inputs were excluded from directing the appropriate changes in ankle torque. Thus, stability of stance could be studied with (normal stance) and without (balancing equivalent body) modulation by vestibular inputs. Vision could be excluded by closing the eyes. Sensory input from the feet and ankles could be removed by local anaesthesia from prolonged ischaemia, induced by occluding blood flow with inflated pneumatic cuffs just above the ankles. With vestibular, visual and peripheral sensory inputs negated, standing could rely only upon remaining sensory inputs, notably those from sensory receptors in the leg muscles. 3. Unlike the human body, the equivalent body used to negate vestibular inputs is not segmented. Therefore, the effects on stability of having a segmented body were determined by splinting subjects during standing so that only ankle movement was possible. This was done in the presence and absence of visual stabilization. 4. For each experimental task, either standing or balancing the equivalent body, sway was recorded while posture was unperturbed. Root mean square values of sway amplitude and power spectra were used to compare conditions. 5. Every subject could balance the equivalent body in a stable way when the eyes were closed, and when the feet were anaesthetized.

Fitzpatrick R, Burke D, Gandevia SC. Task-dependent reflex responses and movement illusions evoked by galvanic vestibular stimulation in standing humans. Journal of Physiology 1994;478:363-72.

1. To identify the vestibular contribution to human standing, responses in leg muscles evoked by galvanic vestibular stimulation were studied. Step impulses of current were applied between the mastoid processes of normal subjects and the effects on the soleus and tibialis anterior electromyograms (EMGs), ankle torque, and body sway were identified by post-stimulus averaging. The responses were measured when subjects stood on a stable platform or on an unstable platform and the effects of eye closure were also assessed. Responses were also recorded during voluntary contraction of the leg muscles and when subjects balanced a load equivalent to their own body in a situation where vestibular postural reflexes would not be useful. 2. At a mean post-stimulus latency of 56 ms, there were reciprocal changes in soleus and tibialis anterior muscle activity followed, at 105 ms, by larger responses of opposite sign. These were termed the short- and middle-latency responses, respectively. Both responses increased with stimulus intensity, but the short-latency response had a higher threshold. The early response had a similar latency to EMG responses evoked by rapid postural perturbations. Both responses were larger when the eyes were closed, but eye closure was associated with increased sway and EMG activity, and the responses were of similar magnitude when scaled to background EMG level. 3. Both short- and middle-latency EMG responses in soleus and tibialis anterior muscles produced small transient postural sways. The transient changes in EMG activity were followed by a larger prolonged sway which was not attributable to the activity in these muscles but rather to reflex or volitional adjustments to movements at other body segments. When subjects were prevented from swaying, the galvanic stimulus produced illusory movements in the opposite direction to the sway evoked when standing, and it is possible that the prolonged sway is a reaction to the illusion of sway. 4. The short- and middle-latency responses were modified during different postural tasks according to the dependence on vestibular reflexes. When the support platform was unstable, the EMG responses to galvanic stimulation were larger. There were no vestibular-evoked responses when seated subjects made voluntary contractions of the leg muscles or when they stood upright with the trunk supported, using the ankles to balance a body-like load.

Fitzpatrick R, McCloskey DI. Proprioceptive, visual and vestibular thresholds for the perception of sway during standing in humans. Journal of Physiology 1994; 478:173-86.

1. Thresholds for the perception of postural sway induced by gentle perturbations were determined for five normal standing subjects. In this context we understand 'perception' to mean 'able to give a subjective report'. The thresholds for the perception of movements that were equivalent to sway in velocity and amplitude were determined when the available sensory input was limited to only one, or a pair, of the vestibular, visual, and proprioceptive systems. To examine vestibular inputs alone, vision was excluded and the whole body was moved with the ankles in a fixed position. To examine visual inputs alone, the body was kept stationary and a 'room' was moved around the subjects to simulate the relative visual-field movement that occurs during standing. To limit the available sensory input to proprioception from the legs, subjects were held stationary and balanced a load that was equivalent to their own body using their ankles. In this situation, perturbations were applied to the 'equivalent body' and these could only be perceived from the resulting ankle movements. Thresholds for perceiving ankle movements were also determined in the same posture, but with the leg muscles bearing no load. 2. The thresholds for the perception of sway during standing were very small, typically 0.003 rad at a velocity of 0.001 rad s-1, and even smaller movements were perceived as the mean velocity of the sway increased up to 0.003 rad s-1. No difference was found between the thresholds for perceiving forward sway and backward sway. Eye closure during standing did not affect the threshold for perceiving sway. 3. When sensory input was limited to proprioception from the legs, the thresholds for the perception of passive ankle movements were equivalent to the thresholds for the perception of sway during standing with all sensory inputs available. When the leg muscles were relaxed, the thresholds for perceiving ankle movements increased approximately twofold. 4. The visual thresholds for perceiving movement were higher than the proprioceptive thresholds at slower velocities of movement, but there was no difference at higher velocities. 5. Both the proprioceptive and visual thresholds were sufficiently small to allow perception of the sway that was recorded when the subjects stood normally in a relaxed manner. In contrast, the vestibular thresholds were an order of magnitude greater than the visual or proprioceptive thresholds and above the largest sway movements that were recorded during normal standing.

Fitzpatrick R, Burke D, Gandevia SC. Loop gain of reflexes controlling human standing measured with the use of postural and vestibular disturbances. Journal of Neurophysiology 1996;76(6):3994-4008.

1. In this study we measured the loop gain of postural reflexes in standing human subjects. Reflex activity is conventionally described in terms of the muscle activation arising from a perturbation, but in this study the ability of the evoked muscle activity to correct the perturbation was also measured, and the behavior of the entire feedback loop is described. 2. A weak continuous random perturbation was applied at waist level to standing subjects. The effects of the perturbation on body sway and soleus electromyogram (EMG) were identified by cross-correlation, and spectral analysis was used to estimate the open-loop reflex transmission characteristics (i.e., sway to EMG). Under the same conditions, activity in the leg muscles was evoked by galvanic vestibular stimulation with the use of a continuous randomly varying current. The effects on soleus EMG and the subsequent body sway were identified by cross-correlation. This allowed calculation of the open-loop muscle and load behavior (i.e., EMG to sway). From these open-loop reflex and muscle and load transfer functions, the loop gain and phase were calculated. 3. In addition to the gain of the feedback loop, the study describes the transmission characteristics of reflex responses in the leg muscles associated with body sway and the effects of excluding visual and proprioceptive contributions to the response; the transfer function of human soleus with a stimulus that preserves the normal recruitment of motoneurons, including the effects of different load conditions on the muscle; and the transmission characteristics of vestibular pathways that evoke responses in the leg muscles during standing in situations that might modify the reflexes. 4. When standing, the loop gain of reflex feedback is approximately unity and is unchanged by eye closure and stability of support. Reflex transmission introduced a marked phase advance, and this served to offset most of the phase lag introduced by muscle and load. The residual phase lag could explain the frequency of tremor observed during standing (6-8 Hz). 5. The gain of the feedback loop (approximately 1) is higher than suggested by both previous estimates and theoretical considerations, but is still insufficient to explain the stability of normal human standing. This implies that, although sensory information is used to control posture, it does not do so exclusively through a negative feedback control process. The experimental findings are consistent with a reflex response based on a feed-forward process, and this would result in prediction of the response necessary to counteract a postural disturbance.

Lord SR, Rogers MW, Howland A, Fitzpatrick R. Lateral stability, sensorimotor function and falls in older people. Journal of the American Geriatrics Society 1999;47: 1077-1081.

AIMS: To design simple tests of lateral stability for assessing balance in older people and to determine whether poor performances in these tests are associated with impaired vision, lower limb sensation, quadriceps strength, simple reaction time, and falling in this group. DESIGN: A cross-sectional and retrospective study. SETTING: Falls and Balance Laboratory, Prince of Wales Medical Research Institute. PARTICIPANTS: One hundred fifty-six community-dwelling men and women aged 63-90 years (mean age 76.5, SD = 5.1). OUTCOME MEASURES: The maximal lateral sway in a near-tandem stability test with eyes open and closed and the necessity of taking a protective step in the near-tandem stability test with eyes closed. RESULTS: All 156 subjects could complete the near-tandem stability test with eyes open, but only 99 subjects (63.5%) could undertake the test with eyes closed without taking a protective step. Subjects with a history of falls had increased lateral sway both with eyes open and eyes closed as well as poorer visual acuity, proprioception, and quadriceps strength. Fallers were also significantly more likely to take a protective step when undertaking the near-tandem stability test with eyes closed. Multiple regression analysis revealed that impaired lower limb proprioception, quadriceps strength, and reaction time were the best predictors of increased maximal sway in the near-tandem stability test with eyes open. Reduced proprioception and quadriceps strength, in addition to age, were also found to be the best determinants of the necessity of taking a protective step in the near-tandem stability test with eyes closed. CONCLUSIONS: The study findings identify simple new tests that are associated with falling in older people and elucidate the relative importance of specific physiological systems in the maintenance of lateral stability.

Lord SR, Fitzpatrick RC. Choice stepping reaction time: a composite measure of falls risk in older people. Journal of Gerontology 2001; 56A: M627-632. PDF

Background: This study investigated the neuropsychological, sensorimotor, speed and balance contributions to a new test of choice stepping reaction time (CSRT), and determined whether this new test is an important predictor of falls in older people. Methods: 477 retirement village residents aged 62-95 years (mean = 79.2 ± 6.2) undertook the CSRT test which required them to step onto one of four panels which were illuminated in a random order. The subjects also undertook tests of neuropsychological, sensorimotor, speed and balance function. Results: Multiple regression analysis revealed that poor performance in the Trails B neuropsychological test and impaired quadriceps strength, simple reaction time, sway with eyes open on a compliant surface and maximal balance range were the best predictors of increased CSRTs (multiple r² = 0.45). Subjects with a history of falls had significantly increased CSRTs compared with non-fallers – 1322 ± 331 and 1168 ± 203 ms respectively. Impaired CSRT was a significant and independent predictor of falls, as were two complementary sensory measures (visual contrast sensitivity and lower limb proprioception). Of these measures, CSRT was the most important in predicting falls. Further, the inclusion of CSRT in the model, excluded measures of strength, central processing speed and balance, as these could not provide non-redundant information to the prediction of falls. Conclusions: The study identifies a new test that provides a composite measure of falls risk in older people and elucidates the relative importance of specific physiological and neuropsychological systems in the initiation of fast and appropriate step responses.  

Rogers MW, Wardman DL, Lord SR, Fitzpatrick RC. Passive tactile sensory input improves postural stability during standing. Experimental Brain Research 2001; 136: 514-522. PDF

The effects of passive tactile cues about body sway on stability during standing were evaluated in subjects with a wide range of sensorimotor and balance performance. Healthy young adults, diabetic subjects with varying degrees of peripheral sensory neuropathy and older subjects aged 70-80 years were studied. Body sway was measured when subjects stood on the floor and on a foam rubber mat, with or without an applied stimulus that rubbed on the skin at the leg or shoulder as the body swayed. The results show that this stimulus reduced body sway (mean reduction 24.8%±1.5) and thus had a stabilizing effect as big as vision or sensory information from the feet. The reduction in sway was not based on active touch. The stimulus was not restricted to a particular region of the body, but was more effective on the shoulder than the leg, and was more effective when standing with eyes shut or when standing on the foam mat. It was also most effective in those subjects who had the greatest sway during normal standing. Thus, the response appears to be graded with the amplitude of the stimulus. We concluded that, if passive sensory input about posture is available, the postural control process adapts to this input, modulating postural stabilizing reactions.The effects of passive tactile cues about body sway on stability during standing were evaluated in subjects with a wide range of sensorimotor and balance performance. Healthy young adults, diabetic subjects with varying degrees of peripheral sensory neuropathy and older subjects aged 70-80 years were studied. Body sway was measured when subjects stood on the floor and on a foam rubber mat, with or without an applied stimulus that rubbed on the skin at the leg or shoulder as the body swayed. The results show that this stimulus reduced body sway (mean reduction 24.8%±1.5) and thus had a stabilizing effect as big as vision or sensory information from the feet. The reduction in sway was not based on active touch. The stimulus was not restricted to a particular region of the body, but was more effective on the shoulder than the leg, and was more effective when standing with eyes shut or when standing on the foam mat. It was also most effective in those subjects who had the greatest sway during normal standing. Thus, the response appears to be graded with the amplitude of the stimulus. We concluded that, if passive sensory input about posture is available, the postural control process adapts to this input, modulating postural stabilizing reactions.

Lord SR, Murray SM, Chapman K, Munro B, Tiedemann A. Sit-to-stand performance depends on sensation, speed, balance, and psychological status in addition to strength in older people. Journal of Gerontology 2002; M539-543.

Background. Sit-to-stand (STS) performance is often used as a measure of lower-limb strength in older people and those with significant weakness. However, the findings of recent studies suggest that performance in this test is also influenced by factors associated with balance and mobility. We conducted a study to determine whether sensorimotor, balance, and psychological factors in addition to lower-limb strength predict sit-to-stand performance in older people. Methods. Six hundred and sixty nine community-dwelling men and women aged 75–93 years (mean age 78.9, SD = 4.1) underwent quantitative tests of strength, vision, peripheral sensation, reaction time, balance, health status, and sit-to-stand performance. Results. Many physiological and psychological factors were significantly associated with sit-to-stand times in univariate analyses. Multiple regression analysis revealed that visual contrast sensitivity, lower limb proprioception, peripheral tactile sensitivity, reaction time involving a foot-press response, sway with eyes open on a foam rubber mat, body weight, and scores on the Short-Form 12 Health Status Questionnaire pain, anxiety, and vitality scales in addition to knee extension, knee flexion, and ankle dorsiflexion strength were significant and independent predictors of STS performance. Of these measures, quadriceps strength had the highest beta weight, indicating it was the most important variable in explaining the variance in STS times. However, the remaining measures accounted for more than half the explained variance in STS times. The final regression model explained 34.9% of the variance in STS times (multiple R = .59). Conclusions. The findings indicate that, in community-dwelling older people, STS performance is influenced by multiple physiological and psychological processes and represents a particular transfer skill, rather than a proxy measure of lower limb strength.

