Investigation of the cerebral response to flicker stimulation in patients with headache.

Migraine affects 10% of the population, yet there is no proven diagnostic test. To date the most promising neurophysiological diagnostic technique has been the analysis of cerebral responses to photic stimulation or flicker (the "H" response). This test has proved to be sensitive in patients with "classic" migraine, but has not been re-evaluated since the introduction of the 1988 International Headache Society (IHS) classification system. In 33 migraineurs, we found that the "H" response was sensitive (86.4%) and specific (97.5%) in those with migraine defined according to IHS Committee as type 1.2.1 (typical aura) and type 1.1 (without aura), but not in basilar migraine (1.2.4).