Allometric analysis of physical performance measures in older adults

BACKGROUND AND PURPOSE: Body mass is a confounding variable in human performance, and adjusting physical performance measures for body mass differences would allow meaningful individual and group comparisons. The purpose of this study was to allometrically determine the relationship between body mass and handgrip and ankle dorsiflexor performance on the Timed "Up & Go" Test (TUGT). SUBJECTS: One hundred thirty-one subjects (33 male and 98 female) participated. METHODS: All physical performance measures were adjusted for the influence of body mass, sex, and age using an allometric scaling procedure. RESULTS: For handgrip force, the body mass exponent from allometric analysis was 0.63. For the TUGT, the body mass exponent was 0.073. For ankle dorsiflexor force and torque, the body mass exponents were 0.82 and 0.91, respectively. DISCUSSION AND CONCLUSION: The body mass exponents for handgrip force and the TUGT agree with previous clinical data and theoretical expectations. Studies investigating normalized handgrip force in older adults should consider an allometric scaling approach.     

Venous thromboembolism knowledge among older post-hip fracture patients and their caregivers

Patient education about venous thromboembolism (VTE) prevention is needed to prevent complications and costly re-hospitalization. Nurses are uniquely positioned to provide vital education as patients transition from the inpatient setting to after discharge. Still, little is known about patient knowledge deficits and those of their caregivers. The purpose of this study was to explore VTE prevention knowledge in a sample of older hip fracture patients and family caregivers. At the time of hospital discharge, surveys were completed by hip fracture surgery patients (≥65; n = 30) and family caregivers (n = 30). Participants reported needs for more prophylactic anticoagulation and side effects education. Mean education satisfaction was 3.49 out of 5 among patients and 3.83 among caregivers. Focused patient education regarding the wisdom of VTE prevention, potential risks involved, and patient and caregiver roles in advocating for better prevention measures is needed for these patients at risk for hospital readmission secondary to VTE.     

Leg preference associated with protective stepping responses in older adults

Background

Asymmetries in dynamic balance stability have been previously observed. The goal of this study was to determine whether leg preference influenced the stepping response to a waist-pull perturbation in older adult fallers and non-fallers.

Methods

39 healthy, community-dwelling, older adult (> 65 years) volunteers participated. Participants were grouped into non-faller and faller cohorts based on fall history in the 12 months prior to the study. Participants received 60 lateral waist-pull perturbations of varying magnitude towards their preferred and non-preferred sides during quiet standing. Outcome measures included balance tolerance limit, number of recovery steps taken and type of recovery step taken for perturbations to each side.

Findings

No significant differences in balance tolerance limit (P ≥ 0.102) or number of recovery steps taken (η²_partial ≤ 0.027; P ≥ 0.442) were observed between perturbations towards the preferred and non-preferred legs. However, non-faller participants more frequently responded with a medial step when pulled towards their non-preferred side and cross-over steps when pulled towards their preferred side (P = 0.015).

Interpretation

Leg preference may influence the protective stepping response to standing balance perturbations in older adults at risk for falls, particularly with the type of recovery responses used. Such asymmetries in balance stability recovery may represent a contributing factor for falls among older individuals and should be considered for rehabilitation interventions aimed at improving balance stability and reducing fall risk.     

Lower-extremity biomechanics during forward and lateral stepping activities in older adults

OBJECTIVE: To characterize the lower-extremity biomechanics associated with stepping activities in older adults. DESIGN: Repeated-measures comparison of kinematics and kinetics associated with forward step-up and lateral step-up activities. BACKGROUND: Biomechanical analysis may be used to assess the effectiveness of various 'in-home activities' in targeting appropriate muscle groups and preserving functional strength and power in elders. METHODS: Data were analyzed from 21 participants (mean 74.7 yr (standard deviation, 4.4 yr)) who performed the forward and lateral step-up activities while instrumented for biomechanical analysis. Motion analysis equipment, inverse dynamics equations, and repeated measures ANOVAs were used to contrast the maximum joint angles, peak net joint moments, angular impulse, work, and power associated with the activities. RESULTS: The lateral step-up resulted in greater maximum knee flexion (P<0.001) and ankle dorsiflexion angles (P<0.01). Peak joint moments were similar between exercises. The forward step-up generated greater peak hip power (P<0.05) and total work (P<0.001); whereas, the lateral step-up generated greater impulse (P<0.05), work (P<0.01), and power (P<0.05) at the knee and ankle. CONCLUSIONS: In older adults, the forward step-up places greater demand on the hip extensors, while lateral step-up places greater demand on the knee extensors and ankle plantar flexors. RELEVANCE:Clinicians may use data from biomechanical analyses of in-home exercises to more effectively target specific lower-extremity muscle groups when prescribing exercise activities for older adults. The forward step-up is recommended for maintaining or improving hip extensor performance; whereas, the lateral step-up is recommended when targeting the knee extensors and ankle plantar flexors.     