JULIE C. WHITNEY, STEPHEN R. LORD, JACQUELINE C. T. CLOSE. Streamlining assessment and intervention in a falls clinic using the Timed Up and Go Test and Physiological Profile Assessments. Age and Ageing 2005; 34: 567–571 http://ageing.oxfordjournals.org/cgi/reprint/34/6/567?ijkey=KmPkh8vGbOVL0Cp&keytype=ref

Background: the Timed Up and Go Test (TUGT) has been recommended as a simple screening tool to identify those at risk of falling. However, subsequent detailed assessment is required to identify underlying falls risk factors to provide direction for optimal targeted intervention strategies.

Methods: 110 consecutive falls clinic patients underwent the TUGT, the Abbreviated Mental Test and the Physiological Profile Assessment (PPA), a validated tool for quantifying risk of falling based on a combination of physiological measures—contrast sensitivity, knee extension strength, proprioception, reaction time and postural sway. Regression analysis was used to determine how well the TUGT and presence of cognitive impairment could identify patients at high risk of falls as defined by the PPA.

Results: TUGT and cognitive status were found to be independent and significant predictors of PPA scores. These variables accounted for 21% of the variance in PPA scores (multiple R = 0.47, P<0.001). The standardised beta weights were 0.403 for TUGT and 0.236 for cognitive status. A receiver–operator curve (ROC) indicated that 15 seconds in the TUGT was the optimal cut-point for identifying those with a high risk of falling: 70% of the total sample.

Conclusions: the TUGT and a simple test of cognition can be used to streamline referrals in a high-risk population, allowing for more efficient use of available resources in clinical practice. A subsequent PPA provides quantification of risk and direction for tailored intervention.

 

Wardman DL, Fitzpatrick RC. What does galvanic vestibular stimulation stimulate? Advances in Experimental Medicine and Biology 2002;508:119-128.

The technique of galvanic vestibular stimulation (GVS) has been used for a long time. The stimulus produces stereotyped automatic postural and ocular responses. The mechanisms underlying these responses are not understood although they are commonly attributed to altered otolith output. Based on animal studies, it seems reasonable to assume that vestibular afferents from the otoliths and semicircular canals are affected similarly by GVS. With this assumption, and anatomical knowledge of the vestibular apparatus, a model is developed to describe the expected responses of vestibular afferents to percutaneous GVS and the physiological implications of this altered sensory signal. Bilateral bipolar GVS, the most commonly used technique, should produce a canal signal consistent with a strong ear-down roll towards the cathodal side, a smaller nose-to-cathode yaw, but no pitch signal. Bilateral bipolar GVS should also produce an otolith signal consistent with tilt towards the cathodal side or a translational acceleration towards the anodal side. The expected responses for other configurations of GVS are also described. The model appears consistent with published data on the ocular and postural responses to GVS, and suggests other testable hypotheses concerning postural, ocular and perceptual responses to GVS.

Fitzpatrick RC, Marsden J, Lord SR, Day BL. Galvanic vestibular stimulation evokes sensations of body rotation. NeuroReport 2002; 13:2379-2383.

Psychophysical experiments identified effects of galvanic vestibular stimulation (GVS) on the perception of whole-body angular rotation. Subjects lay supine on a platform that could rotate about a vertical axis through the vestibular axis so that linear movements were excluded. Movements were applied sufficiently above perception threshold to enable a reliable report of direction and movement size. In some trials, binaural GVS was applied concurrently at 1-2mA. When GVS that was incongruent with the movement was applied, subjects reported lesser spin, on average cancelling the movement perception. When the GVS and movement were congruent, subjects reported greater spin. We conclude that GVS produces a vestibular signal of rotation, probably through and effect on semicircular canals.

Wardman DL, Day BL, Fitzpatrick RC. Position and velocity responses to galvanic vestibular stimulation during standing in man. Journal of Physiology 2003;15;547(Pt 1):293-299.

Galvanic vestibular stimulation (GVS) in animals modulates the firing of otolith and semicircular canal afferents alike. Here, we look for postural responses evoked by GVS from the otolith organs and semicircular canals. To minimise the modifying effects of somatosensory input on the response, low-intensity (0.3-0.5 mA) GVS was applied for 8 s while subjects stood on foam rubber with the feet together and strapped to the floor. The response had three phases: (i) a rapid movement during the first second, (ii) a slower movement that persisted throughout the stimulus, and (iii) a rapid partial return movement after GVS stopped. The three movement velocities were significantly different. The GVS response therefore appears to be the sum of a step response that returns to the starting point when the stimulus stops, and a constant-velocity ramp response for the duration of the stimulus without a return movement. Subjects' responses differed in size and profile, some with the step or ramp responses almost exclusively but most with a combination of both. The 'step-plus-ramp' model was tested by comparing the three velocities. If the responses add, the initial velocity should not be different from the sum of the velocities during the ramp-only period and the step-only period at offset. ANOVA and pairwise comparisons confirmed this. It is concluded that postural responses to GVS arise through stimulation of both otolith and canal afferents.

Lord SR, Sinnett PF. Femoral neck fractures: admissions, bed use, outcome and projections (letter). Medical Journal of Australia 1986;145:493-496.

Lord SR. Hip fractures: Changing patterns in hospital bed use in NSW between 1979 and 1990. Australia and New Zealand Journal of Surgery 1993;63:352-355.

Osteoporotic hip fractures are associated with significant medical, social and financial costs. To examine trends in hip fracture incidence, acute hospital admissions, bed use and outcome for these fractures were reviewed for the period 1979-90. In this period, there was a 45% increase in the total number of fractures. In women aged 65 and over increases in admission rate were found between 1979 and 1986. Fracture admission rates for women stabilized after 1986, but remained approximately 7% higher than in the baseline year of 1979. In men aged 65 years and over there was no discernible change in fracture incidence. Length of stay in hospital was inversely related to the total number of proximal femoral fracture cases in each year. As a result of the large decreases in length of stay, overall bed use in 1991 was very similar to that in 1979, in spite of the large increase in fracture admissions. This reduction in length of stay may reflect, not only the pressures of greater demand, but also improved surgical and postoperative management and the effects of early intervention and rapid transit treatments.

Nguyen TV, Sambrook, PN, Kelly PJ, Jones G, Lord SR, Freund J, Eisman JA. Prediction of osteoporotic fractures by postural stability and bone density. British Medical Journal 1993;307:1111-1115.

OBJECTIVE-To investigate the utility of risk factors such as bone mineral density, lifestyle, and postural stability in the prediction of osteoporotic fractures. DESIGN-Longitudinal, epidemiological, and population based survey. SETTING-City of Dubbo, New South Wales. SUBJECTS-All residents of Dubbo aged > or = 60 on 1 January 1989. MAIN OUTCOME MEASURE-Incidence of fracture for individual subjects. RESULTS-The overall incidence of atraumatic fractures in men and women was 1.9% and 3.1% per annum respectively. The predominant sites of fracture were hip (18.9%), distal radius (18.5%), ribs and humerus (11.9% in each case), and ankle and foot (9.1% and 6.6% respectively). Major predictors of fractures in men and women were femoral neck bone mineral density, body sway, and quadriceps strength. Age, years since menopause, height, weight, and lifestyle factors were also correlated with bone mineral density and body sway and hence were indirect risk factors for fracture. Discriminant function analysis correctly identified 96% and 93% (sensitivities 88% and 81%) of men and women, respectively, who subsequently developed atraumatic fractures. Predictions based on this model indicated that a woman with a bone mineral density in the lowest quartile in the hip together with high body sway had a 8.4% probability of fracture per annum. This represented an almost 14-fold increase in risk of fracture compared with a woman in the highest bone mineral density quartile with low postural sway. An individual with all three predictors in the "highest risk" quartile had a 13.1% risk of fracture per annum. CONCLUSIONS-Bone mineral density, body sway, and muscle strength are independent and powerful synergistic predictors of fracture incidence.

Jones G, Nguyen T, Sambrook PN, Lord SR, Kelly P and Eisman JA. Osteoarthritis, bone density, postural stability and osteoporotic fractures. A population based study. Journal of Rheumatology 1995;22:921-925.

OBJECTIVE. Osteoarthritis (OA) is associated with an increase in bone density both locally and at distant sites. Prospective data are limited on the relationship between OA and fracture. We studied the possible relationship between self-reported OA, bone density, postural stability measures, and atraumatic fractures as part of a study of men and women over 60 years of age. METHODS. Subjects were part of the Dubbo Osteoporosis Epidemiology Study (a longitudinal population based study of fracture risk factors). Bone density was measured by dual energy x-ray absorptiometry. Postural stability was assessed by the validated measures of quadriceps strength and sway. Medication use and self-reported arthritis were assessed by a structured personal interview. Fractures were ascertained retrospectively by interview and prospectively by viewing radiographic reports for fracture. RESULTS. Among a study population of 1101 women and 720 men (mean age 69) there were 462 subjects (25%) who reported a diagnosis of OA. In both sexes, subjects with OA had higher bone density (adjusted for age and body mass index) at both the femoral neck (men, p = 0.026; women, p = 0.048) and lumbar spine (men, p = 0.0007; women, p = 0.0007). However, in both sexes, those with self-reported OA also had higher body sway and lower quadriceps strength. The combination of these observed differences in fracture risk factors led to no predicted change in fracture risk overall when using established nomograms for this population [men, OR = 1.11 (95% CI 0.83-1.45); women, OR = 1.08 (95% CI 0.83-1.39)]. This paralleled our observational finding that self-reported OA was not associated with a decrease in fracture incidence compared to those not reporting OA in both men (RR 0.64, 95% CI 0.29-1.39) and women (RR 1.00, 95% CI 0.66-1.51). CONCLUSION. Individuals with self-reported OA, despite higher bone density, are not protected against nonvertebral osteoporotic fracture, apparently due to worsened postural stability and thus an increased tendency to fall.

Ward JA, Lord SR, Williams P, Anstey K, Zivanovic E. Physiologic, health and lifestyle factors associated with femoral neck bone density in older women. Bone 1995; 16:373S-378S.

Three hundred eleven women aged between 60 and 91 years (mean age 72.2) who were randomly recruited from the community underwent bone density assessments of the femoral neck. Two complementary multivariate techniques were used to assess the relationships between femoral neck bone density and a range of anthropometric, health, and lifestyle measures. Stepwise multiple linear regression analysis revealed age, weight, height, quadriceps strength, and lifelong smoking to be variables that independently and significantly explained part of the variance in femoral neck bone density within the group. Multiple logistic regression revealed that after adjusting for established predictors of bone mineral density, age, height, and weight, reduced quadriceps strength, lifelong smoking, and little childhood activity were significantly associated with low bone density (< 0.70 g/cm2), whereas superior quadriceps strength, nonsmoking, and high levels of current physical activity were significantly associated with high bone density (> 0.84 g/cm2). In contrast, current calcium intake was not significantly associated with bone density. The study findings highlight possible public health initiatives for minimizing age-related femoral neck bone loss in older women.

Zivanovic E, Lord SR, Ward JA. Discriminating factors between hip and other fractures in older women. Australasian Journal on Ageing 1998; 17: 145-147.

Objective: To elucidate discriminating factors between femoral neck fractures and other fractures in older women. Method: A case-control study of 110 women aged 60-91 years. Results: Both cases and controls had reduced bone density, with no significant difference evident between the groups. Hop fracture subjects were older, had lower BMI scores and were more likely to have fallen sideways or backward. The controls were more likely to be taking prenisone. Conclusions: The prevention of hip fractures may depend on strategies such as excessive weight loss prevention, enhancement of strength and provision of local hip protection, in addition to strategies aimed at maintaining bone density.

Sherrington C, Lord SR. Increased prevalence of fall risk factors in older people following hip fracture. Gerontology 1998; 44: 340-344. PDF

BACKGROUND: Many people who suffer a hip fracture do not achieve full functional recovery. Simple tests of physical function such as quadriceps strength and postural sway may provide insight into why this population is at increased risk of experiencing further falls and fractures and assist in developing rehabilitation strategies for preventing falls. OBJECTIVE: To determine whether impairments in a range of physiological measures and specific medical conditions are more prevalent in people who have suffered a fall-related hip fracture than in a matched sample of community-dwelling people without a history of falls. METHODS: This case-control study involved 88 older people. The hip fracture group comprised 44 persons aged 64-94 years, assessed on average 7 months following a fall-related hip fracture. An age- and sex-matched control group (older persons who had not fallen in a 12-month period before recruitment) was drawn randomly from community samples. RESULTS: Compared with the control group, the hip fracture group had markedly reduced quadriceps strength and increased body sway when tested on firm and compliant (foam rubber) surfaces. Patients in the hip fracture group also had higher prevalence rates of poor vision, arthritis and stroke, were taking more medications, were less physically active and perceived themselves to be at greater risk of falling than the control group. No significant differences were apparent for cardiovascular conditions, subjective health status and psychoactive medication use between the groups. Multivariate analyses identified quadriceps strength and body sway on the compliant surface as the most important variables for distinguishing between the hip fracture and no hip fracture groups. These two variables correctly classified 92% of the cases, with equal sensitivity and specificity. CONCLUSION: The findings identify an increased prevalence of certain physical fall risk factors among older persons who have suffered a hip fracture. Decreased quadriceps strength and increased postural sway are potentially modifiable. Intervention programs designed to improve performance on these variables among this population require investigation.

Diamond T, Sambrook P, Williamson M, Flicker L, Nowson C, Fiatarone-Singh M, Lord S, Ferris L, O'Niell S, MacLennan A. Guidelines for treatment of osteoporosis in men. Australian Family Physician 2001; 30: 787-791.

Diamond T, Sambrook P, Williamson M, Flicker L, Nowson C, Fiatarone-Singh M, Lord S, Ferris L, O'Niell S, MacLennan A. Men and osteoporosis. Australian Family Physician 2001; 30: 781-785.

