Feasibility of Transcranial Direct Current Stimulation in Patients with Deep Brain Stimulation: a Case Report

Although deep brain stimulation (DBS) has been reported to be effective to ameliorate motor and non-motor dysfunctions, freezing of gait (FoG) is often resistant to DBS in patients with Parkinson's disease (PD). Transcranial direct current stimulation (tDCS) has been reported as an alternative therapeutic strategy to ameliorate FoG in PD patients. In this case report, we describe the effects of cumulative tDCS over the primary motor cortex of the lower leg to reduce FoG in 2 cases of PD patients with DBS. Two PD patients who had undergone DBS of the subthalamic nucleus visited the rehabilitation medicine department for refractory FoG. Each patient received cumulative tDCS over the primary motor cortex of the lower leg over to reduce FoG. Neither patient required change in dose of dopaminergic medication during the tDCS period nor a significant side effect during and after tDCS. Although the FoG-questionnaire (FoG-Q) in case 1 showed no change after 10 tDCS treatments, the patient in case 2 reported a significant improvement of FoG-Q from 11 to 3 after 5 days of tDCS. We present the safety and feasibility of tDCS in PD patients with DBS who showed refractory FoG.