Search

Purpose: The current study delineated a clinical and theoretical framework that clinicians and researchers can use to guide the assessment of bilingual aphasia at morphosyntactic, lexical-semantic, and phonological levels of language processing., Method: This tutorial outlines cross-linguistic and multicultural considerations that should be addressed in evaluating bilingual adults with aphasia (BWAs)., Results: At the morphosyntactic level, we presented three features that should be taken into account when evaluating linguistic symptoms in languages considering whether they are typologically similar or dissimilar: word order, pro(noun)-drop, and morphological inflections of verbs. We suggest that clinicians need to conduct additional error analyses that reflect typological differences in syntactic templates, argument-deletion phenomena, and morphological inflections to better understand linguistic characteristics of impairments arising from the interactions of the two languages that may differ in many ways. At the lexical-semantic level, we addressed three cross-linguistic features that may impact naming performance in BWAs: cognates, lexical frequency, and semantic typicality. The presence of cognates between the two languages can lead to differential interpretations of naming performance. In addition, the same lexical items may exhibit varying lexical frequency and typicality across languages due to cultural and linguistic differences. We suggest that clinicians should thoroughly prepare the testing items considering the linguistic distance. Finally, we emphasized differences in segmental and suprasegmental features of phonology that could contribute to cross-linguistic phenomena during assessment of two or more languages., Conclusions: This cross-linguistic assessment framework contributes to a better understanding of linguistic impairments and communication difficulties experienced by BWAs. This framework can be utilized in current clinical practice to facilitate culturally and linguistically appropriate assessment and treatment approaches for BWAs.

The Semantic Association Test assesses several aspects of Semantic Memory (Categorical, Encyclopedic, Functional, and Visual Encyclopedic associations: CAs, EAs, FAs and VEAs), using a picture-to-picture matching paradigm. Normative data were collected from a group of 329 healthy participants (178 females) with mean 51.1 (range 20-90) years of age and mean 11.89 (range 5-19) years of education. Raw scores of healthy participants, pre-calculated correction factors for age and educational level, and Equivalent Scores are provided. The SAT was validated in a sample of 139 left brain-damaged persons with aphasia (PWA). Both groups (healthy participants and PWA) scored worse in the CA and EA conditions. The performance of the PWA group was overall defective, and global aphasics scored worse than persons with other types of aphasia. However, several PWA did not show impairments in the SAT. Dissociations were also found, with individual PWA showing defective performance confined to a single category. These results present the SAT as a tool that is useful to detect impairments of visual Semantic Memory, providing normative data from healthy participants and a validation study in PWA., (© 2022. Fondazione Società Italiana di Neurologia.)

Purpose Semantic feature analysis (SFA) is a naming treatment found to improve naming performance for both treated and semantically related untreated words in aphasia. A crucial treatment component is the requirement that patients generate semantic features of treated items. This article examined the role feature generation plays in treatment response to SFA in several ways: It attempted to replicate preliminary findings from Gravier et al. (2018), which found feature generation predicted treatment-related gains for both trained and untrained words. It examined whether feature diversity or the number of features generated in specific categories differentially affected SFA treatment outcomes. Method SFA was administered to 44 participants with chronic aphasia daily for 4 weeks. Treatment was administered to multiple lists sequentially in a multiple-baseline design. Participant-generated features were captured during treatment and coded in terms of feature category, total average number of features generated per trial, and total number of unique features generated per item. Item-level naming accuracy was analyzed using logistic mixed-effects regression models. Results Producing more participant-generated features was found to improve treatment response for trained but not untrained items in SFA, in contrast to Gravier et al. (2018). There was no effect of participant-generated feature diversity or any differential effect of feature category on SFA treatment outcomes. Conclusions Patient-generated features remain a key predictor of direct training effects and overall treatment response in SFA. Aphasia severity was also a significant predictor of treatment outcomes. Future work should focus on identifying potential nonresponders to therapy and explore treatment modifications to improve treatment outcomes for these individuals. Supplemental Material https://doi.org/10.23641/asha.12462596.

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.

Investigating instances where lexical selection fails can lead to deeper insights into the cognitive machinery and architecture supporting successful word retrieval and speech production. In this paper, we used a multiplex lexical network approach that combines semantic and phonological similarities among words to model the structure of the mental lexicon. Network measures at different levels of analysis (degree, network distance, and closeness centrality) were used to investigate the influence of network structure on picture naming accuracy and errors by people with Anomic, Broca's, Conduction, and Wernicke's aphasia. Our results reveal that word retrieval is influenced by the multiplex lexical network structure in at least two ways-(a) the accuracy of production and error type on incorrect productions were influenced by the degree and closeness centrality of the target word, and (b) error type also varied in terms of network distance between the target word and produced error word. Taken together, the analyses demonstrate that network science techniques, particularly the use of the multiplex lexical network to simultaneously represent semantic and phonological relationships among words, reveal how the structure of the mental lexicon influences language processes beyond traditionally examined psycholinguistic variables. We propose a framework for how the multiplex lexical network approach allows for understanding the influence of mental lexicon structure on word retrieval processes, with an eye toward a better understanding of the nature of clinical impairments, like aphasia., (© 2020 Cognitive Science Society, Inc.)

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.

Naming treatment outcomes in post-stroke aphasia are variable and the factors underlying this variability are incompletely understood. In this study, 26 patients with chronic aphasia completed a semantic judgment fMRI task before receiving up to 12 weeks of naming treatment. Global (i.e., network-wide) and local (i.e., regional) graph theoretic measures of pre-treatment functional connectivity were analyzed to identify differences between patients who responded most and least favorably to treatment (i.e., responders and nonresponders) and determine if network measures predicted naming improvements. Responders had higher levels of global integration (i.e., average network strength and global efficiency) than nonresponders, and these measures predicted treatment effects after controlling for lesion volume and age. Group differences in local measures were identified in several regions associated with a variety of cognitive functions. These results suggest there is a meaningful and possibly prognostically-informative relationship between patients' functional network properties and their response to naming therapy., (Published by Elsevier Inc.)