Sambrook PN, Cameron ID, Cumming RG, Lord SR, Schwarz JM, Trube A, March LM. Vitamin D deficiency is common in frail institutionalised older people in northern Sydney [letter]. Medical Journal of Australia 2002; 176 (11): 560. PDF 

Sambrook PN, Seeman E, Phillips SR, Ebeling PR and Working Group. Preventing osteoporosis: outcomes of the Australian Fracture Prevention Summit. Medical Journal of Australia 2002; 176 (8 Suppl): 1-16. PDF

Zochling J, Sitoh YY, Lau TC, Cameron ID, Cumming RG, Lord SR, Schwarz J,
Trube A, March LM, Sambrook PN. Quantitative ultrasound of the calcaneus and falls risk in the institutionalized elderly: sex differences and relationship to vitamin D status. Osteoporosis International 2002;13:882-887.PDF

Very frail older people constitute an increasing proportion of aging populations and are likely to contribute substantially to costs due to osteoporosis. Quantitative ultrasound (QUS) of the calcaneus is potentially a simple method for assessing fracture risk in frail elderly, but there have been few studies of male/female differences in QUS or its relationship to falls risk or vitamin D status, which is often subnormal in this population. We studied QUS, falls risk and serum 25(OH)-vitamin D in subjects living in institutional aged care facilities (hostels or nursing homes). The study sample comprised 294 men (mean age 81.2 years, range 65-102 years) and 899 women (mean age 86.7 years, range 65-104 years). Broadband ultrasound attenuation (BUA) and velocity of sound (VOS) were higher in men than women by approximately 30% and 2% respectively (p<0.0001) and this difference was maintained at all ages. Serum 25(OH)D levels were higher in men than women (p<0.001) but vitamin D deficiency was very common in both sexes and serum 25(OH)D was not associated with QUS in either sex. There was no significant decline in BUA or VOS with age in men; however, for women BUA declined by 2.8-4.7% per decade and VOS by 1% per decade (both p<0.001). Mean BUA T-scores were -1.55 and -2.48 at age 90 years in men and women. Quadriceps strength and weight but not serum 25(OH)D were significantly associated with BUA. These data suggest only minor loss occurs at the calcaneal site in BUA and VOS with very old age in either sex.

Sherrington C, Lord SR, Herbert RD. A randomised trial of weight-bearing versus non-weight-bearing exercise for improving physical ability in inpatients after hip fracture. Australian Journal of Physiotherapy 2003;49:15-22. PDF

The purpose of this study was to assess the effects of weight-bearing and non-weight-bearing exercise on strength, balance, gait and functional performance among older inpatients following hip fracture. Eighty people (mean age 81 years, SD 8) undergoing inpatient rehabilitation after fall-related hip fracture were randomised to receive two-week programs of either weight-bearing or non-weight-bearing exercise prescribed by a physiotherapist. Both groups improved markedly (in the order of 50%) on measures of physical ability. Overall there was little difference between groups in the extent of improvement, however post hoc testing identified some additional strength benefits for the non-weight-bearing group - non-affected leg hip flexion mean difference in extent of improvement was 9.3 N (95% CI 3.7 to 15.0), non-affected leg hip abduction mean difference in extent of improvement was 6.5 N (95% CI 0.1 to 12.9). There were also additional functional benefits for the weight-bearing group - improved ability to complete a lateral step-up on the affected leg with nil or one hand supports (OR 3.4, 95% CI 1.1 to 12.3) and the need for less supportive walking aids (p = 0.045).Weight-bearing and non-weight-bearing exercise programs produce similar effects on strength, balance, gait and functional performance among inpatients soon after hip fracture.

Sambrook PN, Chen JS, March LM, Cameron RG, Cumming RG, Lord SR, Schwarz J, Seibel MJ. Serum parathyroid hormone is associated with increased mortality independent of 25-hydroxy vitamin D status, bone mass, and renal function in the frail and very old: a cohort study. J Clinical Endocrinology & Metabolism 2004; 89(11):5477-5481.PDF

Very frail older people constitute an increasing proportion of the aging population and often have vitamin D deficiency and impaired renal function. Primary hyperparathyroidism has been associated with increased mortality, but it is unclear whether secondary hyperparathyroidism is associated with increased mortality independent of renal function and vitamin D status. This study aimed to examine the effect of vitamin D deficiency and secondary hyperparathyroidism on mortality in frail older people after accounting for renal function and general measures of health. We evaluated 842 subjects (182 men with a mean age of 81.9 yr and 660 women with a mean age of 86.2 yr) living in residential aged care facilities in Sydney, Australia in a prospective, cohort study. Over a mean duration of follow-up of 31 months, 345 subjects died. Baseline serum 25-hydroxy vitamin D, serum PTH, and bone ultrasound attenuation were significantly associated with mortality in univariate and multivariate analyses (for PTH, a hazard ratio of 1.39 for time to death) after correcting for age and gender. In multivariate analyses that corrected for health status, nutritional status, and renal function, PTH remained a significant predictor of mortality but not 25-hydroxy vitamin D or bone ultrasound attenuation. Serum PTH appears to be associated with increased mortality in the frail elderly independent of vitamin D status, renal function, bone mass, and measures of general health. The mechanism of this effect requires further investigation.

Boufous S, Finch C, Lord SR. The incidence of hip fracture: are our efforts having an effect? Medical Journal of Australia 2004;180:623-626. PDF

Objective: To examine trends in hospital admission for hip fracture in New South Wales between July 1990 and June 2000. Design: Analysis of routinely collected hospital separation data. Setting: Public and private acute-care hospitals in NSW. Participants: Admissions of patients aged 50 years and over with a primary diagnosis of fracture of the neck of femur (International classification of diseases, 9th revision [ICD-9] code 820 or ICD-10 codes S72.0–S72.2). Main outcome measures: Number and rates of hospital admission for fracture of the neck of femur per 1000 population; inpatient mortality rates per 1000 admissions. Results: Between July 1990 and June 2000, the number of admissions to NSW acute-care hospitals for hip fracture increased by 41.9% in men (from 1059 to 1503 per year) and by 31.2% in women (from 3160 to 4145 per year). However, age-specific and age-adjusted rates remained practically unchanged. The average length of stay for admissions for hip fracture decreased significantly from 19.2 days (95% CI, 18.5–19.8 days) in 1990–1991 to 14.2 days (95% CI, 13.8–14.6 days) in 1999–2000. No significant change was observed in the overall inpatient death rates per 1000 admissions. Conclusions: The findings support recent reports that the increase in hip fracture rates during most of the past century may have ended. However, the number of admissions for hip fracture is still rising. Preventive measures to reduce the burden of this condition on the healthcare system and community need to be pursued and strengthened.

Sherrington C, Lord SR. Test-retest reliability of simple portable tests of physical performance following hip fracture. Clinical Rehabilitation 2005;19:496-504.

 

Anstey K, Stankov L, Lord S. Primary aging, secondary aging and intelligence. Psychology and Aging 1993;8:562-570.

The distinction between primary aging, representing innate maturational processes, and secondary aging, representing the effects of environment and disease (Busse, 1969), was used to develop a model for the assessment of factors that are associated with age-related individual differences in intelligence. Intelligence was measured by performance on a number of tests that measure cognitive abilities known to decline with age. In a hierarchical multiple regression analysis, primary aging and education but not health explained a significant portion of the variance in fluid intelligence. Chronological age had a residual effect over and above that of primary and secondary aging, indicating that there was remaining age-associated variance unaccounted for in the proposed model. The results suggest that the model of primary and secondary aging is a valid means of operationalizing chronological age.

Lord SR. Predictors of nursing home placement and mortality in residents in intermediate care. Age and Ageing 1994;23:499-504.

Assessments of sensorimotor function, cognitive status and health measures were made in 95 intermediate-care (hostel) residents (mean age 82.7 years). The residents were then followed up for 3 years to determine which measures were associated with nursing-home placement and/or death. Information on the outcome of 92 participants was available at the end of the 3-year period. At this time, 53 residents (58%) were still residing at the hostel, seven (8%) had been transferred to nursing homes and 32 residents (35%) had died. Sixteen of the 32 subjects who had died had been transferred to nursing homes. Discriminant function analysis identified tactile sensitivity, ankle dorsiflexion strength, reaction time, sway with eyes open on a compliant (foam rubber) surface and cognitive impairment as the variables that significantly discriminated between subjects who were still in intermediate care and subjects who had been transferred to nursing homes. This procedure correctly classified 88% of subjects into intermediate care or nursing home groups. These variables, with the exception of ankle dorsiflexion strength, were also included in the final discriminant model when predicting mortality, correctly classifying 71% of the subjects. The findings indicate that cognitive impairment and reduced functioning in a number of sensorimotor factors are strongly related to poor outcomes for residents in hostel care.

Anstey K, Lord SR, Smith GA. Measuring human functional age: a review of empirical studies. Experimental Aging Research 1996;22:245-266.

A review of empirical functional age studies published in English was conducted. Types of biomarkers used in functional age studies included sensorimotor, cognitive, psychosocial, behavioral, anthropometric, biomedical, physiological, and dental variables. Previous criticisms of the validity and utility of functional age research were evaluated with reference to empirical studies. While some of these criticisms remain valid, areas of research currently using established biomarkers to predict functional outcomes were identified, including driving, falls, and cognitive functioning. It was concluded that the success of functional age research is dependent on the relevance of biomarkers to specific functional outcomes.

Anstey K, Lord SR, Williams P. Strength in the lower limbs, visual contrast sensitivity and simple reaction time predict cognition in older women. Psychology and Aging 1997;12:137-144. PDF

The authors investigated the association between sensorimotor variables indicative of biological aging and cognition. A community sample of 202 women ages 60-86 was assessed on 5 measures of lower limb strength, visual contrast sensitivity (VisCS), and reaction time (RT). Hierarchical multiple regression revealed that the sensorimotor variables explained age-related variance in measures of reasoning and total variance in measures of reasoning after education, health, mood, and physical activity were controlled for. It is concluded that in addition to better known predictors of cognitive aging, such as RT and VisCS, lower limb strength is an important predictor of performance on cognitive tests.

Anstey KJ, Smith GA, Lord SR. Test-retest reliability of a battery of sensory motor and physiological measures of aging. Perceptual and Motor Skills 1997;831-834.

We report test-retest reliabilities for a battery of tests (vision, hearing, vibration sense, proprioception, forced expiratory volume, blood pressure, grip strength, and sway) shown previously to predict functional age. Fifty women aged 60 to 86 were retested on the battery after 3 months. All tests except proprioception and blood pressure had reliabilities between .70 and .94. We conclude that the battery provides reliable measures of sensory, motor, and physiological variables which may be used as markers of biological aging in psychological research.

Anstey KJ, Matters B, Brown AK, Lord SR. Normative data on neuropsychological tests for very old adults living in retirement villages and hostels. The Clinical Neuropsychologist 2000; 14: 309-317.

Normative data on neuropsychological tests for very old adults living in retirement villages and hostels are under-represented in the literature. This study reports normative data on the Mini-Mental State Examination, Digit Span Forwards, Digit Span Backwards, the Digit Symbol Substitution Test, the Controlled Oral Word Association Test, the Stroop Neuropsychological Screening Test and the National Adult Reading Test. Age and education showed moderate correlations with neuropsychological test performance. For all tests except the Stroop, differences between residents of retirement villages and hostels were explained by age and education. Men performed better on the NART than women, but this difference was eliminated when education was controlled for statistically.

Anstey KJ, Wood J, Lord SR, Walker JG. Cognitive, sensory and physical factors enabling driving safety in older adults. Clinical Psychology Review 2005;25:45-65. PDF

We reviewed literature on cognitive, sensory, motor and physical factors associated with safe driving and crash risk in older adults with the goal of developing a model of factors enabling safe driving behaviour. Thirteen empirical studies reporting associations between cognitive, sensory, motor and physical factors and either self-reported crashes, state crash records or on-road driving measures were identified. Measures of attention, reaction time, memory, executive function, mental status, visual function, and physical function variables were associated with driving outcome measures. Self-monitoring was also identified as a factor that may moderate observed effects by influencing driving behavior. We propose that three enabling factors (cognition, sensory function and physical function/medical conditions) predict driving ability, but that accurate self-monitoring of these enabling factors is required for safe driving behaviour.

 

 

Caplan GA, Ward JA, Lord SR. The benefits of exercise in post-menopausal women. Australian Journal of Public Health 1993;17:23-26.

Physical exercise is commonly promoted as a panacea. However many of the claimed benefits, in particular any positive effects on bone density, have not been scientifically proved. We assessed the effects of a twice-weekly aerobic weight-bearing exercise program on bone density in postmenopausal women. We tested bone density at the spine and hip in 19 exercisers with a mean age of 66.4 years (SEM +/- 1.2) before and after a two-year exercise program, and in 11 controls, mean age 65.4 years (SEM +/- 1.5). We also assessed risk factors for cardiovascular disease and tested wellbeing and cognitive function. The mean percentage change in lumbar bone mineral density was -0.8 in exercisers and -3.8 in controls (difference 3.0 per cent; 95 per cent confidence interval (CI) 0.3 to 5.7 per cent; P = 0.031). The mean percentage change in trochanteric bone mineral concentration was +9.6 in exercisers and -4.4 in controls (difference 14.0 per cent; CI 4.6 to 23.5; P = 0.0049). The exercisers also had significantly higher wellbeing and diastolic blood pressure. This study adds strong evidence that twice-weekly weight-bearing aerobic exercise has a protective effect on bone density in postmenopausal women as well as being associated with other measurable benefits.

Lord SR, Caplan G, Ward JA. Balance, reaction time and muscle strength in exercising and non-exercising women: A pilot study. Archives of Physical Medicine and Rehabilitation 1993;74:837-840.

Twenty-one women, aged 57 to 75 years, who had been taking part in exercise programs for periods of 12 months or more underwent tests of muscle strength, reaction time, proprioception, and body sway. The performance of these women in the tests was compared with 21 women of the same age who were not taking part in any organized physical activity and were not exercising more than 30 minutes a day. The women who had been taking part in the exercise program performed significantly better in the tests of quadriceps strength, reaction time, and sway on a compliant surface than the nonexercising women. The exercisers also had lower body mass index scores. These pilot results suggest that exercise may play a role in improving a number of sensori-motor systems that contribute to stability, and that exercise of this nature may help prevent falls in older women.

