OBJECTIVES Summarize and critically evaluate research on the effects of Tai Chi on cognitive function in older adults. DESIGN Systematic review with meta-analysis. SETTING Community and residential care. PARTICIPANTS Individuals aged 60 and over (with the exception of one study) with and without cognitive impairment. MEASUREMENTS Cognitive ability using a variety of neuropsychological testing. RESULTS Twenty eligible studies with a total of 2,553 participants were identified that met inclusion criteria for the systematic review: 11 of the 20 eligible studies were randomized controlled trials (RCTs), 1 was a prospective non-randomized controlled study, 4 were prospective non-controlled observational studies, and 4 were cross-sectional studies. Overall quality of RCTs was modest, with 3 of 11 trials categorized as high risk of bias. Meta-analyses of outcomes related to executive function in RCTs of cognitively healthy adults indicated a large effect size when Tai Chi was compared to non-intervention controls (Hedge’s g=0.90; p=0.043) and moderate effect size when compared to exercise controls (Hedge’s g=0.51; p=0.003). Meta-analyses of outcomes related to global cognitive function in RCTs of cognitively impaired adults, ranging from mild cognitive impairment to dementia, showed smaller but statistically significant effects when Tai Chi was compared to both non-intervention controls (Hedge’s g=0.35; p=0.004) and other active interventions (Hedge’s g=0.30; p=0.002). Findings from non-randomized studies add further evidence that Tai Chi may positively impact these and other domains of cognitive function. CONCLUSION Tai Chi shows potential to enhance cognitive function in older adults, particularly in the realm of executive functioning and in those individuals without significant impairment. Larger and methodologically sound trials with longer follow-up periods are needed before more definitive conclusions can be drawn.

Background: Frailty is a geriatric syndrome resulting from age-related cumulative decline across multiple physiologic systems, impaired homeostatic reserve, and reduced capacity to resist stress. Based on recent estimates, 10% of community-dwelling older individuals are frail and another 41.6% are prefrail. Frail elders account for the highest health care costs in industrialized nations. Impaired physical function is a major indicator of frailty, and functional performance tests are useful for the identification of frailty. Objective instrumented assessments of physical functioning that are feasible for home frailty screening have not been adequately developed. Objective: To examine the ability of wearable sensor-based in-home assessment of gait, balance, and physical activity (PA) to discriminate between frailty levels (nonfrail, prefrail, and frail). Methods: In an observational cross-sectional study, in-home visits were completed in 125 older adults (nonfrail: n = 44, prefrail: n = 60, frail: n = 21) living in Tucson, Ariz., USA, between September 2012 and November 2013. Temporal-spatial gait parameters (speed, stride length, stride time, double support, and variability of stride velocity), postural balance (sway of hip, ankle, and center of mass), and PA (percentage of walking, standing, sitting, and lying; mean duration and variability of single walking, standing, sitting, and lying bouts) were measured in the participant's home using validated wearable sensor technology. Logistic regression was used to assess the most sensitive gait, balance, and PA variables for identifying prefrail participants (vs. nonfrail). Multinomial logistic regression was used to identify variables sensitive to discriminate between three frailty levels. Results: Gait speed (area under the curve, AUC = 0.802), hip sway (AUC = 0.734), and steps/day (AUC = 0.736) were the most sensitive parameters for the identification of prefrailty. Multinomial regression revealed that stride length (AUC = 0.857) and double support (AUC = 0.841) were the most sensitive gait parameters for discriminating between three frailty levels. Interestingly, walking bout duration variability was the most sensitive PA parameter for discriminating between three frailty levels (AUC = 0.818). No balance parameter discriminated between three frailty levels. Conclusion: Our results indicate that unique parameters derived from objective assessment of gait, balance, and PA are sensitive for the identification of prefrailty and the classification of a subject's frailty level. The present findings highlight the potential of wearable sensor technology for in-home assessment of frailty status.

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