Visual evoked potential abnormalities in migraine patients

Visual processing in migraine has been targeted indicating that the visual pathways are involved in the migraine pathophysiology. We aimed to assess the nature of visual evoked potential (VEP) changes in migraine patients and to evaluate the role of VEP in the diagnosis of migraine.

We examined 31 female and 10 male patients with a migraine headache diagnosis according to the criteria of the International Headache Society. Control subjects had neither migraine and other types of primary headache nor familial history. VEP were elicited using a checkerboard by monocular and binocular pattern reversal stimulation. The latencies of N75, P100 and N145 and peak-to-peak amplitude of N75-P100 were measured. We compared VEP latencies and amplitudes of the monocular and binocular stimulation within each population.

The N75 and P100 latencies were found to be significantly longer in the study group than the control group (p = 0.014 and p = 0.034, respectively) while the amplitudes in the study group were lower (p = 0.014). N145 latency was found to be longer in patients with longer duration of disease (p < 0.05). P100 latency was found to be significantly longer in patients with aura than the patients without aura (p = 0.029). N75 latency, recorded by left monocular stimulation, was elongated and the amplitude was diminished with left hemicranial headache.

Measurement of VEP latency and amplitude is a valuable and reliable test for the diagnosis of migraine. Our results reflect a persisting dysfunction of precortical visual processing which might be relevant in the pathogenesis of migraine.