Degree and pattern of dual-task interference during walking vary with component tasks in people after stroke: a systematic review.

QUESTIONS: What are the degree and pattern of dual-task interference during walking in people after stroke? How do these vary with disease chronicity and different component tasks in people after stroke? How does dual-task interference differ between people after stroke and people without stroke? DESIGN: Systematic review with meta-analysis of studies reporting gait-related dual-task interference. PARTICIPANTS: People after stroke and people without stroke. OUTCOME MEASURES: Measures of walking and secondary (cognitive or manual) task performance under dual-task conditions relative to those under single-task conditions. RESULTS: Seventy-six studies (2,425 people after stroke and 492 people without stroke) were included. Manual and mental tracking tasks imposed the greatest dual-task interference on gait speed, although there was substantial uncertainty in these estimates. Among mental tracking tasks, the apparently least-complex task (serial 1 subtractions) induced the greatest dual-task interference (-0.17 m/s, 95% CI -0.24 to -0.10) on gait speed, although there was substantial uncertainty in these estimates. Mutual interference (decrement in both walking and secondary component task performances during dual-tasking) was the most common dual-task interference pattern. The results of the sensitivity analyses for studies involving people with chronic stroke were similar to the results of the primary analyses. The amount of dual-task interference from a mental tracking or manual task during walking was similar between people with or without stroke. CONCLUSIONS: The degree and pattern of dual-task interference vary with the choice of component tasks. When evaluating limitations to functional mobility during dual-tasking conditions and in planning interventions accordingly, clinicians should select dual-task assessments that correspond to the daily habits and physical demands of people after stroke. REGISTRATION: CRD42017059004.

Diagnosis of sarcopenia by evaluating skeletal muscle mass by adjusted bioimpedance analysis validated with dual-energy X-ray absorptiometry.

BACKGROUND: This study aimed to adjust and cross-validate skeletal muscle mass measurements between bioimpedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) for the screening of sarcopenia in the community and to estimate the prevalence of sarcopenia in Hong Kong. METHODS: Screening of sarcopenia was provided to community-dwelling older adults. Appendicular skeletal muscle mass (ASM) was evaluated by BIA (InBody 120 or 720) and/or DXA. Handgrip strength and/or gait speed were assessed. Diagnosis of sarcopenia was based on the 2019 revised Asian Working Group for Sarcopenia cut-offs. Agreement analysis was performed to cross-validate ASM measurements by BIA and DXA. Multiple regression was used to explore contribution of measured parameters in predicting DXA ASM from BIA. RESULTS: A total of 1587 participants (age = 72 ± 12 years) were recruited; 1065 participants were screened by BIA (InBody 120) with 18 followed up by DXA, while the remaining 522 participants were assessed by the BIA (InBody 720) and DXA. The appendicular skeletal muscle mass index (ASMI) evaluated by BIA showed a mean difference of 2.89 ± 0.38 kg/m2 (InBody 120) and 2.97 ± 0.45 kg/m2 (InBody 720) against DXA gold standard. A significant overestimation of muscle mass was measured by BIA compared with DXA (P < 0.005). BIA data were adjusted using prediction equation and mean difference reduced to -0.02 ± 0.31 kg/m2 in cross-validation. Prevalence of sarcopenia in older adults ≥65 ranged from 39.4% (based on ASMI by DXA) to 40.8% (based on predicted DXA ASMI from BIA). Low ASMI by DXA was found in 68.5% of the older adults screened. The percentage of older adults exhibited low handgrip strength ranged from 31.3% to 56%, while 49% showed low gait speed. CONCLUSIONS: Bioimpedance analysis was found to overestimate skeletal muscle mass compared with DXA. With adjustment equations, BIA can be used as a quick and reliable tool for screening sarcopenia in community and clinical settings with limited access to better options.

Association of subsequent falls with evidence of dual-task interference while walking in community-dwelling individuals after stroke.

OBJECTIVE: The aim of this study was to examine the fall predictive value of single-task walking tests and extent of interference observed in dual-task walking tests in ambulatory individuals post stroke. DESIGN: This is an observational study with prospective cohort. SETTING: The study was conducted at the university laboratory. PARTICIPANTS: A total of 91 community-dwelling individuals with chronic stroke participated in the study. MAIN OUTCOME MEASURES: Time required to complete a 10-m walk test with and without obstacle negotiation was measured in isolation and in conjunction with performance of a verbal fluency task (category naming). Fall incidence, circumstances, and related injuries were recorded by monthly telephone calls for 12 months. RESULTS: A total of 91 individuals (mean (SD) age = 62.7 (8.3) years; mean (SD) post-stroke duration = 8.8 (5.3) years) participated in the study; 29 (32%) of them reported at least one fall during the follow-up period, with a total of 71 fall episodes. There was a significant difference in obstacle-crossing time under single-task (mean difference = 8.3 seconds) and dual-task (mean difference = 7.4 seconds) conditions, and also the degree of interference in mobility performance (increased dual-task obstacle-crossing time relative to the single-task obstacle-crossing time; mean difference = 3.3%) between the fallers and the non-fallers (P < 0.05). After adjusting for the effects of other relevant factors, a greater degree of interference in mobility performance remained significantly associated with a decreased risk of falling (adjusted odds ratio = 0.951, 95% CI = 0.907-0.997, P = 0.037). CONCLUSION: The degree of mobility interference during dual-task obstacle-crossing was the most effective in predicting falls among all the single-task and dual-task walking measure parameters tested. This simple dual-task walking assessment has potential clinical utility in identifying people post stroke at high risk of future falls.

Cognitive-motor interference in walking after stroke: test-retest reliability and validity of dual-task walking assessments.

OBJECTIVE: To explore the reliability and validity of a series of dual-task mobility assessments among individuals post-stroke. DESIGN: Observational study with repeated measures. SETTING: University laboratory. PARTICIPANTS: Thirty community-dwelling individuals with chronic stroke. INTERVENTIONS: Not applicable. MAIN MEASURES: Each of the two mobility tasks (1-minute level-ground walking with and without obstacle-negotiation) was performed concurrently with each of the eight cognitive tasks (auditory Stroop test, serial subtraction, shopping list recall and category naming at two difficulty levels). Walking distance and obstacle hitting rate (OHR) indicated dual-task mobility performance. Number of correct responses (NCR) indicated cognitive performance. Reaction time was additionally measured for the auditory Stroop test. Construct validity was examined by correlations between the dual-task assessments. The dual-task assessments were repeated within 7-14 days for test-retest reliability. RESULTS: Excellent test-retest reliability in walking distance and OHR was found (intraclass correlation coefficient, ICC(3,1) = 0.891-0.984, P < 0.05). Moderate to excellent reliability was found in NCR and reaction time (ICC(3,1) = 0.480-0.911, P < 0.01). Correlations between walking distance were excellent ( rs = 0.840-0.985, P < 0.01). Correlations of NCR and reaction time between low- and high-level cognitive tasks were mostly moderate to excellent ( rs = 0.515-0.793, P < 0.01). Generally no significant correlations were found in NCR between the dual-task assessments with different cognitive domains. CONCLUSION: The dual-task walking assessments are reliable and valid for evaluating cognitive-motor interference in community-dwelling individuals post-stroke. The lack of correlations between the tasks of different cognitive domains indicates the need of using different cognitive domains in dual-task walking assessment post-stroke.