Comparing the effects between tai chi and conventional exercise in enhancing cognitive performance in older adults with mild cognitive impairment (MCI): A pilot randomized controlled trial.

Abstract

INTRODUCTION: This study examined the effects of tai chi and conventional exercise on improving cognitive function in older adults with mild cognitive impairment (MCI) who have a higher chance of developing Alzheimer’s disease. METHODS: In this three-arm, single-blinded, randomized controlled trial, Chinese adults aged >= 50 years with MCI [score of Montreal Cognitive Assessment Hong Kong version (MoCA-HK) below the 7th percentile of the normative data of Hong Kong] were recruited in the Hong Kong community. A total of 30 eligible individuals were randomly assigned to control group (received no intervention, n=10), conventional exercise group (received three weekly sessions of generic exercise intervention for 24 weeks, n=10), or tai chi group (received three weekly sessions of tai chi intervention for 24 weeks, n=10). The primary endpoint was the change in the score of MoCA-HK after 24-week postrandomization. The secondary endpoints included changes in trail making test and digit span after 24-week post-randomization. Data were analyzed by generalized estimated equation with baseline as covariate. Pairwise comparison was conducted by closed test procedure with Bonferroni and Holm correction. All experimental procedures received human ethics approval. RESULTS: Both tai chi group (+35% in MoCA-HK, P<0.001) and conventional exercise group (+27% in MoCA-HK, P<0.001) showed significant improvement in global cognitive function compared with the control group (+7% in MoCA-HK). The improvement was more profound in tai chi group compared with conventional exercise group (P=0.024). Larger reductions in trail making test B-A score were observed in tai chi (-47%, P<0.001) and conventional exercise (-30%, P=0.001) groups compared with the control group (+18%), thus indicated that both interventions improved executive function. Moreover, tai chi (-33%, P<0.001) and conventional exercise (-8%, P=0.001) groups showed significantly larger reductions in trail making test B/A ratio compared to the control group (+22%), which is indicative of both interventions improved cognitive flexibility. Notably, tai chi training induced a more robust improvement than conventional exercise training in trail making test B/A ratio (P=0.025). Both tai chi (+8%, P<0.001) and conventional exercise (+18%, P<0.001) led to significantly larger improvements relative to control group (-15%) in forward digit span, suggesting that both interventions are beneficial to working-memory. CONCLUSION: These data demonstrated that tai chi and conventional exercise effectively improved global cognitive function, executive function, cognitive flexibility, and working memory. Tai chi induced a more profound improvement than conventional exercise in global cognitive function and cognitive flexibility.