Treating verbs in aphasia: exploring the impact of therapy at the single word and sentence levels

Repetitive Transcranial Magnetic Stimulation for Action Naming in Aphasia Rehabilitation: A Systematic Review and Meta-Analysis

Anomia, characterized by difficulty in word retrieval, particularly action verbs, poses a significant challenge in post-stroke aphasia. Repetitive transcranial magnetic stimulation (rTMS) has gained attention for language processing investigations and interventions. This systematic review explores the potential of rTMS as a modality to address action-verb deficits in post-stroke aphasia. We searched MEDLINE via PubMed, CINAHL via Ebsco and Web of Science in February 2024 for English articles (1996-2024). Eligible studies involved post-stroke aphasia action naming rehabilitation with rTMS. In some of these studies, rTMS was combined with speech-language therapy. In total, 10 studies were included in this systematic review. These articles highlight the potential of rTMS in improving verb retrieval deficits. While significant improvements may not be evident, notable progress both before and after intervention is observed in this review. However, it also underscores the need for further research to enhance language recovery for individuals with post-stroke aphasia.

Elizabeth Usher memorial lecture. Models, mind maps, and metacognition: How theory is the true hero

Within the educational context of identifying the critical ingredients of an effective speech-language pathologist, this paper highlights the centrality of theory in underpinning every level of our practice. A spotlight is placed on us knowing how language and communication work, what makes our interventions work, how we can make the most difference through our choices in therapy, and what makes both us and our clients respond. So, what are the critical ingredients of an effective speech-language pathologist, of an effective therapy, of an effective therapeutic alliance, and why is this so important? While there are many foundational and guiding habits upon which new graduates, early career, and experienced clinicians shape their practice, no one habit is regarded as more important than us exploring the theoretical underpinnings of what we are doing and why. To underscore the role of theory in our everyday practice, a discourse level intervention for people with aphasia is used as an exemplar to track the complex contribution of different theories to a single intervention. Discourse level interventions are relatively new on the scene in the area of acquired language disorders. Child language interventions, on the other hand, have frequently revolved around the story, aiming to bridge the oral-literate divide through the development of narrative structure. This paper will aim to weave its own story around discourse level interventions, combining the narrative genre with the everyday genres used by adults in conversation. I will highlight how this approach taps into lexical theories, sentence processing theories, discourse organisation, and the cognitive underpinnings of language, and closely examine how this multilayering of language in context may hold some of the answers to questions around generalisation, impact, and making the greatest difference to individuals.

Treatment of verb tense inflection and sentence production in Persian individuals with agrammatism

Production of verb morphology, especially tense inflection, is usually impaired in individuals with agrammatism. There have been relatively few studies on treatment of verb tense inflection in agrammatic aphasia. In this study we adapted ACTION (a linguistically motivated treatment) to Persian language, to treat the production of regular and irregular verbs separately in sentence context. A single-subject multiple-baseline across behaviors design was used to establish the treatment effect. Using a non-probable convenience sampling, four Persian agrammatic patients with Broca's aphasia resulting from cerebrovascular accident (CVA) were recruited for this study. Two participants received treatment first for regular verbs (Phase 1, 4 weeks), and then for irregular verbs (Phase 2, 4 weeks). The other two participants received treatment in reverse order. In the final phase of treatment (Phase 3, 4 weeks), all 4 participants underwent a sentence construction treatment. All participants showed improvement in the production of trained tenses. Treatment also generalized to production of untrained regular verbs while generalization to irregular verbs was modest. Furthermore, improvement was found on narrative scores (e.g. MLU) after treatment. These findings suggest that Persian individuals with agrammatism could be trained to correctly apply temporal information to verb inflection in elicited speech.

Generalization in Aphasia Treatment: A Tutorial for Speech-Language Pathologists

PURPOSE

Generalization has been defined and instantiated in a variety of ways over the last half-century, and this lack of consistency has created challenges for speech-language pathologists to plan for, implement, and measure generalization in aphasia treatment protocols. This tutorial provides an overview of generalization with a focus on how it relates to aphasia intervention, including a synthesis of existing principles of generalization and examples of how these can be embedded in approaches to aphasia treatment in clinical and research settings.

METHOD

Three articles collectively listing 20 principles of generalization formed the foundation for this tutorial. The seminal work of Stokes and Baer (1977) focused attention on generalization in behavioral change following treatment. Two aphasia-specific resources identified principles of generalization in relation to aphasia treatment (Coppens & Patterson, 2018; Thompson, 1989). A selective literature review was conducted to identify evidence-based examples of each of these 20 principles from the extant literature.

RESULTS

Five principles of generalization were synthesized from the original list of 20. Each principle was supported by studies drawn from the aphasia treatment literature to exemplify its application.

