Verb transitivity bias affects on-line sentence reading in people with aphasia

Background: Studies of sentence comprehension in non-disordered populations have convincingly demonstrated that probabilistic cues influence on-line syntactic processing. One well-studied cue is verb argument structure bias, which refers to the probability that a verb will occur in a particular syntactic frame. According to the Lexical Bias Hypothesis people with aphasia have difficulty understanding sentences in which the verb's argument structure bias conflicts with the sentence structure (e.g., a transitively biased verb in an intransitive sentence). This hypothesis may provide an account of why people with aphasia have difficulty understanding both simple and complex sentences.

Aims: The purpose of this study was to test the Lexical Bias Hypothesis using an on-line measure of written sentence comprehension, self-paced reading.

Methods & Procedures: The participants were 10 people with aphasia and 10 non-brain-damaged controls. The stimuli were syntactically simple transitive and intransitive sentences that contained transitively or intransitively biased verbs. For example, the transitively biased verb “called” appeared in sentences such as “The agent called (the writer) from overseas to make an offer.” The intransitively biased verb “danced” appeared in sentences such as “The couple danced (the tango) every Friday night last summer.”

Outcomes & Results: Both groups' reading times for critical segments were longer when the verb's transitivity bias did not match the sentence structure, particularly in intransitive sentences.

Conclusions: The results were generally consistent with the Lexical Bias Hypothesis, and demonstrated that lexical biases affect on-line processing of syntactically simple sentences in people with aphasia and controls.     

Argument structure deficit in aphasia: it’s not all about verbs

Background: Verb difficulties in aphasia often co-occur with difficulties specifying argument structure of the sentence. Recent exploration of verb and argument structure deficits has shown dissociations between lexical semantic information, argument structure information, and production of the argument structure. There is currently limited evidence regarding the implications of these dissociations for treatment.

Aims: This paper explores the patterns of generalisation following intervention to increase access to verb argument structure for a 62-year-old woman (YR) with chronic agrammatic aphasia. YR had good access to nouns and verbs in picture naming alongside severe sentence production difficulties characterised by difficulty specifying argument structure.

Methods & Procedures: Detailed pre-therapy language assessment investigated single word and sentence comprehension and production, with a specific focus on whether YR could produce argument structure. Intervention targeted verb retrieval, awareness of argument structure information, cueing of arguments, and production of argument and syntactic structure involving transitive verbs. A single-subject multiple baseline design was used to monitor the effectiveness of treatment. The primary outcome measure was accuracy of two-argument structures in sentence production to picture and sentence generation to written word tasks, with effects on treated and untreated verbs considered. Other measures of sentence comprehension and production were also obtained to determine any further generalisation.

Outcomes & Results: Following the first phase of therapy, YR showed a significant improvement in the production of two-argument structures across both treated and untreated verbs in sentence production to pictures, with a corresponding significant reduction in incomplete argument structures. No change was seen in two-argument structures in sentence generation to written words. After the second phase of therapy, significant gains were seen in two-argument structures with both treated and untreated verbs in the sentence generation task while sentence production to picture performance maintained. Gains in sentence generation were more vulnerable following the cessation of therapy. Other tasks of sentence production also improved with no change seen on a control task.

Conclusions: Argument structure can be selectively impaired in aphasia, in the presence of good verb and noun access at the single word level, and targeted in therapy to improve sentence production. The study highlights the complexity of the relationship between verbs and argument structure and that argument structure difficulties are not always a consequence of a semantic verb deficit. Generalised improvement in argument structure production provides evidence that therapy targeted general processes rather than lexically specified argument structure information.     

Production and comprehension of unaccusatives in aphasia

Background: Recent studies have reported impairments in the production of sentences containing unaccusative verbs (e.g., The ball bounced down the street) in agrammatic patients. In these sentences, the subject is the theme of the verb, resulting in a non‐standard order of thematic roles (often called non‐canonical thematic role order).

