Effects of Tai Chi Cloud Hands on balance and resting-state functional connectivity after stroke: an fNIRS study.

BACKGROUND

Many people experience balance problems after a stroke. It remains unclear how a short Tai Chi Cloud Hands programme affects resting-state connectivity within the prefrontal-motor network.

METHODS

This study included 52 inpatients with post-stroke balance problems. Participants were randomly assigned to receive either standard rehabilitation alone or standard rehabilitation plus Tai Chi Cloud Hands. Both groups completed 30 min of rehabilitation per day, 5 days per week, for 2 weeks. Additionally, the experimental group completed 30 min of Cloud Hands training daily for 2 weeks. Outcome measures were collected before and after the intervention by assessors blinded to group allocation. The primary outcome was the Berg Balance Scale (BBS), and secondary outcomes included the Modified Barthel Index (MBI). Static balance was assessed using the PROKIN system, which measured centre-of-pressure (COP) path length and sway area. Resting-state brain connectivity was assessed using functional near-infrared spectroscopy (fNIRS) to monitor oxygenated haemoglobin. Group differences were analysed using ANCOVA, with false discovery rate (FDR) correction applied to 28 predefined brain region pairs.

RESULTS

The experimental group showed greater improvements in BBS (partial η2 = 0.420; adjusted difference = 3.215 points) and MBI (partial η2 = 0.363; adjusted difference = 6.056 points) than the control group. Notable reductions were also observed in COP path length (partial η2 = 0.295; adjusted difference = -115.816 mm) and sway area (partial η2 = 0.112; adjusted difference = -79.480 mm2). After FDR correction, significant group differences in connectivity included stronger DLPFC-PreM and PreM-M1 coupling, stronger interhemispheric M1-M1 connectivity, and reduced SMA-SMA coupling (all q ≤ 0.047).

CONCLUSION

Adding a 2-week, high-frequency Tai Chi Cloud Hands programme to standard rehabilitation, delivered at a higher total therapy dose, was associated with greater improvements in balance, daily function, and static postural stability. These improvements were observed alongside regionally specific changes in prefrontal-motor connectivity, including enhanced DLPFC-PreM and PreM-M1 coupling and reduced interhemispheric SMA connectivity. These connectivity findings should be interpreted cautiously as associative rather than mechanistic.