The beneficial effects of bright light therapy (BLT) on the disabling non-motor symptoms of Parkinson's disease (PD) remain uncertain. The objective of this study was to investigate if daily BLT, with a head-mounted device (Luminette®), has a beneficial effect on depression, anxiety, daytime sleepiness and fatigue in patients with PD. In this double-blind, placebo-controlled study, 16 patients with PD were randomized to receive either 1 month of BLT or 1 month of placebo therapy, separated by a 2-week washout period, in a crossover fashion. Patients completed questionnaires for the Hospital Anxiety and Depression Scale (HADS), the Epworth Sleepiness Scale (ESS) and the Fatigue Impact Scale (FIS) before and after each treatment period. The primary outcome measures were changed from baseline in scores between treatment groups. No significant changes were observed in the HADS anxiety scores and FIS scores after BLT and after placebo. The ESS scores decreased non-significantly only after BLT. A post hoc analysis of patients who had baseline ESS scores > 11 revealed a significantly greater decrease in ESS scores after BLT than after placebo. Future studies investigating the effect of BLT on sleepiness could focus specifically on patients with high ESS scores.
Keywords: Anxiety; Depression; Parkinson’s disease; Phototherapy; Sleepiness.