Aims: We tested the hypothesis that aphasic patients would be affected by these features of unaccusatives in both production and comprehension, and that they would show similar deficits in sentences with unaccusative verbs and passive sentences, which also have non‐canonical thematic role order.

Methods & Procedures: Single‐word naming, sentence production, and sentence–picture matching tasks were administered to a group of 9 aphasic participants and 12 age‐ and education‐matched control participants.

Outcomes & Results: The aphasic patients performed less well than the controls, and there were effects of the presence of movement in both groups and an interaction between group and sentence type in the sentence production task.

Conclusions: These findings support the view that non‐canonical thematic role order makes action naming, sentence production, and sentence comprehension more difficult, and that aphasic patients are more affected by the demands of these tasks than controls.     

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 Thompson, C. K. 2011. Northwestern Assessment of Verbs and Sentences Evanston, IL [Google Scholar]), 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.     

Verb preference effects in the sentence comprehension of fluent aphasic individuals

Abstract

This investigation examined sentence processing of fluent aphasic subjects with varying severity levels. Subjects performed a cross-modal lexical decision task for transitive and intransitive verbs in preferred and non-preferred frameworks. Verb processing was measured by reaction times during on-line sentence comprehension. Reaction times to the cross-modal lexical decision (CMLD) task indicated that the subjects with aphasia were insensitive to preference information associated with the processing of verbs in sentences. Severity level did not alter the pattern observed regarding verb type and preferences.     

Corpus-based transitivity biases in individuals with aphasia

Background: This study investigated whether individuals with aphasia (IWA) retain verb biases in expressive language. Verb biases refer to the likelihood that a given verb will occur in different sentence structures. We focused on the likelihood of verbs occurring in transitive and intransitive structures.

Aims: The main goal of this study was to determine whether IWA and controls show similar verb biases or whether IWA show a preference for transitive or intransitive structures that supersedes individual verb biases. We also investigated whether IWA show a preference for intransitively or transitively biased verbs, whether verb biases differ as a function of aphasia type, and how verb bias affects errors in IWA’s speech production.

Methods & Procedures: The current study analysed 236 transcribed interviews of IWA from AphasiaBank. All uses of 54 verbs were coded based on the sentence structure and the presence of errors. We report data from 11 transitively biased and 11 intransitively biased verbs.

Outcomes & Results: IWA’s transitivity biases were indistinguishable from controls’ biases. In addition, IWA produced more intransitively biased verbs than transitively biased verbs overall. In ungrammatical productions, IWA’s error rates were higher in sentence structures that conflicted with verb bias and highest when an intransitively biased verb was attempted in a transitive structure.

Conclusions: These findings indicate that IWA are sensitive to verb bias and verb complexity within expressive language. The effects are consistent with previous literature concerning IWA’s sensitivity to verb bias in receptive language tasks and to verb complexity in verb retrieval tasks.     

Effects of therapy targeted at verb retrieval and the realisation of the predicate argument structure: A case study

Background : Verb retrieval and sentence production difficulties are both common features of aphasia. Previous treatment studies have focused predominantly on verb retrieval and the mapping of semantic and syntactic structure. There have been more limited investigations of the production of the predicate argument structure (PAS). Aims : This study aimed to evaluate the outcome of intensive therapy for a client with aphasia. NS had multiple and interacting difficulties that resulted in problems in producing sentences. Therapy aimed to improve his sentence production by: (a) improving the retrieval of verbs, (b) increasing his awareness of the relationship between nouns and verbs, and (c) improving his production of one-, two-, and three-argument structures. The therapy thus targeted access to PAS information and PAS production as well as verb retrieval. Methods & Procedures : A period of intensive therapy, based around a set of 48 self-selected verbs, was preceded and followed by detailed assessment of NS's single word and sentence production and comprehension. Outcomes & Results : Therapy resulted in a significant improvement in NS's retrieval of the verbs involved in treatment but no generalisation to other verbs. His production of sentences showed more widespread changes. He produced more nouns within sentences, omitted fewer obligatory arguments, and produced a greater variety of argument structures in connected speech. Conclusions : Therapy resulted in a greater awareness of the need for a verb within a sentence and a strategy for producing the argument structure frame around that verb. Improved sentence production was therefore seen, although verb retrieval difficulties were still evident. The study replicates previous research that verb and sentence production difficulties can be treated effectively in people with aphasia. The effects of therapy on sentence production in constrained tasks and narrative speech are discussed.     

