Effect of lexical cues on the production of active and passive sentences in Broca's and Wernicke's aphasia

Subject-verb agreement and tense in Jordanian Arabic Broca's aphasia

The present study examined the deficits of people with aphasia in tense (past, present, and future) and agreement (person, number, and gender) in Jordanian Arabic. Forty participants were selected and two tasks were administered for this study using Boston Diagnostic Aphasia Examination (BDAE)-Arabic version. The first task was sentence completion in which sentences have a blank and need to be filled by the participants. The second task was grammaticality judgment, in which participants should determine whether sentences are grammatically correct or not. Results indicated significantly that the Jordanian participants with aphasia violate gender aspect more than person and number in both sentence completion task (p = 0.025) and grammaticality judgment task (p = 0.000), it was also reported that past tense was violated significantly more than present and future in sentence completion task (p = 0.000) as well as grammaticality judgment task (p = 0.012). It is concluded that Arabic speakers with agrammatism were tested with reference to time and agreement and the results showed that they performed as hypothesized, showing a selective deficit for production of inflected forms of past tense.

A reconceptualization of sentence production in post-stroke agrammatic aphasia: the synergistic processing bottleneck model

The language production deficit in post-stroke agrammatic aphasia (PSA-G) tends to result from lesions to the left inferior frontal gyrus (LIFG) and is characterized by a triad of symptoms: fragmented sentences, errors in functional morphology, and a dearth of verbs. Despite decades of research, the mechanisms underlying production patterns in PSA-G have been difficult to characterize. Two major impediments to progress may have been the view that it is a purely morphosyntactic disorder and the (sometimes overzealous) application of linguistic theory without interceding psycholinguistic evidence. In this paper, empirical evidence is examined to present an integrated portrait of language production in PSA-G and to evaluate the assumption of a syntax-specific syndrome. In light of extant evidence, it is proposed that agrammatic language production results from a combination of morphosyntactic, phonomotor, and processing capacity limitations that cause a cumulative processing bottleneck at the point of articulatory planning. This proposed Synergistic Processing Bottleneck model of PSA-G presents a testable framework for future research. The paper ends with recommendations for future research on PSA-G.

Assessment of verb and sentence processing deficits in stroke-induced aphasia: the Italian version of the Northwestern Assessment of Verbs and Sentences (NAVS-I)

Background

The Northwestern Assessment of Verbs and Sentences (NAVS) assesses verb and sentence production and comprehension in aphasia. Results from the original English version and from its adaptation to German have shown that the NAVS is able to capture effects of verb-argument structure (VAS) complexity (i.e., lower accuracy for two- and three-argument vs. one-argument verbs) and syntactic complexity (i.e., lower accuracy for non-canonical vs. canonical sentences) in both agrammatic participants and individuals with mild (residual) forms of aphasia. The NAVS has been recently adapted to Italian (NAVS-I) and tested on a group of healthy participants, with results showing longer reaction times to complex vs. simple verbs and sentences.

Aims

The present study aimed to test the ability of NAVS-I to i) capture verb/sentence production and comprehension deficits in Italian-speaking individuals with agrammatism or with fluent aphasia, and ii) differentiate individuals with aphasia from healthy age-matched participants, with the overall goal to validate its use in clinical practice.

Methods & Procedures

Forty-four healthy participants and 28 individuals with aphasia (10 with agrammatic speech production) were administered the NAVS-I, which includes tasks assessing production and comprehension of verbs requiring one, two or three arguments, as well as production and comprehension of canonical and non-canonical sentences.

Outcomes & Results

On the Verb Naming Task (VNT), better production of one- (vs. two- and three-) argument verbs was found in the agrammatic group, whereas, verb production in the fluent group was solely predicted by word length and imageability. No effects of argument optionality (i.e., greater difficulty for optionally transitive verbs than for 1-argument verbs) were found. Sentence-level tasks found no differences between the agrammatic and the fluent group in production or comprehension of both canonical and non-canonical sentences; rather, sentence comprehension accuracy was predicted by demographic variables and by aphasia severity. At the individual level, performance on the NAVS-I was significantly different from that of healthy speakers in 26/28 patients.

Conclusions

Data show that the NAVS-I is able to capture effects of argument structure complexity in verb production, and effects of syntactic complexity in sentence production and comprehension. In addition, our results point to verb production as the task with greater capability to differentiate agrammatism from other (fluent) forms of aphasia. The study provides support for the use of the NAVS-I in the diagnosis of aphasia, as it is able to detect language deficits at the individual level, even in participants with mild (residual) forms of aphasia.

