1 Department of Veterans Affairs, Hunter Holmes McGuire Veterans Affairs Medical Center, Parkinson's Disease Research Education and Clinical Center, United States; Virginia Commonwealth University, Department of Neurology, United States. Electronic address: mark.baron@va.gov.
2 Department of Veterans Affairs, Hunter Holmes McGuire Veterans Affairs Medical Center, Parkinson's Disease Research Education and Clinical Center, United States; Virginia Commonwealth University, Department of Biomedical Engineering, United States.
3 Virginia Commonwealth University, Department of Biomedical Engineering, United States.