Changes in sleep disturbances and quality of life associated with Istradefylline in patients with Parkinson's disease: an exploratory polysomnographic study

Background Sleep disturbances are common non-motor symptoms in Parkinson's disease (PD) and substantially impair quality of life (QOL). Although istradefylline, an adenosine A2A receptor antagonist, is widely used to improve motor fluctuations, its effects on subjective sleep complaints and objective sleep architecture remain unclear. Methods In this exploratory, single-center, open-label study, we evaluated changes in subjective sleep quality and polysomnographic findings following 12 weeks of istradefylline treatment in patients with PD. Nine patients underwent clinical assessments and overnight polysomnography at baseline and 12 weeks after initiating istradefylline (20 mg/day). Sleep quality, QOL, fatigue, and motor symptoms were assessed using validated clinical scales. Results Following istradefylline initiation, improvements were observed in Parkinson's Disease Sleep Scale-2 (PDSS-2), Parkinson's Disease Questionnaire-39 summary index (PDQ-39 SI), Parkinson Fatigue Scale, and Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part IV scores. Changes in PDSS-2 scores were significantly correlated with changes in PDQ-39 SI (ρ = 0.76, p = 0.017), although both measures were subjective and obtained at the same assessment. Regarding objective sleep measures, most polysomnographic parameters did not significantly change; rapid eye movement (REM) sleep percentage increased numerically, but the change was not statistically significant ( p = 0.058). Conclusions In this small uncontrolled study, initiation of istradefylline was associated with improvements in subjective sleep quality, fatigue, and QOL, whereas objective polysomnographic parameters showed limited changes. These findings are exploratory and hypothesis-generating and require confirmation in larger controlled studies.