Sentence Production in a Discourse Context in Latent Aphasia: A Real-Time Study

PURPOSE

The purpose of this study was to improve our understanding as to which factors determine online, spoken sentence production abilities of adults with latent aphasia in a discourse context.

METHOD

Discourse samples of the story of Cinderella elicited from AphasiaBank were analyzed with speech analysis software. Participants comprised people with latent and anomic aphasia as well as neurotypical controls (10 per group). Durations of pauses (silent and filled) were analyzed according to (a) the location they occurred (between or within sentences), (b) the syntactic complexity of sentences (simple, complex), and (c) sentence length (number of words). Statistical comparisons were conducted using mixed-effect models.

RESULTS

The two clinical groups (latent and anomic) differed from controls in the duration of pauses, both between and within sentences. Syntactic complexity did not exert an effect on either of the two clinical groups as compared with controls. As compared with controls, both clinical groups paused more before long in comparison with short sentences.

CONCLUSION

Reduction in processing speed, which affects the ability to simultaneously maintain multiple linguistic and other cognitive demands associated with planning and monitoring of utterances, is a major factor that compromises sentence production in spoken discourse in latent aphasia.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19448726.

Processing Argument Structure and Syntactic Complexity in People with Schizophrenia Spectrum Disorders

INTRODUCTION

Deficits in language comprehension and production have been repeatedly observed in Schizophrenia Spectrum Disorders (SSD). However, the characterization of the language profile of this population is far from complete, and the relationship between language deficits, impaired thinking and cognitive functions is widely debated.

OBJECTIVE

The aims of the present study were to assess production and comprehension of verbs with different argument structures, as well as production and comprehension of sentences with canonical and non-canonical word order in people with SSD. In addition, the study investigated the relationship between language deficits and cognitive functions.

METHODS

Thirty-four participants with a diagnosis of SSD and a group of healthy control participants (HC) were recruited and evaluated using the Italian version of the Northwestern Assessment of Verbs and Sentences (NAVS, Cho-Reyes & Thompson, 2012; Barbieri et al., 2019).

RESULTS

Results showed that participants with SSD were impaired - compared to HC - on both verb and sentence production, as well as on comprehension of syntactically complex (but not simple) sentences. While verb production was equally affected by verb-argument structure complexity in both SSD and HC, sentence comprehension was disproportionately more affected by syntactic complexity in SSD than in HC. In addition, in the SSD group, verb production deficits were predicted by performance on a measure of visual attention, while sentence production and comprehension deficits were explained by performance on measures of executive functions and working memory, respectively.

DISCUSSION

Our findings support the hypothesis that language deficits in SSD may be one aspect of a more generalized, multi-domain, cognitive impairment, and are consistent with previous findings pointing to reduced inter- and intra-hemispheric connectivity as a possible substrate for such deficits. The study provides a systematic characterization of lexical and syntactic deficits in SSD and demonstrates that psycholinguistically-based assessment tools may be able to capture language deficits in this population.

German Language Adaptation of the NAVS (NAVS-G) and of the NAT (NAT-G): Testing Grammar in Aphasia

Grammar provides the framework for understanding and producing language. In aphasia, an acquired language disorder, grammatical deficits are diversified and widespread. However, the few assessments for testing grammar in the German language do not consider current linguistic, psycholinguistic, and functional imaging data, which have been shown to be crucial for effective treatment. This study developed German language versions of the Northwestern Assessment of Verbs and Sentences (NAVS-G) and the Northwestern Anagram Test (NAT-G) to examine comprehension and production of verbs, controlling for the number and optionality of verb arguments, and sentences with increasing syntactic complexity. The NAVS-G and NAT-G were tested in 27 healthy participants, 15 right hemispheric stroke patients without aphasia, and 15 stroke patients with mild to residual aphasia. Participants without aphasia showed near-perfect performance, with the exception of (object) relative sentences, where accuracy was associated with educational level. In each patient with aphasia, deficits in more than one subtest were observed. The within and between population-groups logistic mixed regression analyses identified significant impairments in processing syntactic complexity at the verb and sentence levels. These findings indicate that the NAVS-G and NAT-G have potential for testing grammatical competence in (German) stroke patients.

