Correlation between habituation of visual-evoked potentials and magnetophosphene thresholds in migraine: A case-control study. (March 2016)

• Record Type: Journal Article
• Authors: Ambrosini, Anna; Iezzi, Ennio; Perrotta, Armando; Kisialiou, Aliaksei; Nardella, Andrea; Berardelli, Alfredo; Pierelli, Francesco; Schoenen, Jean
• Is Part Of: Cephalalgia. Volume 36:Number 3(2016)
• Page Start: 258
• Page End: 264
• Publication Date: 2016-03
• Subjects: Migraine -- cortical excitability -- magnetophosphene threshold -- visual-evoked potentials -- habituation; Headache -- Periodicals; 616.8491
• DOI: 10.1177/0333102415590241
• Languages: English
• ISSNs: 0333-1024

Abstract

Introduction: In migraine most studies report an interictal deficit of habituation of visual-evoked potentials (VEP-hab) and reduced thresholds for phosphene induction (PT) by transcranial magnetic stimulation (TMS). We searched for a possible correlation between VEP-hab and PT in migraine patients and healthy controls to test whether they reflect the same pathophysiological abnormality. Methods: We assessed PT and VEP-hab measured as the percentage change of N1/P1 amplitude over six blocks of 100 responses in 15 healthy volunteers (HV) and in 13 episodic migraineurs without aura (MO) between attacks. Results were compared using Mann-Whitney U test. Interrelationships were examined using Spearman's correlation. Results: In MO patients VEP-hab was reduced compared to HV ( p = 0.001), while PT were not significantly different between HV and MO. There was no correlation between PT and VEP-hab in either group of participants. Conclusions: We confirm that in interictal migraine VEP habituation is deficient, but magnetophosphene threshold normal. VEP-hab and PT were not correlated with each other in healthy controls or in migraineurs. This finding suggests that they index different facets of cortical excitability in migraine, i.e. a punctual normal measure of the cortical activation threshold for PT and a dynamic response pattern to repeated stimuli for VEP habituation.