Task-specific cortical modulation induced by Tai Chi during postural control in older adults with diabetic peripheral neuropathy: An fNIRS study.

Diabetic peripheral neuropathy (DPN) significantly impairs postural control in older adults. While Tai Chi (TC) improves postural stability in this population, the underlying neural mechanisms remain incompletely understood. This study examined whether TC alters task-evoked cortical activation during static and dynamic postural control in older adults with DPN and whether neural changes are associated with functional improvements. Forty older adults with DPN were stratified by DPN scores and randomly allocated to two groups. The TC group received supervised TC training, while the control group attended health education sessions for 8 weeks. Functional near-infrared spectroscopy (fNIRS) was used to measure changes in hemodynamic responses in the premotor cortex and supplementary motor area (PMC/SMA), primary motor cortex (M1), primary somatosensory cortex (S1), and somatosensory association cortex (SAC) during postural control tasks. After Bonferroni-adjusted post hoc testing, the TC group exhibited reduced PMC/SMA and M1 activation during the static task and increased M1 and S1 activation during the dynamic task compared with baseline. Correspondingly, the TC group showed reduced static sway (COP-RMSml and A95) and improved TUG performance. In correlation analyses with Benjamini-Hochberg FDR correction, changes in PMC/SMA and SAC activation were positively associated with changes in A95 during static postural control. In contrast, no significant correlations were found between cortical activation changes and TUG performance during dynamic postural control. These findings suggest that TC modulates cortical activation in a task-specific way and improves postural control in older adults with DPN through distinct neural mechanisms.