Cognitive aging is not created equally: differentiating unique cognitive phenotypes in "normal" adults

Area of Science:

• Neuroscience
• Gerontology
• Public Health

Background:

• Age-related cognitive decline presents a significant public health challenge due to its heterogeneity and unpredictability.
• Identifying distinct cognitive aging phenotypes and their predictive factors is crucial for early intervention.

Purpose of the Study:

• To identify distinct cognitive phenotypes in high-functioning older adults.
• To determine baseline factors that differentiate cognitive trajectories.
• To establish early markers for predicting cognitive decline in memory and processing speed.

Main Methods:

• Longitudinal study of 314 functionally normal adults (mean age 69).
• Classification of "declining" based on longitudinal slopes (< -1 SD) in memory or processing speed.
• Analysis of baseline factors including demographics, inflammation (TNFα), cognitive complaints, depressive symptoms, and neuroimaging (gray matter volume, white matter hyperintensities).

Main Results:

• Distinct phenotypes for processing speed decline (associated with age, inflammation, cognitive complaints) and memory decline (associated with male sex, lower depressive symptoms, gray matter volume, white matter hyperintensities).
• High accuracy in predicting future decline: 96.3% for speed decliners (using baseline speed, TNFα, cognitive complaints) and 88.5% for memory decliners (using baseline memory, sex, precuneal volume, white matter hyperintensities).

Conclusions:

• Cognitive aging is characterized by discrete phenotypes with non-overlapping underlying vulnerabilities.
• Early predictive markers can identify cognitive decline even within the "normal" aging spectrum.
• These findings highlight potential therapeutic targets for personalized interventions in cognitive aging.