Pupillary sympathetic hypofunction and asymmetry in muscle contraction headache and migraine.

Pupillary autonomic dysfunction and right-left differences were investigated in muscle contraction headache (MCH) and migraine, by means of biocular infrared videopupillography (biocular Iriscorder). The study was performed on 36 patients with MCH or migraine and on 23 healthy controls. The pupillary area before light stimuli and maximum dilatation velocity of pupils, in MCH patients and migraineurs, showed significant differences from those of controls. Pupillary asymmetry was observed in both headache categories. The behavior of MCH pupils to light stimuli under dark conditions was rather similar to that of migraine pupils. Both pupillary sympathetic hypofunction and subtle anisocoria were present not only in patients with migraine but also in those with MCH.