Semantic complexity in treatment of naming deficits in aphasia: evidence from well-defined categories

Semantic cognition in healthy ageing: Neural signatures of representation and control mechanisms in naming typical and atypical objects

Effective use of conceptual knowledge engages semantic representation and control processes to access information in a goal-driven manner. Neuropsychological findings of patients presenting either degraded knowledge (e.g., semantic dementia) or disrupted control (e.g., semantic aphasia) converge with neuroimaging evidence from young adults, and delineate the neural segregation of representation and control mechanisms. However, there is still scarce research on the neurofunctional underpinnings of such mechanisms in healthy ageing. To address this, we conducted an fMRI study, wherein young and older adults performed a covert naming task of typical and atypical objects. Three main age-related differences were found. As shown by age group and typicality interactions, older adults exhibited overactivation during naming of atypical (e.g., avocado) relative to typical concepts in brain regions associated to semantic representation, including anterior and medial portions of left temporal lobe (respectively, ATL and MTG). This provides evidence for the reorganization of neural activity in these brain regions contingent to the enrichment of semantic repositories in older ages. The medial orbitofrontal gyrus was also overactivated, indicating that the processing of atypical concepts (relative to typical items) taxes additional control resources in the elderly. Increased activation in the inferior frontal gyrus (IFG) was observed in naming typical items (relative to atypical ones), but only for young adults. This suggests that naming typical items (e.g., strawberry) taxes more on control processes in younger ages, presumably due to the semantic competition set by other items that share multiple features with the target (e.g., raspberry, blackberry, cherry). Together, these results reveal the dynamic nature of semantic control interplaying with conceptual representations as people grow older, by indicating that distinct neural bases uphold semantic performance from young to older ages. These findings may be explained by neural compensation mechanisms coming into play to support neurocognitive changes in healthy ageing.

Stimulus- and Person-Level Variables Influence Word Production and Response to Anomia Treatment for Individuals With Chronic Poststroke Aphasia

PURPOSE

The impact of stimulus-level psycholinguistic variables and person-level semantic and phonological processing skills on treatment outcomes in individuals with aphasia requires further examination to inform clinical decision making in treatment prescription and stimuli selection. This study investigated the influence of stimulus-level psycholinguistic properties and person-level semantic and phonological processing skills on word production accuracy and treatment response.

METHOD

This retrospective analysis included 35 individuals with chronic, poststroke aphasia, 30 of whom completed typicality-based semantic feature treatment. Mixed-effects logistic regression models were used to predict binary naming accuracy (a) at baseline and (b) over the course of treatment using stimulus-level psycholinguistic word properties and person-level semantic and phonological processing skills as predictors.

RESULTS

In baseline naming, words with less complex lexical-semantic and phonological properties showed greater predicted accuracy. There was also an interaction at baseline between stimulus-level lexical-semantic properties and person-level semantic processing skills in predicting baseline naming accuracy. With treatment, words that were more complex from a lexical-semantic standpoint (vs. less complex) and less complex from a phonological standpoint (vs. more complex) improved more. Individuals with greater baseline semantic and phonological processing skills showed a greater treatment response.

CONCLUSIONS

This study suggests that future clinical research and clinical work should consider semantic and phonological properties of words in selecting stimuli for semantically based treatment. Furthermore, future clinical research should continue to evaluate baseline individual semantic and phonological profiles as predictors of response to semantically based treatment.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21256341.

Complexity and feedback during script training in aphasia: A feasibility study

OBJECTIVE

To explore the impact of complexity and feedback on script training outcomes in aphasia DESIGN: Randomized balanced single-blind 2 × 2 factorial design SETTING: Freestanding urban rehabilitation hospital.

PARTICIPANTS

Adults with fluent and nonfluent aphasia (at least six months post-onset).

INTERVENTIONS

Experimental treatment was AphasiaScripts®, a computer-based script training program. Scripts were 10-turns long and developed at different complexity levels to allow for comparison of high versus low complexity. The program was modified to contrast high versus low feedback conditions during sentence practice. Participants were instructed to practice three 30-minute sessions per day, six days a week for three weeks.

MAIN MEASURES

Gains achieved from baseline in accuracy and rate of production of trained and untrained script sentences at post-treatment and at 3-, 6- and 12-weeks after the end of treatment.

RESULTS

Sixteen participants completed the intervention. On the trained script, gains were statistically significant for both accuracy and words per minute, at post-treatment and 3-, 6- and 12-week maintenance. Gains on the untrained script were smaller than on the trained script; they were statistically significant only for accuracy at post-treatment and 3-week maintenance. Complexity had an influence on accuracy at post-treatment (F(1) = 4.8391, p = 0.0501) and at maintenance (F(1) = 5.3391, p = 0.04125). Practicing scripts with high complexity increased accuracy by 11.33% at post-treatment and by 9.90% at maintenance compared to scripts with low complexity. Participants with nonfluent aphasia made greater gains than those with fluent aphasia. There was no significant effect of feedback.

CONCLUSION

This study reinforces script training as a treatment option for aphasia. Results highlight the use of more complex scripts to better promote acquisition and maintenance of script production skills. There is a need for further investigation of these variables with larger samples and with other types of aphasia treatments.

