Item distribution, internal consistency, and structural validity of the German version of the DEMQOL and DEMQOL–proxy

Background Accurate assessment of health-related quality of life as an endpoint in intervention studies is a major challenge in dementia research. The DEMQOL (29 items) and the proxy version (32 items), which is partly based on the DEMQOL, are internationally used instruments. To date, there is no information on the structural validity, item distribution, or internal consistency for the German language version of these questionnaires.