SYNCOPES OF UNCLEAR ORIGIN - 2 HIGHLY SPE CIFIC DIAGNOSTIC-TESTS

We report the diagnostic evaluation of an elderly woman admitted with recurrent syncopes induced by head rotation. A cardiac origin was excl uded by Holter EGG, echocardiography and carotid sinus compression. An giography showed unilateral vertebral artery hypoplasia, suggesting th e possibility of hemodynamic vertebrobasilar insufficiency. This origi n, however, could be ruled out by monitoring of blood flow velocities in both posterior cerebral arteries with transcranial Doppler, which s howed no alteration during syncope induced by head rotation. Detailed analysis of the course of the syncope recorded on videotape suggested a psychogenic event. Furthermore, the syncopes could be prevented with a ''protective'' placebo despite head rotation, and induced by a ''pr ovocative'' placebo without head rotation while EEG monitoring showed normal brain activity. This finding underscored the suggestion of a ps ychogenic cause.