CLINICALTRIALS

gov identifier: NCT01597037.

Bilingual Abstract Semantic Associative Network Training (BAbSANT): A Polish-English case study

INTRODUCTION

This article presents a novel approach to anomia therapy (i.e., BAbSANT: Bilingual Abstract Semantic Associative Network Training) for bilingual persons with aphasia (B-PWA) that capitalizes both on lexico-semantic theories in bilingualism and general theories of semantic organization and learning. Based on previous work, we hypothesized that training abstract words in either language would promote within-language generalization, while training in the nondominant language would promote both within- and cross-language generalization.

METHODS

This case study used a single-subject A₁BA₂CA₃ design. The participant was living with aphasia secondary to stroke and spoke both Polish and English, with Polish being his native and dominant language. Phase B consisted of abstract word training in Polish and phase C consisted of abstract word training in English. Prior to initiating therapy, in addition to a comprehensive language battery, we administered a cognitive control task to explore the relationship between cognitive control and treatment outcome.

RESULTS

We found within-language generalization regardless of the trained language, replicating previous work in monolingual persons with aphasia, further supporting the utility of training abstract words. However, contrary to our second hypothesis, cross-language generalization only occurred when the stronger language was trained.

CONCLUSIONS

The discussion of the results of this case study is framed within previous work and theories of bilingualism. The lack of cross-language generalization when the weaker language was trained is discussed, taking into account nonverbal cognitive control deficits. In addition to showing the efficacy of BAbSANT, these results highlight the importance of considering cognitive control as a factor influencing therapeutic outcomes in anomia treatment in bilingual PWA.

Category Exemplar Production Norms for Hong Kong Cantonese: Instance Probabilities and Word Familiarity

The lexical system of Hong Kong Cantonese has been heavily shaped by the local trilingual environment. The development of cultural- and language-specific norms for Hong Kong Cantonese is fundamental for understanding how the speaker population organize semantic memory, how they utilize their semantic resources, and what information processing strategies they use for the retrieval of semantic knowledge. This study presents a normative database of 72 lexical categories in Hong Kong Cantonese produced by native speakers in a category exemplar production task. Exemplars are enlisted under a category label, along with the instance probabilities and word familiarity scores. Possible English equivalents are given to the exemplars for the convenience of non-HKC speaker researchers. Statistics on categories were further extracted to capture the heterogeneity of the categories: the total number of valid exemplars, the number of exemplars covering 90% of the occurrence and the probabilities of the most frequent exemplars in each category. The database offers a direct lexical sketch of the vocabulary of modern Hong Kong Cantonese in a categorical structure. The category-exemplar lists and the comparative statistics together lay the foundations for further investigations on the Hong Kong Cantonese speaking population from multiple disciplines, such as the structure of semantic knowledge, the time-course of knowledge access, and the processing strategies of young adults. Results of this norm can be also used as a benchmark for other age groups. The database can serve as a crucial resource for establishing initial screening tests to assess the cognitive and psychological functioning of the Cantonese-speaking Hong Kong population in both educational and clinical settings. In sum, this normative study provides a fundamental resource for future studies on language processing mechanisms of Hong Kong Cantonese speaking population, as well as language studies and other cross-language/culture studies on Hong Kong Cantonese.

Using concept typicality to explore semantic representation and control in healthy ageing

Successful use of conceptual knowledge entails the assembling of semantic representations and control processes to access the subsets of knowledge relevant in each situation. Research has suggested that representation and control mechanisms interact to support categorization. Notably, depleted representations in semantic dementia and disrupted control processes in semantic aphasia impair categorization of atypical concepts. Yet, it remains unclear how knowledge accumulation and control decay in healthy ageing impact categorization. To address this question, we compared young and older adults' performance in a categorization task of items varying in concept typicality. Critically, older adults were more accurate in categorizing atypical concepts than the younger counterparts, as indicated by the interaction between group and typicality. Moreover, the elderly outperformed the younger in categorizing atypical concepts that were also less familiar. Thus, the decay in semantic control observed along ageing did not significantly hinder the categorization of atypical items. Our data suggest that, relative to young adults, older adults possess enriched conceptual knowledge, which supports retrieval of the category-related features needed for categorizing atypical and less familiar exemplars.

Effects of Phonomotor Therapy and Semantic Feature Analysis on Discourse Production

Background Anomia treatments typically focus on single word retrieval, although the ultimate goal of treatment is to improve functional communication at the level of discourse in daily situations. Aims The focus of this study was to investigate the impact of two effective anomia treatments on discourse production as measured by a story retell task. Method and Procedure Fifty-seven people with aphasia were randomized to receive either a phoneme-based treatment, Phonomotor Therapy (PMT; 28 participants), or a lexical-semantic treatment, Semantic Feature Analysis (SFA; 29 participants). Groups were matched for age, aphasia severity, education, and years post onset. All received 56-60 hr of treatment in a massed treatment schedule. Therapy was delivered for a total of 8-10 hr/week over the course of 6-7 weeks. All participants completed testing 1 week prior to treatment (A1), immediately following treatment (A2), and again 3 months later (A3). Discourse was analyzed through the percentage of correct information units at each time point. Outcomes and Results Both groups showed nonsignificant improvements from pretreatment to immediately posttreatment. The PMT group showed significant improvement 3 months posttreatment, while the SFA group returned to near-baseline levels. Conclusion These results add to our understanding of the effects of both PMT and SFA. Future research should address understanding variability in discourse outcomes across studies and the effects of aphasia severity and individual participant and treatment factors on treatment outcomes for both of these approaches.

