MULTIPLE SCLEROSIS MSJ JOURNAL1258 journals.sagepub.com/home/msj BackgroundCognitive impairment (CI) is known to be present in all stages of multiple sclerosis (MS); however, the prevalence estimates vary considerably between studies, ranging from 40% to 65%. 1 The profile of CI in the overall MS population is now relatively well known, involving mainly complex attention, information processing speed, episodic memory, and executive functions. 1,2 Therefore, brief neuropsychological batteries for MS 3 and newly developed assessment tools 4 mainly focus on the assessment of these functions. However, few studies investigated the differences in the prevalence and profile of CI between the different MS disease subtypes, providing heterogeneous results. [5][6][7][8][9] Many of these studies included small clinical samples and focused mainly on relapsing remitting (RR) or progressive forms. Moreover, the association of CI with several clinical features, such as physical disability, sex, and disease duration, is not well established, since inconsistent results have been reported in the literature. [10][11][12][13] The heterogeneity of the published literature could be, at least in part, attributable to small sample size and dissimilarities in the clinical characteristics of the studies' samples. Exploring the independent effects of age, physical disability, disease duration, and disease subtype could prove central to provide a better understanding of the potential role and interaction of cognitive reserve, brain aging, and disease severity for determining CI in MS. The severity of impairment and the number of involved domains were significantly higher in SP and primary progressive multiple sclerosis (PPMS) than in CIS and RR. In multivariable logistic regression analysis, the presence of CI was significantly associated with higher Expanded Disability Status Scale (EDSS) and older age. Conclusion: CI is present in all MS subtypes since the clinical onset and its frequency is increased in the progressive forms, but these differences seem to be more associated with patient age and physical disability than to disease subtype per se.

Cognitive outcome in pediatric-onset MS can be heterogeneous. Progression of cognitive problems in a few subjects and potential for compensation and improvement in others call for systematic cognitive screening in this population and development of effective treatment strategies.