Investigating Central Neurophysiologic Correlates of Non-Motor Symptoms of Parkinson's Disease

Degree of change of frontal midline theta (FMT) power on electroencephalography (EEG) after brain stimulation at each site (medial prefrontal cortex, dorsolateral prefrontal cortex, control site).

Degree of correlation between the Scales for Outcomes in Parkinson's disease - Autonomic (SCOPA-AUT) total score and frontal midline theta EEG power extracted from Baseline pre-stimulation initial visit EEG and SCOPA-AUT questionnaire. The SCOPA-AUT is a validated autonomic symptom survey for people with Parkinson's disease. It contains 6 domains (gastrointestinal, urinary, cardiovascular, thermoregulatory, pupillary, and sexual). The investigators will use the total composite score including all domains. The score range is 0-69, with a total of 23 questions. 0 means no symptoms, 69 is highest burden of symptoms. The FMT and SCOPA-AUT were assessed at baseline. FMT power and SCOPA-AUT were correlated using the Spearman Correlation Coefficient calculation. A positive correlation coefficient indicates a positive relationship between the assessments; higher FMT power correlates with higher symptom burden.

Degree of correlation between the Orthostatic Hypotension Questionnaire (OHQ) composite score and frontal midline theta EEG power extracted from Baseline pre-stimulation initial visit EEG and OHQ questionnaire. The OHQ consists of two sections: 1-orthostatic hypotension symptom assessment, which includes 6 questions with a score range of 0-66 (0 is no symptoms, 66 is most severe symptoms); and 2-the orthostatic hypotension daily activity scale, which rates interference of symptoms on activities of daily living. This part consists of four questions, and score range is 0-44 (0 is no interference, 44 is most severe interference). The composite OHQ score is the average score between these two subsections. FMT power and OHQ were correlated using the Spearman Correlation Coefficient calculation. A positive correlation coefficient indicates a positive relationship between the assessments; higher FMT power correlates with higher symptom burden.

Degree of correlation between degree of orthostatic hypotension and frontal midline theta EEG power will be measured extracted from Baseline pre-stimulation visit EEG and blood pressure measures. Orthostatic vital signs will be measured at least 30 minutes before initial iTBS as follows: blood pressure will be measured after at least 3 minutes of rest in the supine position. Blood pressure will again be measured after 3 minutes of standing. Blood pressure reduction is expressed as the magnitude of reduction, thus a positive number reflects a greater reduction. Lack of blood pressure reduction was coded as '0'. A positive correlation coefficient indicates a positive relationship between the assessments; higher FMT power correlates with higher more severe orthostatic hypotension.

Change in the SCales for Outcomes in Parkinson's disease - Autonomic (SCOPA-AUT) from 30 minutes before stimulation to 1 day after stimulation and 4 days after stimulation. The SCOPA-AUT is a validated autonomic symptom survey for people with Parkinson's disease. It contains 6 domains (gastrointestinal, urinary, cardiovascular, thermoregulatory, pupillary, and sexual). The investigators will use the total composite score including all domains. The score range is 0-69, with a total of 23 questions. 0 means no symptoms, 69 is highest burden of symptoms

Change in the Orthostatic Hypotension Questionnaire (OHQ) from before to after iTBS. The OHQ will be administered at least 30 minutes before stimulation, and again 1 day and 4 days after stimulation. The OHQ is an orthostatic hypotension symptom survey and consists of two sections. The first is the orthostatic hypotension symptom assessment, which includes 6 questions with a score range of 0-66 (0 is no symptoms, 66 is most severe symptoms). The second part is the orthostatic hypotension daily activity scale, which rates interference of symptoms on activities of daily living. This part consists of four questions, and score range is 0-44 (0 is no interference, 44 is most severe interference). The investigators will calculate the composite OHQ score, which is the average score between these two subsections.

Change in the orthostatic blood pressure change from before to after iTBS. Orthostatic vital signs will be measured as follows: blood pressure will be measured after at least 3 minutes of rest in the supine position. Blood pressure will again be measured after 3 minutes of standing. This will be measured at least 30 minutes before brain stimulation, and again 30 minutes after brain stimulation.

Change in the Beck Depression Inventory II (BDI-II) from before to after iTBS. Participants will complete the BDI-II at least 30 minutes before brain stimulation. The questionnaire will be repeated 1 day and 4 days after stimulation. The BDI-II is a validated depression symptom survey. This survey contains 21 questions, with a score range of 0-63, where 0 means no depression symptoms and 63 indicates severe depression symptoms.