Neuropsychologic assessment in collaborative Parkinson's disease research: a proposal from the National Institute of Neurological Disorders and Stroke Morris K. Udall Centers of Excellence for Parkinson's Disease Research at the University of Pennsylvania and the University of Washington.

Cognitive impairment (CI) and behavioral disturbances can be the earliest symptoms of Parkinson's disease (PD), ultimately afflict the vast majority of PD patients, and increase caregiver burden. Our two Morris K. Udall Centers of Excellence for Parkinson's Disease Research were supported by the National Institute of Neurological Disorders and Stroke (NINDS) in an effort to recommend a comprehensive yet practical approach to cognitive and behavioral assessment to further collaborative research. We recommend a stepwise approach with two levels of standardized evaluation to establish a common battery, as well as an alternative testing recommendation for severely impaired subjects, and review supplemental tests that may be useful in specific research settings. Our flexible approach may be applied to studies with varying emphasis on cognition and behavior, does not place undue burden on participants or resources, and has a high degree of compatibility with existing test batteries to promote collaboration.