AM receives grants from the Department of Defense of the Israeli Ministry of Justice, the Michael J Fox Foundation, and the EU Joint Program—Neurodegenerative Disease Research; receives consulting fees from Clexio; receives payment for lectures from Biogen; is on the advisory committee of the Michael J Fox Foundation; and is chair of the advisory board of the Michael J Fox Foundation. LR receives grants from the UK National Institute for Health and Care Research, the UK Medical Research Council, the Engineering and Physical Sciences Research Council, the Cure Parkinson's Trust, the Dunhill Medical Trust, Parkinson's UK, the EU, and the Michael J Fox Foundation and is on the advisory committee of the Michael J Fox Foundation. TS receives grants from Amneal, Biogen, Roche, Neuroderm, Sanofi, Prevail, and UCB Pharmaceuticals; is an investigator for the US National Institute of Neurological Disorders and Stroke, the Michael J Fox Foundation, and the Parkinson's Foundation; receives consulting fees from 4D Pharma, Acadia, AcureX, AskBio, Amneal, Blue Rock Therapeutics, Caraway Therapeutics, the Critical Path for Parkinson's Consortium, Denali, the Michael J Fox Foundation, Neuroderm, Sanofi, Sinopia, Sunovion, Roche, Takeda, UCB Pharmaceuticals, Vanqua Bio, and Voyager; is on an advisory board for Acadia, AcureX, AskBio, Amneal, Denali, Sunovion, and Roche; and is on a scientific advisory board for 4D Pharma, Neuroderm, Sanofi, and UCB Pharmaceuticals. JMH receives grants from the US National Institutes of Health, the Michael J Fox Foundation, the European Commission, and the Israeli Ministry of Health; receives consulting fees, paid to their institution (Tel Aviv Medical Center, Tel Aviv, Israel), from Roche; and is a board member of the International Society for the Measurement of Physical Behaviour and the Movement Disorders Technology Task Force. Editorial note: The Lancet Group takes a neutral position with respect to territorial claims in published text and institutional affiliations.