Biomedical subjects

Anne Shumway-Cook

Publications and source records attributed to Anne Shumway-Cook.

At least 19 recordsLinked to original sources

PubMed2007

Age-associated declines in complex walking task performance: the Walking InCHIANTI toolkit.

OBJECTIVES: To describe a set of complex walking tasks (CWTs) that can be used to evaluate mobility and to characterize age- and sex-specific performance on these tests. DESIGN: A population-based study of persons living in the Chianti geographic area (Tuscany, Italy). SETTING: Community. PARTICIPANTS: One thousand two hundred twenty-seven persons (aged 20-95) selected from the city registries of Greve and Bagno a Ripoli (Tuscany, Italy). MEASUREMENTS: Gait velocity (m/s) was measured during 13 walking tests (Walking InCHIANTI Toolkit (WIT)) used to examine walking ability under a range of conditions and distances. Other measures included performance on the Short Physical Performance Battery and self-reported health and functional status, including disability in activities of daily living. RESULTS: Age-associated differences on the WIT were reflected in the number of older adults unable to complete CWTs and a decrease in gait velocity. For all tasks, decrements in walking speed with increasing age were significantly larger at aged 65 and older. Performance on CWTs was highly variable and could not be explained by usual gait speed measured under low-challenge conditions alone. CONCLUSION: CWTs may provide important insight into mobility function, particularly in persons with normal or near-normal usual gait speed. Further research is needed to elucidate the specific physiological mechanisms that contribute to declining performance on CWT with increasing age.

Adult↗

PubMed2006

Understanding the use of weights in the analysis of data from multistage surveys.

Understanding the use of weights in the analysis of data from multistage surveys. Large national surveys are powerful tools with which to examine a variety of important rehabilitation-related issues and are currently the only feasible method to study disability trends over time. Because it is impractical to draw simple random samples from the entire United States, national surveys, such as the Medicare Current Beneficiary Survey (MCBS), select random samples of subgroups of a population. Thus, respondents may have unequal probabilities of being included in the survey, and weighting must be used in the analysis before the results may be generalized to the entire United States. Surveys such as the MCBS are rich sources of data for rehabilitation medicine, and it can be expected that more research will be conducted using these data sources. Statistical analysis of these data should account for the sampling scheme used in data collection. We review the principles involved in the design of multistage samples, the calculation of weights, and their use in the data analysis, focusing on their importance in the estimation of population values. Our objective is to help readers to understand and interpret results of research articles using this methodology. Examples using the MCBS data are provided to clarify the concepts presented in the article.

Aged↗

PubMed2006

Association of executive function and performance of dual-task physical tests among older adults: analyses from the InChianti study.

BACKGROUND: previous studies have reported an association between cognitive function and physical performance, particularly among older adults. OBJECTIVE: to examine the association between executive function and performance difference on complex versus usual walking tasks in a sample of non-demented older adults. DESIGN: population-based epidemiological study of older people residing in the Chianti area (Tuscany, Italy). PARTICIPANTS: 737 community-dwelling individuals aged 65 years and older. METHODS: gait speed (m/s) was measured during the performance of complex walking tasks (walking/talking, walking/picking-up an object, walking/carrying a large package, walking over obstacles, walking with a weighted vest) and reference walking tasks (7 m usual pace, 7 m fast pace and 60 m fast pace). Executive function was assessed using the Trail Making Test (TMT). Other measures included Mini-Mental State Examination (MMSE), sociodemographic characteristics and selected physiological impairments. RESULTS: gait speed for the selected reference and complex walk tasks was consistently lower among participants with poor executive function. Per cent decline in gait speed compared with the reference task differed by executive function for certain tasks (e.g. walking/obstacles: 30 versus 24% decline in low versus high executive function respectively, P = 0.0006) but not for others. CONCLUSIONS: poor executive function is associated with measures of gait, including specific challenges. Overall, the results showed that the cost associated with the addition of a challenge to the basic walking task differs by executive function and the nature of the task. Further research is needed to determine whether improvement in executive function abilities translates to better performance on selected complex walking tasks.

Activities of Daily Living↗

PubMed2006

Adding challenge to performance-based tests of walking: The Walking InCHIANTI Toolkit (WIT).

