Background and purpose
The role of intracranial steno‐occlusive disease in cognitive impairment and dementia is unclear and has not been well studied.
Methods
A total of 32 consecutive patients (13 males, aged 54 ± 12 years) with asymptomatic steno‐occlusive middle cerebral artery (MCA) disease, defined as >70% stenosis on maximum intensity projection images or a complete signal loss of MCA trunk on magnetic resonance angiography, and 20 age‐ and education‐matched normal controls (12 males, 60 ± 8 years old) were compared for neuropsychological performance, gray matter volume and neural network analysis.
Results
The patient group did not show a significant decrease in gray matter volume or cognitive tests except for their performance on the grooved pegboard test. However, graph analysis of resting‐state functional magnetic resonance imaging showed significant decreases in network strength, global efficiency and the clustering coefficient, as well as a longer characteristic path length (P < 0.05). The diffusive decrease pattern was particularly located in interhemispheric connectivity and there was no compensatory hyperconnectivity in any brain regions.
Conclusion
In asymptomatic steno‐occlusive MCA disease, cognition and neural network changes are mismatched and have underlying pathophysiological mechanisms that are different from those of neurodegenerative disease.