Cognitively preserved MS patients demonstrate functional differences in processing neutral and emotional faces

The ability to recognize emotional facial expressions is crucial to adequate social behavior. Previous studies have suggested deficits in emotion recognition in multiple sclerosis (MS). These deficits were accompanied by several confounders including cognitive or visual impairments, disease duration, and depression. In our study we used functional MRI (fMRI) to test for potential early adaptive changes in only mildly disabled MS patients performing an emotion recognition task including the facial expressions of the emotions anger, fear and disgust. Fifteen relapsing-remitting MS patients with a median Expanded Disability Status Scale (EDSS) score of 2 (range: 0-3.5) and 15 healthy controls (HC) matched for age, gender, and education underwent behavioral (BERT: behavioral emotion recognition test; BRB-N: Brief Repeatable Battery for neuropsychological tests, WCST: Wisconsin Card Sorting Test) and clinical assessments (BDI: Beck Depression Inventory). Conventional MRI at 3.0T served to assess whole-brain volume, white matter, gray matter, cerebrospinal fluid, and T2-lesion load; during fMRI, participants were confronted with neutral, scrambled, angry, disgusted, and fearful faces, and houses. In the absence of differences in cognitive performance and in the ability to accurately recognize distinct emotional facial expressions, MS patients demonstrated excess fMRI activations during facial recognition compared to HC. These differences concerned the posterior cingulate cortex (PCC) and precuneus for anger and disgust contrasted to neutral faces, and the occipital fusiform gyri and the anterior CC for neutral faces versus houses. This study provides first evidence for excess activation during processing of higher order visual stimuli of emotional content in the absence of emotional, visual or cognitive behavior abnormalities already in earlier stages of MS.