title: Intensity dependence of auditory evoked potentials during light interference in migraine.
abstract: Migraine patients show interictally a strong intensity dependence of auditory evoked cortical potentials (IDAP) and a lack of habituation of evoked potentials. Photic drive on high-frequency flash stimulation is another well-known interictal feature in migraineurs, associated with alpha-rhythm hyper-synchronisation. We compared therefore the influence of light stimulation on IDAP in healthy volunteers (HV) and migraine patients. A continuous flash stimulation was delivered during the recording of auditory evoked potentials at suprathreshold increasing stimulation intensities. IDAP was measured as the amplitude/stimulus intensity function (ASF) slope. In HV, the ASF slope decreased during flash stimulation, whereas, on average, there was no significant change in migraineurs. A closer analysis of migraineurs disclosed two subgroups of patients with no detectable clinical differences: one, the largest, in which the ASF slope was normal at baseline, but increased during light stimulation, the other with an increased ASF slope at rest and a decrease during light interference. Visual sensory overload is able to increase IDAP in the majority of migraineurs, which contrasts with HV. We hypothesise that this could be due to hyper-synchronisation of the alpha rhythm because of photic drive and possibly thalamo-cortical dysfunction. A minority of migraineurs have, like HV, an IDAP reduction during light interference. They are, however, characterised, unlike most HV, by a high IDAP at baseline. Besides underscoring the pathophysiological heterogeneity of migraine, these results suggest that light interference might improve the phenotyping of migraine patients who have a normal IDAP in the resting condition.
authors.affiliation: Headache Clinic, IRCCS INM Neuromed, via Atinense, 18, I-86077 Pozzilli, Isernia, Italy. anna.ambrosini@neuromed.it
authors.forename: Anna
authors.initials: A
authors.lastname: Ambrosini
authors.forename: Gianluca
authors.initials: G
authors.lastname: Coppola
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Gérardy
authors.forename: Francesco
authors.initials: F
authors.lastname: Pierelli
authors.forename: Jean
authors.initials: J
authors.lastname: Schoenen
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001288:Attention / Q000502:physiology*; D002540:Cerebral Cortex / Q000503:physiopathology; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008881:Migraine Disorders / Q000473:pathology / Q000503:physiopathology*; D011571:Psychoacoustics; D055815:Young Adult