Transient global amnesia and brain lesions: new hints into clinical criteria

Background and purpose:  Transient global amnesia (TGA) is the abrupt onset of anterograde amnesia with repetitive queries. Different hypotheses have been considered for its aetiology, but it still remains obscure. In 1990, Hodges and Warlow proposed clinical criteria for TGA. Applying these criteria, clinical studies looked for an unifying theory, considering TGA almost a primary and benign disorder. However, spare descriptions of TGA in patients with brain structural lesions have been reported. The aim of this study was to evaluate the prevalence of brain structural lesions among TGA patients. Methods:  One hundred and thirty clinically defined TGA were consecutively recruited. Among them, 13 patients (10%) showed brain structural lesions (TGA-b). Results:  No significant difference in clinical features, duration of TGA episode, age of onset, gender between primary TGA (TGA-p) and TGA-b were found. Triggering factors were comparable, suggesting that TGA-b should be considered in the spectrum of TGA, being clinically indistinguishable. Conclusions:  Transient global amnesia deserves a careful neuroimaging study and clinical follow-up considering the high prevalence of brain lesions among these patients and the impossibility to exclude TGA-b by clinical features. The follow-up of these patients and the evaluation of involved brain areas might help to further elucidate the pathogenetic mechanisms of the disease.