Cross-cultural adaptation and validation of a tool to assess dementia specific quality of life: Evidence from a South Asian population

BackgroundDementia is now fast becoming a public health priority worldwide, including in South Asia. But research about the quality of life of patients with dementia in this part of the world is limited. AimsThe present study was aimed at cross-cultural adaptation and validation of the Sinhala version of the Dementia Specific Quality of Life (DEMQOL) and DEMQOL-Proxy tools among patients with dementia and their caregivers in Sri Lanka. MethodsThe 28-item DEMQOL and 31-item DEMQOL-Proxy tools which were originally developed and validated in the United Kingdom were initially translated, culturally adapted using modified Delphi process with a panel of experts and tested for judgmental validity. Construct validity was assessed by using multi-trait scaling analysis and confirmatory factor analysis (CFA), based on data obtained from 100 dyads of patients with mild moderate dementia and their primary caregivers attending state hospital psychiatry clinics in the Gampaha district. The structure of the DEMQOL and DEMQOL-Proxy was evaluated based on a variety of fit indices. Reliability was assessed using the test retest method and internal consistency. ResultsAll the items showed good psychometric properties in judgmental validity and item convergent discriminant validity. In CFA, using robust maximum likelihood method, the original four-factor model emerged with DEMQOL validation data, whereas a five factor model was best fitted with DEMQOL-Proxy validation data. The reliability of the DEMQOL (Cronbach’s alpha=0.87; correlation coefficient=0.864) and DEMQOL-Proxy (Cronbach’s alpha= 0.874; correlation coefficient=0.834) was satisfactory. ConclusionsThe Sinhala versions of the DEMQOL and DEMQOL Proxy scales are valid and reliable in assessing the QOL of dementia patients of mild-moderate severity in Sri Lanka. This tool can be used by healthcare professionals to understand the current level of QOL as well as to give direction towards improvement required.