Cortical Thinning in the Medial Temporal Lobe and Precuneus Is Related to Cognitive Deficits in Patients With Subcortical Ischemic Vascular Disease

Abstract

Subcortical ischemic vascular disease (SIVD) is a major cause of vascular cognitive impairment (CI) and features extensive atrophy in the cerebral cortex. We aimed to test the hypothesis that cognitive deficits in SIVD are linked to decreased cortical thickness in specific brain regions, which may constitute neuroimaging biomarkers of CI. Sixty-seven SIVD patients without (SIVD-NC, n = 35) and with (SIVD-CI, n = 32) CI and a group of healthy controls (HCs, n = 36) underwent structural magnetic resonance imaging (MRI) and cognitive functional assessments. FreeSurfer was used to preprocess structural MRI data and to calculate and compare cortical thickness. The correlation between cortical thickness and cognitive scores was examined in SIVD patients. Significantly altered cortical thickness in the bilateral insula, middle and inferior temporal lobes, precuneus, and medial temporal lobe (MTL) was identified among the three groups (p < 0.05, Monte Carlo simulation corrected). Post hoc results showed significantly decreased thickness in the bilateral insula and temporal lobe in SIVD-NC and SIVD-CI patients compared with HCs. However, the areas with reduced cortical thickness were larger in SIVD-CI than SIVD-NC patients. SIVD-CI patients had significantly reduced thickness in the bilateral precuneus and left MTL (Bonferroni corrected) compared with SIVD-NC patients when we extracted the mean thickness for each region of interest. In SIVD patients, the thicknesses of the left MTL and bilateral precuneus were positively correlated with immediate recall in the memory test. SIVD might lead to extensive cerebral cortical atrophy, while atrophy in the MTL and precuneus might be associated with memory deficits.

Keywords: cerebral small vessel disease; cognition; cortical thickness; magnetic resonance imaging; memory.

FIGURE 1

The lesion probability of white matter hyperintensities in patients with subcortical ischemic vascular disease.

FIGURE 2

The results of one-way analysis of variance (ANOVA). (A) Brain regions with significant differences among the three groups based on one-way ANOVA. (B) Inflated view of the labeled ANOVA results.

FIGURE 3

Comparison of post hoc results in significant brain regions between each pair of groups. (A) The difference in thickness between subcortical ischemic vascular disease without cognitive impairment (SIVD-NC) patients and healthy controls (HCs). Blue indicates that the thickness in SIVD-NC patients was lower than that in HCs. (B) The difference in thickness between the subcortical ischemic vascular disease with cognitive impairment (SIVD-CI) group and HCs. Blue indicates that the thickness in the SIVD-CI group was less than that in HCs. HCs, healthy controls; L, left; R, right.

FIGURE 4

Differences in the mean thickness between the subcortical ischemic vascular disease without cognitive impairment (SIVD-NC) and with cognitive impairment (SIVD-CI) groups; correlation between cognitive scores and the mean thickness. Differences in the left medial temporal lobule (MTL) (A) and left (B) and right (C) precuneus between the SIVD-NC and SIVD-CI groups. (D) Correlations between Rey’s Auditory Verbal Learning Test (RAVLT) immediate recall and the left MTL in patients with SIVD. Correlations between left (E) and right (F) precuneus and Rey-Osterrieth complex figure test (ROCF) immediate recall scores in patients with SIVD. HC, healthy controls; L, left, R, right.

FIGURE 5

Mediation effects of the thickness of left medial temporal lobe on the relationship between the white matter hyperintensities and RAVLT immediate recall scores. RAVLT, Rey’s Auditory Verbal Learning Test.