OBJECTIVE: In this report, we provide a detailed description of and reproducibility data on the 14 performance-based tests of lower limb function included in the Walking InCHIANTI Toolkit, which were designed to mimic challenging situations that are encountered while walking in daily life. DESIGN: Five women and five men were randomly selected from each of the age strata, 65-74, 75-84, and > or =85 yrs, among those who received a functional evaluation in the Greve site at the second InCHIANTI study follow-up (total n = 30). Walking tests were administered twice at 2-wk intervals. Analyses were aimed at assessing reproducibility of the Walking InCHIANTI Toolkit components and the existence of a learning effect. RESULTS: Performance remained stable for eight walking tests and slightly but significantly improved for the 25-cm narrow-path walk, 7-m usual-pace, 7-m obstacle normal light, 7-m holding a package, and 7-m talking while walking tests. Test-retest reliability was in general very high, with 11 of 14 (79%) of the intraclass correlation coefficient values >0.80 and all except one (7-m holding a package) >0.75. CONCLUSION: The walking tests included in the Walking InCHIANTI Toolkit show very good medium-term reproducibility and modest learning effect. Administering components of the Walking InCHIANTI Toolkit may help in the understanding of the effect of challenges encountered in daily life on walking performance.

Aged↗

PubMed2006

Training of balance under single- and dual-task conditions in older adults with balance impairment.

BACKGROUND AND PURPOSE: Traditionally, rehabilitation programs emphasize training balance under single-task conditions to improve balance and reduce risk for falls. The purpose of this case report is to describe 3 balance training approaches in older adults with impaired balance. CASE DESCRIPTIONS: Three patients were randomly assigned to 1 of 3 interventions: (1) single-task balance training, (2) dual-task training under a fixed-priority instructional set, and (3) dual-task training under a variable-priority instructional set. OUTCOMES: The patients who received balance training under dual-task conditions showed dual-task training benefits; these training benefits were maintained for 3 months. The patient who received variable-priority training showed improvement on novel dual tasks. DISCUSSION: Older adults may be able to improve their balance under dual-task conditions only following specific types of balance training. This case report gives insight on how this intervention might be combined with more traditional physical therapy intervention.

Accidental Falls↗

PubMed2006

Exercise adherence following physical therapy intervention in older adults with impaired balance.

BACKGROUND AND PURPOSE: This study looked at adherence, and factors affecting adherence, to a prescribed home exercise program (HEP) in older adults with impaired balance following discharge from physical therapy. SUBJECTS: The subjects were 556 older adults (> or =65 years of age) who were discharged from physical therapy during the period 2000 to 2003. METHODS: A survey was developed to determine participation in a HEP. Univariate logistic regressions identified specific barriers and motivators that were associated with exercise participation following discharge from physical therapy. RESULTS: Ninety percent of respondents reported receiving a HEP; 37% no longer performed it. Change in health status was the primary reason for poor adherence to a HEP. Eight barriers (no interest, poor health, weather, depression, weakness, fear of falling, shortness of breath, and low outcomes expectation) were associated with a lack of postdischarge participation in exercise. DISCUSSION AND CONCLUSIONS: Exercise adherence following discharge from a physical therapy program is poor among older adults. Barriers, not motivators, appear to predict adherence.

Aged↗

PubMed2005

Selective utilization of spatial working memory resources during stance posture.

While it has been shown that visual imagery tasks interfere with balance control, the neural mechanisms underlying the interference are unclear. Within a healthy young adult population, we employed a dual-task methodology to investigate the role of visual working memory in stance postural control. The employment of specific visual object and visual spatial working memory cognitive tasks facilitated the selective activation of cortically dissociated working memory resources. Challenging postural sets did not significantly impact object working memory performance, but clearly degraded performance on a spatial working memory task, suggesting that interactions between stance postural control and visual working memory are limited to the spatial domain. Results demonstrated no significant effect of the cognitive tasks upon postural stability.

Adult↗

PubMed2005

Design and validation of a methodology using the International Classification of Diseases, 9th Revision, to identify secondary conditions in people with disabilities.

OBJECTIVE: To design and validate a methodology that identifies secondary conditions using International Classification of Disease, 9th Revision (ICD-9) codes. DESIGN: Secondary conditions were identified through a literature search and a survey of Washington State physiatrists. These conditions were translated into ICD-9 codes and this list was then validated against a national sample of Medicare survey respondents with differing levels of mobility and activities of daily living (ADL) disability. SETTING: National survey. PARTICIPANTS: Participants (N=9731) in the 1999 Medicare Current Beneficiary Survey with no, mild, moderate, and severe mobility and ADL disability. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Percentage of survey respondents with a secondary condition. The secondary conditions were grouped into 4 categories: medical, psychosocial, musculoskeletal, and dysphagia related (problems associated with difficulty in swallowing). RESULTS: Our literature search and survey of 26 physiatrists identified 64 secondary conditions, including depression, decubitus ulcers, and deconditioning. Overall, 70.4% of all survey respondents were treated for a secondary condition. We found a significant relation between increasing mobility as well as ADL disability and increasing numbers of secondary conditions (chi 2 test for trend, P <.001). This relation existed for all categories of secondary conditions: medical (chi 2 test for trend, P <.001), psychosocial (chi 2 test for trend, P <.001), musculoskeletal (chi 2 test for trend, P <.001), and dysphagia related (chi 2 test for trend, P <.001). CONCLUSIONS: We created a valid ICD-9-based methodology that identified secondary conditions in Medicare survey respondents and discriminated between people with different degrees of disability. This methodology will be useful for health services researchers who study the frequency and impact of secondary conditions.

