Self-reporting quality of life in mild-to-moderate Alzheimer's disease and Lewy body dementia: Comparing capability and health-focused measures using response process validation

While self-reporting remains feasible in mild-to-moderate Alzheimer's disease and Lewy body dementia, capability measures pose greater cognitive demands than health-focused measures, primarily due to comprehension of abstract concepts and distinguishing capability from functioning rather than memory retrieval. Measures should be validated for specific dementia subtypes, and hybrid approaches anchoring capability judgements in concrete experiences warrant exploration. This exploratory study provides preliminary response process validity evidence to inform measure selection in dementia research and clinical practice, ensuring people living with dementia can meaningfully participate in health economics and policy decisions that affect their care.