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Biomedical subjects

Stephen R Lord

Publications and source records attributed to Stephen R Lord.

At least 19 recordsLinked to original sources
PubMed2006

A tactile stimulus applied to the leg improves postural stability in young, old and neuropathic subjects.

The purpose of this study was to determine whether the application of passive tactile cues to the lower limb could improve postural stability in healthy young controls, older people and people with diabetic peripheral neuropathy. Antero-posterior sway was measured with eyes open and closed in 10 healthy young subjects (mean age 27 years, 5 male, 5 female), 10 older subjects without diabetic peripheral neuropathy (mean age 88 years, 2 male, 8 female) and 10 subjects with diabetic peripheral neuropathy (mean age 65 years, 6 male, 4 female) while a small piece of Velcro attached to a flexible mount was applied to three different sites on the leg (ankle, calf, and knee). Across all conditions, the mean sway of the neuropathic subjects was 93% greater than for the young subjects and 11% more than the older subjects. On average, subjects swayed 10% more with the eyes closed than with the eyes open. Each stimulus reduced sway, but the effect increased approximately in proportion to the height of the stimulus above the ankles (ankle 7.6%, calf 13.5%, knee 20.1% reduction compared to the no stimulus condition). This experiment demonstrates that a passive stimulus applied to the skin of the leg, which provides sensory information about body movement, significantly reduces body sway during standing. This applies to older subjects and subjects with peripheral neuropathy as well as healthy young subjects. These results have implications for novel approaches for improving stability in people with peripheral sensory loss.

Adult↗
PubMed2006

A structural equation model relating impaired sensorimotor function, fear of falling and gait patterns in older people.

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.

Accidental Falls↗
PubMed2006

High bone turnover is an independent predictor of mortality in the frail elderly.

UNLABELLED: Osteoporotic fractures are associated with accelerated bone turnover and excess mortality. In a prospective study of 1112 frail subjects (79% female; mean age, 86 years), high bone turnover was an independent predictor of all-cause mortality. This association seemed to be mainly manifested in deaths from cardiovascular causes. INTRODUCTION: Osteoporotic fractures are associated with accelerated bone turnover and excess mortality. In a prospective cohort study of elderly men and women, we assessed whether the rate of bone turnover measured by markers of bone remodeling is a direct predictor of mortality. MATERIALS AND METHODS: We measured serum concentrations of the aminoterminal propeptide of type I collagen (PINP), a marker of bone formation, and of the carboxyterminal telopeptide of type I collagen (CTX-I), a marker of bone resorption, along with serum PTH and 25-hydroxyvitamin D [25(OH)D] levels in 1112 subjects (79% female; mean age, 86 years) living in residential care. Co-morbidity was measured using the Implicit Illness Severity Scale. Fracture data were validated by a radiology report. Mortality and causes of death were ascertained from death certificates. RESULTS: Over a median follow-up of 817 days, 559 (50.3%) subjects died. In univariate analyses, time to death from all causes was significantly (p < 0.01) associated with age (HR = 1.62 per 10 years), male sex (HR = 1.33), immobility (HR = 1.94), co-morbidity (HR = 0.31, mild versus severe), lower weight (HR = 0.83 per 10-kg increase), impaired cognitive function (HR = 2.14, severe versus normal), number of medications (HR = 1.05 each), hip fracture (HR = 2.26), log serum creatinine (HR = 1.67), log PTH (HR = 1.29), CTX-I (HR = 1.70, highest 25% versus lowest 75%), and PINP (HR = 1.46, highest 25% versus lowest 75%). In multivariate analysis adjusting for age, sex, immobility, co-morbidity, weight, cognitive function, number of medications, PTH, and hip fracture status, the highest quartile was significantly more likely to die than the rest for both serum CTX-I (HR = 1.39; 95% CI: 1.14-1.70; p = 0.002) and PINP (HR = 1.25; 95% CI: 1.02-1.52; p = 0.03). For individual causes of death, CTX-I was significantly associated with deaths from cardiac causes (HR = 1.78: 95% CI: 1.27-2.50; p < 0.001). CONCLUSIONS: We conclude that in the frail elderly, high bone turnover is associated with all cause mortality independently of age, sex, health status, serum PTH levels, and hip fracture status. The mechanism of the effect of bone turnover on mortality seems to be mainly manifested in deaths from cardiovascular causes.

