Rogalski Emily, Rademaker Alfred, Mesulam Marsel, Weintraub Sandra
Cognitive Neurology and Alzheimer's Disease Center, Department of Preventative Medicine, Northwestern University, Chicago, IL 60612, USA.
Alzheimer Dis Assoc Disord. 2008 Oct-Dec;22(4):343-51. doi: 10.1097/WAD.0b013e31816c92f7.
The inability to name objects (anomia) is one of the most common findings in the neurologic examination of primary progressive aphasia (PPA). In the semantic variant of PPA, the anomia is profound and reflects a combination of object naming and word comprehension deficits. In contrast, nonsemantic variants of PPA display a more selective impairment of object naming, without corresponding impairments of word comprehension. The aim of the present study was to explore the nature of the anomia in nonsemantic variants of PPA with a sensitive chronometric test of covert word/picture association. We tested priming effects in 12 patients with nonsemantic variant of PPA and 18 controls. Stimuli consisted of written words and line pictures of concrete objects. Within-format (word-word and picture-picture) and cross-format (word-picture and picture-word) priming effects were assessed by measuring the shortening of response times to the second versus initial presentation of corresponding stimulus pairs. In addition to the expected impairment of picture-to-word priming, a condition simulating object naming, the nonsemantic PPA patients also showed unexpected impairments of word-to-picture and word-to-word priming. Picture-to-picture priming was preserved, demonstrating the selectivity of the deficit for lexical processing. These findings show that the information processing bottleneck in patients with nonsemantic variants of PPA is not confined to the stage of lexical access but that it also extends into the prior levels of lexical semantics. The boundaries between the semantic and nonsemantic variants are therefore far from rigid.
无法命名物体（命名障碍）是原发性进行性失语（PPA）神经学检查中最常见的结果之一。在PPA的语义变异型中，命名障碍很严重，反映了物体命名和词汇理解缺陷的综合情况。相比之下，PPA的非语义变异型表现出更具选择性的物体命名障碍，而没有相应的词汇理解障碍。本研究的目的是通过一项敏感的隐蔽词/图联想计时测试，探究PPA非语义变异型中命名障碍的本质。我们测试了12例PPA非语义变异型患者和18名对照者的启动效应。刺激物包括具体物体的书面单词和线条图。通过测量对相应刺激对的第二次呈现与首次呈现相比反应时间的缩短，评估格式内（词-词和图-图）和跨格式（词-图和图-词）的启动效应。除了预期的图到词启动效应受损（一种模拟物体命名的情况）外，非语义PPA患者还表现出意外的词到图和词到词启动效应受损。图到图启动效应得以保留，证明了词汇加工缺陷的选择性。这些发现表明，PPA非语义变异型患者的信息处理瓶颈不仅局限于词汇通达阶段，还延伸到了词汇语义的先前水平。因此，语义变异型和非语义变异型之间的界限远非严格。