Lord SR, Mitchell D, Williams P. Effect of water exercise on balance and related factors in older people. Australian Journal of Physiotherapy 1993;39:217-222.

Fifteen subjects enrolled to take part in a water exercise programme (mean age = 69.7 years) and 13 control subjects (mean age 72.6 years) underwetn assessments of quadriceps and ankle dorsiflexion strength, reaction time, neuromuscular control, body sway, flexibility and joint pain. All subjects were then retested for the same measures after completion of the nine-week programme. The experimental subjects showed improved quadriceps strength and reduced body sway when compared with the control group. There was also a trend towards increased flexibility, improved reaction times and reduced joint pain in the experimental group.

Lord SR, Castell S. Physical activity program for older persons: effect on balance, strength, neuromuscular control, and reaction time. Archives of Physical Medicine and Rehabilitation 1994;75:648-652.

Regular exercise has been recommended to improve balance, strength, and coordination in older persons. In this study, 44 persons, aged 50 to 75 years (mean 62.4 yrs) underwent assessments of quadriceps strength, reaction time, neuromuscular control, and body sway on two occasions before beginning a 10-week exercise program. The subjects were retested for the same measures at the end of the program. The mean number of classes attended for the 40 subjects who were retested was 16.2 (range 11 to 19). On completion of the program, the subjects showed improved performance in the tests of quadriceps strength, reaction time, body sway on a firm surface with the eyes closed, and a compliant surface with the eyes open and closed. In contrast, a group of nonexercisers showed no improvements in any of the test measures. These results suggest that exercise may play a role in improving a number of sensorimotor systems that contribute to stability in older persons.

Lord SR, Castell S. Effect of exercise on balance, strength and reaction time in older people. Australian Journal of Physiotherapy 1994:40:83-88.

Twenty subjects enrolled to take part in an exercise program (mean age = 62.5 years) and 20 control subjects (mean age = 65.5 years) underwent assessments of strength, reaction time, neuromuscular control and body sway.  The exercisers participated in one hour exercise sessions comprising a cardiorespiratory (walking) component and a gentle exercise component twice weekly for 20 weeks. All subjects were then re-tested for the same measures after the completion of the programme. The exercisers showed improved quadriceps strength, reaction time and reduced body sway when compared to the control group; the exercise group showing continued improvement throughout the program in tests of body sway.  The findings suggest that exercise can improve physical function in older people.

Caplan GA, Colagiuri R, Lord SR, Colagiuri S, Ward JA. Exercise in older people with type II diabetes maintains bone density despite weight loss. Australian Journal on Ageing 1995;14:71-75.

A prospective controlled trial to study the effects of 12 months aerobic weight bearing exercise on 8 older diabetic subjects and 10 controls was conducted because although there are no specific data, an appropriate exercise program is recommended for all older persons with diabetes. The trial measures included diabetes control; bone density at the spine; sensorimotor function; risk factors for cardiovascular disease; and wellbeing and cognitive function. The mean percent change in lumbar spine bone mineral concentration (SEM) was +0.29 (3.0) in exercisers and -11.2 (5.1) in controls (p=0.015). The exercise group also improved their body mass index -1.9 (1.3) vs. +1.7 (1.1); p=0.031; weight -1.9 (1.3) vs. +1.8 (1.1); p=0.036; and Life Satisfaction Index-A 51.3 (25.7) vs 2.8 (2.9); p=0.046, compared to controls.  There was no change in sensorimotor function. This study provides encouraging yet tentative evidence of benefit from a twice weekly aerobic exercise program to elderly people with diabetes.

Lord SR, Ward JA, Williams P, Strudwick M. The effect of a 12 month exercise program on balance, strength and falls in older women: a randomised controlled trial. Journal of the American Geriatrics Society 1995;43:1198-1206. PDF

OBJECTIVE: To determine whether a 12-month program of regular exercise can improve balance, reaction time, neuromuscular control, and muscle strength and reduce the rate of falling in older women. DESIGN: A randomized, controlled trial of 12 months duration. SETTING: Conducted as part of the Randwick Falls and Fractures Study in Sydney, Australia. PARTICIPANTS: One hundred ninety-seven women aged 60 to 85 years (mean age 71.6, SD = 5.4) who were randomly recruited from the community. OUTCOME MEASURES: Accidental falls, postural sway, reaction time, neuromuscular control, and lower limb muscle strength. MAIN RESULTS: Exercise and control subjects were tested before, midway through, and at the end of the trial. At initial testing, exercisers and controls performed similarly in all tests and were well matched in relevant health and lifestyle factors. The mean number of classes attended for the 75 exercise subjects who completed the program was 60.0 (range 26-82). At the end of the trial, the exercise subjects showed improved performance in all five strength measures, in reaction time, neuromuscular control, body sway on a firm surface with the eyes open, and body sway on a compliant surface with the eyes open and closed. In contrast, there were no significant improvements in any of the test measures in the controls. In one test measure, hip flexion strength, the exercisers showed continued improvement throughout the study year. There was no significant difference in the proportion of fallers between the exercise and control subjects. Interesting trends were evident, however, between falls frequency and adherence to the exercise program. CONCLUSIONS: These findings show that exercise can produce long-term benefits with regard to improving sensorimotor function in older persons. The findings also suggest that high compliance to an exercise program may reduce falls frequency, although further studies are required to conclusively demonstrate that exercise offers an effective means of preventing falls.

Williams P, Lord SR. Predictors of adherence to a structured exercise program for older women. Psychology and Aging 1995;10:617-624.

This study examined whether psychological, physiological, and health and lifestyle measures were associated with adherence to a structured exercise program for older women. Women aged "60 to 85 years (N = 102)," randomly recruited from the community, were assessed on these measures before and after a 12-month exercise trial. Sixty-nine women completed the trial, and 54 continued participation after the trial for at least 6 months. Adherence was examined at various stages during the trial. Multiple regression analysis revealed that reduced muscle strength, slow reaction time, and psychoactive drug use explained most of the variance in adherence during the trial. In contrast, muscle strength, reasoning ability, depression, and self-reported improvement in strength best predicted continued participation after the trial. The findings have implications for community-based exercise programs and research trials.

Lord SR, Lloyd DG, Nirui M, Raymond J, Williams P, Stewart RA. The effect of exercise on gait patterns in older women: a randomised controlled trial. Journals of Gerontology: Medical Sciences 1996; 51A:M64-M70.

BACKGROUND: This study was undertaken to determine (a) whether a program of regular exercise can improve gait patterns in older women, and (b) whether any such improvement in gait is mediated by increased lower limb muscle strength. METHOD: A 22-week randomized controlled trial of exercise was conducted as part of the Randwick Falls and Fractures Study in Sydney, Australia. Subjects were 160 women aged 60-83 years (Mean age 71.1, SD = 5.2) who were randomly recruited from the community. Exercise and control subjects were tested prior to and at the end of the trial. At initial testing, exercisers and controls performed similarly in the strength and gait parameters. They were well matched in terms of age and a number of health and life-style characteristics. RESULTS: At the end of the trial, the exercise subjects showed improved strength in five lower limb muscle groups, increased walking speed, cadence, stride length, and shorter stride times as indicated by both reduced swing and stance duration. There were no significant improvements in any of the strength or gait parameters in the controls. Within the exercise group, increased cadence was associated with improved ankle dorsiflexion strength, and increased stride length was associated with improved hip extension strength. Exercise subjects with initial slow walking speed showed greater changes in velocity, stride length, cadence, and stance duration than those with initial fast walking speed. CONCLUSION: These findings show that exercise can increase gait velocity and related parameters in older persons, and that part of this increase may be mediated by improved lower limb muscle strength.

Lord SR, Ward JA, Williams P. Exercise effect on dynamic stability in older women: a randomised controlled trial. Archives of Physical Medicine and Rehabilitation 1996;77:232-236. PDF

OBJECTIVE: To determine whether a 12-month program of regular exercise can improve dynamic postural stability in older women. DESIGN: Randomized controlled trial of 12 months' duration. SETTING: Conducted as part of the Randwick Falls and Fractures Study, in Sydney, Australia. PARTICIPANTS: One hundred and twelve community-dwelling women aged 60 to 85 years (mean age 71.2, SD = 5.4). OUTCOME MEASURES: Quantitative measures of dynamic postural stability: maximal balance range and coordinated stability. MAIN RESULTS: Exercise and control subjects were tested before, midway through, and at the end of the trial. The stability measures had good test-retest reliability, and test performances were significantly associated with measures of lower limb muscle strength, reaction time, neuromuscular control, and body sway. At initial testing, exercisers and controls performed similarly in the two stability measures. The mean number of classes attended for the 48 exercise subjects who completed the program was 58.4 (range 26-77). At the end of the trial, the exercise subjects showed significantly improved performance in both the maximal balance range and coordinated stability tests, with no improvement evident in the controls. Improvements in coordinated stability were associated with corresponding improvements in ankle dorsiflexion, hip extension, and hip flexion strength. CONCLUSION: These findings show that exercise can significantly improve dynamic postural stability in older persons and elucidate some possible mechanisms by which such improvements may be mediated.

Lord SR, Ward JA, Williams P, Zivanovic E. The effects of a community exercise program on fracture risk factors in older women. Osteoporosis International 1996;6:361-367.

One hundred and seventy-nine women aged 60-85 years (mean age 71.6 years, SD 5.3 years) were randomly recruited from the community to participate in a 12-month randomized controlled trial to determine whether a program of twice-weekly structured exercise has beneficial effects on three factors associated with osteoporotic fractures: quadriceps strength, postural sway and bone density. At initial testing, there were no significant differences in the strength, sway and bone density measures (assessed at the hip and lumbar spine) between the exerciser and control groups. The exercise classes included strengthening, coordination and balance exercises, and approximately 35 min of each class comprised weight-bearing exercise. The mean number of classes attended for the 68 exercisers who completed the program was 59.8 of the 82 classes (72.9%). At the completion of the trial, the intervention group showed significant improvements in quadriceps strength and sway but not bone mineral density when compared with the control group. Indices of fracture risk, indicated by (i) the sum of standard score results and (ii) the sum of quartile grades of the femoral neck bone density, sway and strength measures, decreased significantly in the exercisers at the end of the trial compared with the controls. In conclusion, the program of general aerobic exercise may have reduced overall fracture risk, even though it did not significantly increase bone density. Further long-term studies are required that include acceptable weight-loaded exercises to determine optimal programs for reducing fracture risk factors by improving bone density as well as strength and balance.

Williams P, Lord SR. The effect of group exercise on intellectual functioning and mood in older women. Australian and New Zealand Journal of Public Health 1997,21:45-52.

A randomised controlled trial was conducted to determine whether a 12-month program of group exercise had beneficial effects on physiological and cognitive functioning and mood in 187 older community-dwelling women. The exercisers (n = 94) and controls (n = 93) were well matched in terms of the test measures and a number of health and life-style assessments. The mean number of classes attended by the 71 exercise subjects who completed the program was 59.0 (range 26 to 82). At the end of the trial, the exercisers showed significant improvements in reaction time, strength, memory span and measures of wellbeing when compared with the controls. There was also an indication that anxiety had been reduced in the exercisers. Within the exercise group, improvements in memory span were associated with concomitant improvements in both reaction time and muscle strength. Also, within this group, initial mood measures were significantly inversely associated with improvements at retest, which suggests that the program may have normalised mood states in subjects who had high initial depression, anxiety and stress levels, rather than inducing improvements in all subjects. These findings suggest that group exercise has beneficial effects on physiological and cognitive functioning and wellbeing in older people.

Sherrington C, Lord SR. Fall risk factors following hip fracture: a randomised controlled trial of home exercise. Archives of Physical Medicine and Rehabilitation 1997;78:208-212.

OBJECTIVE: To determine the effect of a home exercise program on strength, postural control, and mobility following hip fracture. DESIGN: Randomized controlled trial of 1 month's duration. SETTING: Daily exercise carried out within the subjects' home environments. PARTICIPANTS: Forty-two people 64 to 94 years of age, 35 of whom were living independently in the community and 7 of whom were residing in institutional care. Subjects were recruited on average 7 months after a fall-related hip fracture and randomly allocated to either the intervention or the control group (n = 21 each). The groups were well matched in terms of medical conditions, medication use, disability, and activity levels. INTERVENTION: A "home-based" program of weight-bearing exercise established at a visit by a physiotherapist. MAIN OUTCOME MEASURES: Quadriceps strength, postural sway, functional reach, weight-bearing ability, walking velocity, and self-rated fall risk. The subjects undertook these assessments at the beginning and end of the trial. RESULTS: At pretest, exercisers and controls performed similarly in all tests. At the end of the trial, the intervention group showed significantly greater quadriceps strength in the affected (hip-fractured) leg and increased walking velocity. The intervention subjects also improved their weight-bearing ability and reported reduced subjective falls risk. In contrast, there were no significant improvements in any of the test measures in the controls. Within the intervention group, improvements in quadriceps strength were significantly associated with improved performances in the weight-bearing test measures and with increased walking velocity. CONCLUSIONS: This exercise program improved strength and mobility following hip fracture. Further research is needed to ascertain whether the extent of this improvement in these fall risk factors is sufficient to prevent falls.

