Connecting the dots: microstructural properties of white matter hyperintensities predict longitudinal cognitive...

Area of Science:

• Neuroimaging
• Gerontology
• Cognitive Neuroscience

Background:

• White matter hyperintensities (WMHs) are common in aging brains and linked to cognitive impairment.
• Understanding the specific characteristics of WMHs that drive cognitive decline is crucial for early intervention.

Purpose of the Study:

• To investigate the relationship between distinct white matter hyperintensity (WMH) phenotypes and longitudinal cognitive decline in older adults.
• To determine if WMH volume and microstructural integrity predict cognitive decline over time.

Main Methods:

• Analysis of 11,933 WMHs from 497 community-dwelling older adults in The Irish Longitudinal Study on Ageing (TILDA) over six years.
• WMHs were phenotyped based on volume, fractional anisotropy (FA), and mean diffusivity (MD), distinguishing periventricular and deep lesions.
• Statistical analysis correlated WMH phenotypes with cognitive decline trajectories.

Main Results:

• High-volume, low FA deep and periventricular WMHs were significantly associated with accelerated cognitive decline.
• Small periventricular WMHs with near-normal microstructural integrity did not predict cognitive decline.
• WMH characteristics, including volume and microstructural integrity, are key factors in cognitive decline.

Conclusions:

• Distinct WMH phenotypes have differential associations with cognitive decline, suggesting they are not a monolithic entity.
• High-volume, microstructurally compromised WMHs represent a significant risk factor for cognitive impairment in older adults.
• Identifying specific WMH subtypes could enable targeted interventions for cognitive health in aging populations.