J. Graham Beaumont is Head of the Department of Clinical Psychology at the Royal Hospital for Neuro-disability, London and Honorary Professor at the Roehampton Institute, London

Pamela M. Kenealy is Senior Lecturer in Psychology at the Roehampton Institute, London

Marcus J. C. Rogers is Clinical Service Co-ordinator responsible for the Behaviour Disorder and Huntington's Disease Unitss at the Royal Hospital for Neuro-disability, London