1 Aphasia and Neurolinguistics Research Laboratory, Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, USA.
2 Cognitive Neurology and Alzheimer's Disease Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
Am J Alzheimers Dis Other Demen. 2018 Aug;33(5):292-300. doi: 10.1177/1533317518762443. Epub 2018 Mar 16.
Prototypical items within a semantic category are processed faster than atypical items within the same category. This typicality effect reflects normal representation and processing of semantic categories and when absent may be reflective of lexical-semantic deficits. We examined typicality effects in individuals with semantic and nonsemantic variants of primary progressive aphasia (PPA; semantic-PPA-S, agrammatic-PPA-G), a neurodegenerative disorder characterized by specific decline in language function, and age-matched controls. Using a semantic category verification task, where participants were asked to decide whether visual or auditory words (category typical, atypical, or nonmembers) belonged within a specified superordinate category, we found a typicality effect (ie, faster response times for typical vs atypical items) for all participant groups. However, participants with more severe PPA-S did not show a typicality effect in either modality. Findings may reflect increased intracategory semantic blurring as the disease progresses and semantic impairment becomes more severe.
在同一类别中，原型项目的处理速度比非原型项目快。这种典型性效应反映了语义范畴的正常表示和处理，而当不存在时，可能反映了词汇语义缺陷。我们在语义和非语义原发性进行性失语症（PPA；语义-PPA-S，语法性 PPA-G）患者个体中检查了典型性效应，这是一种以语言功能特异性下降为特征的神经退行性疾病，以及年龄匹配的对照组。使用语义类别验证任务，要求参与者判断视觉或听觉单词（类别典型、非典型或非成员）是否属于特定的上位类别，我们发现所有参与者群体都存在典型性效应（即，典型项目的反应时间比非典型项目快）。然而，语义-PPA-S 更严重的患者在任何一种模态中都没有表现出典型性效应。研究结果可能反映出随着疾病的进展，类别内语义模糊度增加，语义损伤变得更加严重。