Herbert RD, Maher CG, Moseley AM, Sherrington C. Effective physiotherapy. BMJ 2001; 323: 788-790.PDF

Day L, Fildes B, Gordon I, Fitzharris M, Flamer H, Lord S. Randomised factorial trial of falls prevention among older people living in their own homes. BMJ 2002; 325: 128. PDF

Objective: To test the effectiveness of, and explore interactions between, three interventions to prevent falls among older people. Design: A randomised controlled trial with a full factorial design. Setting: Urban community in Melbourne, Australia. Participants: 1090 aged 70 years and over and living at home. Most were Australian born and rated their health as good to excellent; just over half lived alone. Interventions: Three interventions (group based exercise, home hazard management, and vision improvement) delivered to eight groups defined by the presence or absence of each intervention. Main outcome measure: Time to first fall ascertained by an 18 month falls calendar and analysed with survival analysis techniques. Changes to targeted risk factors were assessed by using measures of quadriceps strength, balance, vision, and number of hazards in the home. Results: The rate ratio for exercise was 0.82 (95% confidence interval 0.70 to 0.97, P=0.02), and a significant effect (P<0.05) was observed for the combinations of interventions that involved exercise. Balance measures improved significantly among the exercise group. Neither home hazard management nor treatment of poor vision showed a significant effect. The strongest effect was observed for all three interventions combined (rate ratio 0.67 (0.51 to 0.88, P=0.004)), producing an estimated 14.0% reduction in the annual fall rate. The number of people needed to be treated to prevent one fall a year ranged from 32 for home hazard management to 7 for all three interventions combined. Conclusions: Group based exercise was the most potent single intervention tested, and the reduction in falls among this group seems to have been associated with improved balance. Falls were further reduced by the addition of home hazard management or reduced vision management, or both of these. Cost effectiveness is yet to be examined. These findings are most applicable to Australian born adults aged 70-84 years living at home who rate their health as good.

Lord SR, Castell S, Corcoran J, Dayhew J, Shan A, Matters B, Williams P. The effect of group exercise on physical functioning and falls in frail older people living in retirement villages: a randomised controlled trial. J Am Geriatr Soc 2003;51:1685-1692. PDF

Objective: To determine whether a 12-month program of group exercise can improve physical functioning and reduce the rate of falling in frail older people. Design: Cluster randomised controlled trial of 12 months duration. Setting: Retirement villages in Sydney and Wollongong, Australia. Participants: Five hundred and fifty one people aged 62 to 95 years (mean =79.5 years, SD=6.4) who were living in self- and intermediate-care retirement villages. Outcome Measures: Accidental falls, choice stepping reaction time, six-minute walk distance postural sway, leaning balance, simple reaction time, lower limb muscle strength. Main Results: Two hundred and eighty subjects were randomised to the weight-bearing group exercise (GE) intervention that was designed to improve the ability of subjects to undertake activities for daily living. Subjects randomised to the control arm either attended flexibility and relaxation (FR) classes (n=90) or did not participate in a group activity (n=181). In spite of the reduced precision of cluster randomisation, there were few differences in the baseline characteristics between the GE and combined control (CC) subjects. However, the mean age of the GE group was higher than that of the CC group, and there were fewer men in the GE group. The mean number of classes attended was 39.4 (SD=28.7) for the GE subjects and 31.5 (SD=25.2) for the FR subjects. After adjusting for age and sex, there was a 22% reduction in falls during the trial for the GE group compared with the CC group (incident rate ratio = 0.78, 95% CI = 0.62-0.99), and a 31% reduction in the 173 subjects who had fallen in the past year (incident rate ratio= 0.69, 95% CI = 0.48-0.99). At six-month retest, the GE group performed significantly better than the CC group in tests of choice stepping reaction time, six-minute walking distance and simple reaction time requiring a hand press. The groups did not differ at retest in tests of strength, sway or leaning balance. Conclusion: These findings show that group exercise can prevent falls and maintain physical functioning in frail older people.

Barnett A, Smith B, Lord SR, Williams M, Bauman A. Community-based group exercise improves balance and reduces falls in at-risk older people: a randomised controlled trial. Age and Ageing 2003;32:407-414. PDF

BACKGROUND: recent studies have found that moderate intensity exercise is an effective intervention strategy for preventing falls in older people. However, research is required to determine whether supervised group exercise programmes, conducted in community settings with at-risk older people referred by their health care practitioner are also effective in improving physical functioning and preventing falls in this group. OBJECTIVES: to determine whether participation in a weekly group exercise programme with ancillary home exercises over one year improves balance, muscle strength, reaction time, physical functioning, health status and prevents falls in at-risk community-dwelling older people. METHODS: the sample comprised 163 people aged over 65 years identified as at risk of falling using a standardised assessment screen by their general practitioner or hospital-based physiotherapist, residing in South Western Sydney, Australia. Subjects were randomised into either an exercise intervention group or a control group. Physical performance and general health measures were assessed at baseline and repeated 6-months into the trial. Falls were measured over a 12-month follow-up period using monthly postal surveys. RESULTS: at baseline both groups were well matched in their physical performance, health and activity levels. The intervention subjects attended a median of 23 exercise classes over the year, and most undertook the home exercise sessions at least weekly. At retest, the exercise group performed significantly better than the controls in three of six balance measures; postural sway on the floor with eyes open and eyes closed and coordinated stability. The groups did not differ at retest in measures of strength, reaction time and walking speed or on Short-Form 36, Physical Activity Scale for the Elderly or fear of falling scales. Within the 12-month trial period, the rate of falls in the intervention group was 40% lower than that of the control group (IRR=0.60, 95% CI 0.36-0.99). CONCLUSIONS: these findings indicate that participation in a weekly group exercise programme with ancillary home exercises can improve balance and reduce the rate of falling in at-risk community dwelling older people.

Sherrington C, Lord SR, Finch CF. Physical activity interventions to prevent falls among older people: update of the evidence. Journal of Science and Medicine in Sport 2004;7: (Supplement) 43-51.

Sherrington C, Lord SR, Herbert RD. A randomized controlled trial of weight-bearing versus non-weight-bearing exercise for improving physical ability after usual care for hip fracture. Arch Phys Med Rehabil 2004;85:710–6. PDF

Objective. To compare the effects of weight-bearing and non-weight-bearing home exercise programs and a control program on physical ability (strength, balance, gait, functional performance) in older people who have had a hip fracture. Design. Randomized controlled trial with 4-month follow-up. Setting. Australian community-dwellers (82%) and residents of aged care facilities who had completed usual care after a fall-related hip fracture. Participants. One hundred twenty older people entered the trial, 40 per group (average age ± standard deviation, 79±9y) and 90% completed the 4-month retest. Intervention. Home exercise prescribed by a physical therapist. Main outcome measures. Strength, balance, gait, and functional performance. Results. At the 4-month retest, there were differences between the groups in the extent of improvement since the initial assessment for balance (F10,196=2.82, P<.001) and functional performance (F6,200=3.57, P<.001), but not for strength (F12,190=1.09, P=.37) or gait (F8,200=.39, P=.92). The weight-bearing exercise group showed the greatest improvements in measures of balance and functional performance (between-group differences of 30%–40% of initial values). Conclusions. A weight-bearing home exercise program can improve balance and functional ability to a greater extent than a non-weight-bearing program or no intervention among older people who have completed usual care after a fall-related hip fracture.

Liu-Ambrose T, Khan KM, Eng JJ, Lord SR, McKay HA. Balance confidence improves with resistance or agility training: increase is not correlated with objective changes in fall risk and physical abilities. Gerontology 2004;50:373-382. PDF

BACKGROUND: While the fear of falling is a common psychological consequence of falling, older adults who have not fallen also frequently report this fear. Fear of falling can lead to activity restriction that is self-imposed rather than due to actual physical impairments. Evidence suggests that exercise can significantly improve balance confidence, as measured by falls-related self-efficacy scales. However, there are no prospective reports that correlate change in balance confidence with changes in fall risk and physical abilities as induced by participating in a group-based exercise program. OBJECTIVE: The primary purpose of this prospective study was to examine the relationship between the change in balance confidence and the changes in fall risk and physical abilities in older women with confirmed low bone mass after 13 weeks of exercise participation. The secondary purpose of this study was to examine the relationship between the change in balance confidence and the change in physical activity level. METHODS: The sample comprised 98 women aged 75-85 years with low bone mass. Participants were randomly assigned to one of three groups: resistance training (n = 32), agility training (n = 34), and stretching (sham) exercises (n = 32). The 50-min exercise classes for each study arm were held twice weekly at a local YMCA community centre. RESULTS: Both resistance training and agility training significantly improved balance confidence by 6% from baseline after 13 weeks. However, the change in balance confidence was only weakly correlated with improved general physical function and not significantly correlated with the changes in fall risk score, postural stability, gait speed, or physical activity level. As well, we observed balance confidence enhancement in the presence of increased fall risk or deterioration in physical abilities. CONCLUSIONS: Two different types of exercise training improved balance confidence in older women with low bone mass. This change in balance confidence was significantly correlated with change in general physical function. Because of the observation of discordance between balance confidence change and changes in fall risk and physical abilities, those who design group-based exercise programs for community-dwelling older adults may wish to consider including an education component on factors that influence fear of falling. Objective changes in fall risk factors cannot be assumed to mirror change in fear of falling and physical abilities in older adults in the short-term.

Teresa Y. L. Liu-Ambrose, Karim M. Khan, Janice J. Eng, Stephen R. Lord, Brian Lentle and Heather A. McKay. Both resistance and agility training reduce back pain and improve health-related quality of life in older women with low bone mass. Osteoporosis International. 2005 Feb 9. PDF

The purpose of the study was to compare the effects of three different types of group-based exercise programs (resistance training, agility training and general stretching) on back pain and healthrelated quality of life in older (aged 75–85 years) community-dwelling women with low bone mass (i.e., osteopenia or osteoporosis). The design was a 25-week randomized controlled trial. Participating were 98 community-dwelling women with low bone mass between the ages of 75 to 85 years old. We assessed back pain and its related disability and health-related quality of life. All three types of group-based exercise programs significantly reduced back pain and its related disabilities, but only resistance and agility training significantly improved health-related quality of life in community-dwelling older women with low bone mass. Baseline physical activity level and class attendance were significant predictors of change in healthrelated quality of life. Change in back pain and its related disabilities after 25 weeks of exercise intervention was significantly correlated with change in health-related quality of life and changes in the domains of pain and physical function. Resistance and agility training significantly enhanced health-related quality of life and may have done so by increasing social interactions and support, enhancing self-efficacy of physical abilities and modifying the experience of back pain. These data provide valuable insight into the specifics of exercise prescription for older women with low bone mass. Future studies may wish to use individualized quality of life measures to further delineate the effects of different types of exercise on quality of life in older adults with low bone mass.

Stephen R. Lord, Anne Tiedemann, Kirsten Chapman, Bridget Munro, Susan M. Murray, Catherine Sherrington. The Effect of an Individualized Fall Prevention Program on Fall Risk and Falls in Older People: A Randomized, Controlled Trial. J Am Geriatr Soc, 2005; 53:1296–1304 PDF

OBJECTIVES: To determine whether an individualized falls prevention program comprising exercise, visual, and counseling interventions can reduce physiological falls risk and falls in older people. DESIGN: Randomized, controlled trial of 12 months’ duration. SETTING: Falls Clinic, Royal North Shore Hospital, Sydney, Australia. PARTICIPANTS: Six hundred twenty people aged 75 and older recruited from a health insurance company membership database. INTERVENTIONS: Participants in the extensive intervention group (EIG) received individualized interventions comprising exercise and strategies for maximizing vision and sensation; theminimal intervention group (MIG) received brief advice; and the control group (CG) received no intervention. MEASUREMENTS: Accidental falls, vision, postural sway, coordinated stability, reaction time, lower limb muscle strength, sit-to-stand performance, and physiological profile assessment (PPA) falls risk scores. RESULTS: At the 6-month follow-up, PPA falls risk scores were significantly lower in the EIG than in the CG. EIG subjects assigned to the extensive exercise intervention group showed significant improvements in tests of knee flexion strength and sit-to-stand times but no improvements in balance. EIG subjects assigned to the extensive visual intervention group showed significant improvements in tests of visual acuity and contrast sensitivity. The rate of falls and injurious falls within the trial period were similar in the three groups. CONCLUSION: The individualized intervention program reduced some falls risk factors but did not prevent falls. The lack of an effect on falls may reflect insufficient targeting of the intervention to an at-risk group.

Teresa Y. L. Liu-Ambrose, Karim M. Khan, Janice J. Eng, Graham L. Gillies, Stephen R. Lord, and Heather A. McKay. The Beneficial Effects of Group-Based Exercises on Fall Risk Profile and Physical Activity Persist 1 Year Postintervention in Older Women with Low Bone Mass: Follow-Up After Withdrawal of Exercise. J Am Geriatr Soc, 2005; 53:1767–1773. PDF

OBJECTIVES: To determine whether exercise-induced reductions in fall risk are maintained in older women 1 year after the cessation of three types of interventions; resistance training, agility training, and general stretching. DESIGN: One-year observational study. SETTING: Community. PARTICIPANTS: Ninety-eight women aged 75 to 85 with low bone mass. MEASUREMENTS: Primary outcome measure was fall risk, measured using the Physiological Profile Assessment tool. Secondary outcome measures were current physical activity level, assessed using the Physical Activity Scale for the Elderly, and formal exercise participation, assessed using an interview. RESULTS: At the end of the follow-up, the fall risk of former participants of all three exercise programs was maintained (i.e., still reduced) from trial completion. Mean fall risk value at the end of follow-up was 43.3% lower than mean baseline value in former participants of the resistance training group, 40.1% lower in the agility-training group, and 37.4% lower in the general stretching group. Physical activity levels were also maintained from trial completion. Specifically, there was a 3.8% increase in physical activity from baseline for the resistance-training group, a 29.2% increase for the agility-training group, and a 37.7% increase for the general stretching group. CONCLUSION: After three types of group-based exercise programs, benefits are sustained for at least 12 months without further formal exercise intervention. Thus, these 6-month exercise interventions appeared to act as a catalyst for increasing physical activity with resultant reductions in fall risk profile that were maintained for at least 18 months in older women with low bone mass.

