[1] Univ East Anglia, Norwich Med Sch, Dept Clin Psychol & Psychol Therapies, Norwich, England
[2] Univ Edinburgh, Euan MacDonald Ctr Motor Neuron Dis Res, Edinburgh, Scotland
[3] Univ Edinburgh, Alzheimer Scotland Dementia Res Ctr, Edinburgh, Scotland
[4] Cambridgeshire & Peterborough NHS Fdn Trust, Cambridge, England
[5] Norfolk & Norwich Univ Hosp, Norwich, England
[6] Penn State Univ, Dept Neurol, Hershey, PA USA
[7] Univ Edinburgh, Sch Philosophy Psychol & Language Sci, Human Cognit Neurosci Psychol, Edinburgh, Scotland
[8] Univ Dundee, Sch Humanities Social Sci & Law, Psychol, Dundee DD1 4HN, Scotland