Visual cortex excitability in migraine with and without aura

Objectives.-Previous research using transcranial magnetic stimulation has p roduced equivocal findings concerning thresholds for the generation of visu al phosphenes in migraine with aura. These studies were methodologically va ried and did not systematically address cortical excitability in migraine w ithout aura. We therefore studied magnetophosphene thresholds in both migra ine with aura and migraine without aura compared with headache-free control s. Methods.-Sixteen subjects with migraine with aura and 12 subjects with migr aine without aura were studied and compared with 16 sex- and age-matched co ntrols. Using a standardized transcranial magnetic stimulation protocol of the occipital cortex, we assessed the threshold stimulation intensity at wh ich subjects just perceived phosphenes via a method of alternating course a nd fine-tuning of stimulator output. Results.-There were no significant differences across groups in the proport ion of subjects seeing phosphenes, However, the mean threshold at which pho sphenes were reported was significantly lower in both migraine groups (migr aine with aura=47%, migraine without aura=46%) than in controls (66%), More over, there was no significant correlation between individual phosphene thr eshold and the time interval to the closest migraine attack. Conclusion.-Our findings confirm that the occipital cortex is hyperexcitabl e in the migraine interictum, both in migraine with and without aura.