Is word learning enough? Improved verb phrase production following cueing of verbs and nouns in primary progressive aphasia

There is little evidence that, for people with aphasia, successful outcomes following lexical retrieval treatment generalise beyond single word retrieval to sentence production or daily communication. This study aimed to develop greater understanding of the mechanisms of generalisation. We employed a cueing task to simulate the effects of lexical retrieval treatment. A single noun or verb was provided and the effect on production of a corresponding verb phrase examined. Sixteen individuals with primary progressive aphasia (PPA) were asked to produce verb phrases to describe action pictures accompanied by i) a verb cue where a spoken and written verb was also presented with the picture; ii) a noun cue where a spoken and written noun was presented with the picture; iii) a no cue condition where only the picture was presented. Across the case series, both verb and noun cueing improved verb phrase production relative to no cue, with verb cueing being most effective. At the level of the single case, thirteen individuals showed significantly increased production of verb phrases with verb cueing, and seven individuals with noun cueing. In addition, seven individuals showed significantly greater benefit from verb cueing compared to noun cueing, and none showed the reverse. This suggests that improvements in verb phrase production may also be achievable following treatment-induced improvements in lexical retrieval. Greater benefit from verb cues than noun cues raises important theoretical issues regarding sentence construction and clinical issues around the most effective treatment techniques for people with aphasia.

Sentence Recall in Latent and Anomic Aphasia: An Exploratory Study of Semantics and Syntax

We investigated whether semantic plausibility and syntactic complexity affect immediate sentence recall in people with latent and anomic aphasia. To date, these factors have not been explored in these types of aphasia. As with previous studies of sentence recall, we measured accuracy of verbatim recall and uniquely real-time speech measures. The results showed that accuracy did not distinguish performance between latent aphasia and neurotypical controls. However, some of the real-time speech measures distinguished performance between people with latent aphasia and neurotypical controls. There was some evidence, though not pervasive, that semantic plausibility and syntactic complexity influenced recall performance. There were no interactions between semantic plausibility and syntactic complexity. The speed of preparation of responses was slower in latent aphasia than controls; it was also slower in anomic aphasia than both latent and control groups. It appears that processing speed as indexed by temporal speech measures may be differentially compromised in latent and anomic aphasia. However, semantic plausibility and syntactic complexity did not show clear patterns of performance among the groups. Notwithstanding the absence of interactions, we advance an explanation based on conceptual short-term memory as to why semantically implausible sentences are typically more erroneous and possibly also slower in recall.

Syntactic Complexity as a Linguistic Marker to Differentiate Mild Cognitive Impairment From Normal Aging

Purpose In this study, we sought to identify critical linguistic markers that can differentiate sentence processing of individuals with mild cognitive impairment (MCI) from the sentence processing of normal-aging populations by manipulating sentences' linguistic complexity. We investigated whether passive sentences, as linguistically complex structures, can serve as linguistic markers that can contribute to diagnoses that distinguish MCI from normal aging. Method In total, 52 participants, including 26 adults with amnestic MCI and 26 cognitively unimpaired adults, participated in the study. All participants were native speakers of Korean. We administered the two subsets of active and passive conditions using a sentence-picture paradigm with semantically reversible sentences to both groups. Results A mixed-effects model using PROC NLMIXED demonstrated that the MCI group exhibited differentially greater difficulty in processing passive than active sentences compared to the normal-aging group. A logistic regression fitted with the PROC LOGISTIC model identified the sum of the passive sentences, with age and education effects as the best models to distinguish individuals with MCI from the normal-aging group. Conclusion Sentence comprehension deficits emerged in the MCI stage when the syntactic complexity was increased. Furthermore, a passive structure was the best predictor for efficiently distinguishing the MCI group from the normal-aging group. These results are clinically and theoretically important, given that linguistic complexity can serve as a critical behavioral marker in the detection of early symptoms associated with linguistic-cognitive decline.

Effect of lexical accessibility on syntactic production in aphasia: An eyetracking study

PURPOSE

Healthy speakers use both word-level and structure-level information to ease sentence production processes. Structural priming facilitates message-structure mapping in aphasia. However, it remains unclear if and how word-level information affects off-line and on-line sentence production in persons with aphasia (PWA). This eyetracking-while-speaking study examined the effect of lexical priming on production of syntactic (active/passive) structures in PWA.