CONCLUSIONS

Generalization is an essential aspect of meaningful aphasia intervention. Successful generalization requires the same dedication to strategic planning and outcome measurement as the direct training aspect of intervention. Although not all people with aphasia are likely to benefit equally from each of the principles reviewed herein, our synthesis provides information to consider for maximizing generalization of aphasia treatment outcomes.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24714399.

Treatment-Induced Recovery Patterns Between Nouns and Verbs in Mandarin-English Bilingual Adults With Aphasia

PURPOSE

This study aimed to investigate treatment effects of naming therapy targeting nouns and verbs in Mandarin-English bilingual adults with aphasia (BWA).

METHOD

Twelve Mandarin-English bilingual adults with chronic aphasia completed a 40-hr semantic-based naming treatment for either nouns or verbs. Eight of these participants completed both noun and verb treatment, and the other four completed either noun or verb treatment. Participants were trained in either Mandarin or English for both treatment cycles. Weekly naming probes were measured to capture the direct treatment gain and within- and cross-language generalizations. Performance on the standardized language assessments was analyzed to examine further generalizations beyond the word level and to standardized naming tasks.

RESULTS

Responses in the weekly naming probes showed significant treatment gains in both noun and verb treatment, but the effect was greater in verb treatment. Generalization to semantically related items was captured in noun treatment only. Cross-language generalization was identified in both noun and verb treatment with a larger effect in verb treatment. Additionally, widespread generalizations beyond the word level and to standardized naming tasks were found following both noun and verb treatment, but the effect was larger following noun treatment in discourse and verb naming tasks.

CONCLUSIONS

Findings from this study suggested robust treatment effects of semantic-based naming treatment targeting nouns and verbs in Mandarin-English BWA. However, patterns of treatment gains and generalizations differed between these word categories. This study provides strong evidence of bilingual aphasia rehabilitation in Mandarin-English BWA.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23818299.

Naming vs. non-naming treatment in aphasia in a group setting-A randomized controlled trial

INTRODUCTION

Anomia affects numerous persons with aphasia. Treatment effects of anomia group therapy have been reported, but the evidence is not comprehensive. This study aimed to explore treatment effects of a naming treatment compared with a non-naming treatment delivered in a group setting.

METHODS

In a randomized controlled trial, 17 participants with chronic poststroke aphasia underwent group therapy, 2 hours a session, 3 times per week, for a total of 20 hours. The treatment given in the naming group was modified semantic feature analysis (SFA). Treatment content in the non-naming group comprised auditory comprehension, copying text, and reading. The primary outcome measure was accuracy in confrontation naming of participant-selected trained nouns and verbs. Generalization effects were evaluated in single-word naming, connected speech, and everyday communication.

RESULTS

Participants in both groups significantly improved their naming of trained items. There were no differences between the groups. The treatment effect did not remain at follow-up 10 weeks after therapy. No other statistically significant changes occurred in either group.

CONCLUSIONS

Group intervention can improve naming ability in individuals with chronic aphasia. However, similar treatment effects can be achieved using a non-naming treatment as using a naming treatment, such as modified SFA. Further research is warranted to identify the most important elements of anomia group therapy.

What is Functional Communication? A Theoretical Framework for Real-World Communication Applied to Aphasia Rehabilitation

Aphasia is an impairment of language caused by acquired brain damage such as stroke or traumatic brain injury, that affects a person’s ability to communicate effectively. The aim of rehabilitation in aphasia is to improve everyday communication, improving an individual’s ability to function in their day-to-day life. For that reason, a thorough understanding of naturalistic communication and its underlying mechanisms is imperative. The field of aphasiology currently lacks an agreed, comprehensive, theoretically founded definition of communication. Instead, multiple disparate interpretations of functional communication are used. We argue that this makes it nearly impossible to validly and reliably assess a person’s communicative performance, to target this behaviour through therapy, and to measure improvements post-therapy. In this article we propose a structured, theoretical approach to defining the concept of functional communication. We argue for a view of communication as “situated language use”, borrowed from empirical psycholinguistic studies with non-brain damaged adults. This framework defines language use as: (1) interactive, (2) multimodal, and (3) contextual. Existing research on each component of the framework from non-brain damaged adults and people with aphasia is reviewed. The consequences of adopting this approach to assessment and therapy for aphasia rehabilitation are discussed. The aim of this article is to encourage a more systematic, comprehensive approach to the study and treatment of situated language use in aphasia.

