BACKGROUND: Sleep dysfunctions impose a large burden on quality of life for patients with Parkinson’s disease (PD). Several studies on PD reported potential therapeutic effects of transcranial direct current stimulation (tDCS) on motor and non-motor functions, but not related to sleep quality. Therefore, the present study examined sleep quality, depression perception, and quality of life changes after bilateral anodal tDCS in patients with PD.
MATERIAL AND METHODS: Twenty-one patients (n=21) with PD underwent 10 sessions (20 min each, 5 per week) of bilateral anodal tDCS stimulation applied simultaneously over the left and right prefrontal and motor areas. The Pittsburgh Sleep Quality Index (PSQI) total score and sub-scores, Geriatric Depression Scale (GDS), and Health-related quality of life questionnaire (SF-36) were measured pre/post bilateral tDCS anodal stimulation.
RESULTS: PSQI total score (P=0.045), sleep latency sub-score (P=0.02), and GDS total score (P=0.016) significantly decreased, and physical and mental components scores of SF-36 (P=0.018 and P=0.001, respectively) significantly increased after bilateral anodal tDCS stimulation. The GDS score decrease was directly correlated with decrease in PSQI total score (P=0.01), sleep latency sub-score (P=0.002), and sleep disturbance sub-score (P=0.003). In addition, the GDS score decrease was inversely correlated with increasing mental component score of SF-36 (P=0.001), which was directly correlated with an increase in sleep efficiency sub-score (P=0.03) and the physical component score of SF-36 (P=0.0001).
CONCLUSIONS: Bilateral anodal tDCS stimulation showed potential therapeutic effects in patients with PD in terms of sleep quality and depression level improvement, which together improved mental and physical quality of life in patients with PD.

Keywords: Depression, Electric Stimulation Therapy, Parkinson Disease, Quality of Life, Sleep