Lexical biases in aphasic sentence comprehension: An experimental and corpus linguistic study

Background: This study investigates the role of lexical information in normal and aphasic sentence comprehension. Effects of verb biases in normal comprehension have been well documented in previous studies (e.g., Spivey-Knowlton & Sedivy, 1995; Trueswell, Tanenhaus, & Kello, 1993), but their role in aphasic language processing has largely been ignored (with the exceptions of Menn et al., 1998, and Russo, Peach, & Shapiro, 1998). Aims: The aim of the study is to test the lexical bias hypothesis, i.e., the hypothesis that sentence comprehension is influenced by lexical biases in aphasic listeners, as well as in normals. Method & Procedures: Using a sentence plausibility judgement task, we probe for sensitivity to verb transitivity bias, i.e., the likelihood, as estimated from corpus counts, that a verb will be transitive, rather than intransitive. Five normal controls and eighteen participants with aphasia (six with Broca's aphasia, four with Wernicke's aphasia, two with conduction aphasia, and six with anomic aphasia) are included in the study. Based on the lexical bias hypothesis, we predicted that participants would make more errors in sentences with a mismatch of verb bias and syntactic structure, such as a transitive sentence containing a verb with intransitive bias. Outcomes & Results: Both the group of normal controls and the mixed group of aphasic patients make significantly more errors on sentences in which there is a mismatch between verb bias and syntactic structure, as predicted by the lexical bias hypothesis. Specifically, patients with fluent aphasia types, particularly anomic aphasia, show a sensitivity to verb bias, contrary to earlier findings. Conclusions: These results are consistent with the view that lexical factors, not purely syntactic ones, are to blame for many previously observed patterns in aphasic comprehension. The results are further consistent with the view that many aphasic errors differ not qualitatively but quantitatively from normal comprehension errors.     

Comparison of single-word therapy versus sentence therapy for verb retrieval and sentence production in Broca’s aphasia

Background: In the existing literature, verb therapy studies take one of two approaches regarding verb retrieval: (1) the single-word level, in which verbs are treated similarly to nouns, and (2) the sentence level, which emphasises the relationship between verbs and nouns in a sentence. Few studies have directly compared the efficacy of both the approaches.

Aims: The primary aim of this article is, first, to compare the efficacy of single-word therapy versus sentence therapy for verb retrieval and, second, to examine the impact of each type of therapy on single-word and sentence production in connected speech.

Methods & Procedures: Using a single-subject crossover within-subjects design, six participants with Broca’s aphasia were trained to retrieve verbs under two therapy conditions: single-word therapy and sentence therapy. Additionally, a connected speech task was administered in the baseline phase and after each therapy condition. The impact of the two therapies on sentence production was measured using the samples derived from the connected speech.

Outcomes & Results: At the group level, all six participants showed highly significant and equal improvement in verb retrieval after receiving both the types of therapy. However, at the individual level, participants were found to show different results compared with the overall group tendency. One participant benefited more from single-word therapy than sentence therapy, while another showed the reverse pattern. At the group level, in connected speech the number of grammatical sentences, especially single-argument structure sentences, and the number of verbs increased significantly after single-word therapy. After sentence therapy, however, there was no significant change in mean length of utterance (MLU), the number of grammatical sentences and the number of verbs.

Conclusions: At the group level, verb retrieval in participants with Broca’s aphasia improved significantly after both the types of therapy. For connected speech, however, only single-word therapy brought about significant changes.     

