Mapping cognitive dysfunction in relapsing multiple sclerosis with mild disability: A cross-sectional study from South India

Abstract

Background: Cognitive dysfunction in multiple sclerosis (MS) occurs early. Locally adapted neuropsychological data from India in MS is scarce.

Objectives: We aimed to identify the pattern of cognitive impairment in relapsing MS (RMS) with mild disability using a regionally-adapted MS-specific cognitive battery.

Methodology: The study included 59 persons with MS (pwMS) with expanded disability status scale (EDSS)≤ 4 and 62 controls. The battery had 8 neuropsychological tests (Paced Auditory Serial Addition Test [PASAT], Symbol Digit Modalities Test [SDMT], Rey Auditory Verbal Learning Test [RAVLT], Brief Visuospatial Memory Test-Revised [BVMT-R], verbal fluency [VF], Judgement of Line Orientation Test [JOLOT], Wisconsin Card Sorting Test [WCST] and Trail Making Test-B [TMT-B]) with 11 measures. The scores were compared between the groups for pattern and associations of cognitive impairment.

Results: The pwMS cohort had 39 (66.1%) females; mean age of 32.56 (±8.17) years. Scores were significantly worse for pwMS in 10 of 11 tests (except JOLOT). Cohen's-d test showed the largest effect sizes for PASAT, SDMT, VF and TMT-B. Cognitive impairment (defined as ≥2 abnormal tests) were noted in 41 (69.5%) pwMS. Male sex was associated with cognitive impairment (p = 0.002).

Conclusions: In pwMS with mild disability, nearly two-thirds had cognitive abnormalities, predominantly involving processing speed, working memory, executive function, and VF.

Keywords: MACFIMS; Multiple sclerosis; RRMS; cognition; cognitive dysfunction.

Figure 1.

Distribution of abnormal scores in persons with multiple sclerosis (N = 59) and healthy control group (N = 62). (A) Radar plot for the mean of total scores for the different psychological tests among the two groups (excluding TMT-B where higher scores indicate worse performance) (B) Distribution of persons with multiple sclerosis with abnormal scores in each of the 11 neuropsychological tests compared to the control group classified by sex. Abbreviations: BVMT-R TL, Brief Visuospatial Memory Test-Revised total; BVMT-R DR, Brief Visuospatial Memory Test-Revised delayed recall; JOLOT, Judgment of Line Orientation Test; MS, multiple sclerosis; PASAT, Paced Auditory Serial Addition Test; RAVLT-TL, Rey Auditory Verbal Learning Test total; RAVLT-DR, Rey Auditory Verbal Learning Test delayed recall; N, number; SDMT, Symbol Digit Modalities Test; TMT-B, Trail Making Test-B; VF, Verbal Fluency; WCST, Wisconsin Card Sorting Test.