Vulnerability to memory decline in aging - a mega-analysis of structural brain change

Area of Science:

• Neuroscience
• Gerontology
• Radiology

Background:

• Episodic memory loss is a common concern in aging, often linked to brain atrophy.
• The precise relationship between brain structural changes and memory decline, especially with age and genetic predisposition, requires further elucidation.

Purpose of the Study:

• To investigate the association between brain atrophy and episodic memory decline in healthy aging adults.
• To determine if this association is amplified by age and genetic risk for Alzheimer's Disease (AD).
• To explore whether memory decline correlates with global or regional brain atrophy patterns.

Main Methods:

• A mega-analysis of 13 longitudinal datasets comprising 3,737 cognitively healthy adults.
• Utilized 10,343 MRI scans and 13,460 memory assessments.
• Examined associations between brain structural changes and memory change over time, considering age and APOE ε4 carrier status.

Main Results:

• A nonlinear relationship was observed between memory decline and brain atrophy, particularly in individuals with accelerated brain structural decline.
• The association was most pronounced in the hippocampus but also involved widespread cortical and subcortical regions.
• Associations strengthened significantly with age, becoming moderate in individuals in their eighties. APOE ε4 carrier status did not influence the change-change associations.

Conclusions:

• Common macrostructural substrates underlie memory function in older adults, vulnerable to age-related factors.
• Brain atrophy is a significant, age-dependent correlate of memory decline, independent of overt Alzheimer's pathology.
• Memory decline is linked to both global and regional brain structural changes, highlighting the complex interplay of aging factors.