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Peak width of skeletonized mean diffusivity (PSMD) is a new MRI marker, which has shown clinical relevance in some neurological conditions and, in preliminary data, in multiple sclerosis (MS). We aimed here to investigate, in a group of relapsing-remitting MS (RRMS) patients, the relationship between PSMD and cognitive performances, in comparison with other MRI measures. RRMS patients (n = 60) and normal controls (n = 15) underwent a 3 T MRI examination. MRI-based white matter (WM) lesion volume, microstructural integrity (assessed with Tract-Based Spatial Statistics of diffusion tensor imaging [DTI] images) and brain volumes (i.e., total brain, grey matter [GM] and WM) were computed. In addition, PSMD was calculated through "skeletonization" of WM tracts and diffusion histograms. Cognition was evaluated with Rao's Brief Repeatable Battery (BRB), which incorporated tests of verbal and visual memory, attention, concentration, information processing speed and verbal fluency. PSMD closely correlated with symbol digit modalities test (SDMT) (r = −0.70, p < 0.001) and, to a lesser extent, with verbal and visual memory tests. Multiple regression analysis showed that PSMD explained SDMT variance (R2 = 0.54, p < 0.001) more than other MRI measures. Results point out the relevance of microstructural damage, as assessed by PSMD, as a reliable marker of cognition in MS, especially in explaining dysfunction in information processing speed. [ABSTRACT FROM AUTHOR]

Two hundred and twenty-four patients at their first diagnosis of multiple sclerosis (MS) were prospectively followed for a mean period of 9.78 years. We considered as endpoints the time to reach non-reversible disability levels corresponding to EDSS scores of 4.0 and 6.0, and the beginning of a secondary progressive phase in the relapsing-remitting subgroup of patients. An initially progressive course and higher basal EDSS scores proved to be the best predictors of unfavorable prognosis. A greater number of functional systems involved at onset as well as higher residual deficits in pyramidal, visual, sphincteric and cerebellar systems were other factors predictive of a poor outcome, whereas sensory system involvement turnet out to be favorable. A longer first inter-attack interval was associated with a better prognosis. However, overall number of relapses in the first two years of the disease was of no prognostic value. The presence of oligoclonal banding in the cerebrospinal fluid and a cerebral MRI exam strongly suggestive or suggestive of MS in the early phases of the disease were associated with a higher probability of a worse outcome. [ABSTRACT FROM AUTHOR]