ABSTRACT
Multiple Sclerosis is one of the commonest neurological disorders that because of its different clinical presentation, recurrent and progressive attacks, and age spectrum of patients who are usually young, has particular importance. Optic neuritis is common in MS patients and VHP is abnormal in most of the patients with optic neuritis. VHP is also abnormal in most of the MS patients who do not have the history of optic neuritis. The aim of this study was to compare the incidence of VEP in MS patients with and without the history of optic neuritis. This study included 80 patients with definite MS diagnosis who referred to the MS Clinic Ghaem Hospital. A questionnaire used to collect the patients demographic and illness history. Patients were divided into two groups based on the history of optic neuritis. The full neurological examination including VEP carried out for the patients. Collected data analyzed with SPSS and statistical tests. The abnormal VEP found in 92.2% of patients with the history of optic neuritis. The incidence of VEP in patients without the history of optic neuritis was 57.5%. The VEP abnormality recorded 40.5% unilateral and 59.5% bilateral in the first group of patients. In the second group the VEP was 87% unilateral and 13% bilateral. Many MS patients without the history of optic neuritis, had abnormal VEP, therefore VEP can be used for the early diagnosis of MS. Although, patients with the history of optic neuritis will have significant improvement with the time, but many cases with increased PI00 latency is persistence, and can be used as a marker of the pervious optic neuritis attack