A Common Left Occipito-Temporal Dysfunction in Developmental Dyslexia and Acquired Letter-By-Letter Reading?

We used fMRI to examine functional brain abnormalities of German-speaking dyslexics who suffer from slow effortful reading but not from a reading accuracy problem. Similar to acquired cases of letter-by-letter reading, the developmental cases exhibited an abnormal strong effect of length (i.e., number of letters) on response time for words and pseudowords.Corresponding to lesions of left occipito-temporal (OT) regions in acquired cases, we found a dysfunction of this region in our developmental cases who failed to exhibit responsiveness of left OT regions to the length of words and pseudowords. This abnormality in the left OT cortex was accompanied by absent responsiveness to increased sublexical reading demands in phonological inferior frontal gyrus (IFG) regions. Interestingly, there was no abnormality in the left superior temporal cortex which--corresponding to the onological deficit explanation--is considered to be the prime locus of the reading difficulties of developmental dyslexia cases.The present functional imaging results suggest that developmental dyslexia similar to acquired letter-by-letter reading is due to a primary dysfunction of left OT regions

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

Background: A number of hypotheses have been formulated to account for comprehension data in agrammatic aphasia. They explain deficits in comprehending specific structures, such as semantically reversible non-canonical sentences, for example, Trace Deletion Hypothesis (TDH, Grodzinsky, 1986, 1990, 1995), or functional categories, for example, Tree Pruning Hypothesis (TPH, e.g., Friedmann, 2006); Tense Underspecification Hypothesis (TUH, Wenzlaff & Clahsen, 2004, 2005); Interpretable Features' Impairment Hypothesis (IFIH; e.g., Varlokosta et al., 2006). Several studies, however, report evidence contradicting these theories (e.g., Caramazza, Capasso, Capitani, & Miceli, 2005; Dickey, Milman, & Thompson, 2008) and propose new accounts to explain the comprehension deficits in agrammatic aphasia, for example, Distributed Morphology Account (DMA, Dickey et al., 2008). Aims: Against the background above, this study investigates the ability of three Greek-speaking agrammatic individuals to comprehend a wide range of structures and functional categories: semantically reversible (canonical) active and (non-canonical) passive sentences, Complementizer Phrase, subject-verb Agreement, Tense, and Aspect. Methods & Procedures: We administered: (a) two sentence-picture matching tasks to test comprehension of reversible active and passive sentences, and Tense; (b) a sentence grammaticality judgement task to test judgement of Tense, Aspect, and subject-verb Agreement; and (c) a picture-pointing task to test comprehension of Complementizer Phrase. Outcomes & Results: (a) Two of the three agrammatic participants performed at chance on reversible passive sentences and above chance on active sentences. The third participant performed equally high on the two sentence types. Two participants performed at chance on Tense comprehension and one above chance. (b) The three participants were selectively or across-the-board impaired in judgement of Agreement, Tense, and Aspect. One of the two selectively affected participants had chance performance on Aspect and above chance performance on Agreement and Tense. The other one performed at chance on Aspect and Tense, and above chance on Agreement. The third participant's performance was equally poor on all three categories. (c) All three agrammatic participants performed above chance on the comprehension of Complementizer Phrase. Conclusions: In comprehension/judgement, canonical and non-canonical sentences do not dissociate in all agrammatic speakers, while functional categories associated with the verb morphology may be compromised in the face of relatively well-preserved categories that are located higher in the syntactic hierarchy. All three agrammatic participants support the DMA, and two of them support the TDH. Instead, none of them provided support to the TPH, TUH, and IFIH. © 2013 Copyright Taylor and Francis Group, LLC

Exploring wh-questions in agrammatism: Evidence from Greek

This study investigates the ability of three Greek-speaking agrammatic patients to produce and comprehend wh-questions by means of a wh-question elicitation task and a picture-pointing task. The role of question type is explored by comparing argument with adjunct questions and subject with object questions. Overall, production was found significantly more impaired than comprehension. The agrammatic participants had better performance on argument than on adjunct questions, while no dissociation was observed between subject and object questions. The overall difficulty with wh-questions indicates that the agrammatic participants had a deficit in syntactic movement or in handling CP, a finding which is compatible with other cross-linguistic results. Although this finding could be accounted for by existing hypotheses, an alternative account is proposed, according to which wh-questions are difficult to process because they are associated with LF-interpretable features, which increase their processing load. Finally, the preponderance of argument over adjunct questions reinforces the (double) dissociation between these two question types reported in the literature, while the lack of a dissociation between the subject- and the object-questions suggests that both question types involve syntactic movement to CP. © 2010 Elsevier Ltd