Liu-Ambrose T, Khan KM, Eng JJ, Janssen PA, Lord SR, McKay HA. Both resistance and agility training reduce fall risk in 75-85 year old women with low bone mass: a six-month randomized controlled trial. J Am Geriatrics Society 2004;52:657-665. PDF

OBJECTIVES: To compare the effectiveness of group resistance and agility-training programs in reducing fall risk in community-dwelling older women with low bone mass. DESIGN: A randomized, controlled, single-blind 25-week prospective study with assessments at baseline, midpoint, and trial completion. SETTING: Community center. PARTICIPANTS: Community-dwelling women aged 75 to 85 with low bone mass. INTERVENTION: Participants were randomly assigned to one of three groups: resistance training (n532), agility training (n534), and stretching (sham) exercises (n532). The exercise classes for each study arm were held twice weekly. MEASUREMENTS: The primary outcome measure sway, reaction time, strength, proprioception, and vision), as measured using a Physiological Profile Assessment (PPA). Secondary outcome measures were ankle dorsiflexion strength, foot reaction time, and Community Balance and Mobility Scale score. RESULTS: Attendance at the exercise sessions for all three groups was excellent: resistance training (85.4%), agility training (87.3%), and stretching program (78.8%). At the end of the trial, PPA fall-risk scores were reduced by 57.3% and 47.5% in the resistance and agility-training groups, respectively, but by only 20.2% in the stretching group. In the resistance and agility groups, the reduction in fall risk was mediated primarily by improved postural stability, where sway was reduced by 30.6% and 29.2%, respectively. There were no significant differences between the groups for the secondary outcomes measures. Within the resistance-training group, reductions in sway were significantly associated with improved strength, as assessed using increased squat load used in the exercise sessions. CONCLUSION: These findings support the implementation of community-based resistance and agility-training programs to reduce fall risk in older women with low bone mass. Such programs may have particular public health benefits because it has been shown that this group is at increased risk of falling and sustaining fall-related fractures.

Sturnieks D. Calling on exercise scientists to participate in broader efforts to prevent falls in older adults. J Sci Med Sport. 2006 Jun;9(3):195-8.

Editoral (no abstract available)

 

Lord SR, Webster IW. Visual field dependence in elderly fallers and non-fallers. International Journal of Aging and Human Development 1990;31:269-279.

Two tests of visual field dependence (a measure of reliance upon the spatial framework provided by vision in the perception of the upright)--roll vection and the rod and frame test--were administered to 136 participants aged fifty-nine to ninety-seven years. It was found that the fifty-nine participants who had experienced one or more falls in the past year were significantly more visually field dependent in both tests compared with the seventy-seven participants who had not fallen. Mean error in perception of the true vertical in the rod and frame test was 20.7 degrees for the fallers and 17.2 degrees for the non-fallers. Mean error in perception of the true vertical in the roll vection test was 6.6 degrees for the fallers and 3.6 degrees for the non-fallers. The test of roll vection was the better discriminator between fallers and non-fallers, which may be due in part to less misunderstanding of the required task by the participant. The results suggest that tilted or rolling visual stimuli may be factors leading to postural instability and falls in the elderly. The findings support the claim that greater dependence on visual information shown by fallers may be the result of reduced proprioceptive and vestibular function resulting from increased age and chronic health problems.

Lord SR, Clark RD, Webster IW. Visual acuity and contrast sensitivity in relation to falls in an elderly population. Age and Ageing 1991;20:175-181.

Visual acuity and contrast sensitivity were measured in 95 residents of a hostel for the aged (mean age = 83 years) using a dual-contrast letter chart and the Melbourne Edge Test (MET). Vision (as measured by visual acuity, the MET, low-contrast visual acuity, and difference between high- and low-contrast acuity) decreased significantly with age and all four measures were significantly correlated. Subjects with a clinical eye disorder had poorer vision than those without a disorder although the differences were not significant. Visual acuity and contrast sensitivity were not associated with body sway when subjects were standing on a firm base. However, when the subjects were placed in a situation which provided reduced support (standing on a compliant surface), body sway was associated with poor visual acuity and contrast sensitivity. There was also a difference in contrast sensitivity between those who fell one or more times in a year of follow-up and those who did not fall. It appears that reduced vision may be a predisposing factor to postural imbalance and falls in elderly persons.  

Lord SR, Menz HB. Visual contributions to postural stability in older adults. Gerontology 2000; 46(6): 306-310. PDF

Background: With advancing age, there is a generalised reduction in visual functioning which has been associated with impaired postural stability and increased risk of falls. However, little is known about which visual abilities are the most important in the control of postural sway when standing. Objective: To determine whether specific visual abilities predict stability when standing on firm and compliant surfaces. Methods: Tests of visual function, peripheral sensation, strength, reaction time and sway were administered to 156 community-dwelling men and women aged 63 to 90 years. The visual tests included high and low contrast visual acuity, contrast sensitivity, depth perception, stereopsis and lower visual field size. Postural sway was measured with eyes open on a firm and a compliant foam rubber surface. Results: On the firm surface, sway was significantly associated with only one sensorimotor measure: proprioception in the lower limbs. In contrast, on the compliant surface, sway was associated with all of the visual measures, quadriceps strength and reaction time. Multiple regression analysis revealed that contrast sensitivity, stereopsis and quadriceps strength were significant independent predictors of total sway when subjects stood on the compliant surface. Conclusion: The study findings confirm the importance of vision, in particular contrast sensitivity and stereopsis, in the control of posture under challenging conditions, and suggest some mechanisms for the association between impaired vision and falls in older people.  

Lord SR, Dayhew J. Visual risk factors for falls in older people. Journal of the American Geriatrics Society 2001; 49: 508-512. PDF Published with accompanying editorial by Mary Tinetti (PDF).

Objectives: 1. To determine the most predictive tests of falls in community-dwelling older people from a range of visual screening tests (high and low contrast visual acuity, edge contrast sensitivity, depth perception and visual field size). 2. To determine whether one or more of these visual measures in association with measures of sensation, strength, reaction time and balance can accurately predict falls in this group. Design: Prospective cohort study of 12 months duration. Setting: Falls and Balance Laboratory, Prince of Wales Medical Research Institute. Participants: One hundred and fifty six community-dwelling men and women aged 63-90 years (mean age 76.5, SD = 5.1). Measurements: Screening tests of vision, sensation, strength, reaction time and balance, falls. Results: Of the 148 subjects available to follow-up, 64 subjects (43.2%) reported falling, with 32 (21.7%) reporting multiple falls. Multiple fallers had decreased vision as indicated by all visual tests, with impaired depth perception, contrast sensitivity and low contrast visual acuity the strongest risk factors. Subjects with good vision in both eyes had the lowest rate of falls, whereas those with good vision in one eye with only moderate or poor vision in the other had elevated falling rates - equivalent to those with moderate or poor vision in both eyes. Discriminant analysis revealed that impaired depth perception, slow reaction time and increased body sway on a compliant surface were significantly and independently associated with falls. These variables correctly classified 76% of the cases, with similar sensitivity and specificity. Conclusion: The study findings indicate that impaired vision is an important and independent risk factor for falls. Adequate depth perception and distant edge contrast sensitivity, in particular, appear to be important for maintaining balance and detecting hazards in the environment.

Lord SR, Dayhew J, Howland A. Multifocal Glasses Impair Edge-Contrast Sensitivity and Depth Perception and Increase the Risk of Falls in Older People. Journal of the American Geriatrics Society 2002;50:1760-1766.PDF

OBJECTIVES: To determine the extent to which multifocal glasses impair contrast sensitivity and depth perception at critical distances required for detecting hazards in the environment and whether multifocal glasses use increases the risk of falls in older people. DESIGN: One-year prospective cohort study. SETTING: Falls Laboratory, Prince of Wales Medical Research Institute. PARTICIPANTS: One hundred fifty-six community-dwelling people aged 63-90. MEASUREMENTS: Contrast sensitivity, depth perception, accidental falls. RESULTS: Eighty-seven subjects (55.8%) were regular wearers of multifocal (bifocal, trifocal, or progressive lens) glasses. These subjects performed significantly worse in the distant depth perception and distant edge-contrast sensitivity tests in conditions that forced them to view test stimuli through the lower segments of their glasses. Multifocal glasses wearers were more than twice as likely to fall in the follow-up period than nonmultifocal glasses wearers (odds ratio (OR) = 2.29, 95% confidence interval (CI) = 1.06-4.92), when adjusting for age, poor vision, reduced lower limb sensation and strength, slow reaction time, and increased postural sway. Multifocal glasses wearers were also more likely to fall because of a trip (OR = 2.79, 95% CI = 1.08-7.22), when outside their homes (OR = 2.55, 95% CI = 1.14-5.70), and when walking up or down stairs (P <.01). The population attributable risks of regular multifocal glasses use were 35.2% for any falls, 40.9% for falls due to a trip, and 40.9% for falls outside the home. CONCLUSIONS: The study findings indicate that multifocal glasses impair depth perception and edge-contrast sensitivity at critical distances for detecting obstacles in the environment. Older people may benefit from wearing nonmultifocal glasses when negotiating stairs and in unfamiliar settings outside the home.

Lord SR, Bashford G. Shoe characteristics and balance in older women. Journal of the American Geriatrics Society 1996;44:429-433.

OBJECTIVE: To determine whether shoe characteristics affect balance in older women. DESIGN: Randomized order, cross-over, controlled comparison. SETTING: A retirement village. PARTICIPANTS: Thirty women aged 60 to 89 years (mean 78.7 SD = 8.5). Twenty-five subjects were hostel residents, and five were living independently in the community. OUTCOME MEASURES: Postural sway, maximal balance range, and co-ordinated stability. MAIN RESULTS: The subjects underwent assessments of static balance (body sway) and dynamic balance (maximal balance range and co-ordinated stability) under four conditions: (1) barefoot, (2) in standard low-heeled shoes (walking shoes), (3) in standard high-heeled shoes, and (4) in their own shoes. Manova analysis revealed a significant overall shoe condition effect -- subjects performed best in bare feet or low-heeled shoes and worst in high-heeled shoes. There were no significant differences between subjects with and without foot abnormalities in any of the balance measures or test conditions. CONCLUSION: These findings suggest that bare feet and walking shoes maximize balance, whereas high-heeled shoes constitute a needless balance hazard for older women.

Menz HB, Lord SR. Footwear and postural stability in older people. Journal of the American Podiatric Medical Association 1999; 89(7): 346-357. PDF

Accidental falls in the older population are common and often result in serious injury. Although a number of factors have been recognized as risk factors for falling, the effect of footwear on postural stability is often overlooked. This article reviews the literature on the effect of various footwear features on postural stability and suggests areas that warrant further investigation.

Menz HB, Lord SR. Foot problems, functional impairment and falls in older people. Journal of the American Podiatric Medical Association 1999(9): 458-467. PDF

Falls in older people are common and may lead to considerable disability. Although a number of risk factors for falling have been identified, the role of foot problems has received relatively little attention in the literature. This article reviews the literature pertaining to the prevalence of foot problems in older people and discusses the relationship of foot problems to functional impairment and falls. In addition, a number of theoretical considerations regarding specific foot conditions and postural instability are outlined.

Lord SR, Bashford G, Howland A, Munro B. Effect of shoe collar height and sole hardness on balance in older women. Journal of the American Geriatrics Society 1999; 47: 1-4.

OBJECTIVE: To determine whether shoe collar height and sole hardness affect balance in older women. DESIGN: A randomized order, cross-over, controlled comparison. SETTING: Intermediate care institution and regional hospital. PARTICIPANTS: Forty-two women aged 60 to 92 years (mean 76, SD = 9.03). The sample comprised 15 hostel (intermediate care) residents, 11 women who lived in a retirement village, and 16 women who lived independently in the community. OUTCOME MEASURES: Postural sway, maximal balance range and coordinated stability. MAIN RESULTS: The subjects underwent assessments of static balance (body sway) and dynamic balance (maximal balance range and coordinated stability) under five conditions: (1) in soft-soled bowls shoes, (2) in hard-soled bowls shoes, (3) in college-style shoes, (4) in college-style shoes with a high (boot) collar, and (5) barefoot. MANOVA analysis indicated that subjects were more stable when wearing the high collar shoes than when wearing the college shoes (P < .001) or when barefoot (P < .05). In contrast, subjects performed similarly in the balance tests in the soft and hard-soled shoes (P = .30) and no better than when barefoot (P = .12 and P = .93, respectively). CONCLUSIONS: The findings indicate that subjects had better balance when wearing shoes with high collars than when wearing shoes with low collars and that sole hardness was not related to balance.

Menz HB, Sherrington C. The Footwear Assessment Form: a reliable clinical tool to assess footwear characteristics of relevance to postural stability in older adults. Clinical Rehabilitation 2000; 14: 657-664.PDF 

Objective: Falls in older adults are common and may result in serious injury. Inappropriate footwear has been suggested to be a contributing factor to many falls, however no studies have been undertaken to determine whether clinicians can reliably assess footwear variables thought to influence postural stability in older adults. The aim of this study was therefore to develop a simple clinical footwear assessment form and assess its reliability, both between examiners and with repeated assessments over time. Design: Two examiners assessed seven footwear variables (shoe type, heel height, heel counter stiffness, longitudinal sole rigidity, sole flexion point, tread pattern and sole hardness) in twelve different shoes, and repeated the measurements three weeks later. The examiners were blinded to each other's and their own previous results. Results: Analysis using the kappa (k ) and percentage agreement statistics revealed the examiners' footwear assessments to be generally highly reliable (k = 0.47 to 1.00 for inter-tester comparisons, k = 0.40 to 1.00 for intra-tester comparisons), with the exception of inter-tester assessment of sole hardness (k = 0.03 to 0.48). Conclusion: The Footwear Assessment Form is a reliable clinical tool for the assessment of shoe type, heel height, heel counter stiffness, longitudinal sole rigidity and tread pattern, however a more objective protocol may be required to improve the reliability of sole hardness evaluation. The Footwear Assessment Form can now be used with confidence in the clinical setting and in future investigations to determine the contribution of footwear characteristics to instability and falls in older adults (c Arnold 2000).