Aged↗
PubMed2006

The effect of cataract surgery on neuropsychological test performance: a randomized controlled trial.

Recent cross-sectional studies have reported strong associations between visual and cognitive function, and longitudinal studies have shown relationships between visual and cognitive decline in late life. Improvement in cognitive performance after cataract surgery has been reported in patients with Mild Cognitive Impairment. We investigated whether improving visual function with cataract surgery would improve neuropsychological performance in healthy older adults. A randomized clinical trial of cataract surgery performed at acute hospitals was conducted on 56 patients (mean age 73) with bilateral cataract, after excluding a total of 54 patients at the screening stage, of whom 53 did not meet visual acuity criteria and one did not have cataract. In-home assessments included visual and neuropsychological function, computerized cognitive testing and health questionnaires. Results showed no cognitive benefits of cataract surgery in cognitively normal adults. We conclude that visual improvement following cataract surgery is not strongly associated with an improvement in neuropsychological test performance in otherwise healthy adults. Joint associations between visual and cognitive function in late life are likely to be due to central factors, and unlikely to be strongly related to eye disease. Short-term increased neural stimulation from improved visual function does not appear to affect cognitive performance.

Aged↗
PubMed2006

Visual risk factors for falls in older people.

Poor vision reduces postural stability and significantly increases the risk of falls and fractures in older people. Most studies have found that poor visual acuity increases the risk of falls. However, studies that have included multiple visual measures have found that reduced contrast sensitivity and depth perception are the most important visual risk factors for falls. Multifocal glasses may add to this risk because their near-vision lenses impair distance contrast sensitivity and depth perception in the lower visual field. This reduces the ability of an older person to detect environmental hazards. There is now evidence that maximising vision through cataract surgery is an effective strategy for preventing falls. Further randomised controlled trials are required to determine whether individual strategies (such as restriction of use of multifocal glasses) or multi-strategy visual improvement interventions can significantly reduce falls in older people. Public health initiatives are required to raise awareness in older people and their carers of the importance of regular eye examinations and use of appropriate prescription glasses.

Accidental Falls↗
PubMed2006

Home environment risk factors for falls in older people and the efficacy of home modifications.

Most homes contain potential hazards, and many older people attribute their falls to trips or slips inside the home or immediate home surroundings. However, the existence of home hazards alone is insufficient to cause falls, and the interaction between an older person's physical abilities and their exposure to environmental stressors appears to be more important. Taking risks or impulsivity may further elevate falls risk. Some studies have found that environmental hazards contribute to falls to a greater extent in older vigorous people than in older frail people. This appears to be due to increased exposure to falls hazards with an increase in the proportion of such falls occurring outside the home. There may also be a non-linear pattern between mobility and falls associated with hazards. Household environmental hazards may pose the greatest risk for older people with fair balance, whereas those with poor balance are less exposed to hazards and those with good mobility are more able to withstand them. Reducing hazards in the home appears not to be an effective falls-prevention strategy in the general older population and those at low risk of falls. Home hazard reduction is effective if targeted at older people with a history of falls and mobility limitations. The effectiveness may depend on the provision of concomitant training for improving transfer abilities and other strategies for effecting behaviour change.

Accidental Falls↗
PubMed2006

Falls-related self-efficacy is independently associated with balance and mobility in older women with low bone mass.

BACKGROUND: It is currently unknown whether falling is independently associated with measures of balance and mobility in older adults after accounting for relevant physiological functions. This cross-sectional study assessed the independent association of falls-related self-efficacy to balance and mobility after accounting for age, current physical activity, and performances in relevant physiological domains in 98 older women, aged 75-86 years, with low bone mass. METHODS: Falls-related self-efficacy was assessed by the Activities-Specific Balance Confidence Scale (ABC Scale). Measures of balance and mobility included the 13-item Community Balance and Mobility Scale (CB & M Scale) and gait speed under two conditions: normal-paced and fast-paced. Physiological assessment included postural sway, foot reaction time, dominant quadriceps and dorsiflexor strength, proprioception, tactile sensitivity, edge contrast sensitivity, and visual acuity. RESULTS: Falls-related self-efficacy was independently associated with both balance and mobility after accounting for age, current physical activity level, and performances in relevant physiological domains. Based on the standardized beta coefficients, the ABC Scale score was more associated with measures of balance and mobility than measures of physiological function. CONCLUSION: These results highlight the independent association of falls-related self-efficacy with physical performance in older women with low bone mass. Thus, clinicians may need to consider falls-related self-efficacy when assessing and treating balance and mobility in this population, and falls-related self-efficacy may be useful as a screening tool to identify those persons with impaired balance and mobility.

