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Although several experiments reported rapid cortical plasticity induced by passive exposure to novel segmental patterns, few studies have devoted attention to the neural dynamics during the rapid learning of novel tonal word-forms in tonal languages, such as Chinese. In the current study, native speakers of Mandarin Chinese were exposed to acoustically matched real and novel segment-tone patterns. By recording their Mismatch Negativity (MMN) responses (an ERP indicator of long-term memory traces for spoken words), we found enhanced MMNs to the novel word-forms over the left-hemispheric region in the late exposure phase relative to the early exposure phase. In contrast, no significant changes were identified in MMN responses to the real word during familiarisation. Our results suggest a rapid Hebbian learning mechanism in the human neocortex which develops long-term memory traces for a novel segment-tone pattern by establishing new associations between the segmental and tonal representations. (C) 2014 Elsevier Inc. All rights reserved.
An auditory habituation design was used to investigate whether lexical-level phonological representations in the brain can be rapidly accessed after the onset of a spoken word. We studied the N1 component of the auditory event-related electrical potential, and measured the amplitude decrements of N1 associated with the repetition of a monosyllabic tone word and an acoustically similar pseudo-word in Mandarin Chinese. Effects related to the contrastive onset consonants were controlled for by introducing two control words. We show that repeated pseudo-words consistently elicit greater amplitude decrements in N1 than real words. Furthermore, this lexicality effect is free from sensory fatigue or rapid learning of the pseudo-word. These results suggest that a lexical-level phonological representation of a spoken word can be accessed as early as 110ms after the onset of the word-form.
The human language processing mechanism assigns a structure to the incoming materials as they unfold. There is evidence that the parser prefers some attachment types over others; however, theories of sentence processing are still in dispute over the stage at which each source of information contributes to the parsing system. The present study aims to identify the nature of initial parsing decisions during sentence processing through manipulating attachment type and verbs' argument structure. To this end, we designed a self-paced reading task using globally ambiguous constructions in Dutch. The structures included double locative prepositional phrases (PPs) where the first PP could attach both to the verb (high attachment) and the noun preceding it (low attachment). To disambiguate the structures, we presented a visual context in the form of short animation clips prior to each reading task. Furthermore, we manipulated the argument structure of the sentences using 2- and 3-argument verbs. The results showed that parsing decisions were influenced by contextual cues depending on the argument structure of the verb. That is, the visual context overcame the preference for high attachment only in the case of 2-argument verbs, while this preference persisted in structures including 3-argument verbs as represented by longer reading times for the low attachment interpretations. These findings can be taken as evidence that our language processing system actively integrates information from linguistic and non-linguistic sources from the initial stages of analysis to build up meaning. We discuss our findings in light of serial and parallel models of sentence processing.
Background: Morphological errors of tense and agreement are salient in agrammatic aphasia. The PADILIH predicts impairments in discourse linking that translate to greater difficulties in referring to a past event time than to a future or a present event time. In Catalan, the Periphrastic conditional tense (e.g., if the man had had time, he would have...) refers to the past and the Simple conditional tense refers to the future (e.g., if the man had time, he would...). These two tenses refer to an event that may happen (irrealis).Aims: We fill in the gap of the conditional tense and provide further data to study contrasts in verb inflection for time reference. We predict that verb forms that refer to an irrealis past event (Periphrastic conditional) are more impaired than forms that refer to an irrealis future event (Simple conditional and Future). We also predict that there are no differences between verb forms that refer to an irrealis future event (Simple conditional and Future). We also assessed whether problems in time reference extend to individuals with non-fluent aphasia that are not typical agrammatic Broca aphasia.Methods & Procedures: A sentence completion task that included 60 sentences (20 per type) of equal length in a Conditional structure (if-sentences) was designed. We tested three sentence types: Periphrastic conditional, Simple conditional and Future. The task was administered to nine participants with non-fluent aphasia and nine age-matched non-brain-damaged participants.Outcomes & Results: The Control group scored at ceiling on the three sentence types. Participants with non-fluent aphasia were most impaired in the production of the Periphrastic conditional as compared with the Simple conditional and the Future.Conclusions: When irrealis event times are compared, past events are more impaired than future events. These results can be explained by a deficit in time reference as predicted by the PADILIH. Our data reveal that the predictions of the PADILIH also hold for non-fluent speakers who have been diagnosed with Transcortical motor aphasia.
The present study aims to contribute to the ongoing discussion about the impact of discourse-linking deficits on the performance of individuals with aphasia by providing new data from a set of rarely investigated constructions: sentences in which a clitic pronoun coexists alongside with the full DP it agrees with. To do so, we use data of individuals with non-fluent aphasias who need to overcome the difficulties in direct object (accusative) clitic production. This results in overproduction of non-target clitic right dislocations (RDs) and clitic doubling (CD). Data from 15 individual’s native speakers of Spanish and Catalan are discussed. Data complement the results of previous investigations on discourse-linking effects in these languages, allowing the interpretation of results across constructions.