Tests and batteries used in the evaluation of language impairments are overly complex and often ineffective (too difficult) in the assessment of post-stroke patients affected by severe aphasia (global aphasia). The present study reports details on the construction and standardization of a new Italian battery of tasks, specifically designed to assess severe lexical disorders in acquired aphasia (Battery for the Assessment of Severe Acquired Lexical Damage in Italian, BASALDI). The battery is composed of a common set of 64 stimuli (concrete nouns), belonging to both living and non-living categories, and consists of four lexical tasks assessing picture naming, repetition, reading aloud, and oral comprehension. The item selection was based on word frequency, word length, and phonological-articulatory complexity, namely the presence of continuant vs. plosive phones, a variable that may interact with word production in case of severe language damage. Standardization (naming agreement) of a new set of 64 colored images and normative data on Italian healthy subjects pooled across homogenous subgroups for age, gender, and education are reported. Finally, for the four tasks, percentile ranks and z-scores were calculated from a pool of 92 left brain-damaged patients affected by aphasia of different types and severity. The battery allows a fine investigation of lexical disorders, being suitable for diagnostic assessment of mild-to-moderate and severe aphasic lexical deficits, detection of changes over time, and possible dissociations between tasks.

People possess significant knowledge about how real-world events typically unfold. Such event-related semantic memory connects action and object knowledge, is essential for multiple stages of language processing, and may be impaired in neurological conditions like aphasia. However, current assessments are not well designed for measuring this knowledge. This study presents and tests a novel measure of event-related semantic memory. Task-performance data were collected from unimpaired adults across the lifespan and a sample of stroke survivors with aphasia. Individuals with aphasia also completed measures of language processing and action-/object-related semantic memory, to establish the novel measure's convergent validity. Results demonstrate that performance on the event-knowledge measure correlated with action and object semantic-memory measures and was also associated with a broader range of language-processing performance than other semantic-memory measures. These findings suggest that the novel measure can be used to detect the presence and impact of event-knowledge impairments in neurological conditions.

Background: Severe auditory comprehension impairments secondary to aphasia can adversely influence rehabilitative outcomes and quality of life. Studies examining intensive rehabilitative treatments for severe single-word auditory comprehension impairments are needed., Objectives: Our purpose was to examine the feasibility and influence of a high-intensity word-picture verification treatment on high-frequency, word response accuracy. Research questions: (a) Can people with severe aphasia tolerate an intensive comprehension treatment? (b) Does an intensive intervention increase auditory comprehension response accuracy of spoken high-frequency words?, Method: This single-case ABA design study included 2 participants with chronic, severe auditory comprehension deficits secondary to stroke. A high-frequency, word-picture verification treatment was administered 2 hr/day, 5 days/week for 4 weeks and required participants to match the spoken word of the examiner to a picture representing an object., Results: Preliminary results suggest that some people with severe chronic aphasia can tolerate an intensive auditory comprehension treatment and demonstrate improvements in high-frequency, word-level response accuracy with large effect sizes suggesting generalization to untrained stimuli., Conclusions: An intensive auditory comprehension treatment protocol can contribute to improvements in response accuracy for some people with severe aphasia. Larger sample size studies are needed to further examine the influence of intensity on improvements in auditory comprehension.

This study tested the hypothesis that a use-dependent learning mechanism operates at each of two stages of lexical access: retrieval of a word from semantics ("Stage 1"), followed by retrieval of the word's constituent phonemes ("Stage 2"). Two participants with aphasia were selected due to their contrasting types of naming impairment (Stage 1 versus Stage 2 difficulty). For each participant, items were assigned to naming training that involved retrieval practice (retrieval of the name from semantics) or repetition practice (hear the name and orally repeat it). Naming tests were administered one day and one week after training. The results supported the predicted training effects: (a) Because successful naming via retrieval practice requires both Stage 1 and Stage 2, this technique uses and strengthens item-specific connections in both stages. (b) Because word repetition circumvents semantically driven retrieval, this technique primarily uses and strengthens item-specific connections in Stage 2.

Purpose: The goal of this research was to institute an evidence base behind commonly used elicitation materials known as binomials (e.g., "day and night") that are commonly used for persons with aphasia (PWAs). The study explored a number of linguistic variables that could influence successful binomial completion in nonaphasic adults and PWAs., Method: Thirty nonaphasic adults and 11 PWAs were asked to verbally complete 128 binomials; responses were scored by accuracy and reaction time. Binomials were coded according to the following independent variables: frequency of usage, phonological (e.g., alliteration, rhyme) and semantic (i.e., antonymy) relationships, grammatical category of the response, and number of plausible binomial completions., Results: Regression analyses demonstrated that, for both groups, greater accuracy was predicted by presence of antonymy and absence of a phonological relationship. Though reaction time models differed between groups, items that elicited a greater number of response options led to longer latencies across participants., Conclusion: Findings suggest that clinicians consider antonymy as well as the number of plausible responses for a given prompt when adapting the level of difficulty for their clients. Results also contribute to broader interdisciplinary research on how automatic language is processed in adults with and without neurogenic communication disorder., Supplemental Material: https://doi.org/10.23641/asha.6030806.

Purpose: This study investigated the predictive value of practice-related variables-number of treatment trials delivered, total treatment time, average number of trials per hour, and average number of participant-generated features per trial-in response to semantic feature analysis (SFA) treatment., Method: SFA was administered to 17 participants with chronic aphasia daily for 4 weeks. Individualized treatment and semantically related probe lists were generated from items that participants were unable to name consistently during baseline testing. Treatment was administered to each list sequentially in a multiple-baseline design. Naming accuracy for treated and untreated items was obtained at study entry, exit, and 1-month follow-up., Results: Item-level naming accuracy was analyzed using logistic mixed-effect regression models. The average number of features generated per trial positively predicted naming accuracy for both treated and untreated items, at exit and follow-up. In contrast, total treatment time and average trials per hour did not significantly predict treatment response. The predictive effect of number of treatment trials on naming accuracy trended toward significance at exit, although this relationship held for treated items only., Conclusions: These results suggest that the number of patient-generated features may be more strongly associated with SFA-related naming outcomes, particularly generalization and maintenance, than other practice-related variables., Supplemental Materials: https://doi.org/10.23641/asha.5734113.

