Apathy Measures in Older Adults and People with Dementia: A Systematic Review of Measurement Properties Using the COSMIN Methodology

Background: Apathy is highly prevalent in dementia and is also seen in mild cognitive impairment and the general population. Apathy contributes to failure to undertake daily activities and can lead to health problems or crises. It is therefore important to assess apathy. However, there is currently no gold standard measure of apathy. A comprehensive systematic review of the measurement properties of apathy scales is required. Methods: A systematic review was registered with PROSPERO (ID: CRD42018094390). MEDLINE, Embase, PsycINFO, and CINAHL were searched for studies that aimed to develop or assess the validity or reliability of an apathy scale in participants over 65 years, living in the community. A systematic review was conducted in line with the COnsensus-based Standards for the selection of health Measurement INstruments procedure for reviewing patient-reported outcome measures. The studies' risk of bias was assessed, and all relevant measurement properties were assessed for quality. Results were pooled and rated using a modified Grading of Recommendations Assessment, Development, and Evaluation procedure. Results: Fifty-seven publications regarding 18 measures and 39 variations met the eligibility criteria. The methodological quality of individual studies ranged from inadequate to very good and measurement properties ranged from insufficient to sufficient. Similarly, the overall evidence for measurement properties ranged from very low to high quality. The Apathy Evaluation Scale (AES) and Lille Apathy Rating Scale (LARS) had sufficient content validity, reliability, construct validity, and where applicable, structural validity and internal consistency. Conclusion: Numerous scales are available to assess apathy, with varying psychometric properties. The AES and LARS are recommended for measuring apathy in older adults and people living with dementia. The apathy dimension of the commonly used Neuropsychiatric Inventory should be limited to screening for apathy.