Apathy in Parkinson Disease TMS Study

Inclusion Criteria:

• Diagnosis of idiopathic Parkinson Disease.

• At least 5 years of symptoms.

• On dopaminergic medication for Parkinson Disease.

• Stable on dopaminergic medication and other medications which may influence apathy (such as selective serotonin re-uptake inhibitors, stimulant medications) for atleast 4 weeks prior to first study visit and remain stable throughout the studyperiod.

• Hospital's study-specific informed consent must be obtained.

• Must have capacity to provide informed consent in English.

• For female participants, confirmation that they have not had a menstrual period inover 12 months, or that they will use an effective form of contraception during thestudy.

Exclusion Criteria:

• Inability to provide informed consent.

• Inability to perform effort task (determined during the titration session).

• Presence of dementia (Montreal Cognitive Assessment (MoCA) score < 21).

• History of epilepsy or brain surgery.

• Severe tremor or dyskinesia that would interfere with EEG (determined by the PI).

• Patients with clinically significant medical or neurological conditions which may bean alternative cause of parkinsonism such as repeated brain injury,anti-dopaminergic medications, anoxic brain injury, or significant basal gangliastrokes.

• Presence of other known central nervous system disease that may interfere withperformance or interpretation of EEG or TMS.

• Presence of any implanted metal devices including, but not limited to, pacemakers,deep brain stimulators, vagal nerve stimulators, bladder stimulators, or cochlearimplants.

• Presence of medical contraindications to TMS such as implanted stimulators, historyof mania or bipolar disorder, history of epilepsy.