Alzheimer's Imaging Consortium

Area of Science:

• Neuroscience
• Cognitive Aging
• Alzheimer's Disease Research

Background:

• Subjective memory decline (SMD) is a potential early marker for Alzheimer's disease (AD).
• Previous studies show mixed results linking SMD to objective memory and brain changes, possibly due to single-item measures.
• The Everyday Cognition (ECog) scale uses multiple items and informant reports to better detect early AD risk.

Purpose of the Study:

• To investigate the association between ECog-based SMD and objective memory.
• To examine the relationship between ECog-SMD and neurodegenerative changes related to AD.
• To determine if ECog-SMD predicts future changes in memory and AD brain signatures.

Main Methods:

• Utilized data from the Vietnam Era Twin Study of Aging (VETSA) with cognitively unimpaired men.
• Administered the ECog memory subscale to participants and informants at two time points.
• Assessed objective memory and AD brain signature scores (hippocampal volume, cortical thickness) via MRI.
• Employed structural equation models to analyze concurrent and predictive associations.

Main Results:

• ECog-SMD, from both participant and informant reports, correlated with poorer objective memory and lower AD brain signature scores.
• ECog-SMD at baseline predicted future declines in objective memory and reductions in AD brain signatures.
• Increases in ECog-SMD over time were linked to memory declines but not changes in AD brain signatures.

Conclusions:

• ECog ratings of SMD reflect current objective memory and AD-related neurodegeneration.
• Participant-reported SMD shows association with future neurodegeneration, potentially identifying risks not detected by standard tests.