Transcranial Doppler study of cerebrovascular reactivity : are migraineurs more sensitive to breath-hold challenge?

Transcranial Doppler sonography (TCD) of cerebrovascular reactivity has been used to study migraine interictally. However, the previous TCD findings had been quite varied at the post breath-hold period. Autonomic responses were usually studied with cardiac information. The aim of this study was to use TCD as a tool to examine difference in cerebrovascular reactivity between migraineurs and non-headache controls by measuring interictally the whole time course of cerebral blood flow velocity (CBFV) during and after a breath-hold challenge. The percentage change of CBFV was derived in the left and right middle cerebral arteries in 10 migraineurs and 10 controls during and after a 20 s breath-hold. Three phases of CBFV change were identified with an initial positive phase above baseline, a middle negative phase during breath-hold, and a late positive phase which started before the cessation of breath-hold and continued for a period after. In addition to CBFV, we also extracted and utilized the information of the cardiac cycle duration (CC) derived from the time course of CBFV. The percentage change of CC was derived from time intervals between every two points of inflexion in CBFV. Two undershoots of CC change were shown at the transitions of breathing motions. We found evidence that migraineurs had significant difference of CBFV change at the middle negative phase during breath-hold and the pronounced undershoots of CC change compared to non-headache controls.Department of Health Technology and Informatic