Received: 4 May 2020
Accepted: 6 December 2020
First Online: 4 January 2021
Ethics approval and consent to participate
: Not applicable.
: Not applicable. Due to the study design, no human data was collected; therefore, consent for publication was not attained from any persons.
: MH declares the following interests: MAH, grant funding from Merz Neurosciences, Dutch Brain Foundation, Dutch Parkinson Patient Association. Editorial Board, Parkinsonism and Related Disorders, speaker honoraria from International Association of Parkinsonism and Related Disorders. Non-financial: American Congress of Rehabilitation Medicine—Neurodegenerative Diseases Networking Group. All remaining authors declare that they have no competing interests.