Accidental Falls↗
PubMed2006

Foot and ankle risk factors for falls in older people: a prospective study.

BACKGROUND: Foot problems are common in older people and are associated with impaired balance and functional ability. Few prospective studies, however, have been undertaken to determine whether foot problems are a risk factor for falls. METHODS: One hundred seventy-six people (56 men and 120 women, mean age 80.1, 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) and physiological falls risk factors (including vision, sensation, strength, reaction time, and balance) and were followed for 12 months to determine the incidence of falls. RESULTS: Seventy-one participants (41%) reported falling during the follow-up period. Compared to those who did not fall, fallers exhibited decreased ankle flexibility, more severe hallux valgus deformity, decreased plantar tactile sensitivity, and decreased toe plantarflexor strength; they were also more likely to have disabling foot pain. Discriminant function analysis revealed that decreased toe plantarflexor strength and disabling foot pain were significantly and independently associated with falls after accounting for physiological falls risk factors and age. CONCLUSIONS: Foot and ankle problems increase the risk of falls in older people. Interventions to address these factors may hold some promise as a falls prevention strategy.

Accidental Falls↗
PubMed2006

The impact of cataract surgery on visual functioning, vision-related disability and psychological distress: a randomized controlled trial.

PURPOSE: Determine whether there are changes in visual functioning, vision-related disability, health status and mood after cataract surgery. METHODS: 45 adults (mean age = 73.7 years) with bilateral cataract needing surgery for the first eye were recruited from public ophthalmology clinics. The Visual Functioning-14 survey assessed visual disability. Minimal angle of resolution tested visual acuity, and the Melbourne Edge Test examined contrast sensitivity. Demographic, psychological, health and medication use variables were examined. Participants were randomized to either an intervention or control arm. Controls were assessed on two occasions at a 3-month interval before having surgery. The intervention group was assessed 1-2 weeks before surgery and then reassessed 3 months after surgery. RESULTS: Visual functioning improved for those who had cataract surgery with better visual acuity in the better (P = 0.010) and worse (P = 0.028) eye compared with controls. The intervention group reported fewer difficulties with overall vision-related disability (P = 0.0001), reading (P = 0.004) and instrumental activities of daily living (P = 0.010) post-surgery compared with controls. People with improved depression scores (P = 0.048) after surgery had less difficulty with reading compared with those with unchanged or worsened depression scores. Cataract surgery did not improve health status. CONCLUSIONS: First eye cataract surgery is effective in improving outcomes in visual functioning and disability. Improved mood after surgery was related to less vision-related disability compared with unchanged or worse depression.

Aged↗
PubMed2006

Footwear characteristics and risk of indoor and outdoor falls in older people.

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 contributed to their fall. CONCLUSION: Footwear characteristics were not significantly associated with falls either inside or outside the home. Risk of falling indoors was associated with going barefoot or wearing socks. Older people at risk of falling should therefore be advised to wear shoes indoors where possible.

Accidental Falls↗
PubMed2005

Effect of age-related chronic immobility on markers of bone turnover.

