Jeong Moonyoung, Jin Jaehyun, Kim Jeong Hee, Moon Yeonsil, Choi Jin Woo, Kim Hahn Young
*Department of Neurology, Center for Geriatric Neuroscience Research †Department of Radiology, Research Institute of Medical Science, Konkuk University School of Medicine, Seoul, Republic of Korea.
Neurologist. 2017 Jul;22(4):103-106. doi: 10.1097/NRL.0000000000000123.
Dot-like hippocampal hyperintensities (HHs) on diffusion-weighted MRI (DWI) have been reported as an interesting imaging finding of transient global amnesia (TGA) that is characterized by typical anterograde amnesia. However, we found that these dot-like HHs are occasionally seen in some patients without clinical symptoms of TGA.
We identified 8 patients who did not show clinical symptoms of TGA, despite the presence of hippocampal lesions on DWI (No-TGA group, n=8). For the comparison group, 16 age-matched and sex-matched patients were selected from among patients who had been diagnosed with TGA (TGA group, n=16).
No significant difference was found in vascular risk factors, years of education, or underlying cognitive function between the 2 groups. More than half of the patients in each group performed preceding Valsalva-associated activities. Multiple hippocampal lesions or concomitant lesions in the cingulate gyrus were found only in the TGA group.
Dot-like HHs on DWI can be observed without the typical symptoms of TGA. Valsalva maneuver-associated activities could produce asymptomatic hippocampal lesions. The symptoms of TGA may be presented on a spectrum, from no symptoms to mild vegetative symptoms or to the typical symptoms of TGA, depending on individual susceptibility.
扩散加权磁共振成像（DWI）上点状海马高信号（HHs）已被报道为短暂性全面性遗忘症（TGA）的一种有趣的影像学表现，TGA以典型的顺行性遗忘为特征。然而，我们发现这些点状HHs偶尔也会出现在一些没有TGA临床症状的患者中。
我们确定了8例尽管DWI上存在海马病变但未表现出TGA临床症状的患者（非TGA组，n = 8）。为了进行比较，从已被诊断为TGA的患者中选择了16例年龄和性别匹配的患者（TGA组，n = 16）。
两组在血管危险因素、受教育年限或潜在认知功能方面未发现显著差异。每组中超过一半的患者在之前进行过与瓦尔萨尔瓦动作相关的活动。仅在TGA组中发现了多个海马病变或扣带回的伴随病变。
在没有TGA典型症状的情况下也可观察到DWI上的点状HHs。与瓦尔萨尔瓦动作相关的活动可能会产生无症状的海马病变。根据个体易感性，TGA的症状可能呈现出一个范围，从无症状到轻度植物神经症状再到TGA的典型症状。
