ID 94 – Clinically Isolated Syndrome (CIS): Measure of Axonal Status

The clinically isolated syndrome (CIS) is a first episode of neurological symptoms caused by inflammation and demyelination in one or more sites in the central nervous system (CNS). CIS patients may develop multiple sclerosis (MS). Easy and reliable measures of CIS conversion to MS and measures of early axonal loss are lacking. Evoked potentials allow us the functional study of CNS. Visual (VEP) and motor evoked potentials (MEP) have already demonstrated good correlation with disability progression in MS. Optical coherence tomography (OCT) measures the retinal nerve fiber layer (RNFL) and macular ganglion cell layer thickness (GCL). Early quantification of axonal loss in CIS. Prospective transversal study of 20 CIS patients with PEV, MEP and OCT (RNFL (μm);GCL((μm)). CIS were monofocal: 9 optic neuritis, 4 brainstem and 7 long pathways syndrome. PEV and PEM measures were also correlated between them. PEM amplitude ratio with compound motor action potential-CMAP, was the strongest measure correlated with MS conversion. We detected early axonal loss in patients with CIS. PEM measures are well correlated with OCT and clinical measures of neurodegeneration. PEM amplitude ratio was the strongest measure correlated with MS conversion and disability progression.