[Postural vertigo and basilar artery flow increment].
PURPOSE: Research was focused on cerebral arterial flow in normal individuals and in patients suffering from short-term vertigo when sitting up rapidly from a lying position. PATIENTS AND METHODS: The research was performed in normal subjects and 46 patients affected by short term vertigo who underwent transcranial Doppler 32. In normal subjects (16 with an average age of 25 and 16 with an average age of 61) cerebral artery flow was recorded in a sitting and lying position, in Trendelenburg position and during transition from one position to another. In subjects suffering from short-term vertigo, arterial flow was recorded at baseline and during short-term vertigo. RESULTS: In normal subjects the flow remained unchanged in all body positions as well as during transition from one position to another. In subjects with short-term vertigo basilar artery flow increased with the onset of dizziness and returned to normal when dizziness ceased. CONCLUSIONS: In normal subjects cerebral self-regulation maintains constant flow in any body position. Increased basilar artery flow during short term vertigo is probably either due to altered self-regulation or its reduction in the carotid area with compensatory basilar artery hyperflow, or else to over-response in vertebro-basilar territory.