Received: 20 July 2020
Accepted: 26 October 2020
First Online: 10 November 2020
Ethics approval and consent to participate
: Data used in the preparation of this article were obtained from the Parkinson’s Progression Markers Initiative (PPMI) database (ExternalRef removed). Ethics approval and informed written consent of all study participants has been provided by PPMI. For up-to-date information on the study, visit ExternalRef removed.
: The authors have no competing or conflicting interest to report.