Luzzi Simona, Baldinelli Sara, Ranaldi Valentina, Fiori Chiara, Plutino Andrea, Fringuelli Fabio M, Silvestrini Mauro, Baggio Giosuè, Reverberi Carlo
Department of Experimental and Clinical Medicine, Polytechnic University of Marche, Italy.
Department of Experimental and Clinical Medicine, Polytechnic University of Marche, Italy.
Cortex. 2020 Jul;128:174-191. doi: 10.1016/j.cortex.2020.03.012. Epub 2020 Mar 31.
Neuropsychological research on language has largely focused on how the brain processes single words and sentences whose meaning does not depend on the context or on the intentions of the speaker. Fewer studies have investigated the neurobiological bases of discourse semantics and pragmatics in patients and healthy individuals. We studied discourse semantic and pragmatic skills in patients with behavioral variant frontotemporal dementia (bvFTD) or Alzheimer's disease (AD) in comparison to healthy controls. Our goal was to assess whether and how the two patient groups differ in their cognitive and behavioral profiles, and whether these differences may be traced back to disease-specific patterns of neuronal hypometabolism. We combined PET imaging with standard neuropsychological assessment tools and a dedicated test battery designed to evaluate discourse semantics and pragmatics in patients with brain lesions or neurological disorders. We found that AD and bvFTD patients were both impaired compared to controls in discourse comprehension, but largely spared in single word comprehension. Importantly, we also found evidence for behavioral impairments specific to each disease, associated with different brain damage patterns. Compared to AD and controls, bvFTD patients had, behaviorally, more difficulty in evaluating whether certain inferences follow from discourse and in identifying humorous completions of stories; neurally, they had greater damage to medial and lateral regions of PFC. AD patients showed a different pattern of errors in a humor comprehension task than bvFTD patients and controls, and they showed greater posterior temporal and parietal cortical depletion. Both groups had comparable difficulties with understanding idioms and indirect requests. Finally, bvFTD-specific errors were correlated with the severity of hypometabolism in bvFTD. We discuss these results in light of previous research on the dementias as well as consequences for models of semantics and pragmatics in the brain.
关于语言的神经心理学研究主要集中在大脑如何处理单个单词和句子，这些单词和句子的意义不依赖于语境或说话者的意图。较少有研究调查患者和健康个体话语语义学和语用学的神经生物学基础。我们研究了行为变异型额颞叶痴呆（bvFTD）或阿尔茨海默病（AD）患者与健康对照者的话语语义和语用技能。我们的目标是评估这两组患者在认知和行为特征上是否存在差异以及如何存在差异，以及这些差异是否可追溯到疾病特异性的神经元代谢减退模式。我们将正电子发射断层扫描（PET）成像与标准神经心理学评估工具以及专门设计用于评估脑损伤或神经疾病患者话语语义和语用的测试组合相结合。我们发现，与对照组相比，AD和bvFTD患者在话语理解方面均受损，但在单个单词理解方面基本未受影响。重要的是，我们还发现了每种疾病特有的行为损伤证据，这些损伤与不同的脑损伤模式相关。与AD患者和对照组相比，bvFTD患者在行为上更难以评估某些推理是否源于话语以及识别故事的幽默结尾；在神经方面，他们的前额叶皮质内侧和外侧区域受损更严重。AD患者在幽默理解任务中的错误模式与bvFTD患者和对照组不同，并且他们的颞叶后部和顶叶皮质消耗更大。两组在理解习语和间接请求方面都有类似的困难。最后，bvFTD特有的错误与bvFTD患者代谢减退的严重程度相关。我们根据先前关于痴呆症的研究以及这些结果对大脑语义学和语用学模型的影响来讨论这些结果。