Short-term changes in protective stepping for lateral balance recovery in older adults

Background

Fall prevention for older adults is dependent on the ability to maintain protective balance. This study measured the short-term changes of protective stepping following waist-pull perturbations in the medio-lateral direction, to identify what, if any, properties of protective stepping are improved with repeated perturbation exposures.

Methods

Sixty waist-pulls (2 directions × 5 intensities × 6 repetitions) from a single session were analyzed separately as early, middle, and late testing periods, for a comparison over time of typical responses. Outcome measures included the number of evoked steps, type of step, incidence of interlimb collisions, and kinematic and kinetic properties of the first step in frequently used crossover-type responses.

Findings

Improvements were evident as significantly reduced number of steps and collisions. However, these improvements could not be completely accounted for by significant changes in first step kinematic or kinetic properties.

Interpretation

We infer that older individuals experiencing repeated lateral waist-pull perturbations optimize the predictive or feed-forward motor control for balance recovery through stepping.     

Specificity of functional mobility measures in older adults after hip fracture: a pilot study

OBJECTIVE: To determine the relationships between measures of functional mobility (Timed Up and Go [TUG], Self-Paced Walking [SPW], Berg Balance Scale [BBS]) and global functional status (FIM trade mark instrument), the motor component of the FIM instrument (motor FIM), and the mobility/locomotor-specific FIM component (ML-FIM) in older patients admitted to an inpatient rehabilitation program after hip fracture. DESIGN: The TUG, SPW, BBS, and FIM instrument were administered within 24 hr after admission and before discharge to 20 patients undergoing inpatient rehabilitation after a hip fracture. RESULTS: Significant correlations at admission were found between FIM and TUG scores (r = -0.47; p < 0.05), TUG and motor FIM (r = -0.45; p < 0.05), TUG and ML-FIM (r = -0.58; p < 0.01), FIM and BBS (r = 0.60; p < 0.01), motor FIM and BBS (r = 0.50; p < 0.05), and ML-FIM and BBS (r = 0.45; p < 0.05). At discharge, a significant correlation was found between the motor FIM and SPW (r = -0.49; p < 0.05). Change scores between both the motor FIM and ML-FIM and TUG scores were significantly correlated (r = -0.47, p < 0.05, r = -0.50, p < 0.05, respectively). CONCLUSIONS: The FIM instrument, motor FIM, and ML-FIM may not be specific measures of functional mobility in patients with hip fracture.     

Evaluation of frailty in older adults with cardiovascular disease: incorporating physical performance measures

Rapid growth in the numbers of older adults with cardiovascular disease (CVD) is raising awareness and concern of the impact that common geriatric syndromes such as frailty may have on clinical outcomes, health-related quality of life, and rising economic burden associated with healthcare. Increasingly, frailty is recognized to be a highly prevalent and important risk factor that is associated with adverse cardiovascular outcomes. A limitation of previous studies in patients with CVD has been the lack of a consistent definition and measures to evaluate frailty. In this review, building upon the work of Fried and colleagues, a definition of frailty is provided that is applicable for evaluating frailty in older adults with CVD. Simple, well-established performance-based measures widely used in comprehensive geriatric assessment are recommended that can be readily implemented by nurses in most practice settings. The limited studies conducted in older adults with CVD have shown physical performance measures to be highly predictive of clinical outcomes. Implications for practice and areas for future research are described for the growing numbers of elderly cardiac patients who are frail frailty and at risk for disability.     

Bed mobility task performance in older adults

Difficulty in transferring, the ability to rise in and out of a bed and chair, is a common problem in older adults, particularly those residing in skilled nursing facilities. Focusing on one aspect of transferring, rising from supine to sitting position, we devised a set of bed mobility tasks to test key arm, leg, and trunk movements that likely contribute to successful rising from bed. Healthy young controls (YC, n=22, mean age 23), and older adults (aged 60 and over) either residing independently in congregate housing (CH, n=29, mean age 84) or undergoing rehabilitation in a skilled nursing facility (SNF, mean age 77) were assessed in the time to rise from supine to sitting and in the ability or inability to perform 16 other bed mobility tasks. Trunk function-related tasks, specifically those requiring trunk elevation and trunk balance, were most difficult for the SNF, followed by CH, and then YC. Tasks focusing on trunk flexion strength (sit up arms crossed, bilateral heel raise) and lateral trunk strength/balance were the most difficult for both SNF and CH, although there was minimal difference in the percent unable to complete each task. The major CH-SNF differences occurred in trunk elevation tasks where the upper limb was important in facilitating trunk elevation (sit up with head of bed elevation with use of arms, sit up with the use of a trapeze, or sit up with use of arms from a flat bed position). These findings suggest that to improve frail older adult performance on bed mobility tasks, and specifically in rising from supine to sitting, training should move beyond improving trunk function (i.e., trunk strength). There should be an additional focus, either through therapy or bed design modifications, on how upper limb movements and positioning can be used to assist in trunk elevation.     

