Factors associated with informant-reported cognitive decline in older adults: a systemised literature review

Background
Dementia diagnoses are typically made where there is a significant, progressive decline in cognitive functioning. Evidence of such decline is increasingly established through information provided by informants. However, some studies demonstrate that informant reports may not always be accurate and may be biased by extraneous factors. This review aimed to elucidate factors that have been identified as potentially having some influence on informant reports of cognitive decline.

Method
A search of PsychInfo, ASSIA, PubMed and Web of Science databases identified 13 peer-reviewed studies that met criteria for inclusion in the review.

Results
Reviewed studies provide some evidence for associations between informant-reported cognitive decline and demographic characteristics (patient age, education, ethnicity and informant gender), clinical factors (dementia severity, diagnosis, behavioural disturbance, everyday functioning) and psychological factors (patient depressive symptoms and neuroticism, informant psychological distress and burden). Several methodological limitations of the evidence base were identified.

Conclusion
Findings suggest that informant-reported cognitive decline may not always be wholly reliable in that information holds potential to be influenced by both patient and informant characteristics. Clinical and empirical implications are discussed.