METHOD

Eleven PWA and twenty healthy older adults (HOA) described transitive actions (woman pulling horse) following lexical priming, wherein the relative ease of lexical retrieval for the Agent or Theme was manipulated via an auditory probe (what is happening with the woman/horse ?). It was examined whether or not PWA produce the sentence structure that allows earlier production of the primed word (e.g., passives when Theme was primed). Participants' eye fixation times to each character (Agent, Theme) were also monitored to examine if PWA show priming-induced preferential looks to one character from the earliest stage of production, consistent with word-driven planning.

RESULTS

HOA showed increased production of passives over actives in the Theme vs. Agent prime condition. In eye fixation data, HOA showed priming-induced Theme advantage from the earliest time window (picture onset-400 milliseconds). PWA also showed a significant priming effect in off-line sentence production, with this priming effect being greater for the individuals whose syntactic processing is better preserved. In eye fixation data, however, PWA showed preferential fixations to the primed character at a later stage of sentence planning (400-800 milliseconds), following equal fixation time to Agent and Theme during the earliest time window.

CONCLUSION

HOA showed word-driven production in both off-line and real-time (eye fixations) production. Lexical accessibility effectively drove off-line syntactic production in PWA, especially for those whose syntactic capacity remains relatively preserved. However, PWA showed advanced processing of both characters in earliest eye fixation data, suggesting that successful word-driven off-line syntactic production was associated with atypical real-time sentence planning in aphasia.

Verb and sentence processing patterns in healthy Italian participants: Insight from the Northwestern Assessment of Verbs and Sentences (NAVS)

We developed an Italian version of the Northwestern Assessment of Verbs and Sentences (NAVS, Thompson, 2011), a test assessing verb and sentence deficits typically found in aphasia, by focusing on verb-argument structure and syntactic complexity effects, rarely captured by standard language tests. Twenty-one young healthy individuals underwent a computerized experimental version of the NAVS, including three subtests assessing production/comprehension of verbs with different number (one, two, three) and type (obligatory or optional) of arguments, and two investigating production/comprehension of sentences with canonical/non-canonical word order. The number of verb arguments affected participants' reaction times (RTs) in verb naming and comprehension. Furthermore, verbs with optional arguments were processed faster than verbs with only obligatory arguments. Comprehension accuracy was lower for object-cleft vs. subject-cleft sentences. Object clefts and object relatives also elicited longer RTs than subject clefts and subject relatives, respectively. The study shows that the NAVS is sensitive to linguistic aspects of verb/sentence processing in Italian as in the English language. The study also highlights some differences between languages in the verb/sentence processing patterns of healthy individuals. Finally, the study contributes to the understanding of how information about verb-argument structure is represented and processed in healthy individuals, with reference to current models of verb processing.

Investigating the origin of nonfluency in aphasia: A path modeling approach to neuropsychology

A major challenge in understanding the origin of clinical symptoms in neuropsychological impairments is capturing the complexity of the underlying cognitive structure. This paper presents a practical guide to path modeling, a statistical approach that is well-suited for modeling multivariate outcomes with a multi-factorial origin. We discuss a step-by-step application of such a model to the problem of nonfluency in aphasia. Individuals with aphasia are often classified into fluent and nonfluent groups for both clinical and research purposes, but despite a large body of research on the topic, the origin of nonfluency remains obscure. We propose a model of nonfluency inspired by the psycholinguistic approach to sentence production, review several bodies of work that have independently suggested a relationship between fluency and various elements in this model, and implement it using path modeling on data from 112 individuals with aphasia from the AphasiaBank. The results show that word production, comprehension, and working memory deficits all contribute to nonfluency, in addition to syntactic impairment which has a strong and direct impact on fluency. More generally, we demonstrate that a path model is an excellent tool for exploring complex neuropsychological symptoms such as nonfluency.

Recovery of Sentence Production Processes Following Language Treatment in Aphasia: Evidence from Eyetracking

Introduction: Sentence production impairments in aphasia often improve with treatment. However, little is known about how cognitive processes supporting sentence production, such as sentence planning, are impacted by treatment.

