1. Clinical Neurodegenerative Research Unit, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
2. Movement Disorder Clinic, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
3. Department of Neurology, General Hospital, Zacatecas, Zacatecas, México
4. Department of Neurology, General Hospital, Mérida, Yucatan, Mexico
5. Movement Disorder Clinic, Hospital Universitario, Monterrey, Nuevo Leon, Mexico
6. Movement Disorder Clinic, Hospital Civil, Guadalajara, Jalisco, Mexico