A Systematically Conducted Scoping Review of the Evidence and Fidelity of Treatments for Verb and Sentence Deficits in Aphasia: Sentence Treatments

PURPOSE

This review article synthesizes and evaluates the evidence for sentence production treatments in aphasia, systematically charting impairment-based and functional communication outcomes. It reports (a) the level of evidence and fidelity of sentence treatments; (b) the impact of treatment on production of trained and untrained verbs and sentences, functional communication, and discourse; and (c) the potential active ingredients of treatment.

METHOD

The search included studies from January 1980 to June 2019. The level of evidence of each study was documented, as was fidelity in terms of treatment delivery, enactment, and receipt. Studies were also categorized according to treatment methods used.

RESULTS

Thirty-three studies were accepted into the review and predominantly constituted Level 4 evidence (e.g., case control studies and case series). Thirty studies (90%) described treatment in sufficient detail to allow replication, but dosage was poorly reported, and fidelity of treatment was rarely assessed. The most commonly reported treatment techniques were mapping (10 studies: 30%), predicate argument structure treatment (six studies: 18%), and verb network strengthening treatment (five studies: 15%). Production of trained sentences improved for 83% of participants, and improvements generalized to untrained sentences for 59% of participants. Functional communication was rarely assessed, but discourse production improved for 70% of participants.

CONCLUSIONS

The evidence for sentence treatments is predominantly generated from Level 4 studies. Treatments were effective for the majority of participants regarding trained sentence and discourse production. However, there is inconsistent use of statistical analysis to verify improvements, and diverse outcome measures are used, which makes interpretation of the evidence difficult. The quality of sentence treatment research would be improved by agreeing a core set of outcome measures and extended by ascertaining the views of participants on sentence treatments.

Comparing verbal and aided single sentence productions in Malayalam-speaking adults with aphasia: a preliminary investigation

The primary aim of the study was to investigate the semantic and syntactic aspects of verbal and aided single sentence productions in adults with aphasia and neurotypical adults to determine which mode allowed the exchange of information more effectively. The participants of this study included 20 adults with aphasia and 20 neurotypical adults who were native speakers of Malayalam, an Indo-Dravidian language spoken in the south-western state of Kerala in India. Thirteen action picture stimuli were constructed to elicit single sentences. The participants were expected to describe the action picture in a single sentence using spoken language as well as using Picture Communication Symbols (PCS). The semantic aspect of each sentence produced was analysed using Correct Information Unit (CIU) analyses, and the syntactic aspects were measured using (i) percentage of grammatically complete sentences, (ii) percentage of the correct number of verbs, and (iii) total number of syntactic errors. A sentence production accuracy scale was constructed to obtain a combined score for semantic and syntactic aspects of each sentence produced. The results suggested that while both verbal and aided modes were effectively used for the exchange of information by neurotypical adults and adults with anomic aphasia, the aided mode was used more effectively by adults with Broca's aphasia. To conclude, the study highlights the importance of (a) using visual symbols even for those with mild aphasia as it tends to improve phonological and articulatory abilities, (b) use of symbols to construct simple sentences to communicate in adults with severe aphasia, (c) evaluation of the ability to use alternate modes of communication and also the preferred mode of communication in adults with aphasia.

Effects of Verb Network Strengthening Treatment on Sound-Level and Speech Production Errors in Individuals With Aphasia and Acquired Apraxia of Speech

Purpose This retrospective pilot study investigated whether sound-level and speech production errors decreased in confrontation naming following Verb Network Strengthening Treatment (VNeST) for four participants with acquired apraxia of speech (A-AOS) and aphasia for whom lexical retrieval was previously reported. Specifically, we investigated a potential increase in correct number of syllables per word and posttreatment changes across three domains of speech: segmental production, fluency, and prosody. It was hypothesized that treatment shown to increase lexical retrieval in persons with aphasia and A-AOS could potentially facilitate a reduction in sound-level and speech production errors consistent with dual diagnoses of A-AOS and aphasia. Method Naming responses from four participants with aphasia and A-AOS who previously participated in VNeST studies were investigated for correct number of syllables per word and measures of segmental speech, fluency, and prosody. Results Significant gains in at least one measure of speech production were reported for three of the participants. One participant demonstrated decreased segmental speech errors, two showed significant reduction on syllable segmentation, and two demonstrated a significant reduction on false starts and pauses. Significant gains in production of correct number of syllables were limited to one participant, and one participant did not demonstrate increased accuracy on any measure of speech production. Conclusions While speech production errors consistent with motor speech impairment cannot always be definitively distinguished from the confound of aphasia, two participants produced significantly decreased segmentation of syllables, a characteristic unique to A-AOS. The sound-level and speech production changes recorded may be attributed to a combination of interacting motor and language processes and resource allocation. In addition, specific components of VNeST may have contributed to speech production changes. Future work will focus on a prospective study of effects of language therapy (e.g., VNeST) on measures of speech production with investigation beyond the single-word level.

