Lateralization of visual attention in patients with classic migraine and unilateral prodromes.

The present study is aimed to investigate whether and how mechanisms of visual attention are changed into conditions of monohemispheric disorders. For this purpose, Posner's paradygm was applied to classic migraine patients with prodromal phenomena localized in one hemisphere. The subjects were examined in acute phase (within 24 h of the episode end) and after a week or more from the episode (interparoxysmal phase). The patients in interparoxysmal phase behaved as normal subjects. In acute phase, we observed a selective involvement of attentional behaviour in migraineurs with left hemispheric symptoms. A possible explanation might be based on the well-known tendency of this hemisphere to prevail in performing attentive tasks.