Presence and Significant Determinants of Cognitive Impairment in a Large Sample of Patients with Multiple Sclerosis

Abstract

ObjectivesTo investigate the presence and the nature of cognitive impairment in a large sample of patients with Multiple Sclerosis (MS), and to identify clinical and demographic determinants of cognitive impairment in MS.Methods303 patients with MS and 279 healthy controls were administered the Brief Repeatable Battery of Neuropsychological tests (BRB-N); measures of pre-morbid verbal competence and neuropsychiatric measures were also administered.ResultsPatients and healthy controls were matched for age, gender, education and pre-morbid verbal Intelligence Quotient. Patients presenting with cognitive impairment were 108/303 (35.6%). In the overall group of participants, the significant predictors of the most sensitive BRB-N scores were: presence of MS, age, education, and Vocabulary. The significant predictors when considering MS patients only were: course of MS, age, education, vocabulary, and depression. Using logistic regression analyses, significant determinants of the presence of cognitive impairment in relapsing-remitting MS patients were: duration of illness (OR = 1.053, 95% CI = 1.010–1.097, p = 0.015), Expanded Disability Status Scale score (OR = 1.247, 95% CI = 1.024–1.517, p = 0.028), and vocabulary (OR = 0.960, 95% CI = 0.936–0.984, p = 0.001), while in the smaller group of progressive MS patients these predictors did not play a significant role in determining the cognitive outcome.ConclusionsOur results corroborate the evidence about the presence and the nature of cognitive impairment in a large sample of patients with MS. Furthermore, our findings identify significant clinical and demographic determinants of cognitive impairment in a large sample of MS patients for the first time. Implications for further research and clinical practice were discussed.

Age and disability drive cognitive impairment in multiple sclerosis across disease subtypes

“…The use of these measures should probably be expanded in future studies, as education alone is probably not a good enough surrogate of cognitive reserve in many populations, as suggested by the results from the present and several of the previous studies, which have reported no direct association of CI and education. 8,13 In conclusion, the findings obtained from this large clinical series strongly imply that the presence of CI is more related to patient age and disease severity than to disease duration or subtype per se. Furthermore, this study clearly documents a significant presence of CI since the earlier stages of MS, which increases in frequency and severity in the progressive stages.…”

“…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.…”

Verbal Fluencies and Fampridine Treatment in Multiple Sclerosis

“…Regarding the MS forms, in our study, 87% of patients presented a progressive form. A recent study did not identify duration of illness, age, EDSS, fatigue as significant predictors of cognitive impairment in the progressive form [40]. Those results associated with a repeated measure design, where each patient being his own control, may minimize the influence of confounding factors in our study.…”

Association between smoking and cognitive impairment in multiple sclerosis

“…This difference might be due to fact that there is a higher proportion of male smokers as opposed to female smokers in the general population (approximately 3:1), and this is likely reflected in our MS patient sample 23. Additionally, previous studies have reported that male MS patients have greater cognitive impairments than females,26 but in a recent extensive study, it was found that sex is not associated with cognitive impairment 27…”