Effect Of Tai Chi On Resting State Alpha Power And Functional Connectivity In Older Women

Abstract

Aging is associated with reduced resting state functional connectivity (rsFC). A previous study indicated that short term Tai Chi practice along with other interventions altered rsFC and was associated with improved cognitive performance in older adults; however, it is unclear what the direct effect of Tai Chi practice is on rsFC and how long-term practice affects rsFC in older adults. PURPOSE: To investigate the effects of long-term Tai Chi practice on resting state alpha %power and rsFC in older women (TCOA) compared to aged and gender matched non-practitioners (OA) and young women (YA) control by Electroencephalography (EEG). METHOD: Fifteen female participants (5 YA of age 21 ± 1.73 years, 5 OA of age 71 ± 4.53 years, and 5 TCOA of age 71.40 ± 4.34 years) were included in this study. Participants were instructed to remain with their eyes open (EO) or eyes closed (EC) in a seated position for 60 seconds while two sets of EEG signals were recorded. Clean time series of EEG were obtained after preprocessing, and 10 sub-regions of interest were selected to cluster into four regions of interest (Frontal, Central, Parietal, Occipital) for further analysis. The phase log index (PLI) of pairwise regions at the alpha band (8-12 Hz) were calculated to assess rsFC. Power spectrum density of alpha band were also calculated and standardized by total power density (%Power). Linear Mixed Effect Models (LMM) were used to assess the impact of cohort, condition, regions, and their interactions on %power and PLI. RESULTS: There were statistically significant condition effects on both alpha %power (p < 0.01) and PLI (p < 0.01). EC condition demonstrated significantly higher %power (18%) and PLI (0.07). Cohort and condition interactions were also statistically significant in %power (p < 0.01) and PLI (p < 0.05) models. Specifically, %power increased less in OA (-13%, p < 0.01) in comparison to YA and TCOA under EC condition. At the same time, TCOA demonstrated a higher PLI (0.08, p < 0.01) improvement compared to YA and OA. No statistical significance was found in regions and other pairs of interactions. CONCLUSION: Aging affects the regulation of alpha-band power at the resting state with and without visual input. Meanwhile, practicing Tai Chi may alleviate this effect in older adults by improving rsFC.