[19] Notwithstanding the effectiveness of GON blockades

for migrainuers,20-22 the mechanism(s) for the successful outcome remain uncertain.[23] It has been postulated that GON blockade influences central pain processing mechanisms by modulating responses to convergent synaptic input from cervical and trigeminal nociceptive afferents.[23] In our clinical experience, patients often report lessening of their referred, usual pain as the examination of the cervicospinal segment is sustained. The pain usually lessens (to a variable degree, but often with complete resolution) within 90 seconds. Moreover, sustaining the examination repeatedly results not only in decreasing intensity of head Selumetinib in vivo pain referral but also in more expeditious resolution. Furthermore, patients presenting with allodynia frequently report that after lessening of their referred pain, the allodynia has decreased

or resolved,24-26 perhaps indicating that a pre-existing central sensitization state had diminished. The purpose of the present study was to investigate cervical, interictal referral of usual head pain and its effect on the nBR in migraineurs. In particular, effects of PAIVMs of the AO and C2-3 spinal segments on referred head pain and trigeminal nociceptive activity were examined interictally. It was hypothesized that as referred check details head pain decreased, there would be a corresponding increase in latency and decrease in the AUC of R2, reflecting a decrease in excitability of the TCN. Fifteen volunteers participated

in the study (14 females, 1 male; age 24-44 years, mean age 33.3 years). All participants met the International Headache Society’s diagnostic classification criteria for migraine with or without aura, experiencing 2-8 attacks of migraine within the previous 3 months.[2] Each participant had been free from migraine for at least 24 hours. Informed consent was obtained from all participants, and the study was approved by the Ethics Committee of Murdoch University. The PAIVM examination was performed by a single clinician (D.H.W. – Musculoskeletal Physiotherapist) with 22 years of experience, whose medchemexpress practice is limited to examination and treatment of the upper cervical spine in primary headache conditions. Intra-examiner reliability was analyzed using Cohen’s Kappa in a previous study[27] that demonstrated perfect agreement in 17 of 22 PAIVM techniques. Of the 5 remaining tests, the lowest Kappa score was k = 0.667, P = .01, which indicated good agreement. Critical to our study was that usual head pain could be reproduced during the cervical examination. Therefore, to exclude participants who did not develop head pain during this procedure, an “inclusion/exclusion” examination was performed prior to commencing the study.