Multi-session anodal tDCS enhances the effects of postural training on balance and postural stability in older adults with high fall risk: Primary motor cortex versus cerebellar stimulation

Abstract

BackgroundPostural control impairment is a key target for rehabilitation of older adults with high fall risk. ObjectiveTo investigate whether anodal transcranial direct current stimulation (a-tDCS) over primary motor cortex (M1) or cerebellum can enhance the positive effects of postural training on balance and postural stability in older adults with high fall risk. MethodIn this randomised, double-blinded sham-controlled study, 65 participants were randomly assigned into five groups; M1 a-tDCS with postural training, bilateral cerebellar a-tDCS with postural training, sham a-tDCS with postural training, postural training alone and cerebellar a-tDCS alone. Participants in the first two a-tDCS groups received 2 mA stimulation for 20 min concurrently with postural training. Postural training was conducted for three sessions of 20 min per week for two weeks. The Berg Balance Score (BBS) and the stability indices at both static and dynamic levels of the Biodex Balance System were evaluated before and after intervention. A general linear model repeated measure ANOVA was used to assess the effects of variables among groups. ResultSimultaneous postural training with M1 or bilateral cerebellar a-tDCS significantly improved postural stability indices (p < 0.05) and BBS scores (p < 0.05). Besides, the effects of bilateral cerebellar a-tDCS were significantly higher than that of M1 stimulation on these indices (p < 0.05). Moreover, two weeks postural training alone or cerebellar a-tDCS alone is not an adequate intervention to improve the postural stability indices (p > 0.05). ConclusionPostural training with M1 or bilateral cerebellar a-tDCS, especially bilateral cerebellar a-tDCS, can significantly improve postural control or balance in older adults with high fall risk, while two weeks of postural training alone or two weeks cerebellar a-tDCS alone is not a sufficient intervention.