Effects of Lemborexant on Motor-sleep Comorbidity in Parkinson's Disease

Parkinson's disease (PD) is the most common movement disorder. Its core motor symptoms include bradykinesia, resting tremor, muscle rigidity, and postural instability. Furthermore, patients frequently experience severe non-motor symptoms, such as sleep disorders and mood/affective disturbances. Among these, sleep disorders, especially insomnia, are one of the most prevalent non-motor symptoms. They are often overlooked in clinical management. The axons of central orexin neurons project extensively throughout the brain, encompassing key regions such as motor control centers and sleep-wake regulation centers. During the pathological process of PD, dysfunctional orexin neurons may contribute to the disruption of both motor and sleep functions by modulating these target areas. By recruiting PD patients with comorbid motor and insomnia symptoms, the investigators will investigate the efficacy of Lemborexant in treating both motor and sleep disturbances in PD patients. With its advantages of target specificity, established safety, and a lower side-effect profile compared to traditional hypnotics, Lemborexant holds promise as a novel therapeutic intervention for Parkinson's disease. This research may offer new possibilities for expanding clinical treatment strategies for PD. Participants will take 5 mg medication (or placebo) each night for 28 days and be asked to come for 4 times study visits (Baseline, at the end of the 7-day post-treatment, at the end of the 28-day post-treatment, 7-day follow up). The major experiment contents include: 1. To evaluate the effect of oral Lemborexant on Parkinson's disease motor symptoms in participants (using the Unified Parkinson's Disease Rating Scale, UPDRS); 2. To evaluate the effect of oral Lemborexant on the sleep quality of participants (using the Parkinson's Disease Sleep Scale (PDSS), the Insomnia Severity Index (ISI), the Pittsburgh Sleep Quality Index (PSQI)).