Discourse production in aphasia: a current review of theoretical and methodological challenges
(2016)
Background: Discourse abilities play an important role in the assessment, classification, and therapy outcome evaluation of people with aphasia. Discourse production in aphasia has been studied quite extensively in the last 15 years. Nevertheless, many questions still do not have definitive answers.Aims: The aim of this review is to present the current situation in the research on a number of crucial aspects of discourse production in aphasia, focusing on methodological progress and related challenges. This review continues the discussion of the core themes in the field, aiming to render it as up-to-date as possible.Main Contribution: The review focuses on a number of unexplored theoretical issues, specifically, the interface between micro- and macrolinguistic abilities, and the relationship between linguistic competence and communicative success in aphasia. The emphasis on theoretical challenges, along with the thorough discussion of methodological problems in the field, makes this review a starting point and a comprehensive information source for researchers planning to address language production in people with aphasia.Conclusion: Although the picture is not yet complete, recent advancements lead to a better understanding of the processes involved in aphasic discourse production. Different approaches provide insights into the complex multifaceted nature of discourse-level phenomena; however, methodological issues, including low comparability, substantially slow down the progress in the field.
Background: The distribution of pronouns varies cross-linguistically. This distribution has led to conflicting results in studies that investigated pronoun resolution in agrammatic indviduals. In the investigation of pronominal resolution, the linguistic phenomenon of "resumption" is understudied in agrammatism. The construction of pronominal resolution in Akan presents the opportunity to thoroughly examine resumption. Aims: To start, the present study examines the production of (pronominal) resumption in Akan focus constructions (who-questions and focused declaratives). Second, we explore the effect of grammatical tone on the processing of pronominal (resumption) since Akan is a tonal language. Methods & Procedures: First, we tested the ability to distinguish linguistic and non-linguistic tone in Akan agrammatic speakers. Then, we administered an elicitation task to five Akan agrammatic individuals, controlling for the structural variations in the realization of resumption: focused who-questions and declaratives with (i) only a resumptive pronoun, (ii) only a clause determiner, (iii) a resumptive pronoun and a clause determiner co-occurring, and (iv) neither a resumptive pronoun nor a clause determiner. Outcomes & Results: Tone discrimination .both for pitch and for lexical tone was unimpaired. The production task demonstrated that the production of resumptive pronouns and clause determiners was intact. However, the production of declarative sentences in derived word order was impaired; wh-object questions were relatively well-preserved. Conclusions: We argue that the problems with sentence production are highly selective: linguistic tones and resumption are intact but word order is impaired in non-canonical declarative sentences.
Background: The distribution of pronouns varies cross-linguistically. This distribution has led to conflicting results in studies that investigated pronoun resolution in agrammatic indviduals. In the investigation of pronominal resolution, the linguistic phenomenon of "resumption" is understudied in agrammatism. The construction of pronominal resolution in Akan presents the opportunity to thoroughly examine resumption. Aims: To start, the present study examines the production of (pronominal) resumption in Akan focus constructions (who-questions and focused declaratives). Second, we explore the effect of grammatical tone on the processing of pronominal (resumption) since Akan is a tonal language. Methods & Procedures: First, we tested the ability to distinguish linguistic and non-linguistic tone in Akan agrammatic speakers. Then, we administered an elicitation task to five Akan agrammatic individuals, controlling for the structural variations in the realization of resumption: focused who-questions and declaratives with (i) only a resumptive pronoun, (ii) only a clause determiner, (iii) a resumptive pronoun and a clause determiner co-occurring, and (iv) neither a resumptive pronoun nor a clause determiner. Outcomes & Results: Tone discrimination .both for pitch and for lexical tone was unimpaired. The production task demonstrated that the production of resumptive pronouns and clause determiners was intact. However, the production of declarative sentences in derived word order was impaired; wh-object questions were relatively well-preserved. Conclusions: We argue that the problems with sentence production are highly selective: linguistic tones and resumption are intact but word order is impaired in non-canonical declarative sentences.
Background: Comprehension of reversible sentences that have derived word order has often been reported as impaired in agrammatic aphasia. Most accounts of this phenomenon refer to the syntactic differences between derived and base word order of the arguments. However, it has been demonstrated that in agrammatic spontaneous speech in standard Indonesian (SI) passives are produced at a rate that is proportional to that of healthy speakers. The main difference between passives in SI and in other languages is the frequency with which passives are used: passives in SI are highly frequent. The high frequency can be explained by the fact that passives are used for politeness reasons, saliency of the passive morphology, earlier acquisition, and formal simplicity of the passive structure.
Aims: The purpose of the current study is to investigate comprehension of the passive as a derived structure in SI and the influence of frequency.
Methods & Procedures: A sentence-to-picture matching task was developed to test four reversible sentence types (active, passive, subject cleft and object cleft). There are three variables that are of interest, that is, word order, embedding and relative frequency of structures. Eleven agrammatic speakers classified as suffering from Broca’s aphasia were tested.
Outcomes & Results: The passive sentences were comprehended equally well as the active sentences. Embedding had limited effects: subject clefts were understood as well as actives and passives. Object clefts, however, were understood poorly and significantly worse than the three other sentence types.
Conclusions: The sentence comprehension deficit pattern shown in SI individuals with Broca’s aphasia introduces frequency of a syntactic structure as an additional factor to consider. Whether frequency or pragmatic constraints protects against erosion of the passive in Broca’s aphasia in SI remains an open question.