Clinical and electrophysiological responses to dietary challenge in migraineurs

Thirty eight patients with a history of diet-induced migraine were studied with recording of clinical responses, electroencephalography in resting state, in response to photic stimulation, and to hyperventilation and visual evoked potentials. Tests were carried out on an initial baseline day and on a second day, after challenge with chocolate, red wine, cheese, and fasting. Lateralized headache occurred in sixteen subjects (42%), four with scintillating scotomata. Electroencephalograms were abnormal on Day 1 and/or Day 2 in twelve subjects (32%), most abnormalities being non-specific slow waves. In three cases there were paroxysmal features. Electroencephalographic response to hyperventilation was calibrated and was found to be exaggerated in eight subjects (21%) on either Day 1 or Day 2; such response was not related to the occurrence of a headache. Photic simulation showed high frequency driving response (so called "H" response) in all 16 individuals who developed headache but in only 14 out of 22 (64%) who did not (p less than 0.01). Pattern reversal visual evoked responses were normal and failed to show any difference in latency or amplitude between headache responders and non-responders.