James Paget Hospital, Norfolk, United Kingdom
The Royal National Orthopaedic Hospital, Middlesex, United Kingdom
Walton Centre for Neurology and Neurosurgery, Liverpool, United Kingdom
The Royal Berkshire and Battle Hospitals NHS Trust, Reading, United Kingdom
Centre Henri Becquerel, Rouen, Cedex, France
Institut Claudius Regaud, Toulouse, France
Hôpital Henri Mondor, Créteil, France
SleepMed of South Carolina, Columbia, South Carolina, United States
The Center for Sleep and Wake Disorders, Chevy Chase, Maryland, United States
Future Search Trials of Neurology, Austin, Texas, United States
Guy's Drug Research Unit, Quintiles Ltd., London, United Kingdom