Disturbance of venous flow patterns in patients with transient global amnesia

Transient global amnesia (TGA) is an inability to form new memories. The pa thophysiology and cause of TGA have not been defined. We examined the chang es of internal jugular venous flow patterns in 21 patients with TGA and 21 age-matched and sex-matched controls using duplex ultrasonography during tw o Valsalva manoeuvres (blocking venous return through the superior vena cav a). During both manoeuvres a retrograde flow component was seen significant ly more frequently in the TGA group than in the controls. Ten patients repo rted Valsalva-like activities preceding TGA. In these patients a retrograde flow component took place more frequently than in those who did not report preceding Valsalva-like activities. Our results lend support to the hypoth esis that TGA may be attributable to venous congestion, and consequent veno us ischaemia to bilateral diencephalic or hippocampal structures.