Grammatical Planning Units During Real-Time Sentence Production in Speakers With Agrammatic Aphasia and Healthy Speakers

Abstract

Purpose: Grammatical encoding (GE) is impaired in agrammatic aphasia; however, the nature of such deficits remains unclear. We examined grammatical planning units during real-time sentence production in speakers with agrammatic aphasia and control speakers, testing two competing models of GE. We queried whether speakers with agrammatic aphasia produce sentences word by word without advanced planning or whether hierarchical syntactic structure (i.e., verb argument structure; VAS) is encoded as part of the advanced planning unit. Method: Experiment 1 examined production of sentences with a predefined structure (i.e., "The A and the B are above the C") using eye tracking. Experiment 2 tested production of transitive and unaccusative sentences without a predefined sentence structure in a verb-priming study.Results: In Experiment 1, both speakers with agrammatic aphasia and young and age-matched control speakers used word-by-word strategies, selecting the first lemma (noun A) only prior to speech onset. However, in Experiment 2, unlike controls, speakers with agrammatic aphasia preplanned transitive and unaccusative sentences, encoding VAS before speech onset. Conclusions: Speakers with agrammatic aphasia show incremental, word-by-word production for structurally simple sentences, requiring retrieval of multiple noun lemmas. However, when sentences involve functional (thematic to grammatical) structure building, advanced planning strategies (i.e., VAS encoding) are used. This early use of hierarchical syntactic information may provide a scaffold for impaired GE in agrammatism.

Grammatical encoding and learning in agrammatic aphasia: Evidence from structural priming

“…These findings suggest that agrammatic speakers do form abstract structural representations, including thematic representations, that guide sentence production, and are thus inconsistent with representational accounts of sentence production deficits (Friedmann & Grodzinsky, 1997). In contrast, they lend support to grammatical encoding accounts of agrammatism, and in particular are consistent with research suggesting that agrammatic speakers have intact access to thematic and syntactic information but difficulty implementing this information as sentence production unfolds (Cho & Thompson, 2010; Lee & Thompson, 2011a, 2011b; Lee et al, 2015). …”

“…They also have difficulty producing syntactically complex sentences such as passives and embedded clauses (Caplan & Hanna, 1998; Cho-Reyes & Thompson, 2012; Faroqi-Shah & Thompson, 2003). On some theories, agrammatic sentence production deficits stem from an underspecification of linguistic representations (Friedmann & Grodzinsky, 1997), precluding the ability to generate fully-specified grammatical sentences, whereas other accounts link these deficits to impaired grammatical encoding, i.e., inability to implement grammatical representations in real-time (Cho & Thompson, 2010; Lee, Yoshida, & Thompson, 2015; Linebarger, Schwartz, Romania, Kohn, & Stephens, 2000). …”

Phonological facilitation effects on naming latencies and viewing times during noun and verb naming in agrammatic and anomic aphasia

“…This finding suggests that measuring speakers’ viewing times is informative in studies examining the time course of lexical access in individuals with aphasia, particularly those whose naming latencies might be difficult to obtain due to frequently co-occurring motor speech disturbances (Dell et al, 1997; Schwartz et al, 2006). These are novel findings indicating that monitoring eye gaze during controlled naming tasks may overcome this methodological limitation and can provide another sensitive measure for investigating online lexical access (see also Odekar, Hallowell, Kruse et al, 2009 for semantic facilitation effects on eye movement patterns during semantic association tasks in healthy young adults and Lee & Thomson, 2011a, 2011b; Lee, Yoshida, & Thompson, submitted for using eye movements for studying on-line processes of sentence production in agrammatic aphasia).…”

Effects of regiolects on the perception of developmental foreign accent syndrome

“…Recent eyetracking sentence production studies have shown that access of verb argument structure information before speech onset is facilitative of sentence production in IWA, in line with structure-driven production (Lee & Thompson, 2011a;2011b;Lee, Yoshida, & Thompson, 2015). However, it remains an open question if the aphasic language production system also follows word-driven incremental production, opportunistically using wordbased cues to ease syntactic production.…”