Long-term Tai Chi Training Is Associated With Better Dual-task Postural Control and Cognition in Aging Adults

Objective: Many activities within our daily lives require us to stand upright while concurrently performing a cognitive task (ie, dual tasking). The "costs" of dual tasking can present as a detriment to either task, or even both. Evidence supports that tai chi (TC), a mind-body exercise, improves both postural control and cognition. The purpose of this study was to (1) determine whether long-term TC training reduces dual-task costs to standing postural control, and (2) determine whether it characterizes the relationship between these costs and cognition in aging adults with and without long-term TC training. Methods: Twenty-six TC experts (age 63 ± 8 y, TC experience 24 ± 11 y) and 60 controls (TC naïve: age 64 ± 8 y) were studied. Center-of-pressure sway speed and elliptical area were recorded during quiet and dual-task standing. In addition, postural sway speed and range were analyzed in the anterior-posterior and medial-lateral direction. Dual-task cost was calculated as the percent change in center-of-pressure outcomes from quiet to dual-task conditions. Cognition was assessed with the digit span (verbal memory), trail making test (working memory and task switching ability), category naming (semantic verbal fluency), and F-A-S test (phonemic verbal fluency). Results: TC experts had significantly lower dual-task costs to postural control in elliptical area (16.1 vs 110.4%, 95% confidence interval [CI], -94.27 to -0.07) compared with TC-naïves. TC experts also performed better on the digit span (23.5 vs 19.2; 95% CI, 0.68 to 3.59), trail making test A (28.5 vs 32.6 s; 95% CI, -3.83 to -0.21), and category naming (46.2 vs 41.3, 95%, CI 0.80 to 4.09), compared with TC naïves. There was not a clear significant association between better cognitive functioning and lower dual-task costs for either groups. These group differences and associations were independent of age, body mass index, education, and physical activity level. Conclusions: These observations suggest cognitive-motor benefits from TC and the need for future controlled trials.