Abstract Semantic Associative Network Training: A Replication and Update of an Abstract Word Retrieval Therapy Program

Purpose We report on a study that replicates previous treatment studies using Abstract Semantic Associative Network Training (AbSANT), which was developed to help persons with aphasia improve their ability to retrieve abstract words, as well as thematically related concrete words. We hypothesized that previous results would be replicated; that is, when abstract words are trained using this protocol, improvement would be observed for both abstract and concrete words in the same context-category, but when concrete words are trained, no improvement for abstract words would be observed. We then frame the results of this study with the results of previous studies that used AbSANT to provide better evidence for the utility of this therapeutic technique. We also discuss proposed mechanisms of AbSANT. Method Four persons with aphasia completed one phase of concrete word training and one phase of abstract word training using the AbSANT protocol. Effect sizes were calculated for each word type for each phase. Effect sizes for this study are compared with the effect sizes from previous studies. Results As predicted, training abstract words resulted in both direct training and generalization effects, whereas training concrete words resulted in only direct training effects. The reported results are consistent across studies. Furthermore, when the data are compared across studies, there is a distinct pattern of the added benefit of training abstract words using AbSANT. Conclusion Treatment for word retrieval in aphasia is most often aimed at concrete words, despite the usefulness and pervasiveness of abstract words in everyday conversation. We show the utility of AbSANT as a means of improving not only abstract word retrieval but also concrete word retrieval and hope this evidence will help foster its application in clinical practice.

Primed to cue

The behavioral effects of lexical priming are well studied in the cognitive sciences. Clinical use of the term and widespread implementation of priming based behavioral interventions has remained limited. This is despite the fact that response-contingent cueing, a behavioral intervention technique used during many cognitive-linguistic interventions, is grounded in theories of priming research. The aim of this manuscript is to connect behavioral performance changes observed following priming with those noted following cueing, providing a theoretical rationale for the therapeutic use of both priming and cueing in language and cognitive interventions. In this review, we establish a conceptual basis for how both primes and cues serve to pre-engage the neural system by triggering the retrieval of linked conceptual knowledge, resulting in faster and more accurate responses. Differences between the two (primes and cues) have been linked to timing and conscious intentional engagement, though these distinctions are often task dependent. Additionally, this paper will provide evidence of the clinical utility of priming. Studies of priming in adults with acquired brain injuries are discussed and clinical interventions based on theories of priming are examined. Furthermore, the present work will briefly detail the inhibitory effects of priming to aid clinicians and researchers in deciding how to pair primes and cues with intended retrieval targets. In summation, the present work is intended to bridge two related fields providing both theoretical and clinical insight with respect to the use of primes and cues.

Typicality-based semantic treatment for anomia results in multiple levels of generalisation

This study investigated the effects of typicality-based semantic feature analysis (SFA) treatment on generalisation across three levels: untrained related items, semantic/phonological processing tasks, and measures of global language function. Using a single-subject design with group-level analyses, 27 persons with aphasia (PWA) received typicality-based SFA to improve their naming of atypical and/or typical exemplars. Progress on trained, untrained, and monitored items was measured weekly. Pre- and post-treatment assessments were administered to evaluate semantic/phonological processing and overall language ability. Ten PWA served as controls. For the treatment participants, the likelihood of naming trained items accurately was significantly higher than for monitored items over time. When features of atypical items were trained, the likelihood of naming untrained typical items accurately was significantly higher than for untrained atypical items over time. Significant gains were observed on semantic/phonological processing tasks and standardised assessments after therapy. Different patterns of near and far transfer were seen across treatment response groups. Performance was also compared between responders and controls. Responders demonstrated significantly more improvement on a semantic processing task than controls, but no other significant change score differences were found between groups. In addition to positive treatment effects, typicality-based SFA naming therapy resulted in generalisation across multiple levels.

Treatment-related changes in neural activation vary according to treatment response and extent of spared tissue in patients with chronic aphasia

Neuroimaging studies of aphasia recovery have linked treatment-related improvements in language processing to changes in functional brain activation in left hemisphere language regions and their right hemisphere homologues. Although there is some consensus that better behavioral outcomes are achieved when activation is restored to the left hemisphere, the circumstances that dictate how and why regions in both hemispheres respond to naming therapy are still unclear. In this study, an fMRI picture-naming task was used to examine 16 regions of interest in 26 patients with chronic aphasia before and after 12 weeks of semantic naming treatment. Ten control patients who did not receive treatment and 17 healthy controls were also scanned. Naming therapy resulted in a significant increase in cortical activation, an effect that was largely driven by patients who responded most favorably to treatment, as patients who responded less favorably (as well as those who did not receive treatment) had little change in activation over time. Relative to healthy controls, patients had higher pre-treatment activation in the bilateral inferior frontal gyri (IFG) and lower activation in the bilateral angular gyri; after treatment, they had higher activation in bilateral IFG, as well as in the right middle frontal gyrus. These results suggest that the predominant effect of beneficial naming treatment was an upregulation of traditional language areas and their right hemisphere homologues and, in particular, regions associated with phonological and semantic/executive semantic processing, as well as broader domain general functions. Additionally, in some left hemisphere regions, post-treatment changes in activation were greater when there was more damage than when there was less damage, indicating that spared tissue in otherwise highly damaged regions can be modulated by treatment.

