Parkinson's disease (PD) is a disease caused by dopamine deficiency in the striatum resulting from the loss of dopaminergic neuronal cells in the cerebral substantia. It is a progressive neurodegenerative disease characterized by motor symptoms including gait disturbance and balance instability. In the early stages of Parkinson's disease, dysfunction of the sensorimotor area of the basal ganglia typically occurs, leading to habitual control hurdles. Accordingly, cognitive efforts are required to perform habitual tasks such as walking, and the automaticity of walking is reduced. Walking performance in a dual-task condition has been used to assess gait automaticity in patients with Parkinson's disease.~Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation method that can be used to change cortical activity. Recently, there has been growing attention on tDCS as an adjunct tool for rehabilitation. Several tDCS studies in patients with PD have reported the positive results of tDCS on motor function. However, few studies have reported the therapeutic effect of tDCS on the dual-task performance in PD. In addition, inconsistent results have been reported because tDCS protocol has been applied in various way. Therefore, this study aims to investigate an optimized stimulation site of tDCS that could improve the dual-task performance in patients with PD.
The purpose of this study is to investigate the optimal stimulation location of transcranial direct current stimulation to improve the dual-task performance in patients with Parkinson's disease.