tDCS on Parkinson's Disease Cognition

Inclusion criteria

• Patients must meet diagnostic criteria for idiopathic Parkinson's disease, defined as the presence of two or more of the cardinal clinical features of PD in the absence of known causes of parkinsonism such as encephalitis or neuroleptic treatment
• Ability to provide written informed consent
• defined by the Diagnostic and Statistical Manual of Mental Disorders; DSM-5)
• Age > 40
• fluent in English.
• Patients' cognitive statuses will be evaluated by the participating neuropsychiatrist or a trained psychiatry or neurology resident.

Exclusion criteria

• Patients with dementia (defined as a Montreal Cognitive Assessment score < 18)
• Atypical parkinsonian features including myoclonus, apraxia, oculomotor abnormalities, ataxia, sensory loss, or pyramidal signs.
• Abnormal MRI
• metal implants or a cardiac pacemaker
• Pregnant or breastfeeding women (female subjects of child bearing potential will be screened for pregnancy before MRI imaging).
• severe dyskinesia that may interfere with the quality of the scan (e.g., dyskinesia involving head movement).
• severe hypertension.
• cardiovascular disease.
• Patients with a history of seizure, stroke, moderate to severe head injury, high intracranial pressure, severe headaches, or presence of other neurologic disease that may be associated with an altered seizure threshold; or concurrent medication use, such as tricyclic antidepressants, neuroleptic medications, or other drugs that are known to lower seizure threshold
• secondary conditions that may significantly alter electrolyte balance or lower seizure threshold.
• Family history of epilepsy.