Background: Discourse is fundamental to everyday communication, and is an increasing focus of clinical assessment, intervention and research. Aphasia can affect the information a speaker communicates in discourse. Little is known about the psychometrics of the tools for measuring information in discourse, which means it is unclear whether these measures are of sufficient quality to be used as clinical outcome measures or diagnostic tools., Aims: To profile the measures used to describe information in aphasic discourse, and to assess the quality of these measures against standard psychometric criteria., Methods & Procedures: A scoping review method was employed. Studies were identified using a systematic search of Scopus, Medline and Embase databases. Standard psychometric criteria were used to evaluate the measures' psychometric properties., Main Contribution: The current review summarizes and collates the information measures used to describe aphasic discourse, and evaluates their quality in terms of the psychometric properties of acceptability, reliability and validity. Seventy-six studies described 58 discourse information measures, with a mean of 2.28 measures used per study (SD = 1.29, range = 1-7). Measures were classified as 'functional' measures (n = 33), which focused on discourse macrostructure, and 'functional and structural' measures (n = 25), which focused on micro-linguistic and macro-structural approaches to discourse. There were no reports of the acceptability of data generated by the measures (distribution of scores, missing data). Test-retest reliability was reported for just 8/58 measures with 3/8 > 0.80. Intra-rater reliability was reported for 9/58 measures and in all cases percentage agreement was reported rather than reliability. Per cent agreement was also frequently reported for inter-rater reliability, with only 4/76 studies reporting reliability statistics for 12/58 measures; this was generally high (>.80 for 11/12 measures). The majority of measures related clearly to the discourse production model indicating content validity. A total of 36/58 measures were used to make 41 comparisons between participants with aphasia (PWA) and neurologically healthy participants (NHP), with 31/41 comparisons showing a difference between the groups. Four comparisons were made between discourse genres, with two measures showing a difference between genres, and two measures showing no difference., Conclusions: There is currently insufficient information available to justify the use of discourse information measures as sole diagnostic or outcome measurement tools. Yet the majority of measures are rooted in relevant theory, and there is emerging evidence regarding their psychometric properties. There is significant scope for further psychometric strengthening of discourse information measurement tools., (© 2017 Royal College of Speech and Language Therapists.)

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., (© 2017 Royal College of Speech and Language Therapists.)

The cognitive domains of language and memory are intrinsically connected and work together during language processing. This relationship is especially apparent in the area of semantics. Several disciplines have contributed to a rich store of data about semantic organization and processing, and several semantic treatments for aphasic word and sentence production impairments have been based on these data. This article reviews the relationships between semantics and memory as they relate to word and sentence production, describes the aphasic language impairments that result from deficits in these areas, and summarizes treatment approaches that capitalize on what we have learned about these domains and how they work together., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

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., (© 2016 Royal College of Speech and Language Therapists.)

Purpose: We investigated from a theoretically motivated perspective what information differentiated sufficient from insufficient descriptions of objects provided by persons with aphasia., Method: Twenty-one adults with aphasia consequent to single left-hemisphere stroke verbally described 9 living and 9 nonliving objects. Responses were scored for accuracy (i.e., sufficiency) and tallied for type and quantity of semantic feature information provided. Main effects and interactions were identified using repeated measures analyses of variance, with significant findings followed up with planned comparisons., Results: Differences between correct and incorrect descriptions were identified with respect to both feature type and feature distinctiveness for living and nonliving items, in particular highlighting the importance of distinctive features in descriptions of both domains., Conclusions: These findings add to the relatively small body of literature investigating semantic feature processing in adults with aphasia. This is a critical gap to close when considered in light of the preponderance of semantically based treatments for word-retrieval impairment in stroke-aphasia. Our findings provide preliminary support for the notion that semantically guided treatments for word-retrieval impairment in stroke-aphasia may be geared toward increasing specificity of semantic circumlocution to increase semantic self-cueing and to improve communication of information to conversation partners.

Purpose: The purpose of this investigation was to systematically examine outcomes associated with Semantic feature analysis, which is an established treatment for word-retrieval deficits in aphasia. Attributes of the experimental design and stimuli were manipulated to evaluate generalized naming of semantically related and unrelated items. In addition, the study was designed to examine changes in production of semantic information., Method: Semantic feature analysis was applied in the context of multiple-baseline designs with 5 persons with chronic aphasia. Experimental items were controlled for semantic category membership, number of naming attempts, and provision of item names. Acquisition, generalization, and maintenance effects were measured in probes of naming performance. Production of semantic information was also measured in response to experimental items and in discourse tasks., Results: Treatment was associated with systematic increases in naming of trained items for 4 of the 5 participants. Positive generalization to untrained exemplars of trained categories was found for repeatedly exposed items but not for limited-exposure items. Slight increases in production of semantic content were observed., Conclusion: Repeated attempts to name untreated items appeared to play a role in generalization. Provision of the names of untrained items may have enhanced generalized responding for 2 participants.

Purpose: We sought to identify the core lexicon of a picture-description task using transcripts from the AphasiaBank database and to determine differences in core-lexicon usage between control speakers and persons with aphasia (PWAs). We also investigated the relationship between core lexicon and an established discourse measure, main-concept analysis., Method: A core lexicon was developed by identifying lemmas produced by 92 control speakers. Transcripts were scored-165 control transcripts and 238 PWA transcripts-using the core lexicon and a recently developed main-concept list. Median tests examined differences between controls, PWAs, and aphasia subtypes. Spearman's correlations assessed the relationship between core-lexicon and main-concept performance., Results: A 24-item core lexicon was identified. Significant differences were found between control speakers and PWAs, and between aphasia subtypes, for core-lexicon and main-concept scores. Core-lexicon and main-concept performance was significantly and positively correlated for all groups., Conclusions: We report the development of a core lexicon, differences in core-lexicon usage between speakers, and the relationship between core-lexicon and main-concept scores. Research is needed to determine the clinical utility and psychometric properties of these discourse measures and their potential contribution to multilevel discourse analysis of functional communication.

