The goal of this study is to investigate neurophysiologic tests that have the potential of serving as screening tools for Parkinson's disease. These neurophysiologic tests will be administered to individuals with Parkinson's disease and parkinsonian syndrome and validated against a healthy control population.

Specifically, this study will look at changes in motor function, cognitive function, handwriting, speech, and olfactory function in individuals with Parkinson's disease, individuals at risk for Parkinson's disease and healthy controls.

One of the greatest challenges in Parkinson's research is the identification of individuals who are at risk or have early Parkinson's disease (PD) or parkinsonian syndrome (PS). Subtle signs that do not meet the diagnostic criteria for PD may occur during this period.

This study will evaluate a profile of neurophysiologic tests for potentially predictive signs of PD or PS in individuals with PD or PS, those who may be at risk for PD or PS and in a population of individuals without parkinsonian symptoms or any other neurologic conditions.

In addition, the study will evaluate serum samples for changes in proteins or metabolites that may be indicators of early changes associated with Parkinson's disease or parkinsonian syndrome.

Each study participant will be scheduled for a 90 minute study visit.

This visit may include the following procedures:

• Screening for eligibility
• Clinical assessments
• Neurological evaluation
• Computerized cognitive testing
• Olfactory testing
• Computerized handwriting testing
• Speech evaluation
• Blood sample for biochemical and/or genetic analysis

The study will be conducted at the Institute for Neurodegenerative Disorders (IND), which is a not for profit research institute specializing in Parkinson's disease research.

Clinical data will be collected, stored and analyzed at IND to evaluate whether there are significant differences between the performance of the parkinsonian study participants, individuals with risk factors for PD or PS, and the healthy subjects.

Inclusion Criteria:

As a participant with PD or PS:

• Age >21
• Clinical diagnosis of PD or PS (at least two of the three cardinal symptoms: resting tremor, rigidity, bradykinesia) and a clinical response to dopaminergic therapy

For Healthy Control:

• Age >21

Exclusion Criteria:

As a participant with PD or PS:

• Any other concomitant neurologic condition likely to interfere with handwriting, use of the computer, or other motor tasks tested in this study (e.g. stroke, demyelinating disease, visual loss)

For Healthy Control:

• Any indication of parkinsonism on examination
• Any other concomitant neurologic condition likely to interfere with handwriting, use of the computer, or other motor tasks (e.g. stroke, demyelinating disease, visual loss)

These neurophysiologic tests will be administered to individuals with Parkinson's disease and parkinsonian syndrome and validated against a healthy control population.