Habituation of laser-evoked potentials by migraine phase: a blinded longitudinal study

Abstract

BackgroundMigraineurs seem to have cyclic variations in cortical excitability in several neurophysiological modalities. Laser-evoked potentials (LEP) are of particular interest in migraine because LEP specifically targets pain pathways, and studies have reported different LEP-changes both between and during headaches. Our primary aim was to explore potential cyclic variations in LEP amplitude and habituation in more detail with a blinded longitudinal study design.MethodsWe compared N1 and N2P2 amplitudes and habituation between two blocks of laser stimulations to the dorsal hand, obtained from 49 migraineurs with four sessions each. We used migraine diaries to categorize sessions as interictal (> one day from previous and to next attack), preictal (< one day before the attack), ictal or postictal (< one day after the attack). Also, we compared 29 interictal recordings from the first session to 30 controls.ResultsN1 and N2P2 amplitudes and habituation did not differ between preictal, interictal and postictal phase sessions, except for a post hoc contrast that showed deficient ictal habituation of N1. Habituation is present and similar in migraineurs in the interictal phase and controls.ConclusionsHand-evoked LEP amplitudes and habituation were mainly invariable between migraine phases, but this matter needs further study. Because hand-evoked LEP-habituation was similar in migraineurs and controls, the present findings contradict several previous LEP studies. Pain-evoked cerebral responses are normal and show normal habituation in migraine.Electronic supplementary materialThe online version of this article (10.1186/s10194-017-0810-6) contains supplementary material, which is available to authorized users.

Current understanding of cortical structure and function in migraine

“…Visual evoked potentials (VEPs) have been widely studied as indirect readout of visual cortex responsivity (88), whereby several studies reported no change (100) or a reduction (101,102) in VEP amplitude interictally, in line with unaltered (103) or reduced auditory (104) and somatosensory responses (105,106). Enhanced cortical responsivity between attacks is also reported, using visual (88), auditory (107), heat (108,109) or affective picture stimulations (110,111). A combined PET/VEP study recently related enhanced VEP responses to decreased glucose uptake in occipital areas in migraineurs without aura (112), which may suggest activity-induced disturbance of cerebral metabolic homeostasis contributes to attack susceptibility.…”

“…Habituation of evoked responses was described to be either impaired or unaltered between attacks and comparable to controls during attacks for visual and several other stimulation modalities (90,93). Since longitudinal designs were only used in studies that did not observe interictal lack-of-habituation (108,114), it remains to be seen whether cyclic changes in evoked response habituation (120) actually occur. Other observations nevertheless support the idea that transient changes in visual cortex responsivity occur prior to attacks, since photic drive responses (reported to be enhanced interictally) showed attenuation in the preictal period (97).…”

C-tactile touch perception in migraineurs – a case-control study

“…Pain as a reason for decreasing pleasantness can be ruled out as we did not find a significant increase in pain or intensity ratings (66,67). The mean maximum of pain ratings in our study was 0.43 out of 10 which is considered “not painful” (68).…”

Inter-stimulus Interval Effect on Tactile Habituation: An Electrophysiological Approach

“…Accordingly, the present study revealed that as ISI prolonged the amplitudes increased. In the literature, studies revealed an increase in amplitudes as the ISI increased by using the painful 5,8,16,17 , vibration 6 or mechanical (rotation of the hand) stimuli 4 . These stimuli were generally applied to the hand, wrist, arm or leg.…”

“…Despite the importance, especially during the perception of the outside world from the early stage of lifespan 3 include variety in sensation such as pressure, pain, temperature and muscle sense, habituation mechanisms of human somatosensory system was studied in a relatively few number of studies. Generally, somatosensory perception and the possible habituation mechanisms are investigated by using the painful or mechanical (electrical, laser, heat, vibration and rotation) stimuli in the literature [4][5][6][7][8] .…”