Judgment of functional morphology in agrammatic aphasia

Abstract

Individuals with agrammatic Broca's aphasia show deficits in production of functional morphemes like complementizers (e.g., that and if) and tense and agreement markers (e.g., -ed and -s), with complementizers often being more impaired than verbal morphology. However, there has been comparatively little work examining patients' ability to comprehend or judge the grammaticality of these morphemes. This paper investigates comprehension of complementizers and verb inflections in two timed grammaticality-judgment experiments. In Experiment 1, participants with agrammatic Broca's aphasia and grammatical-morphology production deficits (n=10) and unimpaired controls (n=10) heard complement clause sentences, subject relative clause sentences, and conjoined sentences. In Experiment 2, the same participants heard sentences with finite auxiliaries, sentences with finite main verbs, and sentences with uninflected verbs. Results showed above-chance accuracy in aphasic participants' judgments for complementizer sentences in Experiment 1, but chance performance for verb inflections in Experiment 2. This pattern held regardless of whether the verb inflections were affixes or free-standing auxiliaries. Implications of these results for theories of agrammatic morphological impairments, including feature underspecification accounts (Wenzlaff & Clahsen, 2004; Burchert, Swoboda-Moll & DeBleser, 2005a) and hierarchical structure-based accounts (Friedmann & Grodzinsky, 1997; Izvorski & Ullman, 1999), are discussed.

Agrammatic production: Interpretable features and selective impairment in verb inflection

“…Such a claim is also in line with Faroqi-Shah and Thompson's (2007) suggestion that ''the specific difficulty lies in verb form retrieval rather than selecting tense diacritics'' (p. 144). The latter view has gained empirical support by other studies as well (e.g., Dickey et al, 2008;FaroqiShah and Dickey, 2009;Faroqi-Shah and Thompson, 2003).…”

(Morpho)syntactic comprehension in agrammatic aphasia: Evidence from Greek

“…Nanousi et al (2006) and Varlokosta et al (2006), for example, report worse performance of Greek-speaking agrammatic individuals on judgements of Aspect and Tense, compared to judgement of Agreement, which is located higher than Aspect and Tense in the syntactic hierarchy of Greek (e.g., Philippaki-Warburton, 1998). Furthermore, Dickey et al (2008) report significantly better performance of English-speaking agrammatic individuals on judgements of CP-related structures, rather than of IP-related ones. According to the authors, the selective comprehension deficit affecting verbal morphology categories in the face of well-preserved higher projections is in line with the assumptions of Distributed Morphology (Halle & Marantz, 1993;Harley & Noyer, 1999), which posits that the syntactic component operates Downloaded by [Newcastle University] at 07:00 20 December 2014 separately from the morphological component, but that the latter takes the outputs of the former (phrase structures and feature bundles) as input for its computations.…”

“…According to the authors, the selective comprehension deficit affecting verbal morphology categories in the face of well-preserved higher projections is in line with the assumptions of Distributed Morphology (Halle & Marantz, 1993;Harley & Noyer, 1999), which posits that the syntactic component operates Downloaded by [Newcastle University] at 07:00 20 December 2014 separately from the morphological component, but that the latter takes the outputs of the former (phrase structures and feature bundles) as input for its computations. Hence, it is suggested that probably what is genuinely affected in agrammatic individuals is not syntax, but morphological insertion processes (Dickey et al, 2008; see also Thompson, Fix, & Gitelman, 2002). We will refer to Dickey et al's (2008) and Thompson et al's (2002) account as the Distributed Morphology Account (DMA).…”

“…Nevertheless, a number of studies indicate that comprehension or grammaticality judgement of simple active sentences can also be impaired in agrammatism. In particular, active structures that are used to test functional categories-such as subject-verb Agreement, Tense, or CP-can be affected (for example, for impairment in subject-verb Agreement: Mauner et al, 1993; for impairment in subject-verb Agreement and Tense: Dickey, Milman, & Thompson, 2008; for impairment in Tense only: Wenzlaff & Clahsen, 2004; for impairment in Tense and Aspect: Varlokosta et al, 2006; for impairment in Tense and higher projections: Hagiwara, 1995; for CP-related deficits, such as impaired comprehension of wh-questions,: e.g., Avrutin, 2000;Salis & Edwards, 2008;Stavrakaki & Kouvava, 2003;Thompson, Shapiro, Kiran, & Sobecks, 2003;Thompson, Tait, Ballard, & Fix, 1999).…”

Processing Clitic Pronouns in Bulgarian — Evidence from Normal and Agrammatic Comprehension

“…The selfpaced reading task uses negative imperatives as stimulus sentences. Imperatives have an advantage over finite clauses against the background of converging on-and offline experimental findings which locate the source of agrammatic behaviour at the structural and notional representation of tense (Burchert et al 2005a;Faroqi-Shah and Dickey 2009;Yarbay Duman and Bastiaanse 2009;Wenzlaff and Clahsen 2004), and strengthen the notion that tense disturbances do not necessarily prune the syntactic structure (Burchert et al 2008;Dickey et al 2008;Stavrakaki and Kouvava 2003). Additionally, the experiment seeks to contribute to the discussion revolving around differences in the comprehension of personal and reflexive pronouns.…”