Object naming impairments or anomias are the most frequent symptom in aphasia, and can be caused by a variety of underlying neurocognitive mechanisms. Anomia in neurodegenerative or primary progressive aphasias (PPA) often appears to be based on taxonomic blurring of word meaning: words such as "dog" and "cat" are still recognized generically as referring to animals, but are no longer conceptually differentiated from each other, leading to coordinate errors in word-object matching. This blurring is the hallmark symptom of the "semantic variant" of PPA, who invariably show focal atrophy in the left anterior temporal lobe. In this study we used eye tracking to characterize information processing online (in real time) as non-aphasic controls, semantic and non-semantic PPA participants completed a word-to-object matching task. All participants (including controls) showed taxonomic capture of gaze, spending more time viewing foils that were from the same category as the target compared to unrelated foils, but capture was more extreme in the semantic PPA group. The semantic group showed heightened capture even on trials where they ultimately pointed to the correct target, demonstrating the superiority of eye movements over traditional testing methods in detecting subtle processing impairments. Heightened capture was primarily driven by a tendency to direct gaze back and forth, repeatedly, between a set of related foils on each trial, a behavior almost never shown by controls or non-semantic participants. This suggests semantic PPA participants were accumulating and weighing evidence for a probabilistic rather than definitive mapping between the noun and several candidate objects. Neurodegeneration in PPA thus appears to distort lexical concepts prior to extinguishing them altogether, causing uncertainty in recognition and word-object matching.

中文翻译：

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我在看猫还是狗？原发性进行性失语症的语义变异中的凝视受到过度的分类学捕获


物体命名障碍或失忆症是失语症最常见的症状，可能是由多种潜在的神经认知机制引起的。神经退行性失语症或原发性进行性失语症 (PPA) 中的失语症通常似乎是基于词义的分类学模糊：诸如“狗”和“猫”之类的词仍然被普遍认为是指动物，但在概念上不再相互区分，导致词-对象匹配中的坐标错误。这种模糊是 PPA“语义变异”的标志性症状，其总是在左前颞叶表现出局灶性萎缩。在这项研究中，我们使用眼动追踪来表征在线（实时）信息处理，因为非失语控制、语义和非语义 PPA 参与者完成了单词到对象的匹配任务。所有参与者（包括对照组）都表现出对凝视的分类捕获，与不相关的箔片相比，花更多时间观看与目标属于同一类别的箔片，但捕获在语义 PPA 组中更为极端。即使在最终指向正确目标的试验中，语义组也表现出了更高的捕获能力，这证明了眼球运动在检测微妙的处理损伤方面比传统测试方法具有优越性。增强的捕获主要是由每次试验中在一组相关箔片之间反复来回引导目光的倾向所驱动的，而对照组或非语义参与者几乎从未表现出这种行为。这表明语义 PPA 参与者正在积累和权衡名词和几个候选对象之间概率而非确定映射的证据。 因此，PPA 中的神经变性似乎会在完全消除词汇概念之前扭曲它们，从而导致识别和词-对象匹配的不确定性。