Benchmarks of Significant Change After Aphasia Rehabilitation

OBJECTIVE

To establish benchmarks of significant change for aphasia rehabilitation outcome measures (ie, Western Aphasia Battery-Aphasia Quotient [WAB-AQ], Communicative Effectiveness Index [CETI], Boston Naming Test [BNT]) and assess if those benchmarks significantly differ across subgroups (ie, time post onset, dose frequency, treatment type).

DATA SOURCES

A comprehensive literature search of 12 databases, reference lists of previous reviews, and evidence-based practice materials was conducted.

STUDY SELECTION

Randomized controlled trials, quasi-experimental studies, single-subject design, and case studies that used a standardized outcome measure to assess change were included. Titles and full-text articles were screened using a dual review process. Seventy-eight studies met criteria for inclusion.

DATA EXTRACTION

Data were extracted independently, and 25% of extractions were checked for reliability. All included studies were assigned quality indicator ratings and an evidence level.

DATA SYNTHESIS

Random-effects meta-analyses were conducted separately for each study design group (ie, within-/between-group comparisons). For within-group designs, the summary effect size after aphasia rehabilitation was 5.03 points (95% confidence interval, 3.95-6.10, P<.001) on the WAB-AQ, 10.37 points (6.08-14.66, P<.001) on the CETI, and 3.30 points (2.43-4.18, P<.001) on the BNT. For between-group designs, the summary effect size was 5.05 points (1.64-8.46, P=.004) on the WAB-AQ and 0.55 points (-1.33 to 2.43, P=.564) on the BNT, the latter of which was not significant. Subgroup analyses for the within-group designs showed no significant differences in the summary effect size as a function of dose frequency or treatment type.

CONCLUSIONS

This study established benchmarks of significant change on 3 standardized outcome measures used in aphasia rehabilitation.

Acquisition and Generalization Responses in Aphasia Naming Treatment: A Meta-Analysis of Semantic Feature Analysis Outcomes

Purpose This meta-analysis synthesizes results from published studies that used semantic feature analysis (SFA) treatment to improve naming for people with aphasia. It examines how both person- and treatment-related variables affected the likelihood of correct naming responses in individual probe sessions for both acquisition (treated) and generalization (untreated) stimuli. Method The meta-analysis compiled data from 12 studies analyzing a total of 35 participants with aphasia. It used mixed-effects models as a novel statistical tool to examine the effects of 2 sets of variables on naming performance: treatment-related variables, including treatment phase (baseline vs. treatment), dosage (number of treatment sessions), and stimulus type (treated vs. untreated, semantically related vs. unrelated items), and person-specific variables, including degree of language impairment and demographic variables (age, time poststroke). Results Results of the meta-analysis revealed that SFA intervention promoted increased naming accuracy during naming probes when comparing baseline and treatment phases. In addition, increased dosages of SFA were associated with increased naming accuracy, and treatment-related gains were larger for acquisition (treated) than generalization (untreated) stimuli, likewise for related versus unrelated generalization stimuli. Furthermore, a subset of person-specific variables was predictive of SFA-related gains: Language impairment variables were related to treatment-related changes in naming performance, but demographic variables were not. Conclusion These results provide group-level evidence for the efficacy of SFA as well as preliminary estimates of how much naming performance benefit is engendered by varying dosages of SFA. The results also provide promising and previously unobserved evidence of potential person-level predictors of SFA treatment response.

Influence of Linguistic and Nonlinguistic Variables on Generalization and Maintenance Following Phonomotor Treatment for Aphasia

PURPOSE

Although phonomotor treatment shows promise as an effective intervention for anomia in people with aphasia, responses to this treatment are not consistent across individuals. To better understand this variability, we examined the influence of 5 participant characteristics-age, time postonset, aphasia severity, naming impairment, and error profile-on generalization and maintenance of confrontation naming and discourse abilities following phonomotor treatment.

METHOD

Using retrospective data from 26 participants with aphasia who completed a 6-week phonomotor treatment program, we examined the relationships between participant characteristics of interest and change scores on confrontation naming and discourse tasks, measured pretreatment, immediately following treatment, and 3 months following treatment.

RESULTS

Although the participant characteristics of aphasia severity and error profile appeared to predict generalization to improved confrontation naming of untrained items and discourse performance, a post hoc analysis revealed that no one characteristic predicted generalization across participants at 3 months posttreatment.

CONCLUSIONS

Response to phonomotor treatment does not appear to be influenced by aphasia and anomia severity level, error profile, participant age, or time postonset. Other factors, however, may influence response to intensive aphasia treatment and are worthy of continued exploration.

