Background & Objectives: Acute optic neuritis in majority of cases, especially young females, is a common presentation of multiple sclerosis. Visual evoked potential (VEP) study is a non-invasive method for evaluation of nerve conduction of optic nerve. This study is an attempt of follow patients with acute optic neuritis and VEP variations over the time.

 Methods: VEP was studied in 30 patients with acute optic neuritis (25 females (83.3%) and 5 males (16.7%) with a mean age of 28.77±9). Clinical examinations and brain MRI study were performed on each. Examinations were repeated 1 and 6 months later. Statistical analyses were performed with SPSS software^�(rel.11).

 Results: Physical examination revealed another neurologic abnormality in 12 patients (40%). Brain MRI in 19 patients (63.3%) was abnormal. Latency of P100 was abnormal in all cases and only in 7 cases VEP was in normal range after 6 months. Definite MS was diagnosed in 15 cases (50%) and probable MS in 4 patients (13%). P100 amplitude in first study had no prognostic value for recovery.

 Conclusion: VEP has a sensitivity of about 80% for optic nerve injury and the comparison between two eyes is required for the diagnosis of this disorder. Careful clinical examination and brain MRI in the first admission as well as follow-up activities should be done for early detection of multiple sclerosis.

  Background &objections: Migraine is the second most common cause of headache in15% of women and 6% of men. Migraine headaches areperiodic and usually with unilateral and throbbing quality,and often accompanied by nausea, vomiting, phonophobia, photophobia and malaise. Approximately 15-20% of migraine attacks start with visual aura or other neurological symptoms. So far there isn’t accurate and practical diagnostic test for this patients and diagnosis is based on clinical features and other causes. The aim of this study was to investigate the role of visual evoked potential (VEP) in patients with common and classic migraines and t effects on the electrophysiology of visual system and understanding pathophysiology in neurological symptoms.

  Methods: In this study, 44 migraine patients, including 28 patients with common and 16 patients with classical migraines admitted to neurology private clinics from January to June 2013 in Alavi hospital of Ardabil city and16 healthy volunteers (control group) were used. Mean wave, P100 Latency and P100-N140 Amplitude were compared and determined between three groups.

  Results: The mean latency of P100 migraine group was significantly higher than healthy people. Average P100-N140 amplitude of migraine group was fewer than the control group, and the mean P100-N140 amplitude was more common than classical group.

  Conclusions: Despite differences in results of VEP tests, VEP can be used as an adjuvant test in the diagnosis of migraine, as well as a confirmation for distinguishing common and classical migraine and can be used as a tool in determining the severity of migraine and/or a parameter for its electrophysiological effects. However, more detailed studies are needed in this area .