Effects of tai chi on cognition and instrumental activities of daily living in community dwelling older people with mild cognitive impairment

BACKGROUND: Cognitive impairment places older adults at high risk of functional disability in their daily-life activities, and thus affecting their quality of life. This study aimed to examine the effects of Tai Chi on general cognitive functions and instrumental activities of daily living (IADL) in community-dwelling older people with mild cognitive impairment (MCI) in Hong Kong. METHODS: The study adopted a multi-site nonequivalent control-group pretest-posttest design. 160 community-dwelling older people, aged ≥60, with MCI, from four community elderly centers participated in the study. The intervention group (IG, n = 80) received training in the Yang-style simple form of Tai Chi, at a frequency of two lessons per week for 16 weeks. Each lesson lasted for one hour. The control group (CG, n = 80) had no treatment regime and joined different recreational activity groups in community centers as usual within the study period. Outcome measures included measures of global cognitive status and IADL. The Chinese version of the Mini-Mental State Examination (CMMSE) was used for global cognitive assessment. The Hong Kong Chinese version of Lawton’s Instrumental Activities of Daily Living (IADL-CV) was used to assess the participants’ IADL levels. General Estimating Equations (GEE) was used to examine each of the outcome variables for the two groups at the two study time points (the baseline and at the end of the study). Meanwhile, minimum detectable change (MDC) was calculated to estimate the magnitude of changes required to eradicate the possibility of measurement error of outcome measures. RESULTS: Seventy four participants in the IG and 71 participants in the CG completed the study. With adjustments for differences in age, education, marital status and living conditions, the findings revealed that the participants in the IG scored significantly better on the CMMSE test (P = 0.001), and the instrumental ADL questionnaire (P = 0.004). However, those scores changes did not exceed the limits of the respective MDCs in the study, the possibility of measurement variation due to error could not be excluded. CONCLUSION: Tai Chi may be an effective strategy to enhance cognitive health and maintain functional abilities in instrumental ADL in older people with MCI. TRIAL REGISTRATION: NCT03404765 (Retrospectively registered January 19, 2018) ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12877-018-0720-8) contains supplementary material, which is available to authorized users.