Department of Translation and Language Sciences, Universitat Pompeu Fabra, Barcelona, Spain.
Catalan Institute for Advanced Studies and Research (ICREA), Barcelona, Spain.
PLoS One. 2022 Dec 6;17(12):e0278676. doi: 10.1371/journal.pone.0278676. eCollection 2022.
Aphasia following cerebro-vascular accidents has been a primary source of insight for models of language in the brain. However, deviant language patterns in aphasia may reflect processing limitations and cognitive impairment more than language impairment per se.
We sought to obtain new evidence from spontaneous speech in Broca's aphasia (BA) for the intactness of grammatical knowledge, operationalized as the preservation of the basic hierarchical structure of syntactic projections.
METHODS & PROCEDURES: Speech obtained with the AphasiaBank protocol from 20 people with BA, which were independently rated as also being agrammatic, was analyzed and compared to 20 matched non-brain-damaged controls. We quantified (i) marking of Aspect, Tense, and Modality (A-T-M), which are located at specific (high) layers of the syntactic hierarchy and ordered in relation to one another ([M…[T…[A…]]]); (ii) hierarchies of clausal units ([C…[C]]); (iii) discourse markers embedding clauses, located at the highest layer of the hierarchy; and (iv) attachment of adjuncts at different heights of a given hierarchical syntactic structure. Supplementary evidence was obtained from a typology of errors and from pauses subcategorized according to their hierarchical syntactic position.
OUTCOMES & RESULTS: Groups did not quantitatively differ on rates of either Aspect or Modality but underproduced T and embedded clauses. Evidence for compensatory effects was seen in both of the latter two cases. While all adjunct types were underproduced in BA, and pauses overproduced, both showed the same relative proportions within both groups. Errors were largely restricted to omissions, of a kind that would also be expected in condensed neurotypical speech.
Overall, these patterns support the hypothesis of intactness of grammatical knowledge in BA clinically rated as agrammatic, questioning it as a disease model of language impairment.
脑血管意外后的失语症一直是大脑语言模型的主要来源。然而，失语症中的异常语言模式可能反映了处理限制和认知障碍，而不仅仅是语言障碍本身。
我们试图从布罗卡失语症（BA）的自发言语中获得新的证据，证明语法知识的完整性，即句法投射的基本层次结构的保留。
使用失语症库协议从 20 名 BA 患者获得的言语，这些患者被独立评定为也存在语法障碍，进行了分析，并与 20 名匹配的非大脑损伤对照进行了比较。我们量化了（i）体貌、时态和情态的标记（A-T-M），它们位于句法层次的特定（高）层，并按彼此的顺序排列（[M…[T…[A…]]]）；（ii）小句单元的层次结构（[C…[C]]）；（iii）位于层次结构最高层的话语标记嵌入小句；以及（iv）在给定的层次句法结构的不同高度附加修饰语。补充证据来自错误类型学和根据其层次句法位置分类的停顿。
两组在体貌或情态的比率上没有定量差异，但 T 和嵌入式小句的产生率较低。在这后两种情况下，都可以看到补偿效应的证据。虽然 BA 中所有的修饰语类型都产生较少，停顿产生较多，但这两种情况在两组中都表现出相同的相对比例。错误主要限于省略，这在浓缩的神经典型言语中也可以预期。
总的来说，这些模式支持 BA 中语法知识完整性的假设，这与临床评定为语法障碍的 BA 相一致，质疑其作为语言障碍的疾病模型。