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.

Exploring the effects of verb and noun treatment on verb phrase production in primary progressive aphasia: A series of single case experimental design studies

Evidence of generalization to connected speech following lexical retrieval treatment in Primary Progressive Aphasia (PPA) is scarce. Consequently, this study systematically investigated changes in verb phrase production following lexical retrieval treatment in a series of single case experimental design studies. Four individuals with PPA (three semantic- and one logopenic variant PPA) who had previously demonstrated that they could integrate verbs and nouns into sentence structures in a cueing paradigm, undertook a sequence of verb and noun lexical retrieval treatments using Repetition and Reading in the Presence of a Picture. Production of treated nouns- and/or verbs-in-isolation significantly improved following treatment for three of the four participants. Verb phrase production did not improve for one of these participants (logopenic PPA), perhaps due to the relatively small treatment dose. Two participants (semantic variant PPA) did, however, demonstrate across-level generalization, with improvement in treated verbs and using those verbs in (untreated) verb phrases. Their verb phrase production improved most after lexical retrieval treatment for both nouns and verbs, suggesting this combined approach may benefit across-level generalization for some individuals in clinical practice.

Increased links between language and motor areas: A proof-of-concept study on resting-state functional connectivity following Personalized Observation, Execution and Mental imagery therapy in chronic aphasia

A tight coupling of language and motor processes has been established, which is consistent with embodied cognition theory. However, very few therapies have been designed to exploit the synergy between motor and language processes to help rehabilitate people with aphasia (PWA). Moreover, the underlying mechanisms supporting the efficacy of such approaches remain unknown. Previous work in our laboratory has demonstrated that personalized observation, execution, and mental imagery therapy (POEM)-a new therapy using three sensorimotor strategies to trigger action verb naming-leads to significant improvements in verb retrieval in PWA. Moreover, these improvements were supported by significant activations in language and sensorimotor processing areas, which further reinforce the role of both processes in language recovery (Durand et al., 2018). The present study investigates resting state functional connectivity (rsFC) changes following POEM in a pre-/post-POEM therapy design. A whole brain network functional connectivity approach was used to assess and describe changes in rsFC in a group of four PWA, who were matched and compared with four healthy controls (HC). Results showed increased rsFC in PWA within and between visuo-motor and language areas (right cuneal cortex-left supracalcarin (SCC) cortex/right precentral gyrus (PreCG)-left lingual gyrus (LG)) and between areas involved in action processing (right anterior parahippocampal gyrus (aPaHC)-left superior parietal lobule (SPL). In comparison to HC, the PWA group showed increased rsFC between the right inferior frontal gyrus (IFG) and left thalamus, which are areas involved in lexico-semantic processing. This proof-of-concept study suggests that the sensorimotor and language strategies used in POEM may induce modifications in large-scale networks, probably derived from the integration of visual and sensorimotor systems to sustain action naming, which is consistent with the embodied cognition theory.

A Systematically Conducted Scoping Review of the Evidence and Fidelity of Treatments for Verb Deficits in Aphasia: Verb-in-Isolation Treatments

Purpose Aphasia research demonstrates increasing interest in the treatment of verb retrieval deficits. This systematically conducted scoping review reports on the level and fidelity of the current evidence for verb treatments; on its effectiveness regarding the production of trained and untrained verbs, functional communication, sentences, and discourse; and on the potential active ingredients. Recommendations to guide clinical decision making and future research are made. Method The computerized database search included studies from January 1980 to September 2018. The level of evidence of each study was documented, as was fidelity in terms of treatment delivery, enactment, and receipt. Studies were also categorized according to the treatment methods used. Results Thirty-seven studies were accepted into the review, and all but 1 constituted a low level of evidence. Thirty-three studies (89%) described treatment in sufficient detail to allow replication, dosage was poorly reported, and the fidelity of treatment was rarely assessed. The most commonly reported treatment techniques were phonological and semantic cueing in 25 (67.5%) and 20 (54%) studies, respectively. Retrieval of trained verbs improved for 80% of participants, and improvements generalized to untrained verbs for 15% of participants. There was not sufficient detail to evaluate the impact of treatment on sentence production, functional communication, and discourse. Conclusions The evidence for verb treatments is predominantly of a low level. There are encouraging findings in terms of treatments being replicable; however, this is tempered by poor monitoring of treatment fidelity. The quality of verb treatment research would be improved by researchers reaching consensus regarding outcome measures (including generalization to, e.g., sentences and discourse) by manualizing treatment to facilitate implementation and exploring the opinions of participants. Finally, while treatment is largely effective in improving production of trained verbs, lack of generalization to untrained items leads to the recommendation that personally relevant verbs are prioritized.

