Polysomnographic and Clinical Parameters before and after Zonisamide Therapy for Parkinson's Disease

OBJECTIVE: Sleep disturbance is a common nonmotor symptom associated with a decreased quality of life in patients with Parkinson's disease (PD). In this study, we evaluated the effects of zonisamide on motor and non-motor symptomology in patients with PD, especially with respect to objective sleep assessments conducted via polysomnography. METHODS: We conducted a 12-week, open-label study to assess the effects of zonisamide. The patients received 25 mg/day of zonisamide and underwent overnight polysomnography prior to and after 12 weeks of zonisamide treatment. They were assessed for their cognitive function (Mini-Mental State Examination and the Japanese version of the Montreal Cognitive Assessment), gait function (Timed Up-and-Go Test, 10-m Gait Walk Test), Parkinson's symptomology (Movement Disorder Society Revision of the Unified Parkinson's Disease Rating Scale parts 2 and 3), and self-reported sleep (Epworth Sleepiness Score, Parkinson's Disease Sleep Scale-2). RESULTS: Six patients completed the study. Polysomnographic data revealed a statistically significant increase in the percentage of time spent in sleep stage N2 (10.8%±9.2%, p=0.031) and a declining trend in the percentage of time spent in sleep stage N1 (-8.9%±12.7%, p=0.063). Although none of the patients had sleep stage N3 at baseline, 3 of the 6 patients experienced sleep stage N3 (1.1-5.4%) after 12 weeks of zonisamide treatment. The other polysomnographic parameters and clinical scores showed no statistically significant differences. CONCLUSIONS: This preliminary study demonstrated that zonisamide improved objective sleep parameters measured by polysomnography in patients with PD.