Treatment integrity of elaborated semantic feature analysis aphasia therapy delivered in individual and group settings

BACKGROUND & AIMS

This study ran within the framework of the Thales Aphasia Project that investigated the efficacy of elaborated semantic feature analysis (ESFA). We evaluated the treatment integrity (TI) of ESFA, i.e., the degree to which therapists implemented treatment as intended by the treatment protocol, in two different formats: individual and group therapy.

METHODS & PROCEDURES

Based on the ESFA manual, observation of therapy videos and TI literature, we developed two ESFA integrity checklists, for individual and group therapy, and used them to rate 15 videos of therapy sessions, delivered by three speech-language therapists (SLTs). Thirteen people with aphasia (PwA) were involved in this study. Reliability of the checklists was checked using Kappa statistics. Each session's TI was calculated. Differences in TI scores between the two therapy approaches were calculated using independent sample t-tests. Treating SLTs' views on what facilitates TI were also explored through a survey.

OUTCOMES & RESULTS

Inter- and intra-rater reliability were excellent (.75 ≤ κ ≤ 1.00) for all but one video (κ = .63). Overall, a high TI level (91.4%) was achieved. Although both approaches' TI was high, TI for individual therapy sessions was significantly higher than for group sessions (94.6% and 86.7% respectively), t(13) = 2.68, p = .019. SLTs found training, use of the treatment manual, supervision and peer support useful in implementing ESFA therapy accurately.

CONCLUSIONS & IMPLICATIONS

ESFA therapy as delivered in Thales is well described and therapists can implement it as intended. The high TI scores found enhance the internal validity of the main research project and facilitate its replication. The need for more emphasis on the methodological quality of TI studies is discussed.

Multi-step treatment for acquired alexia and agraphia (Part I): efficacy, generalisation, and identification of beneficial treatment steps

Reading and writing impairments are common in individuals with post-stroke aphasia. Treatment typically aims to improve the function of one of these modalities by strengthening aspects of either lexical or sublexical processing. In the present study, eight adults with acquired alexia and agraphia were administered a comprehensive treatment targeting specific lexical and sublexical processes underlying reading and/or writing. Two participants were trained in reading and six were trained in writing. Throughout treatment, reading and writing accuracy were monitored for trained items, as well as untrained but orthographically and semantically related items. Linear mixed effects models indicated that the most substantial gains were made on trained items in the trained modality; generalisation to trained items in the untrained modality and untrained but related items in both modalities was also observed. Participants improved significantly on a subset of treatment steps intended to address lexical access and representations, sublexical conversion mechanisms, and the graphemic and/or phonological buffer processes in both modalities. These results demonstrate the efficacy of a novel, comprehensive treatment protocol and suggest that targeting multiple reading and writing processes in conjunction may facilitate widespread generalisation.

Understanding semantic and phonological processing deficits in adults with aphasia: Effects of category and typicality

BACKGROUND

Semantic and phonological processing deficits are often present in aphasia. The degree of interdependence between the deficits has been widely studied with variable findings. Semantic variables such as category and typicality have been found to influence semantic processing in healthy individuals and persons with aphasia but their influence on phonological processing is unknown.

AIMS

This study examined the nature of semantic and phonological access in aphasia by comparing adults with aphasia to healthy control participants. Semantic and phonological tasks were used to assess the difference in processing requirements between and within each group as well as examine the effects of category and typicality on different stages of semantic and phonological processing.

METHODS & PROCEDURES

Thirty-two persons with aphasia and ten neurologically healthy adults were administered nine tasks: Category Superordinate, Category Coordinate, Semantic Feature, Rhyme Judgment (No-Name), Syllable Judgment (No-Name), Phoneme Verification (No-Name), Rhyme Judgment (Name-Provided), Syllable Judgment (Name-Provided), and Phoneme Verification (Name-Provided). Accuracy and reaction time data were collected for each of these tasks and between-group and within-group differences were analyzed via MANOVA/MANCOVA and hierarchical clustering analyses.

OUTCOMES & RESULTS

Persons with aphasia performed with significantly lower accuracy than controls on phonological tasks but performed comparably on semantic tasks. Participants with aphasia were significantly slower than controls on all semantic and phonological tasks. Clustering of the nine tasks by accuracy revealed different processing requirements in the participants with aphasia compared to the control group while clustering by reaction time revealed similar trends in both groups in that phonological (no-name) items required the most processing time. Significant effects of category and typicality were noted in the semantic tasks but not in any of the phonological tasks.

CONCLUSIONS

Individuals with aphasia demonstrated overall impaired phonological processing with relatively preserved semantic processing as compared to controls. Per accuracy and reaction time measures, distinct trends in processing load for semantic tasks versus phonological tasks were seen in the individuals with aphasia whereas only speed of processing and not accuracy was impacted by phonological processing load in the control group. The results align most closely with discrete serial processing models of lexical processing as category and typicality effects were robust in the semantic tasks but not in any of the phonological tasks. Alternative explanations for these results also are discussed.

