Electrophysiological evidence for trigeminal neuron sensitization in patients with migraine

The electrically elicited corneal reflex is a useful tool for exploring the trigeminal system in humans and it may provide additional evidence pointing to a dysfunction of this system in migrainous patients. Tactile perception, corneal reflex and pain thresholds were studied in 48 migraine without aura patients during pain-free periods and compared with those observed in 24 controls. Twenty-eight of the patients had strictly unilateral headache, while the other 20 had bilateral or side-shifting pain during attacks. Both migraine subgroups (bilateral and unilateral) showed significantly lower thresholds compared with controls. The lowest values were observed on the symptomatic side of unilateral migraine patients. These findings suggest that sensorimotor mechanisms and/or pain control systems at the trigeminal level are impaired in migraine. The bilateral location of these abnormalities seems to point to a centrally located dysfunction.