Cognitive Performance and Neuropsychiatric Symptoms in Early, Untreated Parkinson Disease

Weintraub D, Simuni T, Caspell-Garcia C, Coffey C, Lasch S, Siderowf A, Aarsland D, Barone P, Burn D, Chahine LM, Eberling J, Espay AJ, Foster ED, Leverenz JB, Litvan I, Richard I, Troyer MD, Hawkins, KA, and the Parkinson’s Progression Markers Initiative