Effects of verb bias and syntactic ambiguity on reading in people with aphasia

Background: The Lexical Bias Hypothesis claims that people with aphasia (PWA) have difficulty understanding sentences when the verb’s argument structure bias conflicts with the sentence structure. This hypothesis can account for comprehension deficits that affect simple sentences, but the role of verb bias has not been clearly demonstrated in temporarily ambiguous sentences.

Aims: This study examined how verb bias affects comprehension of temporarily ambiguous and unambiguous sentences using self-paced reading.

Methods & Procedures: PWA and controls read sentences that contained sentential complements (e.g., The talented photographer accepted (that) the fire could not have been prevented). The main verb was biased to take a direct object (e.g., accepted) or a sentential complement (e.g., admitted). In addition, the sentential complement was either introduced by the complementiser that (i.e., unambiguous) or unmarked (i.e., ambiguous).

Results: The reading times of PWA were affected more by verb bias than by the presence of the complementiser, whereas the control group’s reading times were more affected by the presence or absence of the complementiser.

Conclusions: The results were generally consistent with the Lexical Bias Hypothesis, and showed that a mismatch between verb bias and sentence structure affected the processing of unambiguous and temporarily ambiguous sentences in PWA.     

Effects of syntactic and semantic argument structure on sentence repetition in agrammatism: Things we can learn from particles and prepositions

Background: Sentence production impairment in aphasia has been attributed to several possible sources that are not mutually exclusive. Linguistic accounts often attribute the difficulty to the complexity of a verb's syntactic and/or semantic argument structure. Cognitive processing accounts emphasise the reduced processing capacity observed in agrammatic aphasia, which in turn has been attributed to reduced semantic short-term memory (STM) or slowed processing.

Aims: In this study we used verb particles and prepositions to investigate effects of differences in syntactic and semantic argument structure on sentence repetition in aphasia. We predicted that verb particles and sentences containing verb-particle constructions would be easier to repeat than prepositions and prepositional transitive sentences, as the former have a less-complex semantic and syntactic argument structure than the latter. Also, semantic and phonological spans were assessed to determine if a reduction in either capacity correlates with repetition ability.

Methods & Procedures: Participants were eight individuals with chronic aphasia. The experimental task was repetition of transitive sentences balanced for length and lexical content containing either verb particles or prepositional object structures. Accuracy of sentence repetition and repetition of verb particles and prepositions within sentences was examined. We calculated the effect of structural complexity on the sentence repetition task as the difference between proportion correct of verb-particle constructions and prepositional transitives. Semantic and phonological STM spans and word spans were also assessed and correlated with this measure of the structural complexity effect on sentence repetition.

Outcomes & Results: Verb-particle sentences were repeated correctly significantly more often than prepositional transitive sentences, and within those sentences verbal particles were repeated correctly significantly more often than prepositions. The effect was strongly associated with fluency scores: it was present in participants with low fluency scores, but not in those with high fluency scores. The phonological, but not the semantic, STM probe span measure correlated with both the difference in accurate repetition of verb-particle and prepositional transitive sentences and the particles and prepositions within those sentences.

Conclusions: Results indicate that differences in argument structure of particle and preposition constructions influence sentence repetition in agrammatic aphasia. The finding that lower fluency scores are associated with poorer performance on more complex structures suggests that this effect is associated with agrammatism. The impact of these structural distinctions between particles and prepositions should be taken into account during development of treatment stimuli for those with agrammatism.     

Contrasting therapy effects for verb and sentence processing difficulties: A discussion of what worked and why

Background: Over recent years there have been a number of studies investigating the effects of therapy for verb and sentence processing difficulties in people with aphasia. A variety of therapies have been described, with apparently different foci and different methods. Despite this, similarities in the outcomes reported would suggest that the therapy techniques are in fact targeting similar processes.

