Cortical adaptation in patients with clinically isolated syndrome; perspectives for predicting multiple sclerosis

• Published in: Multiple sclerosis 2008-09, Vol.14, p.S207-S207
• Main Authors: Harirchian, M H, Oghabian, MA, Rezvanizade, A R, Fakhri, M
• Format: Article
• Language: English
• ISSN: 1352-4585

Background: Potentially adaptive cortical reorganization in multiple sclerosis (MS) has been reported in various studies. Objective: To depict the earliest steps of brain struggle to compensate for impairments in patients with clinically isolated syndrome (CIS). Methods: Eighteen right-handed patients with proven CIS and disease duration of less than a month were included. Neither of the cases had motor complaints. Ten healthy right-handed volunteers with matched demographic data served as controls. Each subject was conducted to four functional magnetic resonance imaging (MRI) trials in which they were asked to perform hand flexion-extension and ankle plantar and dorsiflexion on two sides of the body. A 1.5 T magnet was utilized and image analysis was carried out by means of FSL (version 4). Results: Within-group analysis showed larger clusters of activation in both stimuli (hand and ankle) in the CIS group compared with the healthy subjects. Most of the foci with maximum intensity were in the ipsilateral somatic sensory area, posterior parietal cortex and cingulate gyrus. Meanwhile patterns of activation when comparing different stimuli revealed more lateralization in hand activation in both control and CIS groups. In patients, most of activations were in the precentral gyrus for the ankle stimulus but hand movements showed a dominance in the postcentral gyrus. The latter finding was not obtained when analyzing the controls. In the case of between-group analysis, CIS vs. controls showed significant differences (p=0.013), either in areas related to motor tasks or novel regions. The most prominent regions of differences were the supplementary motor area, premotor cortex and inferior frontal gyrus on both sides and ipsilateral precuneous cortex. Conclusions: These sets of results indicate early functional changes in novel areas of the brain, which were not dealing with motor duties originally as well as increasing activations of areas dedicated to performing motor tasks, implying early adaptive change in the initial steps of the disease. From the clinical standpoint, a promising pre-diagnosis of MS would be possible before overt structural lesions in MRI.