Differential utility of immediate versus delayed memory measures for the identification of episodic memory impairment: Systematic review and meta-analysis.
Hannah Cruickshank Campbell, Stephen C Bowden, Geoff Saw et al.
✦ AI-curated · Sources linked
In 30 seconds
This systematic review and meta-analysis compared immediate with delayed recall for distinguishing patients with suspected or known episodic memory impairment from healthy controls. Across 290 studies, including 71,381 controls and 45,054 patients, controls performed better on both immediate recall (g = 1.074, 95% CI [0.973, 1.176]) and delayed recall (g = 1.148, 95% CI [1.034, 1.261]). Delayed recall provided statistically greater patient-control differentiation, but the difference was not clinically meaningful. Longer delays did not predict stronger differentiation, and findings varied across clinical subgroups and test types.
Key findings
- Patient-control differentiation was greater for delayed than immediate recall (g = -0.083, 95% CI [-0.126, -0.041]), but the difference was not clinically meaningful.
- Delay length, ranging from 40 s filled delay to 6 weeks, did not predict delayed recall effects or moderate the immediate-versus-delayed difference.
- Word list, story, and shape measures showed no effect of increasing delay; word list measures showed no delayed recall advantage.
- Delayed recall offered a small to medium advantage in mild cognitive impairment and Alzheimer's disease, but not across all measures.
Why it matters
Delayed recall is often treated as especially informative for episodic memory impairment, but these findings suggest that its overall advantage over immediate recall is small and not clinically meaningful. The lack of a consistent benefit from longer delays or across test types cautions against assuming that delay alone improves identification; interpretation may depend on the measure and clinical subgroup.
What to keep in mind
The meta-analysis included varied measures and delay intervals, and the reported advantage was not consistent across test types or clinical subgroups. The abstract notes that further research is needed to clarify delayed recall's utility.