Impairment of Inhibition of Trigeminal Nociception via Conditioned Pain Modulation in Persons with Migraine Headaches.

ABSTRACT

OBJECTIVE: To assess conditioned pain modulation efficiency in persons with and without migraine headaches. DESIGN: Cross-sectional assessment of experimental pain. SETTING: University campus and surrounding community in a large Midwestern US city. SUBJECTS: Twenty-three adults with and 32 without a history of migraine headaches participated in the study. Participants were mostly female (N = 40) with an average age of 23 years. METHODS: Four electrocutaneous stimulations of the supraorbital branch of the left trigeminal nerve were delivered at 150% of an individually determined pain threshold. Conditioned pain modulation was assessed by applying a noxious counterstimulus (forearm ischemia) and delivering four more electrocutaneous stimulations. After each stimulation, pain and the nociceptive blink reflex were assessed. Depression and pain catastrophizing were assessed to control for the potential influence of these variables on pain modulation. RESULTS: Participants with and without migraine headaches had similar baseline pain responsivity, without significant differences in pain report or nociceptive blink reflexes. Pain report was inhibited by conditioned pain modulation in both the migraine and control groups. However, unlike nonmigraine controls, participants with migraines did not exhibit an inhibition of nociceptive blink reflexes during the ischemia task. This pattern persisted after controlling for level of pain catastrophizing and depression. CONCLUSIONS: Migraine sufferers exhibited impaired conditioned pain modulation of the nociceptive blink reflex, suggesting a deficiency in inhibition of trigeminal nociception, which may contribute to the development of migraine headaches.