Cognitive processing in primary headache: A study on event-related potentials

Background: There is experimental evidence for loss of cognitive habituation in migraine but not in other types of headache and not by visual 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 cognitive habituation. Participants: Two hundred thirty-three patients with a headache diagnosis according to the criteria of the International Headache Society: migraine without aura (N = 77); migraine with aura (N = 31); cluster headache during period (N = 26); cluster headache during 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 components was done separately for the first 200 and the second 200 stimuli as well as for the entire series of stimuli. Results: We found an acceleration of the P3 latency during the second trial in migraine with and without aura, but not in the other headache types, and not in healthy controls. Ergotamine and sumatriptan abolished this loss of habituation in migraine patients. Increased ERP latencies as compared with healthy controls were present in patients with cluster headache, tension-type headache, ergotamine-induced headache, and migraine with aura, but not in migraine without aura. Conclusion: There is a loss of cognitive habituation in migraine, which may serve as a specific but not sensitive diagnostic tool. The pathophysiologies of migraine and cluster headache have a specific modifying property on cognitive processing reflected by a loss of cognitive habituation or an increased cognitive processing time. These effects can, in part, be counterbalanced by antimigraine medication.