Purpose: There is a lot of evidence that people with aphasia have more difficulty understanding structurally complex sentences (e.g., object clefts) than simpler sentences (subject clefts). However, subject clefts also occur more frequently in English than object clefts. Thus, it is possible that both structural complexity and frequency affect how people with aphasia understand these structures., Method: Nine people with aphasia and 8 age-matched controls participated in the study. The stimuli consisted of 24 object cleft and 24 subject cleft sentences. The task was eye tracking during reading, which permits a more fine-grained analysis of reading performance than measures such as self-paced reading., Results: As expected, controls had longer reading times for critical regions in object cleft sentences compared with subject cleft sentences. People with aphasia showed the predicted effects of structural frequency. Effects of structural complexity in people with aphasia did not emerge on their first pass through the sentence but were observed when they were rereading critical regions of complex sentences., Conclusions: People with aphasia are sensitive to both structural complexity and structural frequency when reading. However, people with aphasia may use different reading strategies than controls when confronted with relatively infrequent and complex sentence structures.

A significant body of evidence from cross-linguistic and developmental studies converges to suggest that co-speech iconic gesture mirrors language. This paper aims to identify whether gesture reflects impaired spoken language in a similar way. Twenty-nine people with aphasia (PWA) and 29 neurologically healthy control participants (NHPs) produced a narrative discourse, retelling the story of a cartoon video. Gesture and language were analysed in terms of semantic content and structure for two key motion events. The aphasic data showed an influence on gesture from lexical choices but no corresponding clausal influence. Both the groups produced gesture that matched the semantics of the spoken language and gesture that did not, although there was one particular gesture-language mismatch (semantically "light" verbs paired with semantically richer gesture) that typified the PWA narratives. These results indicate that gesture is both closely related to spoken language impairment and compensatory.

Purpose: A microlinguistic content analysis for assessing lexical semantics in people with aphasia (PWA) is lexical diversity (LD). Sophisticated techniques have been developed to measure LD. However, validity evidence for these methodologies when applied to the discourse of PWA is lacking. The purpose of this study was to evaluate four measures of LD to determine how effective they were at measuring LD in PWA., Method: Four measures of LD were applied to short discourse samples produced by 101 PWA: (a) the Measure of Textual Lexical Diversity (MTLD; McCarthy, 2005), (b) the Moving-Average Type-Token Ratio (MATTR; Covington, 2007), (c) D (McKee, Malvern, & Richards, 2000), and (d) the Hypergeometric Distribution (HD-D; McCarthy & Jarvis, 2007). LD was estimated using each method, and the scores were subjected to a series of analyses (e.g., curve-fitting, analysis of variance, confirmatory factor analysis)., Results: Results from the confirmatory factor analysis suggested that MTLD and MATTR reflect LD and little of anything else. Further, two indices (HD-D and D) were found to be equivalent, suggesting that either one can be used when samples are >50 tokens., Conclusion: MTLD and MATTR yielded the strongest evidence for producing unbiased LD scores, suggesting that they may be the best measures for capturing LD in PWA.

Objective: Semantic feature approaches are frequently included in treatment for people with aphasia. The present study investigated the role of distinctiveness and importance in the semantic feature knowledge of people with aphasia. The relationships between feature knowledge and the ability to choose among semantically-related foils, comprehension and naming abilities were examined., Methods: Participants distinguished target nouns from related foils and completed a sorting task involving mid-importance common (MIC), mid-importance distinctive (MID), low-importance common (LIC) and low-importance distinctive (LID) features. Participants also completed sub-tests from the short version of the Boston Diagnostic Aphasia Examination-Third Edition (BDAE-3) and Boston Naming Test-Second Edition (BNT-2). Participants were divided into two groups based on ability to accurately select target nouns from semantically-related foils., Results: Group 1, participants with intact ability to choose among related foils, was significantly less impaired with the identification of distinctive features than Group 2, those with difficulty choosing among related foils. Importance was not a significant factor when comparing mid-importance to low-importance features., Conclusions: These results suggest that distinctive feature knowledge contributes in a significant way to the integrity of semantic representations in people with aphasia which can influence their performance of language tasks.

Primary progressive aphasia is clinically heterogeneous. We report a patient, alias Don, with a novel form of progressive aphasia, characterised by deep dyslexia and dysgraphia and dissociated access to phonological and orthographic word forms. The hallmarks of deep dyslexia and dysgraphia were present early in the course and persisted over time. Writing was initially poorer than reading, but this reversed over time. There was a lack of concordance between reading and writing errors. Don benefited from a semantic mediation strategy to learn letter sounds, involving associating letters with a country name (e.g., A=Afghanistan). Remarkably, he continued to be able to generate those phonologically complex country names when no longer able to name or sound letters. Don's performance is compatible with a traditional dual-route account of deep dyslexia and dysgraphia. The findings have potential practical implications for speech and language therapy in progressive aphasia. Moreover, they illustrate both the remarkable specificity yet clinical diversity in presentation of progressive aphasia., (Copyright © 2012 Elsevier Srl. All rights reserved.)

Purpose: To explore whether individuals with aphasia exhibit differences in the M350, an electrophysiological marker of lexical activation, compared with healthy controls., Method: Seven people with aphasia, 9 age-matched controls, and 10 younger controls completed an auditory lexical decision task while cortical activity was recorded with magnetoencephalography. There were 2 stimulus conditions of interest: identity primed (i.e., a word preceded by itself) and semantic primed (i.e., a word preceded by a semantically related word). Latency and amplitude of the M350 response as well as reaction time were measured., Results: Consistent with the age-matched control group, the group with aphasia showed both identity and semantic priming behaviorally. In contrast to the control groups, the group with aphasia did not show either semantic or identity priming of the M350 response. This group also demonstrated longer M350 latencies than either control group. Furthermore, within this group, M350 latency was positively correlated with a measure of semantic impairment., Conclusions: These findings highlight the usefulness of temporally sensitive measures when studying aphasia and demonstrate that the latency of electrophysiological markers is of interest in this population. In particular, increased M350 latency appears to be indicative of a semantic processing impairment.