An Aphasia Treatment for Verbs With Low Concreteness: A Pilot Study

Purpose Verbs with low concreteness are frequent in discourse samples but rarely targeted in aphasia treatments for verbs. These verbs are an important part of functional communication, and recent studies have called for more research regarding aphasia and treatment stimuli with low concreteness. The aim of this study was to pilot the use of verbs with low concreteness in a novel sentence production intervention with persons with aphasia. Method The study took the form of a single-case experimental design with multiple baselines across behaviors and across participants. Three persons with chronic nonfluent aphasia and apraxia of speech participated in the study. Each participant received treatment designed to increase the semantic networks of verbs with high frequency and low concreteness. Sentence production was closely examined over the course of treatment for treated and untreated verbs of varying concreteness levels. Additional measures of language and cognitive functioning were also taken before and after treatment. Results Results indicated improved sentence production with target verbs attributable to the treatment in the 1st phase of 2 phases for 2 of the 3 participants. The increases corresponded with the application of treatment, despite the difference in number of baseline sessions for the participants. Where there were treatment effects, there was also considerable generalization to untreated sets of items during the 1st treatment phase. Word retrieval also improved for 2 participants. Conclusions The results suggest that the novel treatment may improve sentence production and word retrieval in persons with aphasia, even when using target verbs with low concreteness ratings. Future research is warranted into the use of low concreteness verbs. Supplemental Material https://doi.org/10.23641/asha.10870958.

Written Verb Naming Improves After tDCS Over the Left IFG in Primary Progressive Aphasia

Transcranial direct current stimulation (tDCS), a non-invasive neuromodulation technique, is an effective adjunct to naming treatments in post-stroke aphasia and primary progressive aphasia (PPA). Enhanced performance in oral and written naming and spelling of nouns with tDCS has been quantified in detail, but it is not known whether it is effective for verb treatment in PPA. We addressed the question of whether performance in naming and spelling of verbs can be augmented with anodal tDCS over the left inferior frontal gyrus (IFG). We compared tDCS coupled with oral and written verb naming/spelling treatment with oral and written verb naming/spelling treatment alone. In a double-blind, sham-controlled, crossover design, 11 participants with logopenic or non-fluent variant PPA received approximately 15 consecutive sessions of anodal tDCS and sham over the left IFG coupled with oral and written verb-naming + spelling treatment. Written verb-naming performance improved significantly more for trained verbs in the tDCS than the sham condition. Importantly, tDCS effects generalized to untrained items for written verb naming and were significant even at 2 months post-treatment. We conclude that tDCS over the left IFG can improve written verb naming and spelling in PPA.

The Neural and Behavioral Correlates of Anomia Recovery following Personalized Observation, Execution, and Mental Imagery Therapy: A Proof of Concept

The impact of sensorimotor strategies on aphasia recovery has rarely been explored. This paper reports on the efficacy of personalized observation, execution, and mental imagery (POEM) therapy, a new approach designed to integrate sensorimotor and language-based strategies to treat verb anomia, a frequent aphasia sign. Two participants with verb anomia were followed up in a pre-/posttherapy fMRI study. POEM was administered in a massed stimulation schedule, with personalized stimuli, resulting in significant improvement in both participants, with both trained and untrained items. Given that the latter finding is rarely reported in the literature, the evidence suggests that POEM favors the implementation of a word retrieval strategy that can be integrated and generalized. Changes in fMRI patterns following POEM reflect a reduction in the number of recruited areas supporting naming and the recruitment of brain areas that belong to the language and mirror neuron systems. The data provide evidence on the efficacy of POEM for verb anomia, while pointing to the added value of combined language and sensorimotor strategies for recovery from verb anomia, contributing to the consolidation of a word retrieval strategy that can be better generalized to untrained words. Future studies with a larger sample of participants are required to further explore this avenue.

An analysis of topics and vocabulary in Chinese oral narratives by normal speakers and speakers with fluent aphasia

This study analysed the topic and vocabulary of Chinese speakers based on language samples of personal recounts in a large spoken Chinese database recently made available in the public domain, i.e. Cantonese AphasiaBank ( http://www.speech.hku.hk/caphbank/search/ ). The goal of the analysis is to offer clinicians a rich source for selecting ecologically valid training materials for rehabilitating Chinese-speaking people with aphasia (PWA) in the design and planning of culturally and linguistically appropriate treatments. Discourse production of 65 Chinese-speaking PWA of fluent types (henceforth, PWFA) and their non-aphasic controls narrating an important event in their life were extracted from Cantonese AphasiaBank. Analyses of topics and vocabularies in terms of part-of-speech, word frequency, lexical semantics, and diversity were conducted. There was significant overlap in topics between the two groups. While the vocabulary was larger for controls than that of PWFA as expected, they were similar in distribution across parts-of-speech, frequency of occurrence, and the ratio of concrete to abstract items in major open word classes. Moreover, proportionately more different verbs than nouns were employed at the individual level for both speaker groups. The findings provide important implications for guiding directions of aphasia rehabilitation not only of fluent but also non-fluent Chinese aphasic speakers.

