Longitudinal MRI and cognitive change in healthy elderly

Area of Science:

• Neuroscience
• Gerontology
• Radiology

Background:

• Cross-sectional studies link memory to hippocampus and executive function to frontal circuits.
• Longitudinal MRI changes and cognitive decline relationships are less understood.

Purpose of the Study:

• To investigate longitudinal MRI changes predicting cognitive decline in healthy aging.
• Hypothesized hippocampus change predicts memory decline, and cortical atrophy/cerebrovascular disease predict executive function decline.

Main Methods:

• 50 healthy elderly subjects underwent structural MRI and cognitive testing at baseline and follow-up (mean 45 months).
• MRI measures included hippocampus, cortical gray matter, white matter signal hyperintensity (WMSH), and lacunae.
• Cognitive measures included episodic memory (MEM) and executive functioning (EXEC) composite scores.

Main Results:

• Hippocampal volume decrease correlated with episodic memory decline.
• Cortical gray matter decrease and increased WMSH independently predicted executive functioning decline.
• These findings held true in healthy elderly subjects.

Conclusions:

• Cognitive functioning declines with aging due to decreasing gray matter and hippocampal volume, and increasing WMSH.
• Cerebrovascular disease markers (WMSH) are associated with executive function decline in normal aging.