Comparison of Clinical Characteristics between Transient Global Amnesia with and without Acute Focal Lesion in Hippocampus

ABSTRACT

BACKGROUND: Transient global amnesia (TGA) might be related to an ischemic event with characteristic findings in diffusion-weighted images (DWIs). However, acute lesions are uncommon. The aim of this study was to identify any clinical or radiological differences between TGA patients with and without acute lesions. METHODS: From January 2010 through March 2015, we identified retrospectively TGA patients with DWIs within 7 days from onset. According to the presence of an acute lesion in the hippocampus, clinical features, vascular risk factors, electroencephalography (EEG) findings, and the regional perfusion status in single-photon-emission computed tomography (SPECT) images were compared. RESULTS: Of 57 TGA patients (mean age=60.5 years; 40 females), 19 patients (33.3%) had acute focal lesions in the hippocampus (3.53±0.74 mm, mean±SD). In terms of clinical features, the symptom duration was shorter in the lesion-negative group than in the lesion-positive group (mean=5 hours, interquartile range [IQR]=2-9 hours vs. mean=8 hours, IQR=5-13.5 hours; p=0.072). However, there were no differences between TGA patients with and without DWI lesions in cerebrovascular risk factors, laboratory results, or EEG findings. In 6 of 22 patients who underwent cerebral SPECT (2 of 9 DWI lesions and 4 of 13 without lesions), mild perfusion defects were exhibited without significant differences in both medial temporal regions and in the left frontal and left frontotemporal regions. CONCLUSIONS: Symptom duration was the only clinical difference-including perfusion defects and epileptic evidence-between TGA patients with and without DWI lesions. This suggests that there is a low probability of hypoperfusion or focal seizure in TGA patients without acute lesions.