Aims: The paper describes two periods of speech and language therapy intervention with a person with non‐fluent aphasia, MV. The contrasting effects of the two therapy periods are discussed and the mechanisms underpinning the improvements seen following the second period involving “verb and noun association therapy” are considered.

Methods & Procedures: A case study approach is used to evaluate the effects of two periods of intervention. The client, MV, was diagnosed with a semantic impairment resulting in a noun and verb retrieval deficit, as well as difficulties with argument structure and mapping. In the first intervention period, therapy consisted of verb‐centred mapping therapy and tasks promoting divergent noun and verb retrieval. In the second intervention period, “verb and noun association” therapy was used. Therapy was preceded and followed by detailed assessment of single word and sentence comprehension and production.

Outcomes & Results: The initial period of therapy resulted in no linguistic improvement. In contrast, the verb and noun association therapy resulted in item‐specific improvement in verb naming and a parallel improvement in verb comprehension. Significant gains in sentence production were also seen; MV was able to produce more nouns within a sentence context and produce more thematically complete and grammatically accurate sentences. These gains were not related to her ability to produce the nouns targeted within the therapy.

Conclusions: It is proposed that the gains in sentence production following the verb and noun association therapy were a consequence of the improved specification of the argument structure around verbs. It is not clear whether this resulted from improved access to lexically specified argument structure information or more generalised gains in argument structure production. The study suggests that gains in sentence production can be achieved for some clients without explicit identification or cueing of arguments and that this approach may be more beneficial for people who struggle with the demands of a more “meta‐linguistic” approach.     

Priming sentence comprehension in aphasia: effects of lexically independent and specific structural priming

Background & Aims: Impaired message-structure mapping results in deficits in both sentence production and comprehension in aphasia. Structural priming has been shown to facilitate syntactic production for persons with aphasia (PWA). However, it remains unknown if structural priming is also effective in sentence comprehension. We examined if PWA show preserved and lasting structural priming effects during interpretation of syntactically ambiguous sentences and if the priming effects occur independently of or in conjunction with lexical (verb) information.

Methods & Procedures: Eighteen PWA and 20 healthy older adults (HOA) completed a written sentence-picture matching task involving the interpretation of prepositional phrases (PP; the chef is poking the solider with an umbrella) that were ambiguous between high (verb modifier) and low attachment (object noun modifier). Only one interpretation was possible for prime sentences, while both interpretations were possible for target sentences. In Experiment 1, the target was presented immediately after the prime (0-lag). In Experiment 2, two filler items intervened between the prime and the target (2-lag). Within each experiment, the verb was repeated for half of the prime-target pairs, while different verbs were used for the other half. Participants’ off-line picture matching choices and response times were measured.

Results: After reading a prime sentence with a particular interpretation, HOA and PWA tended to interpret an ambiguous PP in a target sentence in the same way and with faster response times. Importantly, both groups continued to show this priming effect over a lag (Experiment 2), although the effect was not as reliable in response times. However, neither group showed lexical (verb-specific) boost on priming, deviating from robust lexical boost seen in the young adults of prior studies.

Conclusions: PWA demonstrate abstract (lexically-independent) structural priming in the absence of a lexically-specific boost. Abstract priming is preserved in aphasia, effectively facilitating not only immediate but also longer-lasting structure-message mapping during sentence comprehension.     

Structured treatment can improve predicate argument structure impairment

Background: Complementation information is a type of lexical-syntactic information that determines which syntactic environments a verb can be inserted into. It includes information about the verb’s predicate argument structure (PAS), the thematic role of each argument, and the verb’s subcategorisation frames. Complementation information might be impaired in aphasia. Various procedures have been used in treatment studies aimed at improving the production of verbs or sentences (including the verb with its arguments); these have usually yielded an improvement in treated verbs, without generalisation to untreated verbs.

Aims: In this study, we evaluated a structured treatment procedure, aimed at improving impaired PAS information, and examined whether it improved the production of verbs with their arguments in sentences. The research questions were these: (a) Will treatment improve the production of verbs with their arguments in sentences? (b) Will improvement generalise to untreated verbs? (c) Will improvement be maintained after the end of the treatment? and (d) Will improvement generalise to connected speech (in a task of telling a story in response to a series of pictures)?

