White matter damage on diffusion tensor imaging correlates with age-related cognitive decline.

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Aging Research

Background:

• Age-related cognitive decline is linked to damage in white matter tracts, termed 'cerebral disconnection'.
• Understanding the structural and pathological basis of this damage is crucial for addressing cognitive aging.

Purpose of the Study:

• To investigate the relationship between white matter integrity and cognitive function in healthy middle-aged and elderly adults.
• To explore the pathological underpinnings of age-related white matter changes using advanced neuroimaging techniques.

Main Methods:

• Diffusion Tensor Imaging (DTI) was used to assess white matter structure (Fractional Anisotropy, Mean Diffusivity).
• Magnetic Resonance Spectroscopy (MRS) examined the pathological basis, including N-acetyl aspartate levels.
• 106 healthy adults underwent DTI and MRS, with cognitive assessments of executive function, working memory, and processing speed.

Main Results:

• A significant age-related decline in white matter integrity was observed, with reduced FA and increased diffusivity.
• DTI measures correlated with performance across all cognitive domains, particularly working memory, even after controlling for age.
• Neuronal marker N-acetyl aspartate showed a correlation with DTI parameters, suggesting axonal integrity is linked to white matter structure.

Conclusions:

• Findings support white matter damage, likely due to axonal loss, as a driver of age-related cognitive decline.
• Working memory appears especially sensitive to the integrity of complex white matter networks.