[1] Univ Hosp Bern, Dept Neurol, Bern, Switzerland
[2] Univ Bern, Bern, Switzerland
[3] Toronto Western Hosp, Edmond J Safra Program Parkinsons Dis, Toronto, ON, Canada
[4] Toronto Western Hosp, Morton & Gloria Shulman Movement Disorders Clin, Toronto, ON, Canada
[5] Univ Toronto, Toronto, ON, Canada
[6] St Georges Univ London, Neurosci Res Ctr, Inst Mol & Clin Sci, London, England
[7] Univ Hlth Network, Dept Psychiat, Toronto, ON, Canada