1 Instituto Nacional de Movimientos Anormales, Santiago, Chile.
2 Clinica Alemana -Universidad del Desarrollo, Santiago, Chile.
3 Departamento Neurología, Clínica Meds, Fundación Diagnosis, Santiago, Chile.
4 Department of Neurology, James J. and Joan A. Gardner Family Center for Parkinson's Disease and Movement Disorders, University of Cincinnati, Cincinnati, Ohio, USA.
5 Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA.