[Persistent amnestic syndrome due to infarction of the genu of the left internal capsule].

An 85-year-old housewife was admitted owing to the sudden onset of amnestic syndrome on June 27, 1986. There was no history of abulia or somnolence. Though she showed severe amnesia, her understanding was not impaired. There was no aphasia, no dysarthria or other focal sings. The CT showed a low density area in the genu of the left internal capsule. The patient's amnestic syndrome did not improve during the following four years and thus she was readmitted for further examination in July, 1990. Although her WAIS scores were fairly good and intelligence was considered normal, she showed very poor performance on the Wechsler memory scale-R and Benton visual retention test. MRI of the brain showed infarction which extended from the genu to the anterior limb of the left internal capsule. The longstanding amnesia in the present case was induced probably by the infarction of the genu of the left internal capsule, where some fibers of memory pathways, such as the anterior thalamic peduncle, ansa peduncularis, and stria terminalis, may pass.