This two-stage prevalence survey involved geographically delimited areas, four urban (Liverpool, Newcastle, Nottingham and Oxford) and two rural (Cambridgeshire and Gwynedd), including institutions.
Cognitive function and dementia in six areas of England and Wales: the distribution of MMSE and prevalence of GMS organicity level in the MRC CFA Study. The Medical Research Council Cognitive Function and Ageing Study (MRC CFAS).