Assessing quality of life in dementia: preliminary psychometric testing of the Quality of Life Assessment Schedule (QOLAS)

We adapted a generic, individualised, patient-centred quality of life (QOL) assessment technique, the Quality of Life Assessment Schedule (QOLAS) for use with patients with dementia. The QOLAS was administered to a group of patients with mild to moderate dementia alongside a number of other measures of well-being to assess its psychometric properties. Each patient's main carer also completed the QOLAS, giving a proxy rating of the QOL of the patient. The patients understood the interview and were able to describe their quality of life both qualitatively and quantitatively. In this preliminary study the QOLAS was demonstrated to have good validity (content, construct, and criterion) and good internal reliability. The carers rated the patients as having a worse QOL than did the patients themselves on all subdomains of the QOLAS. The results suggest that patients with mild to moderate dementia can rate their own QOL and that the QOLAS is a promising method for assessing QOL in this patient group. The discrepancy between the patients' own views and the views of their carers raises important issues about whether the patient or a proxy is the best judge of QOL in patients with dementia.