Balance Training Modulates Cortical Inhibition in Individuals with Parkinson's Disease: A Randomized Controlled Trial.

Background: Most individuals with Parkinson's disease (PD) develop balance dysfunction. Previous studies showed that individuals with PD have abnormal corticomotor changes related to severity of motor symptoms and disease progression. Cortical disinhibition was observed in PD and this alteration can be an early sign of PD. Balance training seems to be an effective intervention to improve balance in individuals with PD. However, it is not much known about the effect of balance training on cortical neuroplasticity in PD population.

Objective: To investigate the effects of balance training on corticomotor excitability in individuals with PD.

Methods: Twenty-eight PD participants were recruited and randomly assigned to either the balance training (BT) or the control (CON) group. Both groups underwent 16 training sessions over 8 weeks. Outcome measures for corticomotor inhibition included the cortical silent period (CSP) and short-interval intracortical inhibition (SICI) on transcranial magnetic stimulation. Balance performance was measured using the Mini-Balance Evaluation Systems Test (Mini-BEST) and the Timed Up and Go (TUG) test.

Results: Participants in the BT group showed a significant increase in corticomotor inhibition (CSP:  = .028, SICI:  = .04) and a significant improvement in balance performance (Mini-BEST:  = .001, TUG:  = .04) after training. Compared to the CON group, the BT group showed a greater increase in corticomotor inhibition (CSP:  = .017, SICI:  = .046) and better improvement in balance (Mini-BEST:  = .046).

Conclusion: Balance training could modulate corticomotor inhibition in the primary motor cortex and improve balance performance in individuals with PD.