Tai Chi improves global cognitive function in older adults with mild cognitive impairment

A pilot randomized controlled trial (RCT) conducted by the University of Hong Kong (HKU) has demonstrated earlier improvement in global cognitive function in older adults with mild cognitive impairment (MCI) who regularly partook in Tai Chi training vs conventional exercise.

“MCI is a state in which cognitive function declines faster than normal ageing, but not to the extent of affecting daily living. It is suggested that timely intervention may slow down or reverse the decline in cognitive function and ultimately delay or prevent the onset of dementia,” wrote the researchers. [Front Aging Neurosci 2020;doi:10.3389/fnagi.2020.00121]

Guidelines of the WHO and American Association of Neurology recommend physical exercise for reducing the risk of cognitive decline and dementia. [WHO, 2019; Risk Reduction of Cognitive Decline and Dementia; Neurology 2018;90:126-135] Tai Chi is a popular mind-body exercise which, in contrast to conventional exercise such as running, swimming and resistance training, combines meditation with aerobic exercise.

To test the hypothesis that Tai Chi and conventional exercise lead to different improvements in global cognitive function and in specific cognitive domains, including memory and executive function, the researchers carried out a single-centre, assessor-blinded, three-arm, parallel-group, pilot RCT in 34 adults aged ≥50 years with MCI. The participants were randomized 1:1:1 into a Tai Chi group (TC; n=10; three 60-munite sessions of Yang-style Tai Chi training per week for 24 weeks), a conventional exercise group (EX; n=12; three 60-munite sessions of fitness training per week for 24 weeks), or a control group (CON; n=12; no intervention). [Sci Rep 2022;doi:10.1038/s41598-022-12526-5]

Both TC and EX groups showed significant improvements in age- and education-corrected Hong Kong version of the Montreal Cognitive Assessment (MoCA-HK) vs CON at both mid- (12 weeks) and post-assessment (24 weeks; p<0.001 for both). Notably, at mid-assessment, TC group showed greater improvements in MoCA-HK scores than EX group (p<0.001). At post-assessment, TC group exhibited a trend for greater improvement vs EX group, but it was not statistically significant.

At mid- and post-assessment, both interventions were associated with significant improvements in 30-minute delayed recall test vs CON group (12 weeks: TC vs CON, p=0.008; EX vs CON, p=0.036; 24 weeks: TC vs CON, p<0.001; EX vs CON, p<0.001), but there was no significant difference between intervention groups.

“Notably, at mid-assessment, TC showed a greater improvement in global cognitive function and an early improvement in Trail Making Test Part B/A ratio score, which assesses executive function and requires cooperation of several cognitive domains, whereas EX showed an earlier improvement in completion time of the Victoria Stroop Test under the interference condition, which assesses attention and language ability,” reported the researchers. “These data support the idea that conventional exercise and Tai Chi exert different effects on global cognitive function and cognitive domains of interest. Unlike fitness training, which improves global cognition by enhancing cardiorespiratory fitness, motor training in Tai Chi induces task-specific changes in the brain, accounting for different improvement rates across individual cognitive domains.”

“Tai Chi conferred clinically relevant improvement on global cognitive function and improved cognitive flexibility more quickly and as early as 12 weeks into intervention, whereas conventional exercise led to more rapid improvements in attention. Compared with conventional exercise, the more immediate improvements in cognitive performance by Tai Chi training might benefit older adults with MCI. However, further investigations are needed to compare the effects of the two exercise modalities in a long-term intervention setting,” concluded the researchers.