Effects of transcranial direct current stimulation (tDCS) on voice and speech in Parkinson's disease: a case report

Abstract

ABSTRACT This study describes the results of two different interventions for dysarthria in Parkinson’s disease (PD). It concerns two male patients with PD and hypokinetic dysarthria who underwent speech and voice assessment. The first (S1) received ten 20-minute sessions of transcranial direct current stimulation (tDCS), while the second (S2) received ten 20-minute sessions of tDCS as well as speech therapy. The patients were re-evaluated immediately after the intervention and again after 30 days. Improvements in phonation time, velar movement, and other measures of dysarthria were more significant in S1. According to the acoustic analysis source parameters, improvements in the frequency measurements and Jitter, Shimmer, and noise measurements were greater in S2 in both the immediate post-intervention and 30-day postintervention assessments, followed by S1 in the immediate post-intervention assessment. S1 showed better results in the auditory-perceptual evaluation of speech and voice, whereas S2 obtained better scores in acoustic analysis. These findings suggest that conventional speech therapy combined with tDCS has a more significant impact on speech and voice than tDCS alone, demonstrating the potential of tDCS as an adjuvant treatment for patients with PD.