Time reference in aphasia:Evidence from Greek

Several studies have shown selective deficits in the production and comprehension of verb forms referring to the past. On the basis of this evidence the Past Discourse Linking Hypothesis (Bastiaanse et al., 2011) suggests that individuals with aphasia have difficulties with verb forms referring to the past, in comparison to non-past forms such as the present and the future. However, many studies provide counterevidence. This study presents a review of the literature and addresses the question of dissociation between the past and the non-past in aphasia in Greek, a language which distinguishes among three past forms. A mixed group of eight individuals with aphasia and a group of 10 non-brain-damaged speakers performed the two tasks of the Greek version of the Test for Assessing Reference of Time (Bastiaanse, Jonkers, & Thompson, 2008): a sentence completion task (primed by pictures) and a sentence-picture matching task. The sentence completion task tested the present, future and three past tenses: past perfective, past imperfective and present perfect. The sentence-picture matching task tested past perfective, present and future. The production data provide evidence for a deficit in the reference to the past but they also suggest difficulties with the future. Interestingly, a dissociation among the three past tenses tested was found. Above chance performance was found in comprehension across tenses. We consider possible accounts of the data and we discuss the implications of these findings for the Past Discourse Linking Hypothesis

Treatment of verb production: A multiple single-case, multiple baseline study

Two individuals with Broca’s aphasia were trained on (infinitival and finite) verb production in sentence context in an experiment with a multiple baseline, multiple single-case design. Both patients improved on a related task, but no improvement was found on an unrelated test. Improvement generalized to the subtasks ‘naming’ and ‘sentence construction’ of the Aachen Aphasia Test (AAT) and on the comprehensibility scale of the Amsterdam-Nijmegen Everyday Language Test (ANELT). In spontaneous speech, the mean utterance length of both clients increased significantly. One client produced significantly more finite verbs after treatment. The other client’s number of lexical verbs increased to a normal level after treatment

An investigation of time reference in production and comprehension in Thai speakers with agrammatic aphasia

Background It has been demonstrated that reference to the past is difficult for individuals with agrammatic aphasia, leading to the formulation of the PAst DIscourse LInking Hypothesis (PADILIH). Many of the previous studies have focused on Indo-European languages, in which time reference is expressed through verb inflection. The current study examined the PADILIH in Thai, a language that does not use verb inflection but instead uses aspectual markers to refer to time. Aims We aimed to evaluate the pattern of impairment of time reference in Thai speakers with agrammatic aphasia, by investigating how grammatical reference to past, present, and future was processed. Methods and Procedures A total of 15 Thai agrammatic speakers and 18 Thai non-brain-damaged (NBD) speakers participated in a sentence production task and an auditory sentence-to-picture matching comprehension task, both of which probed past, present, and future time reference. Outcomes and Results While the NBD participants performed close to ceiling in both production and comprehension, the agrammatic speakers showed significantly more difficulty in conditions requiring reference to the future in both modalities. In production, however, the agrammatic speakers replaced the target future time reference construction with negation (a construction that can be used as an alternative means for future reference). When responses using negation were counted as correct, the individuals with agrammatic aphasia showed equal impairment across conditions. Conclusions The results of this study were inconsistent with the PADILIH predictions: Thai agrammatic speakers experienced more vulnerability in reference to the future than the present and the past. This suggested that impairments of time reference may differ depending on the structure of the language. We hypothesized that the problems with producing future time reference in Thai may be influenced by the grammatical status of the future marker. In addition, the use of negation in place of the target word might have been because this negative construction reduces the processing load for Thai agrammatic speakers

The Importance of Verbs in Diagnosing Aphasia

In clinical practice, standardized tests are used to assess the presence of aphasia. Verbs often play a minor role in these tests. Their role in language, however, is essential and they are known to be more difficult to retrieve for people with aphasia (PWA). Therefore, milder forms of aphasia might be missed in the diagnostic process. In the current study, we investigate whether people with brain-damage, but no diagnosed aphasia (BDnoA) show specific problems in verb retrieval and if so, whether similar psycholinguistic variables drive the performance as is the case in aphasia, e.g., age of acquisition (AoA) and imageability (Bastiaanse, Wieling, & Wolthuis, 2016). 61 non-brain-damaged speakers (NBD), 48 PWA and 12 BDnoA performed an object naming (ON) and an action naming (AN) task. In ON, PWA were less accurate than NBD and BDnoA, with no difference between the latter two. For AN, PWA scored worse than NBD and tended to be less accurate than BDnoA. BDnoA scored worse than NBD. Further investigation of AN in the BDnoA group showed that ‘AoA’ and ‘imageability’ predicted the outcome, but not ‘frequency’ or ‘length’. While results confirmed that BDnoA did not perform worse than NBD in ON, their deficits in verb retrieval, albeit small, are clearly visible. Common diagnostic batteries might miss these mild language deficits as verbs are not included or only play a minor role in the assessment. The performance of the BD group was driven by age of acquisition and imageability, in line with findings of Bastiaanse, Wieling, and Wolthuis (2016) for PWA. The underlying deficit, therefore, seems comparable and BDnoA might present with a mild form of aphasia. With the current data we cannot exclude other, not language-specific causes for the verb retrieval deficit with certainty. Nonetheless, in order not to overlook mild cases, verb retrieval should play a more prominent role in the assessment process

Looking at the evidence in visual world:eye-movements reveal how bilingual and monolingual Turkish speakers process grammatical evidentiality

