Optimising dementia screening in community-dwelling older adults: A rapid review of brief diagnostic tools in Singapore

Introduction: Timely detection of dementia enables early access to dementia-specific care services and interventions. Various stakeholders brought together to refine Singapore's dementia care strategy identified a lack of a standardised cognitive screening tool and the absence of a comparative review of existing tools. We hence conducted a rapid review to evaluate the diagnostic performance of brief cognitive screening tools in identifying possible dementia among community-dwelling older adults in Singapore.

Method: Brief cognitive screening tools were defined as interviews or tests administered in ≤5 minutes. Studies performed in Singapore on older adults ≥60 years, which used locally-validated comparators and reported outcomes of clinician-diagnosed dementia were included. Rapid review methodology was used in study screening and selection. Quality Assessment of Diagnostic Accuracy Studies version 2 tool was used for risk-of-bias assessment. A negative likelihood ratio (LR-) of ≤0.2 was defined a priori as having a moderate effect in shifting post-test probability.

Results: Fourteen studies were included in qualitative synthesis: 3 studies evaluated self-/informant-based tools only, 4 evaluated performance-based measures only and 7 evaluated combination approaches. Eight-item Informant Interview to Differentiate Aging and Dementia (AD8) was the most studied self-/ informant-based tool. One study found informant AD8 (iAD8) superior to self-rated AD8. Another study found iAD8 superior to Mini-Mental State Examination. Among performance-based measures, Abbreviated Mental Test, Visual Cognitive Assessment Test-Short form version 1 (VCAT-S1), VCAT-S2 and Mini-Cog had LR- <0.2. Minimal improvement of combination approaches compared to iAD8 alone was demonstrated.

Conclusion: Our review suggests the limited utility of dementia screening in communities with low dementia prevalence and supports a case-finding approach instead. With a reliable informant, iAD8 alone has sufficient discriminant ability. Further research is needed to specifically assess the diagnostic ability of performance-based tools in community settings.