統合失調症における文章記憶の検討

Narrative Memory in Schizophrenia

抄録

　本研究では，19名(男性9・女性10)の統合失調症患者の文章記憶能力を，文章の表層形式(逐語的情報)・テキストベース(WMS-R標準的採点基準)・状況モデル(文章理解内容)の3水準に分け，WMS-Rの論理的記憶課題を分析した。結果，すべての水準で即時・遅延再生時ともに患者群は対照群より成績が低下していた。状況モデルでは虚再生が多かったが，遅延再生時で即時再生時との再生量に変化がなかった。統合失調症患者では，文章の詳細部分では登録段階での処理が不正確であり，Working Memoryの障害によると考えた。また，一部誤った形で保持された文章の主要部分は，意味知識構造における障害の関与が示唆された。

　We investigated the ability and nature of narrative memory in schizophrenic patients. Nineteen patients and the same number of matched control subjects performed the logical memory task Ⅰ (immediate recall) and Ⅱ (delayed recall) from Wechsler Memory Scale Revised (WMS-R). In addition to the usual evaluation method employed for the WMS-R, called the text base, which scores the number of propositional units for similar meanings in the stimulus and the recalled data, two other evaluation methods were employed, i.e. the degree of correct recall at the surface level is the number of units that matches exactly the original text, and the degree of correspondence at the situational model which measures to what extent the causal relationships and main characters in the stimulus sentence are retained. The analysis of the results revealed that schizophrenic subjects performed worse than the control group both in immediate and delayed recall at the surface face and the text base level as well as at the situational model level. On the other hand no significant difference between immediate and delayed recall rates was detected at the situational model both for the subjects and the control. However we found that at this level the patients showed more false recalls which deviated from the context of the stimulus even at the immediate recall phase. We conclude that schizophrenic patients in this study poorly encoded the narrative stimulus both at the surface and core level, and the false situational model was saved and reconstructed.