A case series comparison of semantically focused vs. phonologically focused cued naming treatment in aphasia

There is a lack of clarity in the field regarding how to best predict which naming treatment will be most beneficial for a particular individual with aphasia. The purpose of this study was to elucidate whether or not semantic or phonological therapy differentially impacts on outcomes for people with a range of different aphasic profiles when given both therapies. A single-participant design, with multiple repeated baselines for naming, replicated across four participants, was used. Participants were provided with a counterbalanced order of Semantic Feature Analysis (SFA) and Phonological Components Analysis (PCA) treatment. Findings demonstrated differential effects across participants. This seemed to be influenced by factors such as severity of anomia, order of treatment presentation, and capacity limits. Clinical implications of these findings highlight the importance of expanding our picture of a participant's behaviours to consider what other important factors can inform intervention decisions.

Can we separate verbs from their argument structure? A group study in aphasia

BACKGROUND

Given the integral role that verbs play in sentence production, understanding verb deficits is critical to clinical practice. Difficulties in sentence production are often directly related to an inability to retrieve argument structure information which, according to most theoretical accounts, is specified at a lexical level as part of the semantic representation of the verb. The presence of an argument complexity effect when retrieving verbs in isolation, i.e. increased difficulty with increasing number of arguments required by the verb, is considered evidence of the integral link between verbs and the ensuing structure. Recent reports, however, of relatively intact verb retrieval and impaired argument structure suggest that difficulties with verbs and argument structure may not always co-occur. One explanation for this is that lexical-syntactic information may be stored separately to lexical-semantic information at the lemma level and then differentially impaired.

AIMS

To determine whether the presence of difficulties creating argument structure in a group of people with aphasia with verb-retrieval deficits consistently aligned with the underlying nature of their impairment, where semantic involvement resulted in argument structure difficulties and post-semantic impairment resulted in intact argument structure. This would provide evidence either to support or to challenge the view that argument structure is lexically specified. The presence of an argument complexity effect within the participants' single verb naming was also investigated to examine the relationship between verb argument information and any subsequent difficulties creating argument structure for sentence production.

METHODS & PROCEDURES

Verb retrieval and argument structure production were investigated in 12 people with aphasia with verb-retrieval deficits on single-word and sentence-production measures.

OUTCOMES & RESULTS

Eight of the 12 participants presented with a semantic verb deficit (five semantic and three mixed semantic and phonological) and had difficulties in creating argument structure. Four participants presented with a phonological verb deficit. Of these, two had intact argument structure while two had impaired argument structure. An argument complexity effect in verb naming was seen in both groups.

CONCLUSIONS & IMPLICATIONS

Semantic verb-retrieval deficits consistently resulted in argument structure production difficulties, supporting the view that syntactic information is stored within the lemma. The presence of argument structure difficulties in two participants with phonological deficits; however, lends support for the separate coding of lexical-syntactic from lexical-semantic information at the lemma level, a factor that has both theoretical and clinical implications with respect to diagnosis and management.

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

Background: Demographic and clinical predictors of aphasia recovery have been identified in the literature. However, little attention has been devoted to identifying and distinguishing predictors of improvement for different outcomes, e.g., production of treated vs. untreated materials. These outcomes may rely on different mechanisms, and therefore be predicted by different variables. Furthermore, treatment features are not typically accounted for when studying predictors of aphasia recovery. This is partly due to the small numbers of cases reported in studies, but also to limitations of data analysis techniques usually employed.

Method: We reviewed the literature on predictors of aphasia recovery, and conducted a meta-analysis of single-case studies designed to assess the efficacy of treatments for verb production. The contribution of demographic, clinical, and treatment-related variables was assessed by means of Random Forests (a machine-learning technique used in classification and regression). Two outcomes were investigated: production of treated (for 142 patients) and untreated verbs (for 166 patients).

Results: Improved production of treated verbs was predicted by a three-way interaction of pre-treatment scores on tests for verb comprehension and word repetition, and the frequency of treatment sessions. Improvement in production of untreated verbs was predicted by an interaction including the use of morphological cues, presence of grammatical impairment, pre-treatment scores on a test for noun comprehension, and frequency of treatment sessions.

