Electroencephalographic brain mapping and migraine
© Springer-Verlag Italia 2004
Several studies have investigated brain bioelectrical activity with the aid of electroencephalographic brain mapping in migraine patients examined in the interictal period or during a spontaneous attack. The principal finding obtained between attacks was an increase in the power of the rapid activities, particularly in the range of the beta bands and especially in the temporal regions, in migraine patients both with and without aura. Another frequent occurrence between attacks is an increase in the absolute and relative powers of the slow theta and delta bands, which can be focal or diffuse. In our experience, the increase in the relative power of the theta band was prevalent bilaterally in the temporal-parietal regions in migraineurs with and without aura. Other authors detected interhemispheric asymmetries relative to alpha bands, more consistent in patients with migraine with aura. During attacks the most relevant result is the decrease and asymmetry of dominant alpha activity, particularly on the side of the pain during attacks in patients with migraine without aura. In addition to changes in the alpha activities, an increase in the power of the slow delta and/or theta bands was found during attacks of migraine with aura. Although difficult to summarize in an integrated view, results of EEG brain mapping support the occurrence of bioelectrical abnormalities, which are present even between attacks and contribute towards defining the attack threshold, and which are accentuated near and during migraine crises as a consequence of neuronal events that underlie the pathogenic mechanisms of attacks.