Disability Evaluation↗

PubMed2005

An intensive massed practice approach to retraining balance post-stroke.

BACKGROUND AND PURPOSE: Falls are highly prevalent and a significant source of complications post-stroke. This study tested the efficacy of standard physical therapy (based on the task-oriented approach) delivered in a massed practice paradigm. The purpose of this study was to test if the intensive massed practice intervention (6h/day for 2 consecutive weeks) could significantly improve balance function post-stroke. METHODS: A single-subject multiple baseline design across subjects with probes was utilized with ten subjects with chronic stroke disability. Clinical tests and time to stabilization (TTS) of the center of pressure in response to a platform perturbation were calculated during baseline, intervention, and the maintenance phases. RESULTS: The ability of the subjects to recover from a balance threat improved, with mean TTS decreasing from 2.35 +/- .51 s during baseline, to 1.58+/-.23s during training, and further still to 1.45 +/- .29 s during the maintenance phase, ending 3 months post-intervention. Clinical findings demonstrated improvements in anticipatory and steady-state balance control. In addition weight-bearing symmetry improved and the number of falls sustained reduced. CONCLUSIONS: Intensive massed practice of standard physical therapy produced significant results in balance retraining with patients post-stroke. Our finding support the need to offer additional practice to maximize the efficacy of physical therapy sessions.

Adolescent↗

PubMed2005

Effect of balance training on muscle activity used in recovery of stability in children with cerebral palsy: a pilot study.

This study explored possible neural mechanisms that contribute to improvements in balance control produced by reactive balance training in children with cerebral palsy (CP). Six children with CP (four males, two females; mean age 9y 4mo), two with spastic hemiplegia (Gross Motor Function Classification System [GMFCS] level I) and four with spastic diplegia (GMFCS level II,) were given 5 days of intensive training in reactive balance control (100 perturbations per day on a moveable force platform). Surface electromyography was used to characterize changes in neuromuscular responses pretraining, immediately posttraining, and 1 month posttraining. Training in reactive balance control resulted in improvements in directional specificity of responses (a basic level of response organization) and other spatial/temporal characteristics including: (1) faster activation of muscle contraction after training, allowing children to recover stability faster; (2) emergence of a distal-proximal muscle sequence; and (3) improved ability to modulate the amplitude of muscle activity (increased amplitude of agonist and decreased amplitude of antagonist, reducing coactivation). Each child with spastic hemiplegia or diplegia showed a different combination of factors that contributed to improved performance; the level of change in neural factors depended on the severity of involvement of the child: hemiplegia vs diplegia, and level of involvement within each diagnostic category.

Adolescent↗

PubMed2005

Effect of communication disability on satisfaction with health care: a survey of medicare beneficiaries.

PURPOSE: To examine the prevalence and characteristics of community-dwelling Medicare beneficiaries reporting a communication disability and the relationship between that disability and dissatisfaction with medical care. METHOD: A total of 12,769 Medicare Current Beneficiary Survey respondents age 65 and older in 2001 were categorized by level of communication disability. Sampling weights were used to make inferences about the entire Medicare population. RESULTS: Over 16 million beneficiaries reported a communication disability. Hearing problems were most commonly reported (41.99%). The association between dissatisfaction and communication disability was statistically significant (p <or= .05) for 8 of 10 items. CONCLUSIONS: Prevalence of dissatisfaction among those with a communication disability varied, ranging from 3.43% to 19.34%. Respondents with a communication disability reported much more dissatisfaction when compared with those respondents without a communication disability.

Aged↗

PubMed2005

Assessing environmentally determined mobility disability: self-report versus observed community mobility.

