Cross-cultural adaptation of the quality of life assessment scale on Alzheimer disease

Objective: To present the internal validation of the quality of life (QOL) evaluation scale for patients with Alzheimer's disease (AD) and their caregivers/family members, proposed by Logsdon et al. Method: The scale was adapted through translation, back translation and equivalence evaluation. The Portuguese version was administered to a sample of 40 patients with mild to moderate AD according to NINCDS ADRDA and DSM-III-R criteria, and also to their respective caregivers/family members. Results: The reliability of the, instrument was excellent, both in the intra and the inter-examiner test-retest. The correlation coefficients for the intra-examiner assessment were 0.87/0.95/0.95 (p < 0.001)) for the patient, family and caregiver versions, respectively. The correlation coefficients for the inter-examiner assessment were 0.76/0.96/0.93 (p < 0.001) for the patients, family and caregiver versions, respectively. The reliability was excellent for both the patient and the relatives' versions in relation to the patient's QOL (alpha=0.81 and 0.85, respectively), and also in relation to the caregiver's QOL (alpha=0.84). Conclusion: The adapted version of the instrument proved to be straightforward and brief, presenting excellent stability and reliability. The Portuguese version can be obtained by contacting the first author.