Visually evoked responses in migraine

Abstract

Visually evoked responses from the central and occipital areas were compared between 50 patients with migraine (during the headache-free period) and 46 control subjects. The findings suggest that migraine might be associated with altered cerebral responses to visual stimulation. Of three occipital surface negative components studied, the second ("intermediate" cluster) tended to appear slightly earlier in the migrainous individuals whereas the third (OIII) appeared later. Average amplitude of the second major surface positive wave (OIV) was lower. These differences were significant for the total experimental population and the female subgroup. Latency of the OII component (surface positive) was longer for females with migraine, a finding not present for the total population. No significant differences emerged between male experimental and control groups. Vertex responses were similar in migrainous and normal subjects. The routine EEG was abnormal in eleven of 50 (22%) patients.Average pupil size of the patients with migraine was significantly smaller than that of the controls.