Dementia-specific quality of life instruments: a conceptual analysis

Background: Over the past 20 years, many researchers have worked in developing various methods for measuring quality of life (QoL) of people with dementia. The aim of this review is to develop the conceptual frameworks of the dementia-specific QoL instruments, to identify their evolution over time and to provide elements of reflection on the QoL concept in dementia and its evaluation. Methods: An electronic search was conducted on PsycINFO and MEDLINE databases, from January 1985 to June 2015 using a combination of key words that include QoL, dementia, and review. Results: The analysis of the conceptual frameworks of the 18 selected dementia-specific QoL tools shows a great diversity in: (1) the QoL definitions (e.g. health-related QoL definitions, QoL definitions based on Lawton's work, or similar to this latter); (2) the theoretical QoL models (e.g. Lawton' work and modified Lawton, adaptation, personhood); (3) the domains and dimensions; (4) the way to construct the instrument (e.g. development based on literature, opinion of the experts), and (5) the items' formulation (e.g. use of criterion of intensity or frequency). Conclusions: There are different conceptual frameworks in the dementia-specific QoL measures with improvements over time (e.g. inclusion of interesting concepts such as adaptation, taking into account the views of patients themselves). Each of the conceptual parameters (definitions, models, domains, and dimensions) is discussed to identify the scales that are conceptually the strongest. Through their review, recommendations for future instrument refinement and development are discussed and a new QoL definition is proposed.