OBJECTIVES: To examine the test-retest reliability and concurrent validity of a new self-report measure of mobility function by comparing it with observed mobility, self-reported activity of daily living (ADL) function, and performance-based measures of gait and balance. DESIGN: Cross-sectional study involving two groups of older adults. SETTING: Community sites in Seattle, Washington, and Waterloo, Ontario, Canada. PARTICIPANTS: Fifty-four adults aged 70 and older, recruited. MEASUREMENTS: Subjects completed the Environmental Analysis of Mobility Questionnaire (EAMQ), reporting frequency of encounter and avoidance of 24 features of the physical environment, grouped into eight dimensions, on two occasions 1 week apart. Subjects were observed and videotaped during six trips into the community; frequency of encounters with environmental features within the eight dimensions was recorded. EAMQ encounter and avoidance scores were compared with observed environmental encounters, with disability in ADLs and instrumental ADLs (IADLs), and lower extremity functional measures including the Short Physical Performance Battery (SPPB) and the Berg Balance Test. RESULTS: EAMQ test-retest reliability was high for all eight dimensions (intraclass correlation coefficient range=0.81-1.0) and for summary encounter (0.98) and avoidance (0.96) scores. Observed mobility was significantly correlated (Spearman correlation = r) with EAMQ summary encounter (r=0.66) and avoidance (r=-0.58) scores. Moderate correlations were present between the EAMQ (encounter or avoidance) and observed mobility in the distance, temporal, terrain, posture, load, and density dimensions but not in the attention and ambient dimensions. EAMQ encounter/avoidance was significantly associated with ADL and IADL ability and performance on the SPPB and Berg Balance Test. CONCLUSION: Self-reported frequency of encounter and avoidance of specific environmental features appears to be a valid method for determining environmentally specific mobility disability but needs to be confirmed in a larger sample.

Activities of Daily Living↗

PubMed2005

Mobility limitations in the Medicare population: prevalence and sociodemographic and clinical correlates.

OBJECTIVES: To examine the prevalence of and clinical markers associated with mobility limitations in Medicare Current Beneficiary Community Survey (MCBS) respondents. DESIGN: Cross-sectional analysis of a community survey. SETTING: Community. PARTICIPANTS: Twelve thousand seven hundred sixty-nine respondents from the 2001 MCBS, aged 65 and older. MEASUREMENTS: Four questions from the MCBS were used to create four levels of mobility limitation: none, mild, moderate, and severe. Sampling weights were used to calculate estimates of means and proportions of the entire Medicare population for each mobility limitation category. A polytomous logistic regression analysis was used to model the association between four levels of mobility limitation and sociodemographic and clinical variables. RESULTS: Prevalence of mobility limitations ranged from 9.5 million (mild) to 1.2 million (severe). Increasing severity of mobility limitation was associated with older age, being female, reporting fair or poor health, being overweight, smoking, having a greater number of comorbidities, having an annual income below $25,000, having less than a high school education, being unmarried, and living with others. CONCLUSION: National prevalence estimates suggest that functional mobility limitation is a significant problem for many older adults and is associated with some potentially modifiable characteristics.

Activities of Daily Living↗

PubMed2005

Postural dysfunction during standing and walking in children with cerebral palsy: what are the underlying problems and what new therapies might improve balance?

In this review we explore studies related to constraints on balance and walking in children with cerebral palsy (CP) and the efficacy of training reactive balance (recovering from a slip induced by a platform displacement) in children with both spastic hemiplegic and diplegic CP. Children with CP show (a) crouched posture, contributing to decreased ability to recover balance (longer time/increased sway); (b) delayed responses in ankle muscles; (c) inappropriate muscle response sequencing; (d) increased coactivation of agonists/antagonists. Constraints on gait include (a) crouched gait; (b) increased co-activation of agonists/antagonists; (c) decreased muscle activation; (d) spasticity. The efficiency of balance recovery can be improved in children with CP, indicated by both a reduction in the total center of pressure path used during balance recovery and in the time to restabilize balance after training. Changes in muscle response characteristics contributing to improved recovery include reductions in time of contraction onset, improved muscle response organization, and reduced co-contraction of agonists/antagonists. Clinical implications include the suggestion that improvement in the ability to recover balance is possible in school age children with CP.

Cerebral Palsy↗

PubMed2005

Incidence of and risk factors for falls following hip fracture in community-dwelling older adults.

