Role of disturbed structural connectivity network in patients with white matter lesions and cognitive impairment...

ObjectiveThis study aimed to compare small-world network attributes between control participants without memory complaints and patients with white matter lesions showing cognitive impairment.MethodsChanges in diffusion tensor imaging and white matter fiber bundles in patients were analyzed. Brain structural network was constructed based on diffusion tensor imaging data, and topological properties of whole-brain small-world network were discussed. The damaged brain areas of patients with white matter lesions were studied, and the correlation between white matter lesion-related brain structural network abnormalities and cognitive impairment severity was discussed.ResultsCompared with the normal control with normal cognition group, fractional anisotropy was significantly reduced in the white matter lesions-non-dementia vascular cognitive impairment (WMLs-VCIND) and white matter lesions-vascular dementia (WMLs-VaD) groups, while mean diffusivity and radial diffusivity values were significantly increased (p < 0.05). The small-world network attributes demonstrated significant changes in λ/γ/σ values compared with the normal control with normal cognition group (p < 0.05). In the WMLs-VaD group, brain areas with reduced node-efficiency were mainly concentrated in the posterior cingulate gyrus, posterior cingulate gyrus, middle and superior lobes of right occipital region, superior lobe of the left occipital region, and right thalamus (p < 0.05). Nodal efficiencies in the WMLs-VaD group were lower than those in the WMLs-VCIND group (p < 0.05). All small-world parameters were significantly correlated with the total Mini-Mental State Examination and Montreal Cognitive Assessment scores.ConclusionsThere was extensive and subtle white matter fiber bundle damage in patients with white matter lesions. The brain structural network of patients with white matter lesions had small-world characteristics, and a reduction in small-world properties was related to reduction in cognitive function scores.