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BackgroundAimsMethods & ProceduresOutcomes & ResultsConclusionsNarrative production has been widely characterized as providing an ecologically valid way to assess language skills in post-stroke aphasia. Although narrative tasks have been instrumental in delineating patterns of lexical and syntactic production in individuals with agrammatic aphasia, our knowledge of how narrative skills are affected in agrammatic aphasia is still limited.The study’s aims were to (a) compare narrative performance between individuals with agrammatic aphasia and a language-unimpaired group, (b) investigate the contribution of lexical and syntactic skills in each group’s narrative organizational skills, and (c) explore the effects of executive functions on each group’s narrative performance.The study included 14 individuals with agrammatic aphasia and 14 age- and education-matched language unimpaired individuals as the control group. Both groups told the Cinderella story, and their narrative production was analyzed in terms of microstructure (lexical diversity, syntactic complexity, clause length) and macrostructure (story grammar, story structure complexity). Each group’s executive functions were evaluated through the One-Touch Stockings of Cambridge test that assesses working memory, and the Intra-Extra Dimensional Set Shift test that assesses cognitive flexibility.Regarding narrative microstructure, the individuals with agrammatism scored significantly lower than controls in syntactic complexity and clause length, but not in lexical diversity, but they performed lower than controls in both narrative macrostructural measurements. Also, the agrammatic group scored lower than controls in both executive function tasks. A series of linear regression models showed that microstructural skills significantly affected narrative macrostructural abilities in the cohort with agrammatic aphasia, while controls’ macrostructure was affected by both narrative microstructure and executive function skills.The individuals with agrammatic aphasia exhibited impairment in both low-level language features of narrative production, such as syntactic complexity and narrative length, and global measures of narrative organization. Their macrostructural performance critically relied on their language resources, while controls’ narrative macrostructure seemed to also draw on domain-general cognitive skills. These findings suggest that both low-level language and high-level discourse organizational skills are vulnerable in narrative production in agrammatic aphasia, and that macrostructural skills are mainly related to the individuals’ microstructural skills. [ABSTRACT FROM AUTHOR]

In the recent years there has been increasing interest in the effects of attentional control on syntactic comprehension, as measured in garden path sentence resolution. Persons with aphasia (PWA) experience greater penalties in garden path sentences compared to language-unimpaired adults but the origin of this deficit remains a controversial issue. One of the possible deficits has been claimed to be disambiguation of lexical cues in the sentence. However, in languages such as English with little morphological variation this connection is hard to establish. To test this hypothesis we used garden path sentences in a morphologically rich language, Greek, where morphological cues may resolve garden path at the lexical level. We further tested whether domain-general attentional control abilities and in particular shifts in attentional control predict garden path resolution in PWA and age- and education-matched controls. This study aimed to determine whether PWA were able to integrate disambiguating morphological (Case) cues while processing garden path sentences. In addition, we tested whether domain-general attentional control and in particular attentional shift from global to local and local to global information (as defined by) correlates directly with garden path resolution in PWA and healthy controls. Fifteen participants with non-fluent/agrammatic aphasia along with fifteen age- and education-matched language-unimpaired adults performed an online self-paced reading and grammaticality judgment task that included object/subject ambiguous sentences. Syntactic ambiguity was created by the optional transitivity of verbs, while the garden path effect was resolved by morphological Case. The individuals' executive attention skills were tested through an online non-verbal global-local attention shifting task that measured costs stemming from shifting attention from the global to the local level, and vice versa. PWA were slower and more erroneous than controls in integrating Case cues to disambiguate garden path sentences as manifested in the self-paced reading and grammaticality judgment task. In the global local task, PWA exhibited greater global-to-local (vs. local-to-global) attention shifting costs, while controls did not exhibit dissociation. In the regression analysis, garden path resolution in PWA was significantly predicted by global-to-local attention shifting costs, while controls' garden path resolution was significantly predicted by local-to-global attention shift costs. The present study showed for the first time that morphological cues can shed light in sentence comprehension deficits exhibited by PWA. Furthermore, domain-general attentional control abilities were significantly associated with sentence comprehension abilities in both healthy controls and PWA. [ABSTRACT FROM AUTHOR]