Objective: To see whether action and object processing across different tasks and modalities differs in brain-injured speakers of Chinese with varying fluency and lesion locations within the left hemisphere., Method: Words and pictures representing actions and objects were presented to a group of 33 participants whose native and/or dominant language was Mandarin Chinese: 23 patients with left-hemisphere lesions due to stroke and 10 language-, age- and education-matched healthy control participants. A set of 120 stimulus items was presented to each participant in three different forms: as black and white line drawings (for picture-naming), as written words (for reading) and as aurally presented words (for word repetition). Patients were divided into groups for two separate analyses: Analysis 1 divided and compared patients based on fluency (Fluent vs. Nonfluent) and Analysis 2 compared patients based on lesion location (Anterior vs. Posterior)., Results: Both analyses yielded similar results: Fluent, Nonfluent, Anterior, and Posterior patients all produced significantly more errors when processing action (M = 0.73, SD = 0.45) relative to object (M = 0.79, SD = 0.41) stimuli, and this effect was strongest in the picture-naming task., Conclusions: As in our previous study with English-speaking participants using the same experimental design (Arévalo et al., 2007, Arévalo, Moineau, Saygin, Ludy, & Bates, 2005), we did not find evidence for a double-dissociation in action and object processing between groups with different lesion and fluency profiles. These combined data bring us closer to a more informed view of action/object processing in the brain in both healthy and brain-injured individuals.

Word frequency is a powerful predictor of language processing efficiency in healthy individuals and in computational models. Puzzlingly, frequency effects are often absent in stroke aphasia, challenging the assumption that word frequency influences the behavior of any computational system. To address this conundrum, we investigated divergent effects of frequency in two comprehension-impaired patient groups. Patients with semantic dementia have degraded conceptual knowledge as a consequence of anterior temporal lobe atrophy and show strong frequency effects. Patients with multimodal semantic impairments following stroke (semantic aphasia [SA]), in contrast, show little or no frequency effect. Their deficits arise from impaired control processes that bias activation toward task-relevant aspects of knowledge. We hypothesized that high-frequency words exert greater demands on cognitive control because they are more semantically diverse--they tend to appear in a broader range of linguistic contexts and have more variable meanings. Using latent semantic analysis, we developed a new measure of semantic diversity that reflected the variability of a word's meaning across different context. Frequency, but not diversity, was a significant predictor of comprehension in semantic dementia, whereas diversity was the best predictor of performance in SA. Most importantly, SA patients did show typical frequency effects but only when the influence of diversity was taken into account. These results are consistent with the view that higher-frequency words place higher demands on control processes, so that when control processes are damaged the intrinsic processing advantages associated with higher-frequency words are masked.

Semantic errors in aphasia (e.g., naming a horse as "dog") frequently arise from faulty mapping of concepts onto lexical items. A recent study by our group used voxel-based lesion-symptom mapping (VLSM) methods with 64 patients with chronic aphasia to identify voxels that carry an association with semantic errors. The strongest associations were found in the left anterior temporal lobe (L-ATL), in the mid- to anterior MTG region. The absence of findings in Wernicke's area was surprising, as were indications that ATL voxels made an essential contribution to the post-semantic stage of lexical access. In this follow-up study, we sought to validate these results by re-defining semantic errors in a manner that was less theory dependent and more consistent with prior lesion studies. As this change also increased the robustness of the dependent variable, it made it possible to perform additional statistical analyses that further refined the interpretation. The results strengthen the evidence for a causal relationship between ATL damage and lexically-based semantic errors in naming and lend confidence to the conclusion that chronic lesions in Wernicke's area are not causally implicated in semantic error production., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Purpose: This Phase II treatment study examined the effect of Verb Network Strengthening Treatment (VNeST) on individuals with moderate-to-severe aphasia. Research questions addressed (a) pre- to posttreatment changes and pretreatment to treatment phase changes on probe sentences containing trained verbs (e.g., "The carpenter is measuring the stairs") and semantically related untrained verbs (e.g., "The nurse is weighing the baby"); (b) lexical retrieval changes in single-word naming, sentence, and discourse measures; (c) functional communication by way of proxy and participant report; and (d) error evolution., Method: A multiple-baseline approach across participants was used. Effect sizes were calculated for pre- and posttreatment and maintenance probe responses. A C statistic was used to determine changes from the baseline to treatment phases., Results: One participant exhibited improvement on all generalization measures, whereas the other participant exhibited more limited generalization. Both participants showed improvement on the functional communication measure., Conclusions: As predicted, the participants did not show the same extent of improvement that was observed in participants with more moderate aphasia (Edmonds, Nadeu, & Kiran, 2009). Nonetheless, the findings suggest that VNeST may be appropriate for persons with moderate-to-severe aphasia, especially with a small adaptation to the treatment protocol that will be retained for future iterations of VNeST.

Administration time of 1 min for semantic verbal fluency measures can be overly long and therefore bothersome for aphasic patients because they can often retrieve only a few items after a certain period of time. The purpose of this study was to determine whether an administration time of 30 s would be more efficient in differentiating among aphasics, nonaphasic stroke patients, and normal controls. The subjects were 53 stroke patients and 28 normal controls. They had to generate as many animal names as they could within a given time. The number of animal names is gradually diminished in three groups (p < 0.001) in each time frame, that is, during the entire 60 s, the initial 30 s, and the following 30 s. The reaction time (RT) measure indicated that the RT of the aphasic patients was significantly increased compared to those of the other two groups (p < 0.001). The most optimal cutoff scores that differentiated each group are presented. These results suggest that an administration time of 30 s has discriminative validity to differentiate between the two patient groups. This shorter administration time could make the test more efficient by reducing the burden on both examiners and aphasic patients., (Copyright © 2011 S. Karger AG, Basel.)

Patients with "refractory access dysphasia" have been a source of unique insight into the organization of previously unexplored domains of semantic knowledge (i.e., proper nouns, geography, concrete and abstract concepts). However, much of the relevant data have been based on the performance of a small number of patients. Here, we present 2 patients who both display a "refractory access" pattern of performance on spoken-word-written-word matching tasks and test their performance in the domains of famous people, geography, and abstract and concrete words. While these patients show performance similar to that for the previously reported patients in the domains of famous people and geography, they show a very different pattern of performance with abstract and concrete nouns. We discuss possible reasons why patients may differ in performance and evidence for and against the "differential frameworks" hypothesis for the organization of concrete and abstract concepts.