Methods & Procedures: Two chronic aphasic patients with impairment in PAS information participated in the study. Their complementation information, and specifically their PAS information, was assessed prior to treatment, immediately after treatment, and in follow-ups 6 weeks and 6 months after treatment. The treatment consisted of instruction and practice on the number of arguments different verbs select, and taught the participants a strategy they could use. The practice was organised hierarchically, with regard to the number of arguments a given verb requires and the amount of cueing given.

Outcomes & Results: Following treatment, a significant improvement was found in the participants’ ability to produce sentences with the correct number of arguments. This improvement was generalised to untreated verbs and to connected speech and maintained for (at least) 6 months after treatment. However, neither participant showed improvement in other language skills, or even in other types of complementation information (i.e., subcategorisation frames).

Conclusions: The findings suggest that structured treatment focusing on PAS information can improve the use of this specific type of information, manifested in the production of sentences including the verb with its arguments. Theoretically, the findings support the view that complementation information is represented separately from other types of language information, and they suggest that different types of complementation information might be represented separately.     

Training verb argument structure production in agrammatic aphasia: Behavioral and neural recovery patterns

Introduction

Neuroimaging and lesion studies indicate a left hemisphere network for verb and verb argument structure processing, involving both frontal and temporoparietal brain regions. Although their verb comprehension is generally unimpaired, it is well known that individuals with agrammatic aphasia often present with verb production deficits, characterized by an argument structure complexity hierarchy, indicating faulty access to argument structure representations for production and integration into syntactic contexts. Recovery of verb processing in agrammatism, however, has received little attention and no studies have examined the neural mechanisms associated with improved verb and argument structure processing. In the present study we trained agrammatic individuals on verbs with complex argument structure in sentence contexts and examined generalization to verbs with less complex argument structure. The neural substrates of improved verb production were examined using functional magnetic resonance imaging (fMRI).

Methods

Eight individuals with chronic agrammatic aphasia participated in the study (four experimental and four control participants). Production of three-argument verbs in active sentences was trained using a sentence generation task emphasizing the verb's argument structure and the thematic roles of sentential noun phrases. Before and after training, production of trained and untrained verbs was tested in naming and sentence production and fMRI scans were obtained, using an action naming task.

Results

Significant pre- to post-training improvement in trained and untrained (one- and two-argument) verbs was found for treated, but not control, participants, with between-group differences found for verb naming, production of verbs in sentences, and production of argument structure. fMRI activation derived from post-treatment compared to pre-treatment scans revealed upregulation in cortical regions implicated for verb and argument structure processing in healthy controls.

Conclusions

Training verb deficits emphasizing argument structure and thematic role mapping is effective for improving verb and sentence production and results in recruitment of neural networks engaged for verb and argument structure processing in healthy individuals.     

Training verb production in communicative context: Evidence from a person with chronic non‐fluent aphasia

Background: The use of constraint‐induced treatment in aphasia therapy has yielded promising but mixed results.

Aims: We conducted a treatment study with an individual with chronic non‐fluent aphasia. The goal of the treatment was to improve verb production in sentence and narrative contexts.

Methods & Procedures: We administered a modified constraint‐induced aphasia treatment in a single‐participant design. Treatment emphasised the production of verbs within informative exchanges. Verb production in narratives was assessed before and after the treatment.

Outcomes & Results: Results demonstrated a significant increase in the number of verbs produced during narrative generation following treatment. Moreover, a positive change was perceived by naïve listeners who rated the social‐communicative impact of the participant's narratives.

Conclusions: The increase in verb production seen in the post‐treatment measures is attributed to a combination of the constraints imposed on sentence production during the treatment sessions, the informative nature of the treatment exchanges, and the relative intensity of the treatment schedule.     

