Transcultural adaptation and psychometric validation of a French-language version of the QoL-AD

OBJECTIVES: The aim of this study was to assess the psychometric properties and the transcultural adaptation into French of the quality-of-life in Alzheimer's disease (QoL-AD). METHODS: A total of 120 patient-proxy pairs were recruited in six French hospitals and one French-speaking Swiss hospital to take part in the study. The patients presented mild to moderate AD (MMSE > or = 10). The QoL-AD was administered by an interviewer for patients and was self-administered for caregiver proxies. Thus, the psychometric validation enabled the study of feasibility, acceptability, reliability and convergent and discriminant validity of the instrument. RESULTS: The French version of the QoL-AD showed good internal consistency (Cronbach's alpha coefficient > or = 0.70) and good reliability (Intra-class correlation > 0.80) at a 2-week interval, for patient and caregiver questionnaires. Convergent validity, as indicated by correlation between the QoL-AD (disease-specific instrument) and the dimensions of the Duke Health Profile (generic instrument), was also good for eight dimensions in the Duke profile (p < 0.05). Discriminant validity showed a significant difference for depression (p = 0.0025) and did not show significant difference for two groups of dementia (p = 0.11). CONCLUSION: There is now a validated French version of the QoL-AD available, following transcultural adaptation according to international recommendations, which possesses good psychometric qualities.