Aim: We report the case of a 6-year-old female who suffered a left hemisphere stroke attributed to a genetically determined prothrombotic state. She presented a fluent speech pattern with selective difficulty in retrieving names but not verbs. An evaluation was designed to clarify whether her symptoms represented a specific impairment of name retrieval., Method: The child undertook an experimental battery of visual naming tasks requiring the production of 52 nouns (belonging to nine different semantic categories) and 44 verbs. Her performance was compared with that of 12 healthy children, matched for age and IQ, attending a local kindergarten., Results: The child retrieved significantly more verbs than nouns (chi(2)=16.27, p<0.01) and had a significantly lower score in noun (t=-7.2, p<0.005), but not in verb retrieval than the comparison group. This pattern persisted when verbs and nouns were matched for oral word frequency, showing that the results could not be explained by stimuli difficulty., Interpretation: To our knowledge, this is the first report of a grammatical dissociation in a child. It suggests that nouns and verbs are subject to different processing early in development, at least before the formal acquisition of grammar. It contradicts theories that postulate a common processing of different grammatical categories early in life.

In addition to its communicative functions, language has been argued to have a variety of extracommunicative functions, as assessed by its causal involvement in putatively nonlinguistic tasks. In the present work, I argue that language may be critically involved in the ability of human adults to categorize objects on a specific dimension (e.g., color) while abstracting over other dimensions (e.g., size). This ability is frequently impaired in aphasic patients. The present work demonstrates that normal participants placed under conditions of verbal interference show a pattern of deficits strikingly similar to that of aphasic patients: impaired taxonomic categorization along perceptual dimensions, and preserved thematic categorization. A control experiment using a visuospatial-interference task failed to find this selective pattern of deficits. The present work has implications for understanding the online role of language in normal cognition and supports the claim that language is causally involved in nonverbal cognition.

Although semantic dementia (SD) is defined as a selective disruption of conceptual knowledge, a number of group studies have now demonstrated that SD patients also show impaired performance on tasks not usually considered to have a high semantic load (e.g., reading words aloud and lexical or object decision). The aim of the current study was to document the relative deterioration, over time, of a number of semantic and so-called 'non-semantic' tasks in LF, a single case of SD for whom - by virtue of his work as a published cartoonist - we also have extensive data regarding his pre-morbid linguistic and drawing skills. In five testing rounds over a period of five years we administered semantic tests of object naming and object definition (on both of which LF was progressively impaired, as expected for a diagnosis of SD), plus verbal and non-verbal 'non-semantic' tasks of reading aloud, spelling, object and lexical decision, and delayed copy drawing. Initially, his only striking 'non-semantic' deficit was in the domain of spelling - a pronounced surface dysgraphia in an individual with demonstrably superior pre-morbid spelling skill. Over time, and in line with his declining semantic system, LF's performance gradually deteriorated on all of the 'non-semantic' tasks. The most vulnerable items on most tasks were those with low frequency and an atypical form. This report adds to the growing body of evidence that a number of cognitive processes not usually considered to be 'semantic' in their demands rely on the integrity of semantic knowledge for successful execution. Furthermore, it provides the first indication that these non-semantic deficits might emerge in an order predictable from the typicality structure of the relevant domain.

Purpose: The typicality treatment approach on improving naming was investigated within 2 inanimate categories (furniture and clothing) using a single-subject experimental design across participants and behaviors in 5 patients with aphasia., Method: Participants received a semantic feature treatment to improve naming of either typical or atypical items within semantic categories, whereas generalization was tested to untrained items of the category. The order of typicality and category trained was counterbalanced across participants., Results: Results indicated that 2 out of 4 patients trained on naming of atypical examples demonstrated generalization to naming untrained typical examples. One patient showed trends toward generalization but did not achieve criterion. Furthermore, all 4 patients trained on typical examples demonstrated no generalized naming to untrained atypical examples within the category. Also, analysis of errors indicated an evolution of errors as a result of treatment, from those with no apparent relationship to the target to primarily semantic and phonemic paraphasias., Conclusion: These results extend our previous findings (S. Kiran & C. K. Thompson, 2003a) to patients with nonfluent aphasia and to inanimate categories such as furniture and clothing. Additionally, the results provide support for the claim that training atypical examples is a more efficient method of facilitating generalization to untrained items within a category than training typical examples (S. Kiran, 2007).

One of the most common types of errors produced by aphasic patients during oral word production is semantic errors. However, although aphasia semantic errors are often treated as a single homogenous group, there are, in fact, several subtypes defined by the nature of the error-target relationship: paradigmatic, if the two words are category coordinates; syntagmatic, if they are associatively related but from different semantic categories; and superordinate, if the meaning of the error is broader than the meaning of the target. The goal of this study was to investigate whether or not these various subtypes of semantic errors have a similar processing origin. With this objective, we compared the patterns of semantic errors made by a group of Alzheimer patients in a picture-naming task with those made by a group of aphasic patients. We examined the percentages of the different error types, the degree of association between target and error, and the frequency values both of errors and targets. The results suggest that the three subtypes of semantic errors have different origins: the superordinate appear to arise at the semantic level, the syntagmatic at the lexical level, and the paradigmatic at both levels of processing.

Purpose: Our previous work on manipulating typicality of category exemplars during treatment of naming deficits has shown that training atypical examples generalizes to untrained typical examples but not vice versa. In contrast to natural categories that consist of fuzzy boundaries, well-defined categories (e.g., shapes) have rigid category boundaries. Whether these categories illustrate typicality effects similar to natural categories is under debate. The present study addressed this question in the context of treatment for naming deficits in aphasia., Methods: Using a single-subject experiment design, 3 participants with aphasia received a semantic feature treatment to improve naming of either typical or atypical items of shapes, while generalization was tested to untrained items of the category., Results: For 2 of the 3 participants, training naming of atypical examples of shapes resulted in improved naming of untrained typical examples. Training typical examples in 1 participant did not improve naming of atypical examples. All 3 participants, however, showed weak acquisition trends., Conclusions: Results of the present study show equivocal support for manipulating typicality as a treatment variable within well-defined categories. Instead, these results indicate that acquisition and generalization effects within well-defined categories such as shapes are overshadowed by their inherent abstractness.

