P21.9 Evoked potential abnormalities predict disability progression at 5 years in patients with CIS

Introduction and Objective: Previous studies in relapsing remitting Multiple Sclerosis patients found evoked potentials to be reliable predictors of long term disability. Induction strategy is becoming increasingly used in MS and it is particularly valid as therapeutic strategy if applied in the early phases of the disease. The aim of this study was to assess the role of EPs in predicting future disability and the risk of conversion to clinically definite multiple sclerosis (CDMS) in patients with clinically isolated syndromes (CIS). Methods: We retrospectively analyzed 91 patients with CIS. Medical files were reviewed for clinical presentation. All patients underwent multimodal EPs after a mean time of 2±1.9 months from onset: visual (VEP), somatosensory (SEP) and motor (MEP) evoked potentials were obtained in all patients, brainstem auditory evoked potentials (BAEP) in 86. Each EP received an abnormality score from 0 to 3 (normal to absent; maximum possible multimodal total sum score = 36). Results: Average global score of abnormal EPs was 5±4. Basal global EPs score significantly correlated with EDSS5 (ø = 0.27 p = 0.008) and disability progression (EDSS5 EDSS2; ø = 0.30 p = 0.004). EP global score >5 predicted a higher risk of disability at 5 years, defined as an EDSS 3 (PPV = 24% p = 0.001). Lower limb SEP and MEP sum score were better able to predict the development of disability at 5 years (46% p = 0.0001). Subclinical EP abnormalities predicted the development of involvement of the corresponding FS at 5 years. This predictive value was found for VEP (PPV = 15.8% p = 0.04) BAEP (PPV = 55.6% p = 0.04), SEP (PPV = 30.6% p = 0.03), MEP (PPV = 90% p = 0.03). When excluding, in monofocal patients, EPs related to the symptomatic pathway, patients with 2 or 3 abnormal EPs at onset had a higher risk of conversion to CDMS (PPV = 40.4% p = 0.05). Conclusions: The present findings suggest that multimodal EPs at onset in patients with CIS have a predictive value regarding the evolution of disability. Moreover, a subclinical wide involvement of multiple sensorimotor pathways, detected as abnormalities in at least 2 EPs, increases the risk of conversion to CDMS.