Cerebral blood flow velocities and trigeminal ganglion stimulation. A transcranial Doppler study.

Transcranial Doppler sonography (TCD) patterns of middle cerebral arteries (MCA) were recorded in 10 patients before and during unilateral trigeminal ganglion stimulation (TGS). During TGS, TCD flow velocity significantly decreases in all patients: on both sides in 2 patients, only ipsilaterally to the TGS in 7 patients, and only on the opposite side in the remaining patient. In 2 patients, a controlled progressive hypercapnia test was performed before and during TGS. An enhanced vascular response to increased CO2 concentrations was observed during TGS.