This paper examines the relative values of syntactic-semantic relationships in the mental lexicon of aphasic patients, which were tested within syntagmatic and paradigmatic networks of lexical relations. Semantic relations, such as synonymy, antonomy, and hyperonymy, as well as collocational and coordinational syntactic-semantic relations, were examined simultaneously. Twenty-five subjects diagnosed with nominal aphasia were tested, as well as a control group of 20 healthy subjects. The control group was matched with the aphasic group in terms of dominant hemisphere, age, sex, and job. A naming test based on semantic context was used in this research. The test was presented orally to subjects. After the examiner had read a sentence, subjects were supposed to finish it with a target word (the word which was, through context, in a syntactic-semantic relationship with the rest of the sentence). Sentences were composed of highly frequently occurring words. The categories used in the test were randomly patterned. The resultant data were analysed according to adequate semantic relations of the answers in the given context, and according to the type of the semantic-syntactic relation in 'wrong' answers. Results of this analysis are interpreted according to current psycholinguistic theories.

We report B.R.B., a bilingual Turkish-English speaker with deep dysphasia. B.R.B. shows the typical pattern of semantic errors in repetition with effects of lexicality and imageability on performance in both languages. The question we asked is whether language type (Turkish or English) or language status--that is, first acquired (L1) or second acquired (L2)--has a greater impact on performance. Results showed that repetition in L1 (Turkish) was better than that in L2 (English). We also observed effects of language status on oral reading, writing to dictation, and naming (spoken and written) with greater impairment to repetition than other tasks in both languages. An additional finding was that spoken-word translation in both directions was worse than written-word translation, and word class had an effect on translation from L1 to L2. We argue that interactive activation models of deep dysphasia could explain deep dysphasia in bilingual speakers and interactions between task and language, if the weighted connections that support language processing in L2 are assumed to be weaker, thus causing rapid phonological decay to have more impact on task performance in L2. Implications of the results for models of bilingual language processing are also considered.

Deficits of semantic cognition in semantic dementia and in aphasia consequent on CVA (stroke) are qualitatively different. Patients with semantic dementia are characterised by progressive degradation of central semantic representations, whereas multimodal semantic deficits in stroke aphasia reflect impairment of executive processes that help to direct and control semantic activation in a task-appropriate fashion [Jefferies, E., & Lambon Ralph, M. A. (2006). Semantic impairment in stroke aphasia vs. semantic dementia: A case-series comparison. Brain 129, 2132-2147]. We explored interactions between these two aspects of semantic cognition by examining the effects of cumulative phonemic cueing on picture naming in case series of these two types of patient. The stroke aphasic patients with multimodal semantic deficits cued very readily and demonstrated near-perfect name retrieval when cumulative phonemic cues reached or exceeded the target name's uniqueness point. Therefore, knowledge of the picture names was largely intact for the aphasic patients, but they were unable to retrieve this information without cues that helped to direct activation towards the target response. Equivalent phonemic cues engendered significant but much more limited benefit to the semantic dementia patients: their naming was still severely impaired even when most of the word had been provided. In contrast to the pattern in the stroke aphasia group, successful cueing was mainly confined to the more familiar un-named pictures. We propose that this limited cueing effect in semantic dementia follows from the fact that concepts deteriorate in a graded fashion [Rogers, T. T., Lambon Ralph, M. A., Garrard, P., Bozeat, S., McClelland, J. L., & Hodges, J. R., et al. (2004). The structure and deterioration of semantic memory: A neuropsychological and computational investigation. Psychological Review 111, 205-235]. For partially degraded items, the residual conceptual knowledge may be insufficient to drive speech production to completion but these items might reach threshold when they are bolstered by cues.

Objective: To present the case of a woman with a probable vascular dementia and a unique oral spelling behavior (OSB). Our aim was to better characterize the mechanisms underlying OSB in this patient with advanced cognitive and noncognitive deficits., Background: Different kind of language deficits have been described in dementias and other related diseases. Other nonaphasic acquired communication disorders include a heterogeneous group of verbal impairment that are mainly due to attentional and executive impairments., Methods: We describe the neurolinguistic and neuropsychologic analysis of an 88-year-old woman with spontaneous OSB. Computed tomography-scan at the time of the clinical analysis is also presented., Results: OSB occurred preferentially in spontaneous discourse, manifested in other language tasks, concerned all lexical categories, and was not accompanied by spelling deficit although language was not intact and disclosed foreign accent syndrome. Environmental dependency syndrome or utilization behavior was prominent and concerned various sensorimotor activities., Conclusions: We postulate that OSB was not secondary to a linguistic or more specifically to a spelling deficit but to another variant of environmental dependency syndrome and probably associated with a cortico-subcortical lesion including the left prefrontal region.

Semantic errors of oral reading by aphasic patients are said to be comparatively rare in languages with a shallow orthography. The present report concerns three bilingual brain-damaged patients who prior to their stroke were fluent in both English, an orthographically deep language, and Welsh, an orthographically shallow language. On a picture-naming task, each patient made a similar proportion of semantic errors in the two languages. Similarly, in oral reading of the corresponding words, no patient produced proportionally more semantic paralexias in English than in Welsh. The findings are discussed in relation to the summation hypothesis as invoked by Miceli, Capasso, and Caramazza (1994) to explain apparent differences in frequency of semantic errors of reading in languages differing in orthographic depth.

The present study examined lexical representation in early Spanish-English bilinguals using an unmasked semantic and translation priming paradigm. In Experiment 1, participants were divided into two groups based on performance (more-balanced bilinguals, MB and less-balanced bilinguals, LB) on the experimental task. In Experiment 2, four patients with bilingual aphasia (BA) performed the same experiment. Results from both experiments revealed that all groups were more accurate for English targets (S-E direction) than Spanish targets (S-E direction). In Experiment 1, semantic priming was observed from English to Spanish in both the LB and MB groups although the effect was greater for the LB group. Further, only the LB group showed priming from Spanish to English. For both normal groups, there was no difference between translation and semantic priming effects. In Experiment 2, patients with bilingual aphasia demonstrated different patterns of activation with no clear trends. Two participants demonstrated greater priming from Spanish to English whereas two participants demonstrated the opposite effect.

