Reliability and repeatability of testing visual evoked potential habituation in migraine: A blinded case–control study.

Background: Many studies have shown that migraine patients have an interictal habituation deficit of visual evoked potentials (VEPs). Some discordant results were attributed to non-blinded analyses and a lack of repeatability. Aims: In this study, we compared blinded and non-blinded analyses of the same recordings and assessed test–retest repeatability. Methods: VEP recordings of 25 healthy volunteers (HVs) and 78 episodic migraine patients (EMs; 52 interictal, 26 ictal) were analysed by two investigators, one of whom was blinded to diagnosis and headache phase. Twelve HVs and nine EMs had two recordings for test repeatability. Results: In both blinded and non-blinded analyses, VEP habituation was normal in HVs and EMs during an attack, but deficient in EMs interictally. Intra-individual habituation percentages were highly correlated in two recordings separated by ≥7 days. Conclusions: The studies showing a VEP habituation deficit in migraineurs between attacks are unlikely to be biased by non-blinding analysis or poor repeatability. [ABSTRACT FROM AUTHOR]