Regularity revisited: evidence from lexical access of verbs and nouns in Greek

Undetected language deficits in left or right hemisphere post-stroke patients

Previous studies have reported that widely used tests for aphasia identification are unable to detect the subtle language deficits of left hemisphere brain damaged (LHBD) individuals. Similarly, the language disorders of individuals with right hemisphere brain damage (RHBD) usually remain undetected, due to the lack of any specialized test for the evaluation of their language processing skills. The aim of the present study was to evaluate the language deficits of 80 individuals suffering from the effects of either a LHBD or RHBD stroke, who were diagnosed as having no aphasia or language deficits based on the application of Boston Diagnostic Aphasia Examination. Their language abilities were examined with the use of the Adults' Language Abilities Test, which explores morpho-syntactic and semantic phenomena of the Greek language in both the comprehension and production modalities. Results revealed that both groups of stroke survivors performed significantly worse compared to the group of healthy participants. Thus, it appears that the latent aphasia of LHBD and the language deficits of RHBD patients are likely to remain undetected and that patients are at risk of not receiving appropriate treatment if their language abilities are not evaluated by an effective and efficient battery of language tests.

Noun and Verb Impairment in Single-Word Naming and Discourse Production in Mandarin-English Bilingual Adults with Aphasia

BACKGROUND

Previous studies on bilingualism and aphasia have identified a similar pattern of verb-noun dissociation in single-word naming (i.e., lower accuracy for verbs than nouns) in both languages. However, whether a similar pattern of verb and noun dissociation emerges in discourse production remains unknown, particularly in typologically dissimilar languages.

AIMS

This study investigated patterns of verb and noun impairment in both single-word naming and discourse production, and whether naming was associated with lexical retrieval in discourse production in Mandarin-English bilingual adults with aphasia (BWA).

METHODS

Twelve Mandarin-English bilinguals with chronic aphasia completed standardized assessments on object and action naming, and three discourse tasks from the AphasiaBank (i.e., sequential pictures, single-picture, storytelling) in both L1 (Mandarin) and L2 (English). Item-level accuracy of object and action naming was fit into a generalized mixed-effects model to estimate single-word naming ability as a function of grammatical category. Proportion of verb and noun production was fit into a multivariate linear regression model to assess lexical retrieval in discourse. Finally, another linear regression was performed to examine the association between naming and lexical retrieval in discourse production.

RESULTS

The naming accuracy for verbs was lower than for nouns in both L1 and L2. Mandarin-English BWA also demonstrated less production of verbs than nouns in discourse. However, depending on the type of the task, the effect of word category was greater in L2 than in L1. This cross-linguistic difference of the verb-noun dissociation was diminished in individuals with lower aphasia severity. Our results further showed a direct relationship between naming and lexical retrieval in discourse, irrespective of the language.

CONCLUSIONS

Our findings suggest an overall similar pattern of verb and noun dissociation across different linguistic contexts. However, depending on the cognitive-linguistic demands of the task, the verb-noun dissociation may emerge in L1 and L2 to varying degrees in individuals with different levels of aphasia severity. This study facilitates better understanding of verb and noun retrieval in Mandarin-English BWA.

Morphophonological salience as a compensatory means for deficits in the acquisition of past tense in SLI

The aim of this study is threefold: Firstly, to describe the acquisition patterns of Greek past tense by children with specific language impairment (SLI); secondly, to investigate the relationship between the phonological salience of past tense in Greek and its acquisition by children of typical and atypical language development; thirdly, to establish an account on the nature of specific language impairment by comparing the acquisition patterns exhibited by children with SLI to those presented by typically developing children. The performance of 10 children with SLI in elicited past tense production is compared to that of chronological age matched (CA) and language matched (LM) controls. Based on the claim that morphophonological salience aids acquisition (or learning), it is predicted that children with SLI will perform better in the production of past forms of higher salience than less salient forms. The results confirm this prediction, providing support for the claim that salience differences do account for better performances in tense marking in Greek SLI.

LEARNING OUTCOMES

By reading this article, the reader will be able to: (1) describe the problems children with SLI face in Greek tense marking, (2) explain the reasons why SLI performances differ from one language to the next based on the Interpretability Hypothesis, (3) discuss whether children with SLI differ qualitatively from TD controls in past tense marking and explain how.

The trouble with nouns and verbs in Greek fluent aphasia

In the past verb retrieval problems were associated primarily with agrammatism and noun retrieval difficulties with fluent aphasia. With regards to fluent aphasia, so far in the literature, three distinct patterns of verb/noun dissociations have been described for individuals with fluent anomic aphasia in languages with different underlying forms; better verb retrieval, poorer verb retrieval and equal retrieval difficulties for verbs and nouns. Verbs and nouns in Greek are considered of similar morphological complexity thus it was predicted that anomic aphasic individuals would suffer from a non-dissociated impairment of verbs and nouns. Problems with verbs and/or nouns may arise at any stage in the process of lexical retrieval, i.e. lexical-semantic, lemma, lexeme or articulation. The aim of this research was to investigate verb and noun retrieval using a picture-naming task to explore any possible selective noun and/or verb comprehension or retrieval deficits in Greek individuals with anomic aphasia. The results revealed a significant verb/noun dichotomy with verbs significantly more difficult to retrieve than nouns. These findings lend support for the growing body of evidence showing a specific verb impairment in fluent anomic individuals as well as Broca's patients. Given the prevailing view, that anomic patients experience difficulty retrieving the morpho-phonological form of the target word, the results show that specific information of the grammatical category is also important during word form retrieval. LEARNER OUTCOMES: The reader will become familiar with (i) studies investigating grammatical word class breakdown in individuals with aphasia who speak different languages, (ii) the application of the serial model to word production breakdown in aphasia and (iii) the characteristics of verbs and nouns in Greek. It will be concluded that successful verb retrieval for fluent aphasic individuals who speak Greek is dependant on the retrieval of the morpho-phonological information of the target verb.