Syntactic and morphosyntactic processing in stroke-induced and primary progressive aphasia

Issue title: Primary Progressive Aphasia and Post-Stroke Aphasia: Some Complementary Insights into Brain-Behavior Relationships/Hemispatial Neglect and Related Disorders

Article type: Research Article

Authors: Thompson, Cynthia K.^{; ;} | Meltzer-Asscher, Aya | Cho, Soojin^; | Lee, Jiyeon | Wieneke, Christina | Weintraub, Sandra^{; ;} | Mesulam, M.-Marsel^;

Affiliations: Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, USA | Department of Neurology, Northwestern University, Evanston, IL, USA | Cognitive Neurology and Alzheimer's Disease Center, Northwestern University, Evanston, IL, USA | Department of Psychiatry and Behavioral Sciences, Northwestern University, Evanston, IL, USA

Note: [] Corresponding author: Aya Meltzer-Asscher, Aphasia and Neurolinguistics Research Laboratory, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA. Tel.: +1 847 467 7591; Fax: +1 847 467 7377; E-mail: a-meltzer-asscher@northwestern.edu

Abstract: The paper reports findings derived from three experiments examining syntactic and morphosyntactic processing in individuals with agrammatic and logopenic variants of primary progressive aphasia (PPA-G and PPA-L, respectively) and stroke-induced agrammatic and anomic aphasia (StrAg and StrAn, respectively). We examined comprehension and production of canonical and noncanonical sentence structures and production of tensed and nontensed verb forms using constrained tasks in experiments 1 and 2, using the Northwestern Assessment of Verbs and Sentences (NAVS [57]) and the Northwestern Assessment of Verb Inflection (NAVI, Thompson and Lee, experimental version) test batteries, respectively. Experiment 3 examined free narrative samples, focusing on syntactic and morphosyntactic measures, i.e. production of grammatical sentences, noun to verb ratio, open-class to closed-class word production ratio, and the production of correctly inflected verbs. Results indicate that the two agrammatic groups (i.e., PPA-G and StrAg) pattern alike on syntactic and morphosyntactic measures, showing more impaired noncanonical compared to canonical sentence comprehension and production and greater difficulties producing tensed compared to nontensed verb forms. Their spontaneous speech also contained significantly fewer grammatical sentences and correctly inflected verbs, and they produced a greater proportion of nouns compared to verbs, than healthy speakers. In contrast, PPA-L and StrAn individuals did not display these deficits, and performed significantly better than the agrammatic groups on these measures. The findings suggest that agrammatism, whether induced by degenerative disease or stroke, is associated with characteristic deficits in syntactic and morphosyntactic processing. We therefore recommend that linguistically sophisticated tests and narrative analysis procedures be used to systematically evaluate the linguistic ability of individuals with PPA, contributing to our understanding of the language impairments of different PPA variants.

Keywords: Aphasia, primary progressive aphasia, agrammatism, syntactic processing, narrative speech

DOI: 10.3233/BEN-2012-110220

Journal: Behavioural Neurology, vol. 26, no. 1-2, pp. 35-54, 2013