Cognitive impairment in multiple sclerosis (MS) has been linked to functional connectivity abnormalities. In a cross-sectional study, published in Neurology, researchers postulated that functional network regions may be susceptible to disease-related “wear-and-tear” and that this can be observable on co-occurring abnormalities on other MRI metrics.
“While there have been calls to use functional connectivity measures as biomarkers there remains to be a full understanding of why they are affected in MS,” researchers wrote.
The investigators performed multimodal 3T MRI and assessment with the Brief Repeatable Battery of Neuropsychological tests on 102 patients with relapsing-remitting MS and 27 healthy controls. Patients with MS were classified as cognitively impaired if they scored 1.5 or higher standard deviations below the control mean on two or more tests (n=55), or were otherwise considered cognitively preserved (n=47). Functional connectivity was assessed with Independent Component Analysis and dual regression of resting-state functional MRI images.
According to the results, functional connectivity was significantly attenuated in the anterior and posterior default mode networks and significantly increased in the right and left frontoparietal networks in cognitively impaired relative to cognitively preserved patients with MS. Networks showing functional abnormalities showed altered cerebral blood flow and anatomical connectivity locally and distally but not in overlapping locations, the researchers noted.
The authors concluded that the study provides “the first evidence that FC abnormalities are accompanied with local cerebral blood flow and structural connectivity abnormalities but also demonstrate that these effects do not occur in exactly the same location.”
Keywords: MRI, multiple sclerosis, standard deviations