Autonomic Dysfunction in Migraineurs

Abstract

To evaluate autonomic function and sympathovagal balance in migraineurs and healthy controls. The pathophysiology of migraine is still largely unknown. An imbalance of the autonomic nervous system could explain many of the clinical manifestations of the disorder. We undertook autonomic function tests in 17 women suffering from migraine (8 with aura) (average age 36 +/- 7 years) and 16 healthy women (average age 34 +/- 7 years). Autonomic nervous system studies consisted of tests of sympathetic function (the quantitative sudomotor axon reflex test, beat-to-beat blood pressure responses to the Valsalva maneuver, sustained handgrip, cold pressor test, and head-up tilt and tests of parasympathetic function (heart rate responses to deep breathing and the Valsalva maneuver). The data from the tilt test were further evaluated by time-frequency analysis (Wigner distribution). Subjects with migraine with aura had a smaller increase of mean blood pressure during phase IV of the Valsalva maneuver (P<0.05) and a lower blood pressure increment during the handgrip test (P=0.08); their time-frequency distribution showed reduced power at the nonrespiratory frequencies in the R-R interval at both minutes 1 (P<0.03) and 5 (P<0.04) of head-up tilt. Sympathovagal balance (a ratio of spectral power of nonrespiratory frequency variations in blood pressure to that at respiratory frequency variations in the R-R interval) was significantly increased in migraineurs, both with and without aura, by 10 minutes of head-up tilt. Subjects with migraine with aura had resting supine sympathetic hypofunction and intact parasympathetic function. With head-up tilt, sympathovagal balance is increased. The dynamic alterations in autonomic nervous system function may contribute to the development of aura in patients with migraine.