Effect of Dynamic Balance Training Combined with Different Intensities of Cerebellar Transcranial Direct Current Stimulation in People with Parkinson’s Disease: a Randomized Clinical Trial

Abstract

Impaired balance is one of the most disabling symptoms in people with Parkinson’s disease (PwPD). While motor intervention can improve balance control, its effects might be enhanced through cerebellar transcranial direct current stimulation (ctDCS). However, the optimal stimulation intensity remains a point open to investigation. To compare the effects of dynamic balance training combined with different intensities of anodal ctDCS on improvements in body balance and modulation of prefrontal cortex (PFC) activation in PwPD. Thirty-three PwPD were randomized into three groups varying in the intensity of ctDCS (4 mA, 2 mA, Sham) in a double-blind, sham-controlled design. Participants underwent 6 sessions of progressively challenging dynamic balance training combined with ctDCS/sham. Balance improvements were assessed through center of pressure excursion in quiet standing and dynamic transfer tasks. Training-related effects were also evaluated in PFC activation using functional near-infrared spectroscopy. Balance training combined with ctDCS led to higher improvements in balance compared to training without cerebellar stimulation. The 4 mA stimulation intensity led to greater balance gains than the 2 mA and sham stimulation across all transfer task categories assessed. Balance training led to decreased PFC activation, with no detectable differences between the groups. Six sessions of dynamic balance training combined with the ctDCS intensity of 4 mA resulted in superior improvement of balance in PwPD. Balance training led to decreased PFC activation in the performance of different transfer tasks regardless of the ctDCS condition. Brazilian Registry of Clinical Trials (ReBEC) URL: ensaiosclinicos.gov.br/rg/RBR-7yt65zp, data of registration 08/12/2024, retrospectively registered.