The blink reflex in chronic cluster headache: a comparison with migraine patients suffering from unilateral pain*

Abstract Objective. To evaluate the blink reflex (BR) in chronic cluster headache (CH) patients. Design. The electrophysiological data were collected in during the headache-free phase. Setting. Headache patients were recruited from outpatients seen for the first time at the First Neurologic Clinic of Bari University. Patients and participants. Ten CH patients, 19 migraine without aura patients with strictly unilateral headache (MWoA) and 18 normal controls were selected. Measurements and results. The BR procedure was applied. In CH, a significant R2 duration increase was found on the symptomatic side in comparison with MWoA and controls. In both patient groups an early appearance of the R3 component was bilaterally clear. Conclusions. The BR findings confirm the central genesis of CH. The R3 abnormalities suggest a basic dysfunction of the central control on the trigeminal nociceptive circuits. The R2 involvement on the symptomatic side indicates a unilateral facilitation of the trigeminal-facial connections persisting after the CH bout