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

Background: A number of hypotheses have been formulated to account for comprehension data in agrammatic aphasia. They explain deficits in comprehending specific structures, such as semantically reversible non-canonical sentences, for example, Trace Deletion Hypothesis (TDH, Grodzinsky, 1986, 1990, 1995), or functional categories, for example, Tree Pruning Hypothesis (TPH, e.g., Friedmann, 2006); Tense Underspecification Hypothesis (TUH, Wenzlaff & Clahsen, 2004, 2005); Interpretable Features' Impairment Hypothesis (IFIH; e.g., Varlokosta et al., 2006). Several studies, however, report evidence contradicting these theories (e.g., Caramazza, Capasso, Capitani, & Miceli, 2005; Dickey, Milman, & Thompson, 2008) and propose new accounts to explain the comprehension deficits in agrammatic aphasia, for example, Distributed Morphology Account (DMA, Dickey et al., 2008). Aims: Against the background above, this study investigates the ability of three Greek-speaking agrammatic individuals to comprehend a wide range of structures and functional categories: semantically reversible (canonical) active and (non-canonical) passive sentences, Complementizer Phrase, subject-verb Agreement, Tense, and Aspect. Methods & Procedures: We administered: (a) two sentence-picture matching tasks to test comprehension of reversible active and passive sentences, and Tense; (b) a sentence grammaticality judgement task to test judgement of Tense, Aspect, and subject-verb Agreement; and (c) a picture-pointing task to test comprehension of Complementizer Phrase. Outcomes & Results: (a) Two of the three agrammatic participants performed at chance on reversible passive sentences and above chance on active sentences. The third participant performed equally high on the two sentence types. Two participants performed at chance on Tense comprehension and one above chance. (b) The three participants were selectively or across-the-board impaired in judgement of Agreement, Tense, and Aspect. One of the two selectively affected participants had chance performance on Aspect and above chance performance on Agreement and Tense. The other one performed at chance on Aspect and Tense, and above chance on Agreement. The third participant's performance was equally poor on all three categories. (c) All three agrammatic participants performed above chance on the comprehension of Complementizer Phrase. Conclusions: In comprehension/judgement, canonical and non-canonical sentences do not dissociate in all agrammatic speakers, while functional categories associated with the verb morphology may be compromised in the face of relatively well-preserved categories that are located higher in the syntactic hierarchy. All three agrammatic participants support the DMA, and two of them support the TDH. Instead, none of them provided support to the TPH, TUH, and IFIH. © 2013 Copyright Taylor and Francis Group, LLC

Adaptation and validation of standardized aphasia tests in different languages: Lessons from the Boston diagnostic aphasia examination - Short form in Greek

The aim of the current study was to adapt the Boston Diagnostic Aphasia Examination - Short Form (BDAE-SF) [1] to the Greek language and culture, determine the influence of demographic variables on performance and in particular the effects of age and education, develop normative data, and examine the discriminative validity of the test for acute stroke patients. A sample of 129 community healthy adults participated in the study (66 women), covering a broad range of ages and education levels so as to maximize representation of the Greek population and be able to examine the effects of age and education in language performance. Regression models showed that, overall, younger and more educated individuals presented higher performance on several subtests. Normative data for the Greek population are presented in percentile tables. Neurological patients' performance was compared to that of the neurologically intact population using Wilcoxon's rank sum test and for the most part was found to be significantly inferior, indicating good discriminant validity of the test. Qualitative errors of patients diagnosed with aphasia on the test are presented, and limitations and generalizable strengths of this adaptation are discussed. © 2009/2010 - IOS Press and the authors

Effects of executive attention on sentence processing in aphasia

Background: 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. Aims: 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. Methods & Procedures: 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. Outcomes & Results: 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. Conclusions: 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. © 2019 Informa UK Limited, trading as Taylor & Francis Group