Methods: The present study used eyetracking to examine changes in sentence production resulting from a 12-week language treatment program focused on passive sentences (Treatment of Underlying Forms (TUF); Thompson and Shapiro, 2005). In two pre-treatment and two post-treatment sessions, nine participants with mild-to-moderate agrammatic aphasia performed a structural priming task, which involved repeating primed sentences (actives or passives) and then, using the same verb, producing sentences describing pictured events. Two individuals with aphasia performed the eyetracking task on the same schedule without intervening language treatment. Ten unimpaired older adults also performed the task to identify normal performance patterns. Sentence production accuracy and speech onset latencies were examined, and eye movements to the pictured Agent and Theme characters were analyzed in the first 400 ms after picture onset, reflecting early sentence planning, and in the regions preceding the production of the sentence subject and post-verbal noun, reflecting lexical encoding.

Results: Unimpaired controls performed with high accuracy. Their early eye movements (first 400 ms) indicated equal fixations to the Agent and Theme, consistent with structural sentence planning (i.e., initial construction of an abstract structural frame). Subsequent eye movements occurring prior to speech onset were consistent with encoding of the correct sentence subject (i.e., the Agent in actives, Theme in passives), with encoding of the post-verbal noun beginning at speech onset. In participants with aphasia, accuracy improved significantly with treatment, and post-treatment (but not pre-treatment) eye movements were qualitatively similar to those of unimpaired controls, indicating correct encoding of the Agent and Theme nouns for both active and passive sentences. Analysis of early eye movements also showed a treatment-induced increase in structural planning. No changes in sentence production accuracy or eye movements were found in the aphasic participants who did not receive treatment.

Conclusion: These findings indicate that treatment improves sentence production and results in the emergence of normal-like cognitive processes associated with successful sentence production, including structural planning.

Grammatical Encoding and Learning in Agrammatic Aphasia: Evidence from Structural Priming

The present study addressed open questions about the nature of sentence production deficits in agrammatic aphasia. In two structural priming experiments, 13 aphasic and 13 age-matched control speakers repeated visually- and auditorily-presented prime sentences, and then used visually-presented word arrays to produce dative sentences. Experiment 1 examined whether agrammatic speakers form structural and thematic representations during sentence production, whereas Experiment 2 tested the lasting effects of structural priming in lags of two and four sentences. Results of Experiment 1 showed that, like unimpaired speakers, the aphasic speakers evinced intact structural priming effects, suggesting that they are able to generate such representations. Unimpaired speakers also evinced reliable thematic priming effects, whereas agrammatic speakers did so in some experimental conditions, suggesting that access to thematic representations may be intact. Results of Experiment 2 showed structural priming effects of comparable magnitude for aphasic and unimpaired speakers. In addition, both groups showed lasting structural priming effects in both lag conditions, consistent with implicit learning accounts. In both experiments, aphasic speakers with more severe language impairments exhibited larger priming effects, consistent with the "inverse preference" prediction of implicit learning accounts. The findings indicate that agrammatic speakers are sensitive to structural priming across levels of representation and that such effects are lasting, suggesting that structural priming may be beneficial for the treatment of sentence production deficits in agrammatism.

Wh- questions and passive sentences in non-fluent variant PPA and semantic variant PPA: Longitudinal findings of an anagram production task

Using an anagram task, we investigated longitudinal syntactic production by individuals with semantic variant primary progressive aphasia (svPPA) and non-fluent variant PPA (nfvPPA), compared to controls. The accuracy of the production of active and passive, and reversible and non-reversible sentences, as well as of wh- questions was compared across the three groups. Results showed a different pattern of syntactic impairment across the two patient groups. The nfvPPA group showed difficulty with wh- questions at Time 1 and impairment with the passive structure approximately one year later, at Time 2. Surprisingly, the svPPA group also showed difficulty with wh- questions from Time 1, but still no difficulty on passive sentences, two years later, at Time 3. Neither group had difficulty with reversibility. The results of the nfvPPA patients were as expected, and the results of the svPPA patients suggest that this group may exhibit a greater syntactic impairment than is typically recognized.

Assessing Syntactic Deficits in Chinese Broca's aphasia using the Northwestern Assessment of Verbs and Sentences-Chinese (NAVS-C)

BACKGROUND

English-speaking patients with Broca's aphasia and agrammatism evince difficulty with complex grammatical structures, including verbs and sentences. A few studies have found similar patterns among Chinese-speaking patients with broca's aphasia, despite structural differences between these two languages. However, no studies have explicitly examined verb properties, including the number and optionality of arguments (participant roles) selected by the verb, and only a few studies have examined sentence deficits among Chinese patients. In addition, there are no test batteries presently available to assess syntactically important properties of verbs and sentences in Chinese patients.

