脳動脈瘤破裂によるくも膜下出血後の言語性記憶の特徴

Characteristics of Verbal Memory after Subarachnoid Hemorrhage caused by Ruptured Aneurysm

要旨　目的：脳動脈瘤破裂によるくも膜下出血術後の記憶障害の詳細を明らかにするため，破裂部位や重症度の違いによる聴覚的言語性記憶検査の成績を健常群と比較した．方法：くも膜下出血の術後患者45名（前大脳動脈系14名，中大脳動脈系12名，椎骨動脈系7名，内頸動脈系12名）に対し，Auditory verbal learning test（AVLT）を行い，記憶の指標を算出し，学習曲線を比較した．結果：短期記憶や全即時記憶，再認に差はなかったが，前大脳動脈系では言語学習能力，椎骨動脈系では逆向性干渉効果で健常群と差を認め，学習後半での学習曲線の平坦化がみられた．AVLTの成績とくも膜下出血の重症度には有意な関連はなかった．結論：前大脳動脈系や椎骨脳底動脈系の破裂動脈瘤後は，記憶に問題を生じやすく，記憶障害の質や重症度を詳細に評価する必要があるものと思われた．

Abstract　Objective : To clarify the characteristics of memory impairment caused by ruptured aneurysm induced subarachnoid hemorrhage, we examined memory function using the auditory verbal learning test (AVLT). Methods : Subjects were 45 patients with subarachnoid hemorrhage caused by ruptured aneurysm in 14 anterior cerebral arteries (ACA), 12 middle cerebral arteries, 7 vertebrobasilar arteries (VA), and 12 internal cerebral arteries. We discussed the scores of short-term memory (STM), total immediate memory (TIM), verbal learning ability (VLA), retroactive interference effect (RI), recognition and learning curve in different portions of ruptured aneurysm. Additionally, we compared them with healthy subjects (HS). Results : The scores of VLA in ACA were lower than that in HS, and the scores of RI in VA were higher than that in HS. There were no difference in STM, TIM and recognition among groups. The learning curve in ACA and VA were flattening in later trials. Conclusion : Because patients after ruptured subarachnoid hemorrhage in ACA and VA have higher rate of memory impairment, we supposed detailed assessment for memory is important.