RESUMO
BACKGROUND: Migraine is a common cause of headache in adolescents. Assuming that the cerebral vasculature is involved in the pathophysiology of migraine, we compared cerebral vasoreactivity in adolescents both during a migraine attack and a headache-free interval. METHODS: A functional transcranial Doppler test utilizing a visual stimulation paradigm was undertaken to measure the evoked flow velocity in the posterior cerebral artery of adolescents suffering from a migraine without aura or a tension-type headache. To serve as a control, data previously obtained from age-matched adolescents with no primary headache disorder were used. The flow curves were evaluated by determining the maximal flow velocity increase and by modeling their time course according to a control system analysis. In that analysis, the main dynamic features of the flow response were described mathematically in terms of a control system model of low order. The parameters were time delay, gain, attenuation, rate time, and natural frequency. RESULTS: The attenuation parameter (P<.005), indicative of an increased tone of the vessel, and the resting absolute flow velocity (P<.01) both showed a significant increase during an attack in the adolescents with migraine; the gain parameter showed a trend towards similar increase (P =.07). The maximal flow velocity did not increase significantly during an attack. CONCLUSIONS: The control system approach utilized here appears to be more sensitive for detecting migraine-associated changes in cerebral vasoreactivity than examination of the maximal flow velocities alone.
