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.