Fatigue is a common and early symptom in multiple sclerosis (MS). The cause of fatigue is still unclear. Neuroimaging results have been contradictory and inconclusive. Fatigue co-occurs with depression, and there is some evidence linking fatigue with circulating pro-inflammatory processes and elevated body temperature. We examined the relationship between fatigue and several variables including MRI measures, mood, systemic inflammation, and disability in one MS cohort, which has not been done before.

Fatigue Severity Scale (FSS) assessed fatigue in 185 early MS patients (RADIEMS cohort). T2 lesion volume and normalized volumes of cortical and subcortical gray matter were measured from 3D T1 and T2 MRIs. Mental Health Inventory (MHI) assessed mood. Body temperature was measured aurally. BMI was recorded. Erythrocyte sedimentation rate (ESR rank) assessed systemic inflammation. EDSS assessed disability. Controlling for age and sex, stepwise regression (entry p=.05) predicted FSS with all variables.