AIMS

This study used a Chinese version of the Northwestern Assessment of Verbs and Sentences (NAVS; Thompson, 2011), originally developed for English speakers with aphasia, to examine the verb and sentence deficit patterns among Chinese speakers with aphasia. As in the original NAVS, the Chinese version (NAVS-C) assessed verbs by the number and optionality of arguments as well as sentence canonicity, in the both production and comprehension.

METHODS AND PROCEDURES

Fifteen Chinese patients with Broca's aphasia and fifteen age-matched healthy normal controls participated in this study. All NAVS-C tests were administered, in which participants were asked either to produce or identify verbs and sentences coinciding with action pictures.

OUTCOMES & RESULTS

Despite grammatical differences between Chinese and English, the impairment caused by structural complexity of verbs and sentences was replicated in Chinese-speaking patients using the NAVS-C. Verbs with more arguments were significantly more impaired than those with fewer arguments and verbs with optional arguments were significantly more impaired than those with obligatory arguments. One deviation from English-speaking patients, however, is that the Chinese-speaking patients exhibited greater difficulty with subject relative clauses than with object relative clauses because the former, rather than the latter, involve non-canonical order in Chinese. Similar to English-speaking patients, Chinese patients exhibited more difficulty with object extracted wh-questions than with subject extracted wh-questions. Suggesting that wh-movement in Logical Form may also cause processing difficulty. Moreover, Chinese-speaking patients exhibited similar performance in both production and comprehension, indicating the deficits in both modalities.

CONCLUSIONS

The number and optionality of verb arguments as well as canonicity of the Agent-Theme order in sentences impacts Chinese-speaking individuals with aphasia as it does in the case of English-speaking patients. These findings indicate that the NAVS-C is a useful tool for detailing deficit patterns associated with syntactic processing in patients with aphasia cross-linguistically.

Verb and sentence production and comprehension in aphasia: Northwestern Assessment of Verbs and Sentences (NAVS)

BACKGROUND

Verbs and sentences are often impaired in individuals with aphasia, and differential impairment patterns are associated with different types of aphasia. With currently available test batteries, however, it is challenging to provide a comprehensive profile of aphasic language impairments because they do not examine syntactically important properties of verbs and sentences.

AIMS

This study presents data derived from the Northwestern Assessment of Verbs and Sentences (NAVS; Thompson, 2011), a new test battery designed to examine syntactic deficits in aphasia. The NAVS includes tests for verb naming and comprehension, and production of verb argument structure in simple active sentences, with each examining the effects of the number and optionality of arguments. The NAVS also tests production and comprehension of canonical and non-canonical sentences.

METHODS & PROCEDURES

A total of 59 aphasic participants (35 agrammatic and 24 anomic) were tested using a set of action pictures. Participants produced verbs or sentences for the production subtests and identified pictures corresponding to auditorily provided verbs or sentences for the comprehension subtests.

OUTCOMES & RESULTS

The agrammatic group, compared to the anomic group, performed significantly more poorly on all subtests except verb comprehension, and for both groups comprehension was less impaired than production. On verb naming and argument structure production tests both groups exhibited difficulty with three-argument verbs, affected by the number and optionality of arguments. However, production of sentences using three-argument verbs was more impaired in the agrammatic, compared to the anomic, group. On sentence production and comprehension tests, the agrammatic group showed impairments in all types of non-canonical sentences, whereas the anomic group exhibited difficulty primarily with the most difficult, object relative, structures.

CONCLUSIONS

Results show that verb and sentence deficits seen in individuals with agrammatic aphasia are largely influenced by syntactic complexity; however, individuals with anomic aphasia appear to exhibit these impairments only for the most complex forms of verbs and sentences. The present data indicate that the NAVS is useful for characterising verb and sentence deficits in people with aphasia.

