側頭葉内側部病変による記憶障害

Memory Disturbance Caused by Medial Temporal Lesion

I．はじめに

　側頭葉内側部は，脳梗塞，一酸化炭素中毒，無酸素症，心肺停止後等の脳虚血^{6,7,8,18,22,25,27）}，脳出血，くも膜下出血，巨大動脈瘤，cavernousangioma, venous angioma, arteriovenous malfor-mation（AVM）等の血管障害^{6,7,8,18,22,27）}，脳挫傷等の外傷性疾患，glioma, neuroblastoma, malig-nant lymphoma, dysembryoplastic neuroectoder-mal tumor, dermoid or epidermoid cyst, hamarto-ma等の腫瘍性病変，単純ヘルペス脳炎，abscess，meningitis, cysticercosis, toxoplasmosis等の感染性疾患^{6,7,8,18,22,23,27）}，cortical dysplasia, arrhinencephalia, holoprosen-cephaly等の発生障害，側頭葉てんかん，radia-tion necrosis，脳ヘルニア，アセチルサリチル酸による中毒などさまざまな疾患^{6,7,8,18,22,27）}で障害される．

　このような側頭葉内側部の障害では，記憶の一時的貯蔵庫である海馬の障害のため，記憶の固定化ができず健忘症を生じるが，その障害部位と症状との関係はまだまだ臨床的には明らかになっていないものと思われる^25）．われわれは，脳出血，脳梗塞，脳腫瘍，頭部外傷等の側頭葉内側部病変により，記憶障害を呈した6例を経験したので報告する．

The memory disturbance caused by medial temporal lesion is reported concerning 6 cases of cerebralhemorrhage, infarction, brain tumor, and contusion. The memory disturbance was significant comparedwith the patient's intact orientation and normal intelligence. In the category of memory, recent memorywas more markedly disturbed than the immediate or remote memory. From the viewpoint of the lesion, thememory disturbance was more severe when, in addition to the hippocampus, the entorhinal gyrus or amyg-dala was damaged.

The visual memory disturbance was mild and no difference was observed in the verbal or visual memoryaccording to whether the lesion was right or left. The memory disturbance was usually transient andmarked improvement was observed in some cases.