This study presents pioneering data on how adult early bilinguals (heritage speakers) and late bilingual speakers of Turkish and German process grammatical evidentiality in a visual world setting in comparison to monolingual speakers of Turkish. Turkish marks evidentiality, the linguistic reference to information source, through inflectional affixes signaling either direct (-DI) or indirect (-mIş) evidentiality. We conducted an eye-tracking-during-listening experiment where participants were given access to visual ‘evidence’ supporting the use of either a direct or indirect evidential form. The behavioral results indicate that the monolingual Turkish speakers comprehended direct and indirect evidential scenarios equally well. In contrast, both late and early bilinguals were less accurate and slower to respond to direct than to indirect evidentials. The behavioral results were also reflected in the proportions of looks data. That is, both late and early bilinguals fixated less frequently on the target picture in the direct than in the indirect evidential condition while the monolinguals showed no difference between these conditions. Taken together, our results indicate reduced sensitivity to the semantic and pragmatic function of direct evidential forms in both late and early bilingual speakers, suggesting a simplification of the Turkish evidentiality system in Turkish heritage grammars. We discuss our findings with regard to theories of incomplete acquisition and first language attrition

The electrophysiological manifestation of Dutch Verb Second violations

We investigated the processing of violations of the verb position in Dutch, in a group of healthy subjects, by measuring event-related potentials (ERPs) through electroencephalography (EEG). In Dutch, the base position of the verb is clause final, but in matrix clauses, the finite verb is in second position, a construction known as Verb Second. In embedded clauses, the finite verb remains in its clause-final base position. The results show that ungrammatical placement of finite verbs in second position in embedded clauses yields a P600 response, which suggests that the parser treats this type of violation as a clear syntactic anomaly. This is in contrast to accounts by which a general preference for subject-verb-object word order in languages like Dutch is reflected by an absence of P600 effects in response to violations of Verb Second.</p

Improving Production of Treated and Untreated Verbs in Aphasia:A Meta-Analysis

Background: Demographic and clinical predictors of aphasia recovery have been identified in the literature. However, little attention has been devoted to identifying and distinguishing predictors of improvement for different outcomes, e.g., production of treated vs. untreated materials. These outcomes may rely on different mechanisms, and therefore be predicted by different variables. Furthermore, treatment features are not typically accounted for when studying predictors of aphasia recovery. This is partly due to the small numbers of cases reported in studies, but also to limitations of data analysis techniques usually employed. Method: We reviewed the literature on predictors of aphasia recovery, and conducted a meta-analysis of single-case studies designed to assess the efficacy of treatments for verb production. The contribution of demographic, clinical, and treatment-related variables was assessed by means of Random Forests (a machine-learning technique used in classification and regression). Two outcomes were investigated: production of treated (for 142 patients) and untreated verbs (for 166 patients). Results: Improved production of treated verbs was predicted by a three-way interaction of pre-treatment scores on tests for verb comprehension and word repetition, and the frequency of treatment sessions. Improvement in production of untreated verbs was predicted by an interaction including the use of morphological cues, presence of grammatical impairment, pre-treatment scores on a test for noun comprehension, and frequency of treatment sessions. Conclusion: Improvement in the production of treated verbs occurs frequently. It may depend on restoring access to and/or knowledge of lexeme representations, and requires relative sparing of semantic knowledge (as measured by verb comprehension) and phonological output abilities (including working memory, as measured by word repetition). Improvement in the production of untreated verbs has not been reported very often. It may depend on the nature of impaired language representations, and the type of knowledge engaged by treatment: it is more likely to occur where abstract features (semantic and/or grammatical) are damaged and treated.</p

Functional and usage-based approaches to aphasia:the grammatical-lexical distinction and the role of frequency

Background: Functional and usage-based theories of language are gaining increasing influence in linguistics. These theories understand language structure as underpinned by domain-general neurocognitive capacities and as shaped by usage patterns and the function of language as a means for communication. Accordingly, they entail an approach to aphasia which differs markedly from established ones based on formal theories. Aims: Based on an outline of central claims in functional and usage-based theories, we aim to show how such theories can cast new light on aphasia. Methods & Procedures: We focus on two strands of functional and usage-based aphasiological research: 1) research on frequency effects in aphasic speech, 2) and research on the grammatical-lexical distinction and its significance for the description of aphasic speech and the understanding of the causes of aphasia. We review available studies that fall within the two aforementioned strands of research, assessing their strengths and limitations. Outcomes & Results: Usage-based methodologies are currently being developed that allow for fast quantification of the degree of formulaicity of a language sample and may thus be helpful in ascertaining the role of fossilized multiword expressions in aphasia. In line with central claims in usage-based linguistics, the first results of studies employing these methodologies have shown that frequency and collocation strength facilitate the retrieval of multiword expressions in a way that resembles the way in which lexical frequency facilitate retrieval of isolated words. A recent functional and usage-based theory understands the grammatical-lexicon distinction as a means for prioritizing parts of complex linguistic messages. Defining grammatical items as items that are discursively secondary (background) and dependent on host items, this theory entails an account of grammatical deficits which bridges the gap between existing structure-oriented and processing-oriented accounts. The theory entails word-class general criteria that allow fine-grained classification of linguistic items as grammatical or lexical. Cross-linguistic studies of verb, pronoun and preposition production show that this classification is significant for the description of aphasic language. Conclusions: Functional and usage-based studies of aphasia are still sparse, but show promising results. This approach seems especially qualified for understanding 1) the neurocognitive causes of various types of aphasia, 2) the variability across languages, communicative settings (including tasks and modalities), groups of individuals and individuals, which is characteristic of aphasic speech, and 3) the link between aphasia symptoms and the basic need and challenge for people with aphasia: to remain a social being by communicating with other social beings