Measuring the Impact of Caring for a Spouse with Alzheimer's Disease: Validation of the Alzheimer's Patient Partners Life Impact Questionnaire (APPLIQue).

Alzheimer's disease (AD) is the most common form of dementia, characterized by cognitive, psychiatric and behavioral symptoms and increasing dependency. Family members typically assume increasing caregiving responsibilities, with considerable quality of life (QoL) impact. This article describes the testing of a needs-based QoL questionnaire for AD family caregivers. Initial analyses, according to Rasch measurement theory, suggested that items applied to spousal rather than non-spousal caregivers. Following removal of non-spousal responders, a 25-item questionnaire was identified that exhibited acceptable model fit, a mean (SD) person location of 0.194 (1.42) logits, residual correlations 0.173 and absence of DIF by age, gender or administration. Reliability was 0.85. This new measure, the Alzheimer's Patient Partners Life Impact Questionnaire (APPLIQue), may fill an important gap in assessing the impact of AD on spousal caregivers and outcomes of interventions aimed at caregivers as well as persons with AD.