What Goes Wrong during Passive Sentence Production in Agrammatic Aphasia: An Eyetracking Study

BACKGROUND: Production of passive sentences is often impaired in agrammatic aphasia and has been attributed both to an underlying structural impairment (e.g., Schwartz, Saffran, Fink, Myers, & Martin, 1994) and to a morphological deficit (e.g., Caplan & Hanna, 1998; Faroqi-Shah & Thompson, 2003). However, the nature of the deficit in passive sentence production is not clear due to methodological issues present in previous studies. AIMS: This study examined active and passive sentence production in nine agrammatic aphasic speakers under conditions of structural priming using eyetracking to test whether structural impairments occur independently of morphological impairments and whether the underlying nature of error types is reflected in on-line measures, i.e., eye movements and speech onset latencies. METHODS #ENTITYSTARTX00026; PROCEDURES: Nine participants viewed and listened to a prime sentence in either active or passive voice, and then repeated it aloud. Next, a target picture appeared on the computer monitor and participants were instructed to describe it using the primed sentence structure. OUTCOMES #ENTITYSTARTX00026; RESULTS: Participants made substantial errors in sentence structure, i.e., passives with role reversals (RRs) and actives-for-passives, but few errors in passive morphology. Longer gaze durations to the first-produced noun for passives with RRs as compared to correct passives were found before and during speech. For actives-for-passives, however, this pattern was found during speech, but not before speech. CONCLUSIONS: The deficit in passive sentence production does not solely arise from a morphological deficit, rather it stems, at least in part, from a structural level impairment. The underlying nature of passives with RRs is qualitatively different from that of actives-for-passives, which cannot be clearly differentiated with off-line testing methodology.

Complexity in treatment of syntactic deficits

PURPOSE

This article addresses complexity in the context of treatment for sentence structural impairments in agrammatic aphasia, with emphasis on noncanonical sentences involving linguistic movement and their related counterparts. Extensions of the complexity effect to recovery of canonical sentences also are discussed, stressing the linguistic properties of verbs as well as grammatical morphology in building complexity hierarchies.

METHOD

A number of variables to consider in developing complexity hierarchies in the syntactic domain are addressed, and a series of studies using single-subject controlled experimental analysis are discussed.

RESULTS

Findings across studies show that training complex sentences results in improvement of simpler structures when, and only when, the underlying linguistic properties are shared by both. The opposite approach, training simple structures first and building to more complex ones, does not provide the full benefit of treatment, in that little or no generalization occurs across structures.

CONCLUSION

Using complex language material as a starting point for treatment of sentence structural deficits in aphasia results in cascading generalization to simpler, linguistically related material and expands spontaneous language production in many language-disordered adults with aphasia. Clinicians are, therefore, urged to adopt this approach in clinical practice, even though it is counterintuitive and departs significantly from conventional treatment methods.

Verb inflections in agrammatic aphasia: Encoding of tense features

Across most languages, verbs produced by agrammatic aphasic individuals are frequently marked by syntactically and semantically inappropriate inflectional affixes, such as Last night, I walking home. As per language production models, verb inflection errors in English agrammatism could arise from three potential sources: encoding the verbs' morphology based on temporal information at the conceptual level, accessing syntactic well-formedness constraints of verbal morphology, and encoding morphophonological form. We investigate these aspects of encoding verb inflections in agrammatic aphasia. Using three sentence completion experiments, it was demonstrated that production of verb inflections was impaired whenever temporal reference was involved; while morphological complexity and syntactic constraints were less likely to be the source of verb inflection errors in agrammatism. These findings are discussed in relation to current language production models.

Neural circuits subserving the retrieval of stems and grammatical features in regular and irregular verbs

Many languages, including English and Spanish, feature regular (dance --> danced) and irregular (catch --> caught) inflectional systems. According to psycholinguistic theories, regular and irregular inflections are instantiated either by a single or by two specialized mechanisms. Those theories differ in their assumptions concerning the underlying information necessary for the processing of regular verbs. Whereas single mechanism accounts have stated an increased involvement of phonological processing for regular verbs, dual accounts emphasize the prominence of grammatical information. Using event-related functional magnetic resonance imaging, we sought to delineate the brain areas involved in the generation of complex verb forms in Spanish. This language has the advantage of isolating specific differences in the regular-irregular contrasts in terms of the number of stems associated with a verb while controlling for compositionality (regular and irregular verbs apply suffixes to be inflected). The present study showed that areas related to grammatical processing are active for both types of verbs (left opercular inferior frontal gyrus). In addition, major differences between regular and irregular verbs were also observed. Several areas of the prefrontal cortex were selectively active for irregular production, presumably reflecting their role in lexical retrieval (bilateral inferior frontal area and dorsolateral prefrontal cortex). Regular verbs, however, showed increased activation in areas related to grammatical processing (anterior superior temporal gyrus/insular cortex) and in the left hippocampus, the latter possibly related to a greater implication of the phonological loop necessary for the reutilization of the same stem shared across all forms in regular verbs.

