Non-motor symptoms in early Parkinson's disease: a 2-year follow-up study on previously untreated patients
Roberto Erro, Marina Picillo, Carmine Vitale, Marianna Amboni, Marcello Moccia, Katia Longo, Autilia Cozzolino, Flavio Giordano, Anna De Rosa, Giuseppe De Michele, Maria Teresa Pellecchia, Paolo Barone
Journal of Neurology, Neurosurgery & Psychiatry Jan 2013, 84 (1) 14-17; DOI: 10.1136/jnnp-2012-303419