COGNITIVE PROCESSING IN PRIMARY HEADACHE - A STUDY ON EVENT-RELATED POTENTIALS

Background: There is experimental evidence for loss of cognitive habit uation in migraine but not in other types of headache and not by visua l event-related potentials (ERP). Objective: Determining the latencies (msec) and amplitudes (mu V) of ERP components and the differences of these values in a two-trial analysis representing the amount of cogni tive habituation. Participants: Two hundred thirty-three patients with a headache diagnosis according to the criteria of the International H eadache Society: migraine without aura (N = 77); migraine with aura (N = 31); cluster headache during period (N = 26); cluster headache duri ng interval (N = 11); chronic paroxysmal hemicrania (N = 8); episodic tension-type headache (N = 33); ergotamine-induced headache (N = 47). Thirty age-matched healthy subjects served as a control group. Methods : ERPs were evoked by a visual oddball paradigm consisting of 2 x 200 flashes of light (85% white light; 15% red light). Evaluation of ERP c omponents was done separately for the first 200 and the second 200 sti muli as well as for the entire series of stimuli. Results: We found an acceleration of the P3 latency during the second trial in migraine wi th and without aura, but not in the other headache types, and not in h ealthy controls. Ergotamine and sumatriptan abolished this loss of hab ituation in migraine patients. Increased ERP latencies as compared wit h healthy controls were present in patients with cluster headache, ten sion-type headache, ergotamine-induced headache, and migraine with aur a, but not in migraine without aura. Conclusion: There is a loss of co gnitive habituation in migraine, which may serve as a specific but not sensitive diagnostic tool. The pathophysiologies of migraine and clus ter headache have a specific modifying property on cognitive processin g reflected by a loss of cognitive habituation or an increased cogniti ve processing time. These effects can, in part, be counterbalanced by antimigraine medication.