Kurita Akira, Yonezawa Jin, Suzuki Masahiko, Kawaguchi Sachiko, Ito Yasuhiko, Inoue Kiyoharu
Department of Neurology, Jikei University School of Medicine.
Rinsho Shinkeigaku. 2004 Jan;44(1):14-9.
A 29-year-old man was admitted because of sudden onset of retrograde amnesia. The patient was unable to recall events having occurred during the past 2 years. The impairment was especially serious with regard to personal memories during the 5 months prior to admission, while he had first been working as a full-time employee under stressful circumstance. A diagnosis of dissociative amnesia was made on the basis of absence of any systemic or neurological diseases that could cause amnesia, the inadaptable character of the patient, the nature of amnesia, and presence of stressful condition possibly related to the amnesia. Visual event-related potential (ERP) studies recorded with human face discrimination tasks demonstrated a P3a wave in response to a face of his superior in the office, whom he said that he had never seen before. The similar P3a wave was observed in response to a face quite familiar to the patient, his mother, but not to a face "truly" unknown to him. These findings suggest that the visual memory of his superior's face exists in the brain, but the patient is unable to retrieve it by some psychogenic mechanism. 131I-IMP SPECT revealed decreased perfusion in the left medial temporal lobe and the basal forebrain, suggesting the association between dissociative amnesia and focal brain dysfunction. While dissociative amnesia has been understood as psychogenic nature, both ERPs and SPECT are quite important tools to understand the association between the psychological phenomenon and biological changes of the brain in this disorder.
一名29岁男性因突发逆行性遗忘症入院。患者无法回忆起过去两年发生的事情。这种损害在入院前5个月的个人记忆方面尤为严重，当时他刚开始在压力环境下担任全职工作。基于不存在任何可能导致失忆的全身性或神经系统疾病、患者不适应的性格、失忆的性质以及可能与失忆相关的压力状况，诊断为分离性遗忘症。用人脸辨别任务记录的视觉事件相关电位（ERP）研究表明，对于他在办公室的上级的脸（他说他从未见过），出现了一个P3a波。对于患者非常熟悉的脸，他的母亲的脸，也观察到了类似的P3a波，但对于他“真正”不认识的脸则没有。这些发现表明，他上级的脸的视觉记忆存在于大脑中，但患者由于某种心理机制无法提取它。131I-IMP单光子发射计算机断层扫描（SPECT）显示左内侧颞叶和基底前脑灌注减少，提示分离性遗忘症与局灶性脑功能障碍之间存在关联。虽然分离性遗忘症被认为具有心理源性，但ERP和SPECT都是理解这种疾病中心理现象与大脑生物学变化之间关联的重要工具。
