[Clinical and pathophysiological contribution of event-related potentials used to study migraine headache]

Event-related potentials are electric brain manifestations evoked by mental activities. This neurophysiological technique is able to describe temporal succession of cognitive processing and allows to measure the neurobiological correlates of each cognitive activity. The evoked potentials of the oddball paradigm and the Contingent Negative Variation (CNV) are also concerned by clinical applications in neuropsychiatry, in neurology and in psychopharmacology. In the case of migraine, the studies with CNV recorded between migraine attacks are characterized by two major phenomena, cerebral hyperreactivity and lack of habituation to repetitive stimuli. From cognitive point of view, this can be interpreted as a difficulty from migraine sufferers to adapt their information-processing to environmental constraints. From neurological point of view, this trouble is related with dysregulation of norepinephrin and serotonin ascending pathways. Studies with the oddball paradigm potentials remain non consistent. The mismatch between different methodologies could explain such a lack of consistency. The neurophysiological studies have contributed to new physiopathological hypothesis of migraine. Those hypothesis reveal that a shift in the brain metabolic homeostasis could be the common factor of migraine attacks. The clinical contribution of event-related potentials is of little use in the diagnosis of migraine. But two purposes have been suggested: the differential diagnosis between common migraine and tension-type headaches and the monitoring of beta-blocking agents prophylaxis.