Robson Holly, Pilkington Emma, Evans Louise, DeLuca Vincent, Keidel James L
School of Psychology and Clinical Language Sciences, University of Reading, UK.
School of Psychology and Clinical Language Sciences, University of Reading, UK.
Neuropsychologia. 2017 Jun;100:144-154. doi: 10.1016/j.neuropsychologia.2017.04.012. Epub 2017 Apr 20.
Comprehension impairments in Wernicke's aphasia are thought to result from a combination of impaired phonological and semantic processes. However, the relationship between these cognitive processes and language comprehension has only been inferred through offline neuropsychological tasks. This study used ERPs to investigate phonological and semantic processing during online single word comprehension. EEG was recorded in a group of Wernicke's aphasia n=8 and control participants n=10 while performing a word-picture verification task. The N400 and Phonological Mapping Negativity/Phonological Mismatch Negativity (PMN) event-related potential components were investigated as an index of semantic and phonological processing, respectively. Individuals with Wernicke's aphasia displayed reduced and inconsistent N400 and PMN effects in comparison to control participants. Reduced N400 effects in the WA group were simulated in the control group by artificially degrading speech perception. Correlation analyses in the Wernicke's aphasia group found that PMN but not N400 amplitude was associated with behavioural word-picture verification performance. The results confirm impairments at both phonological and semantic stages of comprehension in Wernicke's aphasia. However, reduced N400 responses in Wernicke's aphasia are at least partially attributable to earlier phonological processing impairments. The results provide further support for the traditional model of Wernicke's aphasia which claims a causative link between phonological processing and language comprehension impairments.
韦尼克失语症患者的理解障碍被认为是由语音和语义加工受损共同导致的。然而，这些认知过程与语言理解之间的关系仅通过离线神经心理学任务推断得出。本研究使用事件相关电位（ERP）来探究在线单词语义理解过程中的语音和语义加工。在一组韦尼克失语症患者（n = 8）和对照组参与者（n = 10）执行单词 - 图片验证任务时记录脑电图（EEG）。分别将N400和语音映射负波/语音失配负波（PMN）事件相关电位成分作为语义和语音加工的指标进行研究。与对照组参与者相比，韦尼克失语症患者表现出降低且不一致的N400和PMN效应。在对照组中，通过人为降低语音感知来模拟韦尼克失语症组中降低的N400效应。在韦尼克失语症组中的相关性分析发现，PMN而非N400波幅与行为学单词 - 图片验证表现相关。结果证实了韦尼克失语症患者在理解的语音和语义阶段均存在障碍。然而，韦尼克失语症患者中降低的N400反应至少部分归因于早期的语音加工障碍。这些结果为韦尼克失语症的传统模型提供了进一步支持，该模型认为语音加工与语言理解障碍之间存在因果关系。