Changes in task-based effective connectivity in language networks following rehabilitation in post-stroke patients with aphasia

In this study, we examined regions in the left and right hemisphere language network that were altered in terms of the underlying neural activation and effective connectivity subsequent to language rehabilitation. Eight persons with chronic post-stroke aphasia and eight normal controls participated in the current study. Patients received a 10 week semantic feature-based rehabilitation program to improve their skills. Therapy was provided on atypical examples of one trained category while two control categories were monitored; the categories were counterbalanced across patients. In each fMRI session, two experimental tasks were conducted: (a) picture naming and (b) semantic feature verification of trained and untrained categories. Analysis of treatment effect sizes revealed that all patients showed greater improvements on the trained category relative to untrained categories. Results from this study show remarkable patterns of consistency despite the inherent variability in lesion size and activation patterns across patients. Across patients, activation that emerged as a function of rehabilitation on the trained category included bilateral IFG, bilateral SFG, LMFG, and LPCG for picture naming; and bilateral IFG, bilateral MFG, LSFG, and bilateral MTG for semantic feature verification. Analysis of effective connectivity using Dynamic Causal Modeling (DCM) indicated that LIFG was the consistently significantly modulated region after rehabilitation across participants. These results indicate that language networks in patients with aphasia resemble normal language control networks and that this similarity is accentuated by rehabilitation.

Psycholinguistics of Aphasia Pharmacotherapy: Asking the Right Questions

BACKGROUND

Among the obstacles to demonstrating efficacy of pharmacological intervention for aphasia is quantifying patients' responses to treatment in a statistically valid and reliable manner. In many of the review papers on this topic (e.g., Berthier et al., 2011; de Boissezon, Peran, de Boysson, & Démonet, 2007; Small & Llano, 2009), detailed discussions of various methodological problems are highlighted, with some suggestions on how these shortcomings should be addressed. Given this deep understanding of caveats associated with the experimental design of aphasia pharmacotherapy studies (e.g., Berthier et al., 2011), investigations continue to produce inconsistent results.

AIM

In this review paper we suggest that inclusion of theory-driven linguistic measures in aphasia pharmacotherapy studies would add an important step toward elucidating precise patterns of improvement in language performance resulting from pharmacotherapeutic intervention.

MAIN CONTRIBUTION

We provide a brief review of the clinical approaches currently used in pharmacotherapy studies of aphasia, which often lack psycholinguistic grounding. We then present ways in which psycholinguistic models can complement this approach, offering a rationale for task selection, and as a result, lead to a better understanding of treatment effects. We then follow with an example of how such an integrative approach can be implemented in studies targeting stress reduction in people with aphasia, via beta-blocking agents, as a means to augment language performance, using the psycholinguistic framework of "linguistic anxiety" outlined in Cahana-Amitay et al, 2011 as our guideline.

CONCLUSION

We conclude that the incorporation of psycholinguistic models into aphasia pharmacotherapy studies can increase the resolution with which we can identify functional changes.

"Penguins don't fly": An investigation into the effect of typicality on picture naming in people with aphasia

BACKGROUND

PREVIOUS RESEARCH HAS HIGHLIGHTED PSYCHOLINGUISTIC VARIABLES INFLUENCING NAMING ABILITY FOR INDIVIDUALS WITH APHASIA, INCLUDING: familiarity, frequency, age of acquisition, imageability, operativity, and length (Nickels & Howard, 1995) and a potential link between typicality and generalisation to untreated items in intervention (Kiran, Sandberg, & Sebastian, 2011). However, the effect of concept typicality (the extent to which an item can be considered a prototype of a category) on naming in aphasia warrants further examination.

AIMS

To investigate first whether typicality can be reliably rated across a range of natural semantic categories and second whether, and if so in which direction, typicality influences naming performance for people with aphasia. To provide quantitative and qualitative information on typicality for a set of stimuli for use in future research.

METHODS & PROCEDURES

Typicality ratings were obtained and the results compared with those in the existing literature. The influence of typicality on picture naming was investigated employing both matched sets (high and low typicality matched for other psycholinguistic variables) and logistic regression analyses for the group and individual participants with aphasia (n = 20).

OUTCOMES & RESULTS

Typicality rating correlated strongly with ratings obtained in previous research (Rosch, 1975: r = .798, N = 35, p < .001; Uyeda & Mandler, 1980: r = .844, N = 47, p < .001). Typicality was a significant predictor of picture naming for the group and some individuals, with generally better performance for typical items. This was demonstrated in both matched sets and regression analyses. However, other psycholinguistic variables proved more strongly related to naming success, particularly age of acquisition.

CONCLUSIONS

Typicality can be rated reliably and should be considered alongside other psycholinguistic variables when investigating word retrieval and intervention in aphasia. Further research is necessary to accurately model the direction of typicality effects found in word retrieval. Finally, the differing nature, size, and internal structure of categories require further exploration when investigating typicality effects.

Rehabilitation in bilingual aphasia: evidence for within- and between-language generalization

PURPOSE

The goal of this study was to examine if there was a principled way to understand the nature of rehabilitation in bilingual aphasia such that patterns of acquisition and generalization are predictable and logical.