BACKGROUND AND PURPOSE: Hip fracture is a major medical problem among older adults, leading to impaired balance and gait and loss of functional independence. The purpose of this study was to determine the incidence of and risk factors for falls 6 months following hospital discharge for a fall-related hip fracture in older adults. SUBJECTS: Ninety of 100 community-dwelling older adults (> or =65 years of age) hospitalized for a fall-related hip fracture provided data for this study. METHODS: An observational cohort study used interviews and medical records to obtain information on demographics, prefracture health, falls, and functional status. Self-report of falls and performance-based measures of balance and mobility were completed 6 months after discharge. RESULTS: A total of 53.3% of patients (48/90) reported 1 or more falls in the 6 months after hospitalization. Older adults who fell following discharge had greater declines in independence in activities of daily living and lower performance on balance and mobility measures. Prefracture fall history and use of a gait device predicted postdischarge falls. DISCUSSION AND CONCLUSION: Falls following hip fracture can be predicted by premorbid functional status.

Accidental Falls↗

PubMed2004

Muscle responses to seated perturbations for typically developing infants and those at risk for motor delays.

This study examined spatial and temporal organization of muscle activity in response to seated forward platform perturbations in typically developing (TD) infants and in infants at risk for ongoing neuromotor delays. Twelve high-risk (HR) infants (six males, six females) and 12 TD infants (nine males, three females) aged 8 to 10 months (corrected for prematurity), who were all independent sitters, participated in this study. Surface electromyograms recorded muscle responses to forward perturbation in the neck, trunk, and leg (6cm amplitude, 12cm/s). Center of pressure measures were also recorded. The TD infants demonstrated significantly more phasic responses than the HR infants, who had more trials with tonic activity and more trials with no burst of muscle activity (Mann-Whitney U test, two-tailed, p=0.006). The TD infants demonstrated caudalcephalo, directionally appropriate recruitment patterns more often than the HR infants. There were some similarities between the two groups, with no significant difference between any of the center of pressure measures or onset latencies. Results suggest that postural development in HR infants with motor delays is complex. Some elements of seated postural control appear to be developmentally appropriate, e.g. presence of phasic activity in directionally appropriate muscles sequenced in a caudalcephalo pattern. However, frequency of these age appropriate responses was significantly lower in HR infants, who demonstrated many normal, albeit immature, responses, such as cephalocaudally sequenced muscle activity.

Child Development↗

PubMed2003

Effect of balance training on recovery of stability in children with cerebral palsy.

This study examined the effect of massed practice in balance recovery of stability in six children (four males, two females; mean age 9 years 2 months, SD 2 years, range 7 years 5 months to 12 years 11 months) with cerebral palsy (CP). Four children were diagnosed with spastic diplegia (Gross Motor Function Classification System [GMFCS] level II) and two with spastic hemiplegia (GMFCS level I). A single-subject, multiple-baseline experimental design involving three pairs of children matched for diagnosis was used. A moveable forceplate system was used to test and train reactive balance control. Area per second (i.e. area covered by the center of pressure over a one second period) and time to stabilization from center of pressure measures were calculated following perturbations. The intervention phase consisted of massed practice on the moving platform (100 perturbations/day for 5 days). Analysis included hierarchical linear modeling and a repeated measures ANOVA. All children demonstrated a significant improvement in their ability to recover stability as demonstrated by reduced center of pressure area and time to stabilization following training. These improvements were still present 30 days following completion of training. Results suggest that postural control mechanisms in school-age children (7 to 13 years) with CP are modifiable.

Adolescent↗

PubMed2003

Environmental components of mobility disability in community-living older persons.

OBJECTIVES: To examine the relationship between characteristics of the physical environment and mobility disability in community-living older persons. DESIGN: Cross-sectional study conducted on three groups of community-dwelling older adults. SETTING: Community-dwelling older people in Seattle, Washington, and Waterloo, Ontario, Canada. PARTICIPANTS: Fifty-four older adults (> or =70) were recruited from two geographic sites and grouped according to level of physical function (elite, physically able, physically disabled). MEASUREMENT: Subjects reported on frequency of encounter versus avoidance of 24 features of the physical environment, grouped into eight dimensions, using a five-point ordinal scale (never, rarely, sometimes, often, always). Never and rarely responses were combined and coded as not encountered or not avoided, whereas the sometimes, often or always responses were combined and coded as encountered or avoided. RESULTS: Disabled older adults reported fewer encounters with and concomitantly greater avoidance of physical challenges to mobility than nondisabled older adults. However, both encounter and avoidance varied by environmental dimension. CONCLUSION: Results support the hypothesis that mobility disability results from an interaction of individual and environmental factors. Mobility disability is associated with avoidance of some, but not all, physically challenging features within the environment, suggesting that some environmental features may disable community mobility more than others.

Age Factors↗