The influence of stimulus cue on the initiation of stepping in young and older adults

OBJECTIVES: To investigate the influence of different reaction stimulus cues on the characteristics of ground reaction forces during the initiation of rapid forward stepping, and to determine whether age-related differences in step initiation are influenced by the type of stimulus cue used to trigger stepping. DESIGN: Case-control study. SETTING: University-based research laboratory. PARTICIPANTS: Fifteen healthy younger adults and 35 community-dwelling older adult volunteers. MAIN OUTCOME MEASURES: Subjects performed forward step initiation in response to 3 different reaction stimulus cues (light, sound, electrocutaneous) during simple reaction-time conditions. Ground reaction force data were collected and used to characterize the timing and magnitude features of the postural (weight-transfer) and step components. RESULTS: In comparison with the light and sound stimuli, the nonnoxious electrocutaneous trigger cue was associated with an increase in the magnitude of the initial displacement of the center of pressure (COP) in the mediolateral direction. Overall, older subjects were slower to initiate the postural and step components, and displayed a reduction in the initial posterior displacement of the COP. CONCLUSIONS: The postural component for lateral weight transfer was augmented by the electrocutaneous trigger cue, suggesting its potential to enhance step initiation among clinical populations. Age-related changes in stepping were unaffected by the type of stimulus cue, but the older group had a slower response initiation time and less forward propulsion. The abilities of many older persons may be compromised in situations where rapid adjustments in the base of support through stepping are triggered by environmental stimuli.     

Development of a clinical Multiple-Lunge Test to predict falls in older adults

Wagenaar R, Keogh JW, Taylor D. Development of a clinical Multiple-Lunge Test to predict falls in older adults.ObjectiveTo develop a new Multiple-Lunge Test to distinguish between fallers and nonfallers in community-dwelling older adults.DesignA cross-sectional design was used to establish the sensitivity and specificity of the test to predict faller status based on retrospective self-reported fall history.SettingLocal retirement villages.ParticipantsCommunity-dwelling older adults (N=130; mean age ± SD, 77±7y) with (n=40) and without (n=90) a history of falls.InterventionsThe Multiple-Lunge Test required individuals to lunge forward to a step length determined as 60% of their leg length, and return to start, for 5 consecutive repetitions. Interday and intraday test-retest reliability of the Multiple-Lunge Test was established across 2 testing occasions.Main Outcome MeasuresNumber of steps performed correctly, total time to complete 5 steps.ResultsThe Multiple-Lunge Test was found to be reliable across trials (Intraday: intraclass correlation coefficient [ICC]=.79–.81 for steps, ICC=.86–.88 for time; Interday: ICC=.77 for steps; ICC=.84 for time). Sensitivity and specificity values were calculated as 73% and 63%, respectively, for predicting multiple fallers using the measure of all 5 steps done correctly.ConclusionsThe test is easily administered and because of its challenging nature, it may be well suited to detect subtle differences in abilities of higher functioning, community-dwelling older adults. A practitioner can be confident in 7 of 10 cases that an older adult who cannot complete all 5 steps of the Multiple-Lunge Test is at high risk of falls. The results suggest that there is potential for the Multiple-Lunge Test to be used in clinical practice; however, additional research on how to further increase its validity appears warranted.     

Personal factors,communication and vision predict social participation in older adults

Social isolation is a predictor of morbidity and mortality in older people. Speech pathologists often consider that communication disabilities associated with normal ageing (sensory loss, language and discourse changes) contribute to social isolation. The aims of this study were to describe the functioning of older people using the International Classification of Functioning, Disability and Health (WHO, ) as a conceptual framework for language and sensory functioning, communicative activity, and social participation, and to explore the relationship between communication (both at an impairment level and an activity level), social participation and personal factors (demographics and emotional health). In a prospective study, 47 women and 28 men aged 62 to 98 years (mean = 74 yrs) completed objective and subjective assessments of functioning and participation, and provided personal information. Assessments were individually conducted in a face-to-face interview situation with the primary researcher, who was a speech pathologist. Assessments revealed the sample had predominantly mild hearing and vision impairments, unimpaired naming ability, frequent involvement in a wide range of communication activities, and variable social network size and social activities participation. Social participation was shown to be associated with vision, communication activities, age, education and emotional health. Naming and hearing impairments were not reliable predictors of social participation. It was concluded that professionals interested in maintaining and improving social participation of older people could well consider these predictors in community-directed interventions. Speech pathologists should therefore promote older people's involvement in everyday communicative activities while also limiting the impact of communication-related impairments, so that social participation is maintained in our ageing population.     

