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.