Migraine and autonomic nervous system function

OBJECTIVE: This study determines if measures of the function of the autonomic nervous system (ANS) differ in a population study of 80 migraine cases vs 85 controls matched for age, race, and sex. BACKGROUND: The authors sought to confirm clinic-based studies suggesting that migraine is associated with abnormal ANS function. METHODS: Resting systolic and diastolic blood pressure, Valsalva maneuver, heart rate variability (pulse rate RR variation) during deep breathing, and cardiovascular reactivity were measured during headache-free intervals. Migraineurs were subdivided into those with (n = 28) and without (n = 52) disabling headaches. RESULTS: Resting diastolic, but not systolic, blood pressure was elevated in disabled (73.2 mm) compared with nondisabled cases (71.6 mm; p < 0.10) and controls (69.8 mm; p < 0.096). RR variation also was significantly different among the three groups. Disabled migraine cases (1.19) had significantly lower RR variation compared with nondisabled migraine cases (1.26; p < 0.001) and controls (1.26; p < 0.001). The Valsalva ratio and mean circular resultant were lower in disabled cases compared with other migraine cases and with controls, but the differences were not statistically significant. No differences were found between the three groups when comparing blood pressure response to a psychological stressor. CONCLUSIONS: Migraineurs with disabling attacks may be prone to ANS hypofunction. These findings may suggest that ANS dysfunction either may be a risk factor for migraine headaches or be a consequence of frequent disabling attacks. Moreover, ANS dysfunction and migraine may share a common neural substrate.