Executive dysfunction represents an underestimated component of cognitive impairment in multiple sclerosis

• Published in: Multiple sclerosis Vol. 14; p. S258
• Main Authors: Khalil, M, Enzinger, C, Petrovic, K, Loitfelder, M, Tscherner, M, Jehna, M, Wallner-Blazek, M, Ropele, S, Schmidt, R, Fuchs, S, Fazekas, F
• Format: Journal Article
• Language: English
• Published: 01.09.2008
• ISSN: 1352-4585

Background: Subtle deficits in various cognitive domains exist in approximately 30 to 70% of multiple sclerosis (MS)patients. Converging evidence suggests that cognitive deficits can be found even in early stages of the disease. It is more controversial what type of deficits are the earliest to appear and how this is affected by the scrutiny of the evaluation. Objective: The aim of this ongoing study is to more fully explore the spectrum of cognitive impairment in consecutive MSoutpatients with a focus on early MS. Methods: To the present, 87 MS patients (29 clinically isolated syndrome (CIS); mean Expanded Disability Status Scale (EDSS) 1.2 (SD 1.0), mean disease duration 0.7 (SD 2.6) years and 58 relapsed-remitting multiple sclerosis (RRMS); mean EDSS 2.1 (SD 1.3), mean disease duration 8.8 (SD 8.4) years) underwent the Brief Repeatable Battery of Neuropsychological Tests (BRB-N) and the Wisconsin Card Sorting Test (WCST) to specifically search for executive dysfunction. Results: While the global index score of the BRB-N was normal for both subgroups, the subtests showed deficits in the domains of memory in 6.9% (CIS 0.0%, RRMS 10.3%), long-term memory in 8.0% (CIS 3.4%, RRMS 10.3%), concentration in 17.4% (CIS 10.7%, RRMS 20.7%), and for executive functions in 6.9% (CIS 3.4%, RRMS 8.6%). Using the WCST, however, more than doubled the proportion of subjects scoring abnormal results (16.5%; CIS 14.3%, RRMS 17.5%). The differences between the subgroups were statistically not significant. Conclusions: These results confirm that cognitive impairment occurs at the earliest stages of MS and increases with ongoing disease. The frequency of domain specific deficits may be underestimated by using a global test battery such as seen for executive dysfunction.