UNLABELLED: The effects of acute immobilization on bone turnover are well known, but the effects of chronic hypomobility with aging have not been studied. In a cohort of 1064 frail elderly subjects, immobility was significantly associated with serum PINP but not serum CTx after adjusting for confounders. The effect of immobility may be more marked on bone formation than on bone resorption. INTRODUCTION: Accelerated bone turnover and rapid bone loss caused by acute immobilization is well recognized, but the effects of age-related chronic reduction in mobility on bone turnover have been less well studied. We assessed the associations between bone turnover and measures of mobility in a cohort of elderly subjects. MATERIALS AND METHODS: We measured serum levels of the aminoterminal propeptide of type I collagen (PINP), a marker of bone formation, and serum concentrations of the carboxyterminal telopeptide of type I collagen (CTx), a marker of bone resorption, as well as serum intact PTH, serum 25 hydroxyvitamin D (25OHD), mobility, and static balance in a well-characterized sample of 1064 elderly men and women living in residential aged care facilities. Serum creatinine, phosphate, albumin, and calcium were measured in a randomly selected subgroup of 447 subjects. RESULTS: The subjects were elderly and frail; their mean age was 86.0 years (range, 65-101 years); 69% used a walking aid; and 77% were vitamin D deficient (serum 25OHD level < 39 nM). Both serum PINP and CTx increased with age in both sexes. Elevated PINP or CTx was significantly correlated with high PTH, creatinine, and albumin in both genders, except for albumin in women. Age- and gender-adjusted serum CTx and PINP were significantly higher in those with poorer mobility and those with worse static balance. In multivariate analyses, higher serum PINP but not CTx was associated with poorer mobility and worse static balance. CONCLUSIONS: Our findings suggest that poor mobility contributes to the state of accelerated bone turnover usually seen in the elderly. The effect of chronic relative immobility may be more marked on bone formation than bone resorption.

Age Factors↗
PubMed2005

Foot and leg problems are important determinants of functional status in community dwelling older people.

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 random sample of 1000 community-dwelling people aged 65 - 94 years (533 females, 467 males, mean age 73.4 years +/- 5.87). A structured interview and brief physical examination were used to investigate the associations between self-reported foot and 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 with foot and leg problems were significantly more likely to exhibit poorer functional status in all parameters measured. After adjusting for socio-demographic, physical and medical factors, foot and leg problems remained significantly associated with impaired timed 'Up & Go' performance (OR = 2.15, 95%CI 1.55 - 2.97), difficulty climbing stairs (OR = 3.33, 95%CI 1.98 - 5.61), difficulty walking one kilometer (OR = 3.13, 95%CI 2.09 - 4.69), and history of falling (OR = 1.73, 95%CI 1.26 - 2.37). CONCLUSIONS: Foot and leg problems are reported by one in three community-dwelling people aged 65 years and older. Independent of the influence of age, gender, common medical conditions and other socio-demographic factors, foot and leg problems have a significant impact on the ability to perform functional tasks integral to independent living.

Accidental Falls↗
PubMed2005

Both resistance and agility training reduce back pain and improve health-related quality of life in older women with low bone mass.

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 health-related 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 health-related 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.

Aged↗
PubMed2005

Streamlining assessment and intervention in a falls clinic using the Timed Up and Go Test and Physiological Profile Assessments.

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.

Accidental Falls↗
PubMed2005

Foot and ankle characteristics associated with impaired balance and functional ability in older people.

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.

Aged↗
PubMed2005

Atypical antipsychotic medications and risk of falls in residents of aged care facilities.

OBJECTIVES: To determine whether use of atypical antipsychotics (olanzapine and risperidone) is associated with lower risk of falls than use of typical antipsychotics. DESIGN: Prospective cohort study with 1-month follow-up. SETTING: Residential aged care facilities in Sydney, Australia. PARTICIPANTS: Two thousand five people aged 65 to 104 (mean age 86). MEASUREMENTS: Medication use at baseline was collected from medical records. Data on potential confounders were collected at interview and physical examination and from medical records. The outcome was accidental falls (one or more). RESULTS: One thousand one hundred seven subjects (55%) used at least one type of psychotropic medication, with 289 (14%) using an antipsychotic. There were 82 olanzapine users, 38 risperidone users, and 181 users of typical antipsychotics. Eleven percent of subjects (n=226) had at least one fall during follow-up. After adjusting for a comprehensive range of falls risk factors, hazard ratios (HRs) for falls were 1.35 (95% confidence interval (CI)=0.87-2.09) for typical antipsychotics, 1.32 (95% CI=0.57-3.06) for risperidone, and 1.74 (95% CI=1.04-2.90) for olanzapine. Antidepressants were also associated with falls (adjusted HR=1.45, 95% CI=1.09-1.93). CONCLUSION: Despite fewer extrapyramidal side effects, atypical antipsychotic medications are not associated with fewer falls than the older, more-established antipsychotics.

Accidental Falls↗
PubMed2005

The effect of an individualized fall prevention program on fall risk and falls in older people: a randomized, controlled trial.

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; the minimal 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.

Accidental Falls↗