METHOD

Seventeen Spanish-English bilingual individuals with aphasia participated in the experiment. For each participant, three sets of stimuli were developed for each language: (a) English Set 1, (b) English Set 2 (semantically related to each item in English Set 1), (c) English Set 3 (unrelated control items), (d) Spanish Set 1 (translations of English Set 1), (e) Spanish Set 2 (translations of English Set 2; semantically related to each item in Spanish Set 1), and (f) Spanish Set 3 (translations of English Set 3; unrelated control items). A single-subject experimental multiple baseline design across participants was implemented. Treatment was conducted in 1 language, but generalization to within- and between-language untrained items was examined.

RESULTS

Treatment for naming on Set 1 items resulted in significant improvement (i.e., effect size >4.0) on the trained items in 14/17 participants. Of the 14 participants who showed improvement, within-language generalization to semantically related items was observed in 10 participants. Between-language generalization to the translations of trained items was observed in 5 participants, and between-language generalization to the translations of the untrained semantically related items was observed in 6 participants.

CONCLUSION

The results of this study demonstrated within- and between-language patterns that were variable across participants. These differences are indicative of the interplay between facilitation (generalization) and inhibition.

Semantic feature analysis: incorporating typicality treatment and mediating strategy training to promote generalization

PURPOSE

This investigation was designed to examine the generalization effects of semantic treatment for word retrieval deficits in people with aphasia. Semantic feature analysis (SFA; Boyle & Coelho, 1995), typicality treatment (Kiran & Thompson, 2003), and mediating strategy training were combined to maximize potential generalization effects.

METHOD

Treatment, which included SFA and a semantic feature judgment task, was conducted with 9 participants with chronic aphasia in the context of multiple baseline designs across behaviors. Typical and atypical exemplars were trained across animate and inanimate categories. Treatment was sequentially modified to overtly train the use of SFA as a mediating strategy.

RESULTS

Eight of the 9 participants demonstrated improvements in naming of trained stimuli. Positive generalization effects were limited overall; possible response generalization was evident for 5 participants. Instruction in the use of a mediating strategy resulted in improved naming of treated words for all participants; however, generalization to untreated words did not occur.

CONCLUSION

Treatment using SFA resulted in improved naming of treated typical and atypical exemplars in both animate and inanimate categories for 8 of 9 participants. Training in a mediating strategy also resulted in improved retrieval of experimental words. Regardless of intervention approach, generalization to untreated items was limited.

A Computational Account of Bilingual Aphasia Rehabilitation

Current research on bilingual aphasia highlights the paucity in recommendations for optimal rehabilitation for bilingual aphasic patients (Roberts & Kiran, 2007; Edmonds & Kiran, 2006). In this paper, we have developed a computational model to simulate an English-Spanish bilingual language system in which language representations can vary by age of acquisition (AoA) and relative proficiency in the two languages to model individual participants. This model is subsequently lesioned by varying connection strengths between the semantic and phonological networks and retrained based on individual patient demographic information to evaluate whether or not the model's prediction of rehabilitation matched the actual treatment outcome. In most cases the model comes close to the target performance subsequent to language therapy in the language trained, indicating the validity of this model in simulating rehabilitation of naming impairment in bilingual aphasia. Additionally, the amount of cross-language transfer is limited both in the patient performance and in the model's predictions and is dependent on that specific patient's AoA, language exposure and language impairment. It also suggests how well alternative treatment scenarios would have fared, including some cases where the alternative would have done better. Overall, the study suggests how computational modeling could be used in the future to design customized treatment recipes that result in better recovery than is currently possible.

Effects of language proficiency and language of the environment on aphasia therapy in a multilingual

We examined the relative proficiency of four languages (Spanish, German, French, English) of a multilingual speaker with aphasia, JM. JM's self-rated proficiency was consistent with his naming accuracy for nouns and verbs (The Object and Action Naming Battery, Druks & Masterson, 2000) and with his performance on selected subtests of the Bilingual Aphasia Test (Paradis & Libben, 1987). Within and between-language changes were measured following two periods of language treatment, one in a highly-proficient language (Spanish) and one in a less-proficient language (English). The various outcome measures differed in their sensitivity to treatment-associated changes. Cross-language treatment effects were linked to the language of the environment at the time of testing and to relative language proficiency.

Typicality mediates performance during category verification in both ad-hoc and well-defined categories

BACKGROUND

The typicality effect is present in neurologically intact populations for natural, ad-hoc, and well-defined categories. Although sparse, there is evidence of typicality effects in persons with chronic stroke aphasia for natural and ad-hoc categories. However, it is unknown exactly what influences the typicality effect in this population.

AIMS

The present study explores the possible contributors to the typicality effect in persons with aphasia by analyzing and comparing data from both normal and language-disordered populations, from persons with aphasia with more semantic impairment versus those with less semantic impairment, and from two types of categories with very different boundary structure (ad-hoc vs. well-defined).

METHODS AND PROCEDURES

A total of 40 neurologically healthy adults (20 older, 20 younger) and 35 persons with aphasia (20 LSI (less-semantically impaired) patients, 15 MSI (more-semantically impaired) patients) participated in the study. Participants completed one of two tasks: either category verification for ad-hoc categories or category verification for well-defined categories.