Background: Few studies have investigated how individuals diagnosed with post-stroke Broca’s aphasia decompose words into their constituent morphemes in real-time processing. Previous research has focused on morphologically complex words in non-time-constrained settings or in syntactic frames, but not in the lexicon. Aims: We examined real-time processing of morphologically complex words in a group of five Greek-speaking individuals with Broca’s aphasia to determine: (1) whether their morphological decomposition mechanisms are sensitive to lexical (orthography and frequency) vs. morphological (stem-suffix combinatory features) factors during visual word recognition, (2) whether these mechanisms are different in inflected vs. derived forms during lexical access, and (3) whether there is a preferred unit of lexical access (syllables vs. morphemes) for inflected vs. derived forms. Methods & Procedures: The study included two real-time experiments. The first was a semantic judgment task necessitating participants’ categorical judgments for high- and low-frequency inflected real words and pseudohomophones of the real words created by either an orthographic error at the stem or a homophonous (but incorrect) inflectional suffix. The second experiment was a letter-priming task at the syllabic or morphemic boundary of morphologically transparent inflected and derived words whose stems and suffixes were matched for length, lemma and surface frequency. Outcomes & Results: The majority of the individuals with Broca’s aphasia were sensitive to lexical frequency and stem orthography, while ignoring the morphological combinatory information encoded in the inflectional suffix that control participants were sensitive to. The letter-priming task, on the other hand, showed that individuals with aphasia—in contrast to controls—showed preferences with regard to the unit of lexical access, i.e., they were overall faster on syllabically than morphemically parsed words and their morphological decomposition mechanisms for inflected and derived forms were modulated by the unit of lexical access. Conclusions: Our results show that in morphological processing, Greek-speaking persons with aphasia rely mainly on stem access and thus are only sensitive to orthographic violations of the stem morphemes, but not to illegal morphological combinations of stems and suffixes. This possibly indicates an intact orthographic lexicon but deficient morphological decomposition mechanisms, possibly stemming from an underspecification of inflectional suffixes in the participants’ grammar. Syllabic information, however, appears to facilitate lexical access and elicits repair mechanisms that compensate for deviant morphological parsing procedures. [ABSTRACT FROM AUTHOR]

We investigated the on-line processing of unaccusative and unergative sentences in a group of eight Greek-speaking individuals diagnosed with Broca aphasia and a group of language-unimpaired subjects used as the baseline. The processing of unaccusativity refers to the reactivation of the postverbal trace by retrieving the mnemonic representation of the verb's syntactically defined antecedent provided in the early part of the sentence. Our results demonstrate that the Broca group showed selective reactivation of the antecedent for the unaccusatives. We consider several interpretations for our data, including explanations focusing on the transitivization properties of nonactive and active voice-alternating unaccusatives, the costly procedure claimed to underlie the parsing of active nonvoice-alternating unaccusatives, and the animacy of the antecedent modulating the syntactic choices of the patients. [ABSTRACT FROM AUTHOR]

The aim of this study is to test the validity and reliability of the Bilingual Aphasia Test as a measure of language impairment in a Greek-speaking Broca's aphasic population and to investigate relationships with the same aphasic group's performance on the Greek version of the short form of the Boston Diagnostic Aphasia Examination battery, mainly focusing on a series of subtests which are shared by the two batteries, yet occasionally differ in content. Correlation analyses showed that the two instruments yielded highly comparable results with respect to the measurement of reading and listening comprehension, as well as in the performance-based measurement of the automated sequence capacity of the patients. Nevertheless, the Bilingual Aphasia Test, as a more extensive battery, proved to be more sensitive and objective in characterizing the patients' language abilities in a number of individual language functions, including commands, sentence repetition, naming, verbal fluency and syntactic comprehension. [ABSTRACT FROM AUTHOR]