Microstructural degeneration and cerebrovascular risk burden underlying executive dysfunction after stroke.

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Executive dysfunction is common in stroke patients (40%) but poorly predicted by stroke characteristics.
• Cerebrovascular burden significantly impacts cognitive function and brain network integrity.
• Understanding predictors of executive dysfunction is crucial for patient outcomes.

Purpose of the Study:

• To investigate if white matter integrity and cerebrovascular risk factors better explain executive dysfunction than stroke severity.
• To explore the mediating role of cerebrovascular burden in the relationship between white matter integrity and executive function.

Main Methods:

• Structural equation modeling was used to analyze data from 126 stroke patients and 40 controls.
• Measures included white matter integrity (fractional anisotropy, mean diffusivity) via MRI, cerebrovascular risk factors, and neuropsychological tests of executive function.
• Neuroimaging and cognitive assessments were conducted three months post-stroke.

Main Results:

• Executive function deficits were observed in stroke patients compared to controls.
• White matter microstructural integrity showed a stronger correlation with executive dysfunction (r=-0.74) than stroke severity (r=0.22).
• Cerebrovascular burden mediated the link between white matter integrity and executive function, with degeneration in the superior longitudinal fasciculus being a key factor.

Conclusions:

• White matter microstructural degeneration, particularly in the superior longitudinal fasciculus, is a better predictor of executive dysfunction than stroke severity.
• Both executive dysfunction and stroke incidence appear to be manifestations of underlying cerebrovascular risk factors.
• Targeting cerebrovascular risk factors may be key to mitigating cognitive deficits post-stroke.