Grammar in ‘agrammatical’ aphasia: What’s intact?

• DOI: 10.1371/journal.pone.0278676
• Publication Date: 2022-12-06T19:06:30Z
• Authors: Han Zhang; Wolfram Hinzen
• Keywords: Adjunct; Modality (human–computer interaction)

Background Aphasia following cerebro-vascular accidents has been a primary source of insight for models language in the brain. However, deviant patterns aphasia may reflect processing limitations and cognitive impairment more than per se. Aims We sought to obtain new evidence from spontaneous speech Broca’s (BA) intactness grammatical knowledge, operationalized as preservation basic hierarchical structure syntactic projections. Methods & procedures Speech obtained with AphasiaBank protocol 20 people BA, which were independently rated also being agrammatic, was analyzed compared matched non-brain-damaged controls. quantified (i) marking Aspect, Tense, Modality (A-T-M), are located at specific (high) layers hierarchy ordered relation one another ([M…[T…[A…]]]); (ii) hierarchies clausal units ([C…[C]]); (iii) discourse markers embedding clauses, highest layer hierarchy; (iv) attachment adjuncts different heights given structure. Supplementary typology errors pauses subcategorized according their position. Outcomes results Groups did not quantitatively differ on rates either Aspect or but underproduced T embedded clauses. Evidence compensatory effects seen both latter two cases. While all adjunct types overproduced, showed same relative proportions within groups. Errors largely restricted omissions, kind that would be expected condensed neurotypical speech. Conclusions Overall, these support hypothesis knowledge BA clinically questioning it disease model impairment.