Overview

The purpose of this project is to use transcranial magnetic stimulation (TMS) to explore the state of excitability of corticocortical and corticofugal (cortex to spinal cord, cortex to brainstem to spinal cord) pathways that project to muscles that control the legs and trunk in people with Parkinson's disease. The outcome variables will be further analyzed to understand their relationship to quantitative measures of postural instability and gait dysfunction. As such, the project can be classified as basic physiologic research. The protocol is not designed to determine if measures of corticocortical or corticofugal excitability can be used as a biomarker to predict disease progression.

Eligibility

Inclusion Criteria:

Participants with Parkinson's disease

• Diagnosis of idiopathic PD or dystonia as determined by a movement disorders neurologist in accordance with the UK Society Brain Bank diagnostic criteria.
• Age 45-80 years.
• Able to ambulate independently without the use of an assistive device (e.g. cane) for 50 meters.

Healthy Older Adults (Control participants)

• Age 45-80 years (this group will be age and sex-matched to the PD group)
• Able to ambulate independently without the use of an assistive device (cane or walker)

Healthy Young Adults

• Age 21-44 years (this group will be age and sex-matched to the PD group)
• Able to ambulate independently without the use of an assistive device (cane or walker)

Exclusion Criteria:

• Subjects who describe a history of a frequent vasovagal syncope (fainting) in response to blood, emotional stress, or sensory triggers.
• Subjects who are on anti-coagulant medications.
• Any musculoskeletal disorder that affects the ability to stand.
• History of seizures, epilepsy, stroke, multiple sclerosis, or traumatic brain injury.
• Intracranial metallic or magnetic devices.
• Pacemaker or any implanted device.
• History of surgery on blood vessels, brain or heart.
• Unexplained, recurring headaches or concussion within the last six months.
• Moderate to severe hearing impairment.
• Subjects who are pregnant.
• Dementia diagnosis
• Other significant neurological disorders that may affect participation or performance in the study
• Implanted deep brain stimulator or other neurosurgeries to treat PD.