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 .