Salisbury Dean F, Shenton Martha E, Nestor Paul G, McCarley Robert W
Cognitive Neuroscience Laboratory NBG21, Harvard Medical School at McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA.
Clin Neurophysiol. 2002 Mar;113(3):383-95. doi: 10.1016/s1388-2457(02)00003-2.
It is controversial whether a semantic processing bias for strong associates is present in schizophrenia, and unknown whether the language abnormalities observed in schizophrenia can be attributed to dysfunctions early or late in cognitive processing. Combined behavioral and event-related potential (ERP) data can indicate the nature and timing of such abnormalities.
Sensibility judgements of dominant and subordinate homograph sentences were measured in 12 schizophrenia patients and 13 normal controls. ERPs were recorded to the disambiguating sentence-ending word.
All subjects showed greatest misinterpretation of subordinate homograph sentences, but schizophrenia patients particularly misinterpreted these sentence types. For control subjects, subordinate homograph sentences that were classified as nonsensical showed greater N400 than those classified as sensible. By contrast, the N400 of patients was large, regardless of the sensibility judgement--patients' brains initially responded to all subordinate sentences as if nonsensical. These data are consonant with a semantic bias. However, the patients' N400 to dominant homograph sentence endings was also larger than that of controls, a finding not consonant with a semantic bias.
The behavioral results indicate a selective comprehension abnormality in schizophrenia dependent on the content of verbal memory. The ERP results suggest a pervasive contextual memory failure. A semantic activation decay model is proposed to explain these results.
精神分裂症患者是否存在对强关联词语的语义加工偏差存在争议，且精神分裂症中观察到的语言异常是归因于认知加工早期还是晚期功能障碍尚不清楚。行为数据与事件相关电位（ERP）数据相结合可以表明此类异常的性质和发生时间。
对12名精神分裂症患者和13名正常对照者进行显性和隐性同形异义词句子的语义判断测量。记录对消除歧义的句子结尾词的ERP。
所有受试者对隐性同形异义词句子的误解最大，但精神分裂症患者对这些句子类型的误解尤为明显。对于对照受试者，被归类为无意义的隐性同形异义词句子比被归类为有意义的句子显示出更大的N400。相比之下，患者的N400较大，无论语义判断如何——患者的大脑最初对所有隐性句子的反应都好像是无意义的。这些数据与语义偏差一致。然而，患者对显性同形异义词句子结尾的N400也比对照组大，这一发现与语义偏差不一致。
行为结果表明精神分裂症患者存在依赖言语记忆内容的选择性理解异常。ERP结果提示存在普遍的情境记忆障碍。提出了一个语义激活衰减模型来解释这些结果。