Conclusion: Improvement in the production of treated verbs occurs frequently. It may depend on restoring access to and/or knowledge of lexeme representations, and requires relative sparing of semantic knowledge (as measured by verb comprehension) and phonological output abilities (including working memory, as measured by word repetition). Improvement in the production of untreated verbs has not been reported very often. It may depend on the nature of impaired language representations, and the type of knowledge engaged by treatment: it is more likely to occur where abstract features (semantic and/or grammatical) are damaged and treated.

Children's comprehension of an unfamiliar speaker accent: a review

BACKGROUND

The effect of speaker accent on listeners' comprehension has become a key focus of research given the increasing cultural diversity of society and the increased likelihood of an individual encountering a clinician with an unfamiliar accent.

AIMS

To review the studies exploring the effect of an unfamiliar accent on language comprehension in typically developing (TD) children and in children with speech and language difficulties. This review provides a methodological analysis of the relevant studies by exploring the challenges facing this field of research and highlighting the current gaps in the literature.

METHODS & PROCEDURES

A total of nine studies were identified using a systematic search and organized under studies investigating the effect of speaker accent on language comprehension in (1) TD children and (2) children with speech and/or language difficulties.

MAIN CONTRIBUTION

This review synthesizes the evidence that an unfamiliar speaker accent may lead to a breakdown in language comprehension in TD children and in children with speech difficulties. Moreover, it exposes the inconsistencies found in this field of research and highlights the lack of studies investigating the effect of speaker accent in children with language deficits.

CONCLUSIONS & IMPLICATIONS

Overall, research points towards a developmental trend in children's ability to comprehend accent-related variations in speech. Vocabulary size, language exposure, exposure to different accents and adequate processing resources (e.g. attention) seem to play a key role in children's ability to understand unfamiliar accents. This review uncovered some inconsistencies in the literature that highlight the methodological issues that must be considered when conducting research in this field. It explores how such issues may be controlled in order to increase the validity and reliability of future research. Key clinical implications are also discussed.

Translational treatment of aphasia combining neuromodulation and behavioral intervention for lexical retrieval: implications from a single case study

BACKGROUND

Transcranial direct current stimulation (tDCS), a non-invasive method of brain stimulation, is an adjunctive research-therapy for aphasia. The concept supporting translational application of tDCS is that brain plasticity, facilitated by language intervention, can be enhanced by non-invasive brain stimulation. This study combined tDCS with an ecologically focused behavioral approach that involved training nouns and verbs in sentences.

METHOD

PARTICIPANT

A 43-year-old, right-handed male with fluent-anomic aphasia who sustained a single-left-hemisphere-temporal-parietal stroke was recruited.

TREATMENT

Instrumentation included the Soterix Medical 1 × 1 Device. Anodal tDCS was applied over Broca's area. Behavioral materials included: sentence production, naming in the sentence context, and implementation of a social-conversational-discourse treatment.

DESIGN AND PROCEDURES

The independent variable of this crossover case-study was tDCS, and the dependent variables were language and quality-of-life measures. In each session the subject received language treatment with the first 20 minutes additionally including tDCS.

RESULTS

Performance in naming nouns and verbs in single words and sentences were obtained. Verb production in the sentence context increased after active anodal tDCS and speech-language treatment.

CONCLUSION

Aphasia treatment that involves naming in the sentence context in conjunction with translational application of tDCS may be a promising approach for language-recovery post stroke.

Can tDCS enhance item-specific effects and generalization after linguistically motivated aphasia therapy for verbs?

BACKGROUND

Aphasia therapy focusing on abstract properties of language promotes both item-specific effects and generalization to untreated materials. Neuromodulation with transcranial Direct Current Stimulation (tDCS) has been shown to enhance item-specific improvement, but its potential to enhance generalization has not been systematically investigated. Here, we test the efficacy of ACTION (a linguistically motivated protocol) and tDCS in producing item-specific and generalized improvement in aphasia.

METHOD

Nine individuals with post-stroke aphasia participated in this study. Participants were pre-tested with a diagnostic language battery and a cognitive screening. Experimental tasks were administered over multiple baselines. Production of infinitives, of finite verbs and of full sentences were assessed before and after each treatment phase. Nonword repetition was used as a control measure. Each subject was treated in two phases. Ten daily 1-h treatment sessions were provided per phase, in a double-blind, cross-over design. Linguistically-motivated language therapy focusing on verb inflection and sentence construction was provided in both phases. Each session began with 20 min of real or sham tDCS. Stimulation site was determined individually, based on MRI scans.