Communicative value of self cues in aphasia: A re-evaluation

BACKGROUND: Adults with aphasia often try mightily to produce specific words, but their word-finding attempts are frequently unsuccessful. However, the word retrieval process may contain rich information that communicates a desired message regardless of word-finding success. AIMS: The original article reprinted here reports an investigation that assessed whether patient-generated self cues inherent in the word retrieval process could be interpreted by listener/observers and improve on communicative effectiveness for adults with aphasia. The newly added commentary identifies and reports tentative conclusions from 18 investigations of self-generated cues in aphasia since the 1982 paper. It further provides a rationale for increasing research on self-generated cueing and notes a surprising lack of attention to the questions investigated in the original article. The original research is also connected with more recent qualitative investigations of interactional, as opposed to transactional, communicative exchange. METHODS #ENTITYSTARTX00026; PROCEDURES: While performing single-word production tasks, 10 adults with aphasia produced 107 utterances that contained spontaneous word retrieval behaviours. To determine the "communicative value" of these behaviours, herein designated self cues or self-generated cues, the utterance-final (potential target) word was edited out and the edited utterances were dubbed onto a videotape. Six naïve observers, three of whom received some context about the nature of word retrieval in aphasia and possible topics for the utterances, and three of whom got no information, predicted the target word of each utterance from the word-finding behaviours alone. The communicative value of the self-generated cues was determined for each individual with aphasia by summing percent correct word retrieval and percent correct observer prediction of target words, based on word retrieval behaviours. The newly added commentary describes some challenges of investigating a "communicative value" outcome, and indicates what would and would not change about the methods, if we did the study today. OUTCOMES #ENTITYSTARTX00026; RESULTS: The observer group that was given some context information appeared to be more successful at predicting target words than the group without any such information. Self-generated cues enhanced communication for the majority of individuals with aphasia, with some cues (e.g., descriptions/gestures of action or function) appearing to carry more communicative value than others (e.g., semantic associates). The commentary again indicates how and why we would change this portion of the investigation if conducting the study at this time. CONCLUSIONS: The results are consistent with Holland's (1977) premise that people with aphasia do well at communication, regardless of the words they produce. The finding that minimal context information may assist observers in understanding the communicative intent of people with aphasia has important implications for training family members to interpret self-generated cues. The new commentary reinforces these conclusions, highlights potential differences between self cues that improve word-finding success and those that enhance message transmission, and points to some additional research needs.

Agrammatic sentence production: is verb second impaired in Dutch?

This study investigates effects of verb movement in nine Dutch-speaking agrammatic aphasics. According to linguistic theory, in verb second languages such as Dutch and German, the verb remains in its clause-final base position in embedded clauses, whereas it moves to second position in main clauses. In recent linguistic accounts of agrammatic sentence production, it has been suggested that the production of sentences with moved verbs is relatively difficult. However, we argue that evidence provided by previous studies on this matter is inconclusive. An experiment is reported in which the production of both types of clauses is compared. No evidence is found that sentences with moved verbs are relatively difficult to produce. In fact, there was a tendency for the base order sentences to be harder. Implications of these findings for theories of normal and agrammatic sentence production are discussed.

Morphological processing in early bilinguals: An ERP study of regular and irregular verb processing

Although the age of acquisition of a language has an effect when learning a second language, the similarity between languages may also have a crucial role. The aim of the present study is to understand the influence of this latter factor in the acquisition of morphosyntactic information. With this purpose, two groups of highly proficient early Catalan-Spanish bilinguals were presented with a repetition-priming paradigm with regular and irregular verbs of Spanish. Catalan and Spanish have a similar suffix (-o) for regular verbs and completely different alternations for irregular verbs. Two types of irregular verbs were studied (semi-regular verbs with a systematic diphthong alternation, sentir-siento, and verbs with idiosyncratic changes, venir-vengo). Regular verbs showed the same centro-parietal N400 priming effect in the second-language speakers (L2) as in primary-language (L1) speakers. However, differences between groups, in the ERP pattern and the topography of the N400 effect, were observed for irregular morphology. In L1 speakers, the N400 effect was attenuated only for semi-regular verbs. In contrast, L2 speakers showed a reduced N400 priming effect in both irregular contrasts. This pattern of results suggests that the similarity between languages may help for similar structures but may interfere for dissimilar structures, at least when the two languages have very similar morphological systems.