Severe amnesia is caused by bilateral damage to the medial temporal lobe, specifically cornus ammonis (CA)1 of the hippocampal body.¹ Although some authors have reported that profound amnesia results from a unilateral temporal lobe stroke,^2,3 the part of the hippocampus that causes severe amnesia remains unknown. Here, we report the case of a patient who developed severe anterograde amnesia and minimal retrograde amnesia after a focal haemorrhage in the hippocampal body.

A 72-year-old right-handed man was admitted to the International Medical Center of Japan, Tokyo, Japan, in May 1999 because of acute memory impairment. A few days before admission, he started forgetting what he had done and said several minutes earlier, and he could no longer name nearby objects. On admission, he was disoriented as to the year, month and day, and could not recall the names of objects that he had been told to remember a few minutes earlier. His symptoms continued and were persistent 1 month later. MRI T1-weighted images 1 month after onset showed a haemorrhage in the left hippocampal body and in part of the hippocampal tail. The lesion included CA1, CA2 and CA3, the dentate gyrus and subiculum (fig 1), and extended subcortically in the parahippocampal gyrus.