In this study, we use an auditory picture-word interference task to examine an anomic individual, NP. NP produced semantic errors in picture naming, but his comprehension was relatively well preserved. In the task, pictures to be named were accompanied by semantically, phonologically or unrelated distractors, presented at onsets ranging from -200ms (before target) to +400ms (after target). Naming latencies were measured. A group of 12 older controls showed semantic interference (slower latencies with semantic than with unrelated distractors), which was significant at -200ms, and steadily diminished across later onsets. In contrast, at 0ms, NP showed powerful semantic facilitation. There were no significant semantic effects at other onsets, but the trends, particularly at later onsets, were towards interference. Phonological effects for NP were in the same direction as for controls (facilitation) but were of greater magnitude. Indeed, NP showed a reliable facilitatory effect at 0ms (and trends at -200ms and +200ms), but a similar trend in controls failed to reach significance. Within recent models of this task, in which semantic facilitation effects are attributed to an early, pre-lexical semantic processing stage, NP's pattern indicates that semantic processing is abnormally prolonged. The phonological facilitation effects are also consistent with this interpretation. We discuss their implications and future applications of the task to aphasia.

Idiom comprehension in 15 aphasic patients was assessed with three tasks: a sentence-to-picture matching task, a sentence-to-word matching task and an oral definition task. The results of all three tasks showed that the idiom comprehension in aphasic patients was impaired compared to that of the control group, and was significantly affected by the type of task and type of idiom. Whilst performance on the oral definition and sentence-to-picture matching tasks was similarly impaired, the patients performed significantly better on the sentence-to-word matching task. The results confirm the relevance of task and idiom type in drawing conclusions about figurative language interpretation in brain-damaged patients.

We studied noun and verb naming in three main variants of frontotemporal dementia: the frontal variant(Fv-FTD), primary progressive aphasia (PPA) and semantic dementia (SD). We further distinguished PPA in nonfluent and fluent forms and restricted diagnosis of SD to subjects with progressive semantic breakdown leading to agnosia for words and objects. Fv-FTD and nonfluent-PPA named objects better than actions, SD showed an inverse dissociation and no specific pattern emerged in fluent-PPA. In this last group, in spite of the broad definition of fluent aphasia, quite heterogeneous patterns of language disorders and word class dissociation emerged when single-subject analyses were performed. In fv-FTD correlations between executive tasks and action naming were stronger than between executive tasks and object naming. We conclude that both linguistic and non linguistic factors, in particular an executive deficit, contribute to grammatical class dissociation. We also suggest that the fluent vs. nonfluent distinction does not reflect the complexity of primary aphasia.

Caramazza et al. [Caramazza, A., Chialant, D., Capasso, R., & Miceli, G. (2000). Separable processing of consonants and vowels. Nature, 403(6768), 428-430.] report two patients who exhibit a double dissociation between consonants and vowels in speech production. The patterning of this double dissociation cannot be explained by appealing to sub-phonemic distinctions, such as sonority level or damage to specific phonological features. They argue that consonant/vowel status is an autonomous level of representation. Monaghan and Shillcock [Monaghan, P., & Shillcock, R. (2003). Connectionist modelling of the separable processing of consonants and vowels. Brain and Language, 86(1), 83-98.] present computational models which supposedly exhibit a similar double dissociation. They contend that these models can explain the patient data, without appeal to such supra-phonemic distinctions as consonant/vowel status. Here we argue that their claim fails to meet two necessary criteria. Their models do not fit the pattern of the patient data, either quantitatively or qualitatively. Furthermore, the motivation for these models is unclear beyond just being an attempt to explain this specific phenomenon. We conclude that these models, in their current form, do not provide an alternative explanation to the representation of consonants and vowels.

Previous research has shown that word-to-picture matching for targets that cannot be named at pre-test results in improved naming relative to untreated control items for people with aphasia. This paper replicates and extends this finding and investigates its source. Is the effect a result of priming of semantic representations, or of post-semantic mechanisms in word retrieval? The first experiment shows that word-to-picture matching with unrelated distractors improves naming at short (2-3 minutes) and long (up to 25 minute) lags. There was no effect of being made aware of the relationship between word-to-picture matching and picture naming. People who have a semantic impairment improve only with a short lag between word-to-picture matching and naming. Participants with less semantic impairment show larger priming effects that are equal at short and long lags between word-to-picture matching and naming. The second experiment shows that the facilitation effect is just as large for word-to-picture matching with unrelated distractors as with semantically-related distractors. Furthermore, overall there was no difference between matching with coordinate items and with associated items. The results of these experiments show that facilitation of naming by word-to-picture matching in people with aphasia cannot be a result of the priming of semantic representations. Instead they are consistent with two effects: word-to-picture matching results in priming at a lemma level for aphasic people with a semantic impairment that is only found with a short lag between word-to-picture matching and naming. Word-to-picture matching causes priming of the lemma to output lexicon entry mapping that benefits participants with less semantic impairment that is evident at both a short and long lag between word-to-picture matching and naming. These findings fit well with previous research on repetition priming of naming with normal subjects.

Individuals with agrammatic aphasia may have difficulty with verb production in comparison to nouns. Additionally, they may have greater difficulty producing verbs that have fewer semantic components (i.e., are semantically "light") compared to verbs that have greater semantic weight. A connectionist verb-production model proposed by Gordon and Dell (2003) learns through error correction to "divide the labor" between syntax and semantics. Verbs that are semantically heavier come to depend less on syntax and more on semantics. For lighter verbs, the reverse is true. We performed this study to clarify the role of semantic weight in aphasic verb production and to test the prediction from Gordon and Dell that a brain lesion that impairs the syntactic input to verb retrieval will impair lighter verbs more than heavier ones. Consistent with this prediction, we found that the decrement for lighter verbs was present in a group with agrammatic aphasia but not in a matched group without agrammatism.