OUTCOMES AND RESULTS

Neurologically healthy participants showed typicality effects for both ad-hoc and well-defined categories. MSI patients showed a typicality effect for well-defined categories, but not for ad-hoc categories, whereas LSI patients showed a typicality effect for ad-hoc categories, but not for well-defined categories.

CONCLUSIONS

These results suggest that the degree of semantic impairment mediates the typicality effect in persons with aphasia depending on the structure of the category.

LEARNING OUTCOMES

After reading this article, the reader should be able to: (1) Describe the typicality effect and in which populations it occurs. (2) Explain how the typicality effect might change depending on category structure. (3) summarize how semantic impairment influences category representation and/or access.

Extending the use of Spanish Computer-assisted Anomia Rehabilitation Program (CARP-2) in people with aphasia

PURPOSE

To extend the use of the Spanish Computer-assisted Anomia Rehabilitation Program (CARP-2) for anomia from a single case to a group of 15 people with aphasia. To evaluate whether the treatment is active (Phase 1) for this group (Robey & Schultz, 1998), providing potential explanations as to why.

METHODS

Fifteen participants with chronic aphasia (with a range from moderate to mild anomia) were recruited to 15 weeks of computer-assisted therapy for anomia. A single treatment period with pre- and post-treatment assessments evaluated participants' ability to name 200 words using the multiple cues provided by the computer. Pre- and post-naming measures of all items examined the effect of treatment. Background linguistic and cognitive skills were measured before and after the therapy to investigate whether the improvements in naming were therapy specific.

RESULTS

All 15 participants showed significant benefits in their naming skills after the therapy. There were no changes to cognitive and linguistic skills unrelated to anomia. There was evidence of some carry-over effects in naming.

CONCLUSION

The Spanish Computer-assisted Anomia Rehabilitation Program (CARP-2) for anomia is an active treatment for a range of people who have anomia as part of their aphasia profile.

LEARNING OUTCOMES

By the end of the paper you will be able to answer the CEU questions and consider whether to use computer assisted therapy on a wide range of clients with anomia difficulties.

Treatment of category generation and retrieval in aphasia: effect of typicality of category items

PURPOSE

Kiran and colleagues (Kiran, 2007, 2008; Kiran & Johnson, 2008; Kiran & Thompson, 2003) previously suggested that training atypical examples within a semantic category is a more efficient treatment approach to facilitating generalization within the category than training typical examples. In the present study, the authors extended previous work examining the notion of semantic complexity within goal-derived (ad hoc) categories in individuals with aphasia. Methods Six individuals with fluent aphasia (age range = 39-84 years) and varying degrees of naming deficits and semantic impairments were involved. Thirty typical and atypical items, each from 2 categories, were selected after an extensive stimulus norming task. Generative naming for the 2 categories was tested during baseline and treatment.

RESULTS

As predicted, training atypical examples in the category resulted in generalization to untrained typical examples in 5 of 5 patient-treatment conditions. In contrast, training typical examples (which was examined in 3 conditions) produced mixed results. One patient showed generalization to untrained atypical examples, whereas 2 patients did not show generalization to untrained atypical examples.

CONCLUSION

Results of the present study supplement existing data on the effect of a semantically based treatment for lexical retrieval by manipulating the typicality of category examples.

Triangulating speech sound generalization

Generalization refers to the extension of learned behaviours to novel conditions, and it is one of the criteria by which the effectiveness and efficiency of a remediation programme may be judged. This article extracts principles of generalization from the treatment literature, and provides examples of how this information may be used to help guide treatment decisions. Included is a discussion of client, clinician, and treatment variables that may contribute to the generalization process.

Treatment for lexical retrieval using abstract and concrete words in persons with aphasia: Effect of complexity

BACKGROUND: The significance of imageability and concreteness as factors for lexical tasks in aphasic individuals is under debate. No previous treatment studies have looked specifically at training abstract words compared to concrete for improved lexical retrieval in patients with chronic aphasia. AIM: The goal of the present study was to determine the efficacy of a treatment for lexical retrieval that is based on models of lexical processing by utilizing abstractness as a mode of complexity. It was hypothesized that training abstract words in a category will result in improvement of those words and generalization to untrained target concrete words in the same category. Training concrete words in a category, however, will result in the retrieval of trained concrete words, but not generalization to target abstract words. METHODS #ENTITYSTARTX00026; PROCEDURES: A single subject experimental design across participants and behaviors was used to examine treatment and generalization. Generative naming for three categories (church, hospital, courthouse) was tested during baseline and treatment. Each treatment session was carried out in five steps: (1) category sorting, (2) feature selection, (3) yes/no feature questions, (4) word recall, and (5) free generative naming. RESULTS: Although participant 1 demonstrated neither significant learning nor generalization during abstract or concrete word training, participants 2, 3, and 4 showed significant learning during abstract word training and generalization to untrained concrete words. Participants 3 and 4 were also trained on concrete words which they improved on but did not show generalization to untrained abstract words. CONCLUSIONS: The results of the present experiment support our hypothesis that training abstract words would result in greater learning and generalization to untrained concrete words. They also tentatively support the idea that generalization is facilitated by treatment focusing on more complex constructions (Kiran & Thompson, 2003; Thompson, Shapiro, Kiran, & Sobecks, 2003).