Effect of zonisamide on sleep and rapid eye movement sleep behavioral disorders in patients with Parkinson’s disease: A randomized control trial

•The present study is a randomized placebo-controlled trial in Parkinson’s disease.•This study is to verify the safety and efficacy of zonisamide for sleep disorders.•This study also objectively evaluate REM sleep behavioral disorders (RBD).•Mobile electroencephalography /electrooculography recording system was used. Zonisamide is a medication developed in Japan that is effective for motor symptoms and wearing off in Parkinson’s disease (PD). Zonisamide has properties that may improve sleep disorders. The aim of this study is to verify the safety and efficacy of zonisamide for sleep disorders and rapid eye movement (REM) sleep behavioral disorders (RBD) using a mobile two-channel electroencephalography /electrooculography recording system in patients with PD. The present study is a single-blind randomized placebo-controlled trial.The subjects in the treatment group took zonisamide (25 mg per day) before bedtime. The primary outcome was sleep efficiency. The secondary endpoints were assessed as followed; objective outcomes of TST, WASO, SOL, REM sleep/non-REM sleep ratio, deep sleep (N3) time, ratio of RWA to total REM sleep epochs, and subjective outcomes of the PDSS-2, Pittsburgh sleep questionnaire, and RBDSQ. Between the zonisamide and placebo groups, no significant differences were found in the primary outcome and secondary outcomes. The objective and subjective sleep metrics in this clinical trial did not significantly demonstrate zonisamide efficacy for sleep disorder in patients with PD. Although not significant,improvement in WASO and SOL was observed when zonisamide was compared with the placebo.