Transient global amnesia: a clinical and sonographic study.

BACKGROUND

The aetiology of transient global amnesia (TGA) is still unknown. The aim of this study was to identify potential risk factors for TGA, vascular risk factors, the role of patent foramen ovale (PFO) and of retrograde jugular venous flow.

METHODS

138 subjects entered the study, including 48 patients with TGA, 42 age-matched patients with transient ischaemic attack (TIA) and 48 controls. PFO was studied by contrast transcranial duplex sonography. Retrograde jugular venous flow was tested with air contrast ultrasound venography (ACUV).

RESULTS

TGA patients and controls showed a lower prevalence for vascular risk factors than TIA patients. No statistical difference was found between the 3 groups with regard to PFO. ACUV detected jugular valve incompetence in 72.9% TGA, 35.7% TIA and 39.5% controls (TGA vs. TIA and TGA vs. controls p < 0.01).

CONCLUSIONS

TGA patients have fewer vascular risk factors than TIA patients. Paradoxical embolism due to PFO as a cause of TGA is not confirmed in our study. Cerebral venous hypertension due to incompetence of the internal jugular valve may play a role in the pathogenesis of TGA.