Intensity dependence of auditory evoked potentials is pronounced in migraine: an indication of cortical potentiation and low serotonergic neurotransmission?
Migraine is associated with stimulus hypersensitivity, increased evoked cortical responses, and abnormal 5-HT levels in peripheral blood. We studied cortical auditory evoked potentials (AEPs) between attacks in 35 patients suffering from migraine without aura (MO, n = 25) or with aura (MA, n = 10) and in 25 healthy volunteers. Binaural tones were delivered at 40, 50, 60, and 70 dB sensation level (SL) in a pseudorandomized order. The intensity dependence of the auditory N1-P2 component was significantly greater in MO (p = 0.003) and MA (p = 0.02) patients than in healthy controls, resulting in a much steeper amplitude/stimulus intensity function slope. When three sequential blocks of 40 averaged responses were analyzed at the 40- and 70-dB SL intensities, N1-P2 amplitude decreased in second and third blocks at both intensities in controls, but increased in migraineurs, a difference that was significant in both blocks for the 70-dB SL stimulus. The strong interictal dependence of AEPs on stimulus intensity may thus be due to potentiation (instead of habituation) of the response during repetition of the high-intensity stimulation. In concordance with previous studies of visual evoked potentials, these results confirm that migraine is characterized between attacks by an abnormality of cortical information processing, which might be a consequence of low 5-HT transmission and favor cortical energy demands.
Wang
W
W
Department of Neurology, University of Liège, Belgium.
Timsit-Berthier
M
M
Schoenen
J
J
D000161:Acoustic Stimulation; D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology / Q000503:physiopathology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D017774:Long-Term Potentiation; D008297:Male; D008881:Migraine Disorders / Q000503:physiopathology*; D011897:Random Allocation; D012016:Reference Values; D012701:Serotonin / Q000502:physiology*; D009435:Synaptic Transmission; D013997:Time Factors
D012701:Serotonin