Transient Global Amnesia: Thorough Study of 183 Cases from One Center

Transient global amnesia (TGA) is characterized by transient deficit of episodic memory. In spite of its typical benign prognosis, patients and their relatives are frightened by TGA. Moreover, a TGA usually leads to extensive evaluation of patients in search of organic alterations. However, no comprehensive survey has been yet carried out in order to validate its diagnostic criteria and findings. The purpose of the present study is to seek for the demographic and clinical features of TGA more accurately. A total of 183 cases of TGA admitted to the Seoul National University Bundang Hospital over a seven-year period were studied. The patients performed clinical and neurological evaluation, electroencephalogram, structural and functional brain imaging scan. TGA-trigger events were evaluated and comorbidities were carefully recorded. A follow up was conducted in all patients at 12 months after presentation. No signi[[Unsupported Character - fi]]cant di[[Unsupported Character - ff]]erence in clinical features, duration, age of onset and vascular risk factors between the literature published since Hodges and Warlow's study and our study were found. In our study of 183 subjects, however, women were significantly more numerous (70.49% women 29.51% men). Fourty five percent of episodes started after some form of exercise, 48% after emotional distress. This revealed that in women, episodes are mainly associated with an emotional precipitating event (64%). In men, they occur more frequently after a physical precipitating event (61%). Abnormalities were detected in 78% of 135 patients were examined using DWI by our own MRI protocol for TGA, which was higher detection rate of lesions than literature published. SPECT have pointed out haemodynamic changes of the medial temporal lobe in 61.11% of 144 TGA patients examined during the acute phase. A follow-up SPECT showed that the lesions disappeared after 12 months. These observations claim that TGA may be considered a complex epiphenomenon, and the sum of the trigger factors can be responsible for this event. Given the good prognosis and the lack of association with organic abnormalities, we advance the hypothesis that TGA may be related to psychological disturbances causing transient alteration in brain metabolism in memory-relevant structures and, consequently, amnesia.