Effects of Transcranial Focused Ultrasound Stimulation (tFUS) on Neurological and Cognitive Outcomes in Parkinson's Disease

Inclusion Criteria: * Adults aged 22 to 80 years. * Diagnosis of idiopathic Parkinson's disease. * MDS-UPDRS Part III score ≥25 in OFF-medication state at baseline. * Stable dopaminergic therapy for at least 30 days prior to enrollment. * English proficiency. * Normal or corrective hearing and vision. * Ability to provide informed consent (or availability of an LAR) and comply with protocol requirements. Exclusion Criteria: * Atypical or secondary Parkinsonism. * Prior deep brain stimulation or intracranial surgery. * MoCA score \<23. * Severe psychiatric illness (e.g., psychosis, suicidality, untreated major depression). * History of seizure or intracranial pathology. * Significant neurologic disease (e.g. brain tumor, multiple sclerosis) * Contraindication to MRI or ultrasound. * Unstable systemic medical conditions. * Active malignancy or history of cancer within the past 5 years. * Pregnancy or breastfeeding. * Participation in another interventional trial.