RESUMO
OBJECTIVE: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system, with epileptic seizures sometimes observed in the same patients. In this study, we used evoked responses to study the pathogenesis of epilepsy in MS. METHODS: Patients with a diagnosis of definite MS and who had EPs performed (visual (VEP), brainstem auditory (BAEP) and short latency somatosensory (upper (USSEP) and lower (LSSEP))) were retrospectively included in this study. They were divided into three groups; Group I: Patients with no epilepsy and who were not taking anti-epileptic drugs (AED); Group II: Patients with epilepsy and taking AEDs; and Group III: Patients with no epilepsy who were taking AEDs for symptoms related to neuropathic pain. RESULTS: Three hundred and fifty-five patients were included in this study; Group I: 229 patients (64.5%), Group II: 20 patients (5.6%) and Group III: 106 patients (29.9%). The proportion of patients with abnormal BAEP and USSEP was higher in Group II. CONCLUSIONS: A positive association exists between the presence of epilepsy in MS patients and BAEP and USSEP abnormalities. Analysis of Group III ruled out AED use as a factor. SIGNIFICANCE: Brainstem lesions may be the cause of epileptogenicity in MS.