Knee extensor isometric unsteadiness does not predict functional limitation in older adults

OBJECTIVE: To determine how knee extensor steadiness is related to age and difficulty performing everyday tasks. DESIGN: In this cross-sectional study performed at a research laboratory, 50 older adults (age range, (56-95 yrs) performed steadiness testing at 50% of maximum strength and were timed and rated on four tasks of daily living: chair rise, stair ascent and descent, and walk. The independent variables of age, steadiness, and strength-to-weight ratio were entered into regression models with the ratings and time to complete the four everyday tasks as dependent variables. RESULTS: The strength-to-weight ratio was the only significant predictor in the multiple regression models, explaining 29%, 33%, 14%, and 14% of the variance in gait speed and time to complete a chair rise, stair ascent, and stair descent, respectively. Similar results were seen with task ratings. Age was not correlated with steadiness (r = 0.25, P = 0.07). CONCLUSION: This study suggests that knee extensor isometric steadiness performance does not carry over to tasks of everyday living, and older subjects, regardless of age, have similar steadiness values. Because the strength-to-weight ratio predicted the most variance in functional performance, it is recommended that muscle strength be improved to increase function in older adults.     

Examining "success" in post-hip fracture care transitions: a strengths-based approach

Transitions between health care settings are a high-risk period for care quality and patient safety (Coleman, 2003; Picker Institute, 1999), particularly for older patients - such as those with hip fracture - who have complex needs and may undergo multiple care transitions. We sought to understand the key elements of "success" in care transition. Using a strengths-based perspective (Rapp, 1998; Saleebey, 2006), we focused on interprofessional health care providers' perspectives of what constitutes a "good" care transition for elderly hip fracture patients. As part of a larger ethnographic field study, semi-structured interviews were conducted with 17 health providers across a number of disciplines employed across the continuum of post-hip fracture management in British Columbia, Canada. We found two hallmarks of "success" in care transitions: a focus on process - information gathering and communication, and a focus on outcomes - autonomy and care pathways. Strategies for promoting and improving success, such as using practitioner-driven ground-up solutions to address challenges in care transitions, are highlighted.     

A novel video game--based device for measuring stepping performance and fall risk in older people

Schoene D, Lord SR, Verhoef P, Smith ST. A novel video game–based device for measuring stepping performance and fall risk in older people.

Objective

To determine whether a dance mat test of choice stepping reaction time (CSRT) is reliable and can detect differences in fall risk in older adults.

Design

Randomized order, crossover comparison.

Setting

Balance laboratory, medical research institute, and retirement village.

Participants

Older (mean age, 78.87±5.90y; range, 65–90y) independent-living people (N=47) able to walk in place without assistance.

Interventions

Not applicable.

Main Outcome Measures

Reaction (RT), movement, and response times of dance pad–based stepping tests, Physiological Profile Assessment (PPA) score, Digit Symbol Substitution Test (DSST) score, time to complete the Trail Making Test (TMT) A+B, Fall Efficacy Scale International (FES-I) score, Activities-specific Balance Confidence (ABC) Scale score, and Incidental and Planned Exercise Questionnaire (IPEQ) incidental IPEQ activity subscore.

Results

Test-retest reliability of the dance mat CSRT response time was high (intraclass correlation coefficient model 3,k=.90; 95% confidence interval [CI], .82–.94; P<.001) and correlated highly with the existing laboratory-based measure (r=.86; 95% CI, .75–.92; P<.001). Concurrent validity was shown by significant correlations between response time and measures of fall risk (PPA: r=.42; 95% CI, .15–.63; P<.01; TMT A: r=.61; 95% CI, .39–.77; TMT B: r=.55; 95% CI, .31–.72; DSST: r=−.53; 95% CI, −.71 to −.28; P<.001; FES-I: Spearman ρ=.50; 95% CI, .25–.69; ABC Scale: Spearman ρ=−.58; 95% CI, −.74 to −.35; P<.01). Participants with moderate/high fall-risk scores (PPA score >1) had significantly slower response times than people with low/mild fall-risk scores (PPA score <1) at 1146±182 and 1010±132ms, respectively (P=.005), and multiple fallers and single/nonfallers showed significant differences in RT (883±137 vs 770±100ms; P=.009) and response time (1180±195 vs 1031±145ms; P=0.017).

Conclusions

The new dance mat device is a valid and reliable tool for assessing stepping ability and fall risk in older community-dwelling people. Because it is highly portable, it can be used in clinic settings and the homes of older people as both an assessment and training device.