Testing a blood-flow conditioning method for sleep

Inclusion Criteria: * Diagnosis of Parkinson's disease according to the Movement Disorder Society (MDS) clinical diagnostic criteria. * Age between 50 and 70 years. * Disease duration ≤ 5 years. * Hoehn and Yahr stage I-III in the "on" state. * Presence of insomnia that meets the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria and clinically significant sleep complaints (for example, Parkinson's Disease Sleep Scale-2 \[PDSS-2\] total score ≥ 18 points). * On a stable regimen of antiparkinsonian medications for at least 4 weeks prior to enrollment, with no expected dose changes during the study period. * Able to understand the study procedures and provide written informed consent (or consent provided by a legally authorized representative when appropriate). Exclusion Criteria: * Secondary insomnia due to other severe medical conditions (e.g., uncontrolled cardiopulmonary, hepatic, renal, or endocrine diseases). * Current psychotic symptoms or severe anxiety or depression (e.g., Hamilton Anxiety Scale score ≥ 14 or Hamilton Depression Scale score ≥ 17). * Other primary sleep disorders such as moderate-to-severe obstructive sleep apnea, restless legs syndrome, periodic limb movement disorder, or rapid eye movement sleep behavior disorder that require specific treatment. * History of significant cerebrovascular disease, brain tumor, central nervous system infection, or other neurological disorders that may interfere with sleep or study assessments. * Contraindications to remote ischemic conditioning (RIC), including severe peripheral arterial disease of the upper limbs, local soft tissue infection or damage at the cuff site, subclavian artery thrombosis, malignant hypertension, severe cardiac disease, active bleeding disorders, or other conditions judged unsafe by the investigator. * Contraindications to MRI or EEG examinations (e.g., pacemaker, severe claustrophobia, metallic implants incompatible with MRI). * Participation in another interventional clinical trial within the past 3 months. * Inability to comply with the study procedures or follow-up visits, as judged by the investigator.