Characteristics of cognitive impairment and resting-state functional MRI in patients with ischemic deep white matter lesions

Abstract

Objective To investigate characteristics of cognitive impairment in patients with ischemic deep white matter lesions (DWMLs) and the correlation of cognitive impairment with changes in cortical functionality in different brain regions. Methods We analyzed the data of 38 hospitalized patients or outpatients with mild ischemic DWMLs in our department, including 18 with cognitive impairment and 20 with normal cognitive function. Eighteen patients without DWMLs matched for age, gender and education level served as the control group. The cognitive function of the participants was assessed with neuropsychological tests, and resting-state functional magnetic resonance imaging (fMRI) was performed to detect the cortical regions with functional abnormalities based on the fractional amplitude of low frequency fluctuation (fALFF). Results We found that the patients with DWMLs had significant impairment of executive, attention, memory and visuospatial functions (P < 0.05), and deterioration of executive function and attention function could occur in early stage of cognitive impairment. The fALFFs of the bilateral middle frontal gyrus, bilateral cuneiform lobe, left anterior cuneiform lobe, left anterior cingulate gyrus, bilateral middle temporal gyrus, and left medial occipitotemporal gyrus were markedly reduced, while those of the left hippocampus-amygdaloid nucleus, left superior parietal gyrus, and left cerebellum vermis were obviously increased in patients with both DWMLs and cognitive impairment as compared with the control group (P < 0.05). In patients with DWMLs but normal cognitive function, the fALFFs of the bilateral middle frontal gyrus, left anterior cingulate gyrus, and bilateral middle temporal gyrus were also significantly decreased in comparison with the control group (P < 0.05), but no brain regions with increased fALFF were detected in these patients. Pearson correlation analysis suggested a significant correlation between these abnormalities in the brain regions and cognitive impairment in the patients with DWMLs. Conclusion DWMLs can induce impairment of the executive, attention, memory and visuospatial functions, and deteriorated executive and attention functions can be the initial symptoms of cognitive impairment caused by DWMLs. Resting-state fMRI can detect functional deterioration in multiple brain regions, which was significantly correlated with cognitive impairment in patients with ischemic DWMLs. Impaired cortical function may be one of the causes of cognitive impairment induced by ischemic DWMLs.

Keywords

• deep white matter lesions
• cognitive impairment
• neuropsychological tests
• resting-state functional magnetic resonance imaging
• cerebral cortex