ABSTRACT
BACKGROUND: The visual evoked potential (VEP) is used in the evaluation of multiple sclerosis (MS) patients, showing a delay in P100 wave latency with no changes in amplitude in 60-100% of cases. In the last decade, the recurrent form of neuromyelitis optica (NMO) has been recognized, and clinically characterized by acute events of transverse myelitis (TM) and optic neuritis (ON), differing from MS in clinical and laboratory criteria. Despite these differences, so far, the VEP parameters described in MS have been used in the evaluation of patients with NMO. The objective of this study was to investigate VEP responses in NMO. METHODS: Patients with NMO underwent pattern-reversal visual stimulation. Nineteen patients were selected for the study. RESULTS: Among the 38 eyes examined, 18 (47.4%) had no visual evoked responses and 13 (34.2%) had a reduction of P100 wave amplitude with normal latency. Only two (5.3%) had the pattern described in MS and five (13.2%) were normal. CONCLUSION: Evaluation of VEP in patients with definite NMO revealed a pattern that is different from that of MS in 81.6% of eyes examined, characterized by the absence of responses, or decreased amplitude with normal latency.