RESULTS

Group data showed improved production of treated and untreated verbs, attesting the efficacy of behavioral treatment, and its potential to yield generalization. Each individual showed significant item-specific improvement. Generalization occurred in the first phase of treatment for all subjects, and in the second phase for two subjects. Stimulation effects at the group level were significant for treated and untreated verbs altogether, but a ceiling effect for Sham cannot be excluded, as scores between real tDCS and Sham differed only before treatment.

CONCLUSION

Our data demonstrate the efficacy of ACTION and suggest that tDCS may enhance both item-specific effects and generalization.

Effects of context and word class on lexical retrieval in Chinese speakers with anomic aphasia

BACKGROUND

Differences in processing nouns and verbs have been investigated intensely in psycholinguistics and neuropsychology in past decades. However, the majority of studies examining retrieval of these word classes have involved tasks of single word stimuli or responses. While the results have provided rich information for addressing issues about grammatical class distinctions, it is unclear whether they have adequate ecological validity for understanding lexical retrieval in connected speech which characterizes daily verbal communication. Previous investigations comparing retrieval of nouns and verbs in single word production and connected speech have reported either discrepant performance between the two contexts with presence of word class dissociation in picture naming but absence in connected speech, or null effects of word class. In addition, word finding difficulties have been found to be less severe in connected speech than picture naming. However, these studies have failed to match target stimuli of the two word classes and between tasks on psycholinguistic variables known to affect performance in response latency and/or accuracy.

AIMS

The present study compared lexical retrieval of nouns and verbs in picture naming and connected speech from picture description, procedural description, and story-telling among 19 Chinese speakers with anomic aphasia and their age, gender, and education matched healthy controls, to understand the influence of grammatical class on word production across speech contexts when target items were balanced for confounding variables between word classes and tasks.

METHODS & PROCEDURES

Elicitation of responses followed the protocol of the AphasiaBank consortium (http://talkbank.org/AphasiaBank/). Target words for confrontation naming were based on well-established naming tests, while those for narrative were drawn from a large database of normal speakers. Selected nouns and verbs in the two contexts were matched for age-of-acquisition (AoA) and familiarity. Influence of imageability was removed through statistical control.

OUTCOMES & RESULTS

When AoA and familiarity were balanced, nouns were retrieved better than verbs, and performance was higher in picture naming than connected speech. When imageability was further controlled for, only the effect of task remained significant.

CONCLUSIONS

The absence of word class effects when confounding variables are controlled for is similar to many previous reports; however, the pattern of better word retrieval in naming is rare but compatible with the account that processing demands are higher in narrative than naming. The overall findings have strongly suggested the importance of including connected speech tasks in any language assessment and evaluation of language rehabilitation of individuals with aphasia.

Effect of Verb Network Strengthening Treatment (VNeST) in persons with aphasia: extension and replication of previous findings

PURPOSE

Verb Network Strengthening Treatment (VNeST) is an aphasia treatment that targets verbs (e.g., measure) and their related thematic roles (e.g., carpenter-lumber). Previous studies reported encouraging results in a number of participants using single-subject design with improvements observed on naming, sentence production, and discourse. The purpose of the current study was to conduct a group analysis evaluating the effect of VNeST on similar outcomes.

METHOD

A multiple baseline design across participants was conducted with 11 persons with aphasia due to stroke. Wilcoxon signed-ranks tests were used to evaluate potential improvement from pre- to posttreatment and maintenance. Individual effect sizes were also calculated to evaluate magnitude of change within and across participants.

RESULTS

Results showed significant improvement at posttreatment and maintenance on trained and untrained sentence probes and object and action naming. Improvement in the production of sentences not targeted in treatment was nonsignificant at posttreatment assessment but significant at maintenance. Moderate increases in percentage of complete utterances and overall informativeness were observed on discourse.

CONCLUSION

The results of this study replicate previous findings and provide evidence that VNeST may promote specific and generalized lexical retrieval abilities and affect basic syntax production in both constrained and discourse production tasks.

Options to enhance recovery from aphasia by means of non-invasive brain stimulation and action observation therapy

Aphasia is a highly disabling language disorder usually caused by a left-lateralized brain damage. Even if traditional linguistic-based therapies have been proved to induce an adequate clinical improvement, a large percentage of patients are left with some degree of language impairments. Therefore, new approaches to common speech therapies are urgently needed in order to maximize the recovery from aphasia. The recent application of non-invasive neurostimulation techniques to language rehabilitation has already provided promising results particularly for the recovery of word-retrieval deficits in chronic stroke aphasic patients. Positive outcomes also come from action observation therapy. Indeed, some very recent studies have shown that the observation and/or execution of gestures positively influences language recovery especially for words related to human actions. This article gives an overview of the most important results achieved using these two approaches and discusses how the application of these treatments might potentiate aphasia recovery.