Linguistic Specific Treatment: Just for Broca's aphasia?

Background: Several studies have documented the efficacy of Linguistic Specific Treatment (LST) for addressing sentence production deficits associated with agrammatism (e.g., Ballard & Thompson, 1999; Thompson, Shapiro, Kiran, & Sobecks, 2003). LST is based on the proposition that training production of complex, noncanonical sentence structures should produce generalisation to syntactically related, and less complex, sentence structures. Because empirical support for LST has been established via research that has exclusively involved patients with agrammatic production with or without asyntactic comprehension, it is not yet known whether this treatment is suitable for patients with other clinical aphasia types. Aims: Four adults who represented a variety of clinical aphasia types were provided with LST to determine whether (a) these patients would show acquisition of trained sentences with generalisation to untrained but syntactically related sentence forms; (b) LST would enhance written sentence production if only spoken production was directly treated and writing was indirectly stimulated through a home work programme; (c) treatment of spoken sentence production would assist comprehension of trained and untrained sentence forms; and (d) LST would facilitate spoken narrative skills in terms of informativeness, syntactic accuracy or complexity, or both. Methods & Procedures: Single subject, multiple baseline design across behaviours methodology was used to examine acquisition and generalisation of trained (object‐ and subject‐extracted embedded questions) and untrained sentence structures (object‐ and subject‐extracted matrix questions, passives) in four participants representing a spectrum of nonfluent and fluent aphasia types. They received individual, weekly 60–90 minute sessions of LST, and were asked to complete written sentence production homework practice. Outcomes & Results: Variable response patterns were observed across the participants in terms of changes in their spoken production or comprehension of trained and untrained sentence forms, written production of trained forms, and narrative discourse. Generally, LST was less helpful to participants with poorer comprehension and concomitant cognitive deficits. Conclusions: LST may provide some benefit not only to patients with nonfluent or agrammatic aphasia, but also to some patients with fluent aphasia profiles. Further investigation of LST is needed to delineate further the clinical populations for whom this treatment approach is most appropriate, and to evaluate LST procedural modifications that might foster production and comprehension generalisation effects.     

Effects of noun–verb conceptual/phonological relatedness on verb production changes in Broca's aphasia

Background: Individuals with Broca's aphasia show better performance on nouns than on verbs, but the distinction between nouns and verbs is not always clear; some verbs are conceptually and/or phonologically related to nouns, while others are not. Inconsistent results on effects of noun–verb relatedness on verb production have been reported in the literature.

Aims: We investigated (1) whether verb instrumentality (a conceptual relationship to nouns) or homonymy (a phonological relationship to nouns) would affect verb production in individuals with Broca's aphasia and (2) whether conceptual/phonological noun–verb relationship would affect responsiveness to aphasia therapy that focused on verb production.

Methods & Procedures: Three English-speaking individuals with Broca's aphasia produced 96 verbs in sentences in response to picture stimuli. The target verbs included those that use an instrument and those that do not (e.g., to hammer vs. to yawn) and verbs that are phonologically identical to a related noun (e.g., to comb vs. a comb), morpho-phonologically related to a noun (e.g., to grind vs. a grinder) and those that are not morphologically related to a noun (e.g., to lean). The participants’ verb retrieval ability was assessed before and after a 4-week period of aphasia therapy.

Outcomes & Results: The participants produced more accurate instrumental than non-instrumental verbs both pre- and post-treatment. They also produced more verbs correctly that are homonyms with nouns than verbs that are phonologically related or unrelated to nouns before treatment. However, the effect of homonymy was not observed following treatment.

Conclusion: Individuals with Broca's aphasia were more accurate in their production of verbs that were conceptually and phonologically related to nouns than on verbs that were not. The performance of verb production improved significantly after therapy. We interpret the results to indicate that, whereas prior to treatment, the participants relied on phonologically related nouns to retrieve the target verbs, this reliance on knowledge of nouns decreased following therapy that was designed to improve verb production.