Thalamic atrophy, duration of illness, and years of education are the best predictors of cognitive impairment in multiple sclerosis

Abstract

Background: Cognitive impairment (CI) is common in multiple sclerosis. We assessed the relationship between CI and demographic, motor disability, and volumetric brain atrophy in relapsing remitting multiple sclerosis (RRMS). Methods: In all, 43 RRMS patients and 40 age-sex-, and education-matched normal volunteers were enrolled. Assessments included: demographic, Expanded Disability Status Scale (EDSS); Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS); and brain volumetric assessment.Results: The mean age of onset of RRMS patients was 25.72 y and the mean number of attacks was 3.30 ± 2.33/year. The total brain volume, cerebral, and cerebellar hemispheres, brainstem as well as thalamic and hippocampal gray matter were significantly reduced in RRMS patients compared with controls. CI was detected in 41.9% of patients. Patients with CI had fewer years of education (P = .001), a higher number of attacks (P = .002), worse EDSS scores (P = .030); reduced gray matter volume, particularly of the thalamus, and hippocampus compared with patients without CI. There were significant negative correlations between CI with duration of illness, number of attacks, time elapsed between onset and diagnosis, and EDSS. Thalamic volume showed strong positive correlations with CI (P < .0001). The best predictors of CI were thalamic atrophy, duration of illness, and years of education (P = .001, .010, and .035 respectively). Conclusion:We confirmed the presence of gray matter atrophy of the brain in RRMS patients. Volumetric magnetic resonance imaging measures of thalamus, duration of illness, and years of education could be useful biomarkers of CI in RRMS.