Brain Advance Access originally published online on January 24, 2007
Brain 2007 130(3):765-770; doi:10.1093/brain/awl351
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Interictal habituation deficit of the nociceptive blink reflex: an endophenotypic marker for presymptomatic migraine?
Headache Research Unit, University Departments of 1Neurology and 2Neuroanatomy, University of Liège, Liège, Belgium, 3Department of Neurological Sciences, University ‘La Sapienza’ and 4Department of Neurophysiology of Vision and Neurophthalmology, G.B. Bietti Eye Foundation-IRCCS, Rome, Italy
Corresponding author: Professor Jean Schoenen, University Department of Neurology, CHR Citadelle, Bld. du 12ème de Ligne 1, B–4000 Liège, Belgium E-mail: jean.schoenen{at}chrcitadelle.be; jschoenen{at}ulg.ac.be
Habituation of the nociception-specific blink reflex (nBR) is reduced interictally in migraine patients. This could be related to the habituation deficit of evoked cortical responses, a reproducible abnormality in migraine which has a familial character, or to central trigeminal sensitization due to repeated attacks. We compared nBR habituation in healthy volunteers devoid of personal or family history of migraine (HV), in migraine without aura patients (MO) and in healthy volunteers with a family history of migraine in first degree relatives (HV-F). We elicited the nBR by stimulating the right supraorbital region with a custom-built electrode in 16 MO between attacks, 15 HV and 14 HV-F. Habituation was measured as the percentage area-under-the-curve decrease in 10 consecutive blocks of five averaged rectified responses. nBR habituation was clearly reduced in MO and HV-F compared to HV. Percentage area under the curve decreased between the 1st and the 10th block by 55.01% in HV, 25.71% in MO (P = 0.001) and 26.73% in HV-F (P = 0.043). HV-F had the most pronounced abnormality with potentiation instead of habituation in the second block. We found a positive intraindividual correlation between attack frequency and habituation in MO (r = 0.621; P = 0.010). Migraine patients have interictally a deficient habituation of the nBR which is inversely related to attack frequency, suggesting that it is not due to trigeminal sensitization. Surprisingly, the most pronounced habituation deficit is found in asymptomatic individuals with a family history of migraine. Deficient nBR habituation could thus be a trait marker for the genetic predisposition to migraine.
Key Words: sensory processing; brain circuits; migraine
Abbreviations: HV, health volunteers devoid of personal or family history of migraine; HV-F, healthy volunteers with a family history of migraine in first degree relatives; MO, migraine without aura patients; nBR, nociception-specific blink reflex
Received August 14, 2006. Revised November 5, 2006. Accepted November 16, 2006.