Menz HB, Lord SR, McIntosh AS. Slip resistance of casual footwear: implications for falls in older adults. Gerontology 2001; 47: 145-149. PDF

Background: A large proportion of falls in older people are caused by slipping. Previous occupational safety research suggests that inadequate footwear may contribute to slipping accidents; however, no studies have assessed the slip resistance of casual footwear. Objective: To evaluate the slip resistance of different types of casual footwear over a range of common household surfaces. Methods: The slip resistance of men's Oxford shoes and women's fashion shoes with different heel configurations was determined by measuring the dynamic coefficient of friction (DCoF) at heel contact (in both dry and wet conditions) on a bathroom tile, concrete, vinyl flooring and a terra cotta tile using a specially-designed piezoelectric force plate apparatus. Results: Analysis of variance revealed significant shoe, surface, and shoe-surface interaction effects. Men's Oxford shoes exhibited higher average DCoF values than the women's fashion shoes, however, none of the shoes could be considered safe on wet surfaces. Application of a textured sole material did not improve slip resistance of any of the shoes on wet surfaces. Conclusion: Heel geometry influences the slip resistance of casual footwear on common household surfaces. The suboptimal performance of all of the test shoes on wet surfaces suggests that a safety standard for casual footwear is required to assist in the development of safe footwear for older people.

Menz HB, Lord SR. Foot pain impairs balance and functional ability in community dwelling older people. Journal of the American Podiatric Medical Association 2001; 91: 222-229. PDF

Foot problem assessments were performed on 135 community dwelling older people in conjunction with clinical tests of balance and functional ability. Eighty-seven percent of the sample had at least one foot problem, and women had a higher prevalence of foot pain, hallux valgus, plantar hyperkeratosis, digital deformity and digital lesions than men. Performance in tests of postural sway did not differ between older people with and without each of these foot conditions. However, the presence of specific foot conditions impaired performance in a more challenging balance test and in some functional tests. In particular, older people with foot pain performed worse in a leaning balance test, stair ascent and descent, an alternate leg stepping test and a timed six metre walk. Furthermore, multiple regression analyses revealed that foot pain was a significant independent predictor of performance in each of these tests. These results show that the presence of foot problems, particularly foot pain, impairs balance and functional ability. The findings suggest that as foot pain is amenable to treatment, podiatric intervention has the potential to improve mobility and independence in older people.

Menz HB, Lord SR. The contribution of foot problems to mobility impairment and falls in older people. Journal of the American Geriatrics Society 2001;49:1651-1656.PDF

Objective: To investigate the relationship between foot problems, balance and functional ability in community-dwelling older people, and to determine whether older people with a history of multiple falls exhibit greater foot impairment than those who have not fallen or who have fallen once only. Design: A cross-sectional and retrospective study. Setting:  Falls and Balance Laboratory, Royal North Shore Hospital, Sydney, Australia. Participants:  One hundred and thirty-five community-dwelling men and women aged 75-93 years (mean age 79.8, SD=4.1). Measures: Foot problem score, postural sway, coordinated stability, stair ascent and descent, an alternate stepping test, timed six metre walk, and tests of vision, sensation, strength and reaction time. Results: Eighty-seven percent of the sample had at least one foot problem.  Women had a significantly higher foot problem score than men. The foot problem score was significantly associated with performance on the coordinated stability test, stair ascent and descent, alternate stepping test and timed six metre walk.  Multiple regression analyses revealed that the foot problem score was a significant independent predictor of performance in the coordinated stability test, stair ascent and descent, and the alternate stepping test.  Subjects with a history of multiple falls had a significantly higher foot problem score than those who had not fallen or who had fallen once only, however the prevalence of individual foot conditions or the presence of foot pain did not differ between these groups. Conclusions:  Foot problems are common in older people and are associated with impaired balance and performance in functional tests.  Furthermore, older people with a history of multiple falls have greater foot impairment than non- or once-only fallers. These findings provide further evidence that foot problems are a falls risk factor, and suggest that the cumulative effect of multiple foot problems is more important in increasing falls risk than the presence or absence of individual foot conditions.

Menz HB, Tiedemann A, Kwan M, Latt M, Sherrington C, Lord SR. Reliability of clinical tests of foot and ankle characteristics in older people. J Am Podiatric Soc 2003;93:380-387.

Sherrington C, Menz HB. An evaluation of footwear worn at the time of falls-related hip fracture. Age and Ageing 2003 2003;32(3):310-314.PDF

Background: a range of footwear features have been shown to influence balance in older people, however little is known about the relationships between inappropriate footwear, falls and hip fracture.  Objectives: to describe the characteristics of footwear worn at the time of fall-related hip fracture and establish whether the features of the shoe influenced the type of fall associated with the fracture.  Methods: 95 older people (average age 78.3 years, SD 7.9) who had suffered a fall-related hip fracture were asked to identify the footwear they were wearing when they fell. Footwear characteristics were then evaluated using a standardised assessment form. Information was also collected on the type and location of fall. Results: the most common type of footwear worn at the time of the fall was slippers (22%), followed by walking shoes (17%) and sandals (8%). Few subjects were wearing high heels when they fell (2%). The majority of subjects (75%) wore shoes with at least one theoretically sub-optimal feature, such as absent fixation (63%), excessively flexible heel counters (43%) and excessively flexible soles (43%). Subjects who tripped were more likely to be wearing shoes with no fixation compared to those who reported other types of falls [χ²=4.21, df=1, p=0.033; OR=2.93 (95%CI 1.03 – 8.38)]. Conclusions: many older people who have had a fall-related hip fracture were wearing potentially hazardous footwear when they fell. The wearing of slippers or shoes without fixation may be associated with increased risk of tripping. Prospective studies into this proposed association appear warranted.

Menz HB, Lord SR. Gait Instability in Older People with Hallux Valgus. Foot & Ankle International. 2005; 26(6):483-489. PDF

Background: Hallux valgus is a common condition that may lead to considerable pain and disability. There is also evidence that hallux valgus may impair balance and increase the risk of falling in older people. Although a number of plantar pressure studies have been undertaken in people with and without hallux valgus, little is known about how hallux valgus affects basic gait patterns or the movement of the upper body when walking. Methods: Measurements of temporospatial parameters of gait and acceleration patterns of the head and pelviswere obtained in 71 people (24 men, 47 women) between 75 and 93 (mean 80 ± 4) years of age when walking on both a level surface and a specially designed irregular walkway. Foot problems, vision, peripheral sensation, strength, and reaction time alsowere evaluated. Results: After adjusting for potential confounders, subjects with moderate to severe hallux valgus were found to exhibit significantly reduced velocity and step length on both walking surfaces and less rhythmic acceleration patterns in the vertical plane when walking on the irregular surface compared to subjects with no or mild hallux valgus. Conclusion: These findings indicate that hallux valgus has a significant detrimental impact on gait patterns that may contribute to instability and risk of falling in older people, particularly when walking on irregular terrain.

Elizabeth LM Barr, Colette Browning, Stephen R Lord, Hylton B Menz & Hal Kendig. Foot and leg problems are important determinants of functional status in community dwelling older people. Disability and Rehabilitation, 2005; 27(16): 917 – 923. PDF

Purpose. To determine whether foot and leg problems are independently associated with functional status in a community sample of older people after adjusting for the influence of socio-demographic, physical and medical factors. Method. Data were analysed from the Health Status of Older People project, a population-based study involving a sample of 1000 community-dwelling people aged 65 – 94 years (533 females, 467 males, mean age 73.4 years+ structured interview and brief physical examination were used to investigate the associations between self-reported leg problems and functional status. Functional status was assessed using: (i) timed ‘Up & Go’ test, (ii) self-reported difficulty climbing stairs, (iii) self-reported difficulty walking one kilometer, (iv) self-reported difficulty performing instrumental activities of daily living (IADLs), and (v) self-reported history of one or more falls in the previous 12 months. These associations were then explored after adjusting for socio-demographic, physical and medical factors. Results. Thirty-six percent of the sample reported having foot or leg problems. Univariate analyses revealed that people foot and leg problems were significantly more likely to exhibit poorer functional status in all parameters measured. adjusting for socio-demographic, physical and medical factors, foot and leg problems remained significantly associated impaired timed ‘Up & Go’ performance (OR = 2.15, 95%CI 1.55 – 2.97), difficulty climbing stairs (OR= 3.33, 1.98 – 5.61), difficulty walking one kilometer (OR =3.13, 95%CI 2.09 – 4.69), and history of falling (OR = 1.73, 1.26 – 2.37). Conclusions. Foot and leg problems are reported by one in three community-dwelling people aged 65 years and Independent of the influence of age, gender, common medical conditions and other socio-demographic factors, foot problems have a significant impact on the ability to perform functional tasks integral to independent living.

Hylton B. Menz, Meg E. Morris, Stephen R. Lord. Foot and Ankle Characteristics Associated With Impaired Balance and Functional Ability in Older People, Journal of Gerontology, 2005; 60A (12): 1546–1552. PDF

Background. Ageing is associated with changes to the structure and function of the foot and ankle, and there is preliminary evidence that foot problems impair balance and increase the risk of falls. To explore this in more detail, we conducted a study to determine the relative contribution of several foot and ankle characteristics to performance on a range of balance and functional tests. Methods. One hundred seventy-six people (56 men and 120 women, mean age 80.1 years, standard deviation 6.4 years) residing in a retirement village underwent tests of foot and ankle characteristics (including foot posture, range of motion, strength, and deformity), sensorimotor function (including vision, sensation, strength, and reaction time), and balance and functional ability (including tests of standing balance, leaning balance, stepping, sit-to-stand, and walking speed). Results. Many foot and ankle characteristics and sensorimotor measures were associated with performance on the balance and functional tests in univariate analyses. Multiple regression analysis consistently revealed that ankle flexibility, plantar tactile sensitivity, and toe plantarflexor strength were significant and independent predictors of balance and functional test performance, explaining up to 59% of the variance in these test scores. Conclusions. Foot and ankle characteristics, particularly ankle flexibility, plantar tactile sensation, and strength of toe plantarflexor muscles, are significant independent predictors of balance and functional ability in older people. Programs to improve the strength and flexibility of the foot and interventions to augment plantar sensation may be beneficial in improving mobility and reducing the risk of falls.

Hylton B. Menz, Meg E. Morris, Stephen R. Lord. Footwear Characteristics and Risk of Indoor and Outdoor Falls in Older People. Gerontology 2006;52:174–180.

Background: Footwear characteristics have been shown to influence balance in older people; however, the relationship between footwear and falls is unclear. Objective: To determine the relationships between footwear characteristics and the risk of indoor and outdoor falls in older people. Methods: Footwear characteristics (shoe type, heel height, heel counter height, heel width, critical tipping angle, method of fixation, heel counter stiffness, sole rigidity and flexion point, tread pattern and sole hardness) were assessed in 176 people (56 men and 120 women) aged 62–96 (mean age 80.1, SD 6.4) residing in a retirement village. Falls were recorded over a 12-month follow-up period and comparisons made between fallers and non-fallers. Results: 50 participants (29%) fell indoors and 36 (21%) fell outdoors. After controlling for age, gender, demographic characteristics, medication use, physiological falls risk factors and foot problems, those who fell indoors were more likely to go barefoot or wear socks inside the home (OR = 13.74; 95% CI 3.88–48.61, p ! 0.01). However, there were no significant differences in indoor or outdoor footwear characteristics between fallers and non-fallers. Five indoor fallers (10%) and three outdoor fallers (8%) stated that their shoes.

 

 

Lord SR, Lloyd DG, Li S-K. Sensorimotor function, gait patterns and falls in community dwelling women. Age and Ageing 1996;25:292-299.

Tests of vision, vestibular function, peripheral sensation, strength, reaction time, balance and gait were administered to 183 community-dwelling women aged 22-99 years. Walking speed, stride length and cadence declined with age with corresponding increases in stance duration and percentage of the stride in the stance phase. Visual acuity and contrast sensitivity, tactile and vibration sense in the lower limb, vestibular function (as assessed by the vestibular X Writing Test), quadriceps and ankle dorsiflexion strength and reaction time were significantly associated with all five gait parameters. Postural sway measures were associated with walking speed, stride length and percentage of the stride in the stance phase. Multiple regression analyses revealed seven sensori-motor measures as significant predictors for one or more of the gait parameters: low contrast visual acuity, tactile sensitivity, vibration sense, vestibular X-test writing performance, quadriceps strength, reaction time and sway. Quadriceps strength was included as a predictor variable for every gait parameter and in each case had the strongest beta weight. Women who fell on two or more occasions in a one-year prospective period had significantly reduced and more variable cadence and significantly increased stance duration (measured in absolute terms and as a percentage of stride) than those who did not fall or fell on one occasion only. The study findings elucidate the relative importance of specific physiological systems in the maintenance of normal gait and identify temporal gait measures that are associated with falling in older people.

Fitzpatrick RC, Wardman DL, Taylor JL. Effects of galvanic vestibular stimulation during human walking. Journal of Physiology 1999; 517:931-939. PDF

1. To identify vestibular influences on human walking, galvanic vestibular stimulation was applied to normal adult subjects as they walked to a previously seen target. A transmastoidal step stimulus commenced as subjects started walking. With the eyes shut, the galvanic stimulus caused large turns towards the side with the anodal current. 2. Ability to perceive the trajectory of gait without visual cues was measured by guiding blindfolded subjects from one arbitrary point to another, either walking or seated in a wheelchair. On reaching a destination position and removing the blindfold, subjects pointed to indicate the starting position. Subjects made considerable errors in estimating the trajectory, but were equally accurate whether in the wheelchair or walking. 3. To determine the effects of vestibular stimulation on the perception of trajectory, the galvanic stimulus was applied to blindfolded subjects as they were guided from one point to another in the wheelchair. The vestibular stimulus produced an illusory shift in the trajectory traveled. This shift was towards the side with the cathode, i.e. in the opposite direction to the turn produced by the stimulus during walking. 4. We conclude that galvanic vestibular stimulation during walking causes subjects to turn from their planned trajectory. In part, this altered course may compensate for an altered perception of trajectory produced by the stimulus. However, altered perception of the vertical or the base of support, or direct vestibulo-fugal influences on the leg muscles could contribute to the changes in gait.

