Additional Effects of 1-Hz rTMS Combined With Tai Chi Chuan on Dual-Task Performance Among Older Adults With Sleep Disorders and MCI: An fNIRS-Based Randomized Controlled Trial.

OBJECTIVE: This study aimed to determine whether 1-Hz repetitive transcranial magnetic stimulation (rTMS) combined with Tai Chi Chuan exerts an additional effect on dual-task performance in older adults with sleep disorders and mild cognitive impairment (MCI) and to explore the underlying cerebral hemodynamic mechanisms. METHODS: A total of 110 older adults with sleep disorders and MCI were randomly assigned to receive 6 weeks of either 1-Hz rTMS or sham stimulation in combination with Tai Chi Chuan. Dual-task performance, gait and balance outcomes, and task-evoked cerebral hemodynamic responses and functional connectivity measured using functional near-infrared spectroscopy (fNIRS) were assessed at baseline and after the intervention. RESULTS: Compared with sham, active rTMS combined with Tai Chi Chuan significantly improved dual-task performance (p = 0.005). During dual-tasking, greater activation was observed in the left dorsolateral prefrontal cortex (DLPFC) and frontal pole (both p = 0.003), along with stronger connectivity between the premotor area and frontal pole (p < 0.001) and between the premotor area and orbitofrontal cortex (OFC; p = 0.001). Changes in left DLPFC activation correlated with changes in subtraction accuracy (r = 0.313, p = 0.034). Furthermore, changes in right DLPFC-right OFC connectivity correlated with changes in subtraction accuracy (r = 0.382, p = 0.009). CONCLUSIONS: When added to Tai Chi Chuan, 1-Hz active rTMS improved dual-task performance more than sham rTMS in older adults with sleep disorders and MCI. The observed changes in prefrontal and premotor activation and functional connectivity may contribute to this additional effect. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2200063274). Registered on September 2, 2022; https://www.chictr.org.cn/showproj.html?proj=176982.