Tai Chi practice enables prefrontal cortex bilateral activation and gait performance prioritization during dual-task negotiating obstacle in older adults

BACKGROUND: With aging, the cognitive function of the prefrontal cortex (PFC) declined, postural control weakened, and fall risk increased. As a mind–body exercise, regular Tai Chi practice could improve postural control and effectively prevent falls; however, underlying brain mechanisms remained unclear, which were shed light on by analyzing the effect of Tai Chi on the PFC in older adults by means of functional near-infrared spectroscopy (fNIRS). METHODS: 36 healthy older adults without Tai Chi experience were divided randomly into Tai Chi group and Control group. The experiment was conducted four times per week for 16 weeks; 27 participants remained and completed the experiment. Negotiating obstacle task (NOT) and negotiating obstacle with cognitive task (NOCT) were performed pre- and post-intervention, and Brodmann area 10 (BA10) was detected using fNIRS for hemodynamic response. A three-dimensional motion capture system measured walking speed. RESULTS: After intervention in the Tai Chi group under NOCT, the HbO(2) concentration change value (ΔHbO(2)) in BA10 was significantly greater (right BA10: p = 0.002, left BA10: p = 0.001), walking speed was significantly faster (p = 0.040), and dual-task cost was significantly lower than pre-intervention (p = 0.047). ΔHbO(2) in BA10 under NOCT was negatively correlated with dual-task cost (right BA10: r = −0.443, p = 0.021, left BA10: r = −0.448, p = 0.019). There were strong negative correlations between ΔHbO(2) and ΔHbR under NOCT either pre-intervention (left PFC r = −0.841, p < 0.001; right PFC r = −0.795, p < 0.001) or post-intervention (left PFC r = −0.842, p < 0.001; right PFC r = −0.744, p < 0.001). CONCLUSION: Tai Chi practice might increase the cognitive resources in older adults through the PFC bilateral activation to prioritize gait performance during negotiating obstacles under a dual-task condition.