Memory Test Performance of People with Subjective Cognitive Decline Recruited From Different Settings: A Systematic...

Area of Science:

• Neuroscience
• Cognitive Psychology
• Gerontology

Background:

• Subjective cognitive decline (SCD) is self-reported cognitive impairment without objective deficits.
• SCD may represent the earliest stage of neurodegeneration.
• Understanding memory performance in SCD is crucial for early detection.

Purpose of the Study:

• To determine if objective memory performance differs between individuals with and without SCD.
• To compare memory performance between SCD and mild cognitive impairment (MCI) groups.
• To synthesize existing evidence on memory deficits in SCD.

Main Methods:

• Systematic literature search (2014–2023) across multiple databases.
• Random-effects meta-analysis of episodic memory task performance.
• Inclusion of studies recruiting SCD from community/medical settings.
• Separate meta-analysis for SCD vs. MCI comparison.

Main Results:

• Individuals with SCD showed significantly worse memory performance than non-SCD controls (Hedges' g = -0.19).
• Individuals with SCD performed significantly better than MCI participants (Hedges' g = 1.20).
• Significant heterogeneity and risk of publication bias were noted.

Conclusions:

• Detailed memory assessments may detect subtle objective memory impairments in SCD.
• The clinical significance of the observed small effect size in SCD requires further investigation.
• Higher quality, larger studies are needed to explore moderating factors.