Lord SR, Menz HB. Physiologic, psychologic, and health predictors of 6-minute walk performance in older people. Archives of Physical Medicine and Rehabilitation 2002;83:907-11.PDF

OBJECTIVE: To determine the extent to which physiologic, psychologic, and health-related factors predict 6-minute walk distance (6MWD) in older people. DESIGN: Cross-sectional study. SETTING: Retirement villages. PARTICIPANTS: A total of 515 people between the ages of 62 and 95 years (mean +/- standard deviation, 79.5+/-6.4y) residing in retirement villages in Australia. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Quantitative tests of vision, strength, peripheral sensation, reaction time, and balance and short Mini-Mental State Examination, Geriatric Depression Scale, Positive and Negative Affect Schedule (PANAS), Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), and 6MWD. RESULTS: All physiologic, psychologic, and health scores were significantly associated with 6MWD. Multiple regression analysis revealed that 10 factors (visual contrast sensitivity, lower-limb strength, simple reaction time, postural sway, maximal balance range, PANAS positive scale score, SF-36 pain score, number of medications used, SF-36 general health subscale score, age) were significant and independent predictors of 6MWD performance. Of these measures, strength, maximal balance range, medication use, and age explained the largest proportions of the variance in 6MWD. The final regression model explained over half (52.5%) of the variance in 6MWD (multiple r=.72). CONCLUSIONS: In older people, 6MWD depends on multiple physiologic, psychologic, and health factors. Thus, 6MWD appears to provide a measure of overall mobility and physical functioning in this population group rather than a specific measure of cardiovascular fitness.

Menz HB, Lord SR, Fitzpatrick RC. Acceleration patterns of the head and pelvis when walking on level and irregular surfaces. Gait and Posture 2003 (in press).

The aim of this study was to evaluate acceleration patterns at the head and pelvis while subjects walked on a level and an irregular walking surface, in order to develop an understanding of how the postural control system responds to challenging walking conditions. Thirty young, healthy subjects walked on a level corridor and on artificial grass underlain with foam and wooden blocks placed in an arbitrary manner. Temporo-spatial gait parameters and acceleration patterns at the head and pelvis were measured. The results revealed that when walking on the irregular surface, subjects were able to maintain their velocity, but adopted a slower and more variable cadence and a significantly longer stride length. The magnitude of pelvis accelerations increased, however head accelerations were not affected by the walking surface. When considered as an overall pattern of movement, these findings suggest that one of the primary objectives of the postural control system when walking on irregular surfaces is head control, and that subjects adapt their stepping pattern on irregular surfaces to ensure that the head remains stable.  

Menz HB, Lord SR, Fitzpatrick RC. Age-related differences in walking stability. Age and Ageing 2003;32:137-142.PDF

Background: A large proportion of falls in older people occur when walking, however the mechanisms underlying impaired balance during gait are poorly understood. Objective: To evaluate acceleration patterns at the head and pelvis in young and older subjects when walking on a level and an irregular walking surface, in order to develop an understanding of how ageing affects postural responses to challenging walking conditions. Methods: Temporo-spatial gait parameters and variables derived from acceleration signals were recorded in thirty young people aged 22 to 39 years (mean 29.0, SD 4.3), and thirty older people with a low risk of falling aged 75 to 85 years (mean 79.0, SD 3.0) while walking on a level and an irregular walking surface. Subjects also underwent tests of vision, sensation, strength, reaction time and balance. Results: Older subjects exhibited a more conservative gait pattern, characterised by reduced velocity, shorter step length and increased step timing variability. These differences were particularly pronounced when walking on the irregular surface. The magnitude of accelerations at the head and pelvis were generally smaller in older subjects, however the smoothness of the acceleration signals did not differ between the two groups. Older subjects performed worse on tests of vision, peripheral sensation, strength, reaction time and balance. Conclusion: The adoption of a more conservative basic gait pattern by older people with a low risk of falling reduces the magnitude of accelerations experienced by the head and pelvis when walking, which is likely to be a compensatory strategy to maintain balance in the presence of age-related deficits in physiological function, particularly reduced lower limb strength.

Menz HB, Lord SR, Fitzpatrick RC. Acceleration patterns of the head and pelvis when walking are associated with risk of falling in community-dwelling older people. Journal of Gerontology; 58(5):M446-52. PDF

Background. A large proportion of falls in older people occur when walking, however the mechanisms underlying impaired balance during gait are poorly understood. This study evaluated acceleration patterns of the head and pelvis when walking on a level and an unpredictably irregular surface to determine whether older people at risk of falling demonstrate an impaired ability to stabilise the body under challenging conditions. Methods. One hundred community-dwelling older people aged between 75 and 93 years were evaluated for their risk of falling using a range of physiological tests previously found to be accurate predictors of falling in prospective studies. Temporo-spatial gait parameters and acceleration patterns at the head and pelvis were then measured in three orthogonal planes while subjects walked on a flat corridor and an unpredictably irregular walkway. Harmonic ratios of head and pelvis accelerations in each plane were calculated to provide an indicator of stability. Results. Subjects with a high risk of falling exhibited reduced temporo-spatial gait parameters and increased step timing variability. Harmonic ratios of acceleration patterns were reduced at the head and pelvis in the vertical and antero-posterior directions. These differences were particularly evident when walking on the irregular surface. Conclusion. Older people at risk of falling adopt a more conservative basic walking pattern, but this does not ensure that the movements of the head and pelvis are stable. The irregular pelvis and head accelerations evident in the high risk group suggests that these subjects may have difficulty controlling trunk motion and maintaining a stable visual field when walking, particularly on irregular terrain.

Menz HB, Lord SR, St George R, Fitzpatrick RC. Walking stability and sensorimotor function in older people wtih diabetic peripheral neuropathy. Arch Phys Med Rehabil 2004; 85: 245-52. PDF

Objective: To evaluate, in older people with diabetic peripheral neuropathy (DPN) and in age-matched controls, acceleration patterns of the head and pelvis when walking to determine the effect of lower-limb sensory loss on walking stability. Design: Case-control study. Setting: Falls and balance laboratory in Australia. Participants: Thirty persons with diabetes mellitus (age range, 55–91y) and 30 age-matched controls. Interventions: Acceleration patterns of the head and pelvis were measured while participants walked on a level surface and an irregular walkway. Participants also underwent tests of vision, sensation, strength, reaction time, and balance. Main outcome measures: Temporospatial gait parameters and variables derived from acceleration signals. Results: Participants with DPN had reduced walking speed, cadence, and step length, and less rhythmic acceleration patterns at the head and pelvis compared with controls. These differences were particularly evident when participants walked on the irregular surface. Participants with DPN also had impaired peripheral sensation, reaction time, and balance. Conclusions: Older people with DPN have an impaired ability to stabilize their body when walking on irregular surfaces, even if they adopt a more conservative gait pattern. These results provide further insights into the role of peripheral sensory input in the control of gait stability, and suggest possible mechanisms underlying the increased risk of falling in older people with diabetic neuropathy.

Menz HB, Latt M, Tiedemann A, Kwan M, Lord SR. Reliability of the GAITRite® walkway system for the quantification of temporo-spatial parameters of gait in young and older people. Gait and Posture 2004; 20:20-25. PDF

The purpose of this study was to evaluate the test-retest reliability of an instrumented walkway system (the GAITRite mat) for the measurement of temporal and spatial parameters of gait in young and older people. Thirty young subjects (12 males, 18 females) aged between 22 and 40 years (mean 28.5, S.D. 4.8) and 31 older subjects (13 males, 18 females) aged between 76 and 87 years (mean 80.8, S.D. 3.1) walked at a self-selected comfortable walking speed across the pressure-sensor mat three times and repeated the process approximately 2 weeks later. Intra-class correlation coefficients (ICC), coefficients of variation (CV) and 95% limits of agreement were then determined. For both groups of subjects, the reliability of walking speed, cadence and step length was excellent (ICCs between 0.82 and 0.92 and CVs between 1.4 and 3.5%). Base of support and toe in/out angles, although exhibiting high ICCs, were associated with higher CVs (8.3-17.7% in young subjects and 14.3-33.0% in older subjects). It is concluded that the GAITRite mat exhibits excellent reliability for most temporo-spatial gait parameters in both young and older subjects, however, base of support and toe in/out angles need to viewed with some caution, particularly in older people.

Menz HB, Lord SR. Gait Instability in Older People with Hallux Valgus. Foot & Ankle International. 2005; 26(6):483-489. PDF

Background: Hallux valgus is a common condition that may lead to considerable pain and disability. There is also evidence that hallux valgus may impair balance and increase the risk of falling in older people. Although a number of plantar pressure studies have been undertaken in people with and without hallux valgus, little is known about how hallux valgus affects basic gait patterns or the movement of the upper body when walking. Methods: Measurements of temporospatial parameters of gait and acceleration patterns of the head and pelviswere obtained in 71 people (24 men, 47 women) between 75 and 93 (mean 80 ± 4) years of age when walking on both a level surface and a specially designed irregular walkway. Foot problems, vision, peripheral sensation, strength, and reaction time alsowere evaluated. Results: After adjusting for potential confounders, subjects with moderate to severe hallux valgus were found to exhibit significantly reduced velocity and step length on both walking surfaces and less rhythmic acceleration patterns in the vertical plane when walking on the irregular surface compared to subjects with no or mild hallux valgus. Conclusion: These findings indicate that hallux valgus has a significant detrimental impact on gait patterns that may contribute to instability and risk of falling in older people, particularly when walking on irregular terrain.

Anne Tiedemann, Catherine Sherrington, Stephen R. Lord. Physiological and Psychological Predictors of Walking Speed in Older Community-Dwelling People. Gerontology 2005;51:390–395. PDF

Background: Six-metre walking speed (SMWS) is a commonly used test for measuring functional performance in older people. However, apart from lower limb strength, few studies have examined the range of physiological and psychological factors that influence performance in this test. Objective: To investigate the relative contributions of a range of sensoriomtor, balance and psychological factors to SMWS in a large sample of older people. Methods: 668 community-dwelling people aged 75–98 years (mean age 80.1, SD = 4.4) underwent the SMWS test as well as quantitative tests of vision, peripheral sensation, strength, reaction time, balance, fear of falling, pain and vitality. Results: Many physiological and psychological factors were significantly associated with SMWS in univariate analyses. Stepwise multiple regression analyses revealed that a composite lower limb strength measure (sum of knee extension, knee flexion and ankle dorsiflexion muscle strength scores), postural sway, leaning balance as assessed with the coordinated stability test, reaction time, edge contrast sensitivity, SF12 body pain and vitality scores and age were significant and independent predictors of SMWS. Of these measures, the combined lower limb strength measure had the highest beta weight indicating it was the most important variable in explaining the variance in SMWS. However, the other sensorimotor, balance and psychological measures each provided important independent information. The combined set of variables explained 40% of the variance in SMWS (multiple r = 0.63). Conclusions: The findings indicate that in community-dwelling older people, self-selected walking speed is influenced not only by lower limb strength but also by balance, reaction time, vision, pain and emotional well-being.

Hylton B. Menz, Stephen R. Lord, Richard C. Fitzpatrick. A structural equation model relating impaired sensorimotor function, fear of falling and gait patterns in older people. Gait Posture. 2006 May 11;XX-XX.

Many falls in older people occur while walking, however the mechanisms responsible for gait instability are poorly understood. Therefore, the aim of this study was to develop a plausible model describing the relationships between impaired sensorimotor function, fear of falling and gait patterns in older people. Temporo-spatial gait parameters and acceleration patterns of the head and pelvis were obtained from 100 community-dwelling older people aged between 75 and 93 years while walking on an irregular walkway. A theoretical model was developed to explain the relationships between these variables, assuming that head stability is a primary output of the postural control system when walking. This model was then tested using structural equation modeling, a statistical technique which enables the testing of a set of regression equations simultaneously. The structural equation model indicated that: (i) reduced step length has a significant direct and indirect association with reduced head stability; (ii) impaired sensorimotor function is significantly associated with reduced head stability, but this effect is largely indirect, mediated by reduced step length, and; (iii) fear of falling is significantly associated with reduced step length, but has little direct influence on head stability. These findings provide useful insights into the possible mechanisms underlying gait characteristics and risk of falling in older people. Particularly important is the indication that fear-related step length shortening may be maladaptive.

 

Sinnett PF, Lord SR. The ageing process and prevention. In Wahlqvist M.L. and Truswell A.S. Recent advances in clinical nutrition. John Libbey London, 1986.

Lord SR, Ward JA, Williams P, Strudwick M. Effect of exercise on balance and related factors in older women: a randomized controlled trial, in Taguchi K, Igarashi M and Mori S. Vestibular and Neural Front. Elsevier Press, Amsterdam, 1994.

Lord SR. Postural Stability and Falls in the Elderly. In Lafont C. et al (Eds). Facts and Research in Gerontology: Falls, Gait and Balance Disorders in the Elderly. Springer Publishing Company, 1996.

Lord SR, St George RJ. Neuropsychological, Sensory and Motor Changes with Ageing. In Sachdev PS (Ed). The Ageing Brain. Swets and Zeitlinger, The Netherlands, 2003.

Other publications

Lord SR, Sherrington C, Menz HB. Falls in older people - methodological considerations. Australasian Epidemiologist 2000;7:13-17.

Lord SR, Sherrington C. NHMRC health research partnership: Prevention of injuries in older people. NSW Public Health Bulletin 2002; 13: 21-22.PDF

Allen GM, Middleton J, Katrak PH, Lord SR, Gandevia SC. Prediction of voluntary activation, strength and endurance of elbow flexors in post-polio patients. Muscle and Nerve. 2004;30(2):172-81. PDF

Mathie MJ, Coster ACF, Lovell NH, Celler BG, Lord SR, Tiedemann A. A Pilot Study of Long Term Monitoring of Human Movements in the Home Using Accelerometry. Journal of Telemedicine and Telecare 2004;10:144-151.

Sitoh YY, Lau TC, Zochling J, Schwarz J, Chen JS, March LM, Cumming RG, Lord SR, Sambrook PN, Cameron ID. Determinants of health-related quality of life in institutionalised older persons in northern Sydney. Internal Medicine Journal 2005;35:131–134. PDF

Liu-Ambrose TYL, Khan KM, Eng JJ, Lord SR, Lentle B, McKay HA. Both resistance and agility training reduce back pain and improve quality of life in older women with low bone mass. Osteoporosis International 2005 Nov;16(11):1321-9.