1. Movement Disorders Clinic, Southern General Hospital, Glasgow G51 4TF,
2. Institute of Psychiatry, King's College, London, and Medical Director of the National Parkinson Foundation International Centre of Excellence, Kings College, London,
3. Maudsley Hospital, London, and King's College London Institute of Psychiatry, London,
4. Norfolk and Norwich University Hospital, Norwich
5. Northumbria Healthcare NHS Foundation Trust, Wansbeck General Hospital, Ashington, Northumberland