Specific locations within the white matter and cortex are involved in the cognitive impairments associated with periventricular white matter lesions (PWMLs)

Abstract

The aim of this study was to test the hypothesis that both white matter disruption and the corresponding cortical dysfunction are involved in the cognitive impairments associated with periventricular white matter lesions (PWMLs). Twenty-two PWMLs subjects were divided into cognitively impaired (PWMLs-CI) and normal (PWMLs-CN) groups. Twelve subjects with normal magnetic resonance imaging (MRI) and cognition were recruited as controls. After cognitive evaluation, diffusion tension image (DTI) and resting-state functional MRI (rfMRI) scans, the fractional anisotropy (FA) values of DTI and the fractional amplitude of low-frequency fluctuation (fALFF) values of rfMRI were measured. Finally, correlations between the cognitive scores and MRI values were analyzed in PWMLs subjects. Our results demonstrated that compared with the other groups, the PWMLs-CI group demonstrated significantly decreased scores in Trail-Making Test (TMT), Symbol Digit Modalities Test (SDMT) and Logical Memory Test (LMT). Compared with the PWMLs-CN group, the PWMLs-CI group displayed decreased FA values in the right splenium of the corpus callosum and right posterior cingulum bundle; lower fALFF values in the left frontal middle gyrus, left precentral gyrus, right angular gyrus and right precuneus; and higher fALFF values in the right mid cingulum cortex, right hippocampus amygdala, right cerebellar hemisphere and left vermis. Meanwhile, the cognitive assessment scores were significantly correlated with the FA or fALFF values in some of the above-mentioned white matter or cortical regions. Conclusively, our results indicate that specific regions of WMLs and cortical dysfunction are involved in the cognitive impairments associated with PWMLs.

Keywords: Cognitive impairments; Cortical dysfunction; Periventricular white matter lesions; White matter lesions.