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Objectives: Cognitive dysfunction (CD) is frequent in multiple sclerosis (MS) and can occur at early stages. Whereas functional reorganization with disease progression has been described for the motor system in MS using fMRI, no such studies exist for cognition. We attempted to assess the concept of functional reorganization concerning cognition using a simple "Go/No-go" fMRI paradigm., Methods: Patients with a clinically isolated syndrome (CIS, n = 10), relapsing-remitting MS (RRMS) (n = 10), or secondary progressive MS (SPMS) (n = 10), and 28 healthy controls (HC), underwent a comprehensive neuropsychological test battery, clinical examination, structural imaging, and an fMRI Go/No-go discrimination task at 3 T., Results: Patients performed worse than HC regarding memory, sustained attention and concentration, and information processing. These differences were driven by patients with SPMS. The fMRI task elicited activation in a widespread network including bilateral mesial and dorsolateral frontal, parietal, insular, basal ganglia, and cerebellar regions. Task performance was similar between phenotypes, but deviation from the activation pattern observed in HC and patients with CIS increased with disease progression. Patients with RRMS showed increased brain activation in the precuneus, both superior parietal lobes, and the right fusiform gyrus, and recruited the hippocampus with increasing demands. Patients with SPMS demonstrated the most abnormal network function, including recruitment of pre-SMA, bilateral superior and inferior parietal, dorsolateral prefrontal, right precentral, bilateral postcentral, and right temporal brain areas., Conclusion: Using a cognitive fMRI paradigm, we were able to confirm adaptive changes of neuronal activation with progressing MS and to provide strong evidence for their compensatory nature, at least partially.

Background: Cognitive deficits are frequent in multiple sclerosis (MS) and have been associated with morphologic brain changes. Less information exists on their extent and relation to MRI findings in clinically isolated syndrome (CIS). It is also unclear if structural changes as detected by magnetization transfer (MT) imaging may provide an additional explanation for cognitive dysfunction., Objective: To analyse the extent of cognitive deficits and their relation to MRI metrics including MT imaging in CIS compared to relapsing-remitting MS (RRMS)., Methods: Forty-four CIS and 80 RRMS patients underwent the Brief Repeatable Battery of Neuropsychological Tests (BRB-N) and a 3 T MRI scan., Results: BRB-N subtests revealed similar results in CIS and RRMS. Impaired mental processing speed was most prevalent in both groups (CIS 13.6%; RRMS 16.3%) and thus served for correlation with MRI metrics. Using stepwise linear regression analyses, the strongest predictor for decreased mental processing speed was normalized cortex volume (p < 0.001) followed by T₂-lesion load (p < 0.05) in RRMS, whereas cortical MT ratio was the only MRI parameter associated with decreased mental processing speed in CIS (p < 0.005)., Conclusion: Cognitive dysfunction occurs in CIS in a pattern similar to RRMS, with impaired mental processing speed being most prevalent. Cortical MT-ratio changes may be an early sign for tissue changes related to impaired mental processing speed in CIS while this association shifts to increased signs of cortical atrophy and lesion load in RRMS.

Background: Cognitive deficits are frequent in multiple sclerosis (MS) and have been associated with morphologic brain changes. Less information exists on their extent and relation to MRI findings in clinically isolated syndrome (CIS). It is also unclear if structural changes as detected by magnetization transfer (MT) imaging may provide an additional explanation for cognitive dysfunction.Objective: To analyse the extent of cognitive deficits and their relation to MRI metrics including MT imaging in CIS compared to relapsing-remitting MS (RRMS).Methods: Forty-four CIS and 80 RRMS patients underwent the Brief Repeatable Battery of Neuropsychological Tests (BRB-N) and a 3 T MRI scan.Results: BRB-N subtests revealed similar results in CIS and RRMS. Impaired mental processing speed was most prevalent in both groups (CIS 13.6%; RRMS 16.3%) and thus served for correlation with MRI metrics. Using stepwise linear regression analyses, the strongest predictor for decreased mental processing speed was normalized cortex volume (p < 0.001) followed by T2-lesion load (p < 0.05) in RRMS, whereas cortical MT ratio was the only MRI parameter associated with decreased mental processing speed in CIS (p < 0.005).Conclusion: Cognitive dysfunction occurs in CIS in a pattern similar to RRMS, with impaired mental processing speed being most prevalent. Cortical MT-ratio changes may be an early sign for tissue changes related to impaired mental processing speed in CIS while this association shifts to increased signs of cortical atrophy and lesion load in RRMS. [ABSTRACT FROM AUTHOR]