A data-driven approach to post-stroke aphasia classification and lesion-based prediction.

Aphasia is an acquired impairment in the production or comprehension of language, typically caused by left hemisphere stroke. The subtyping framework used in clinical aphasiology today is based on the Wernicke-Lichtheim model of aphasia formulated in the late 19th century, which emphasizes the distinction between language production and comprehension. The current study used a data-driven approach that combined modern statistical, machine learning, and neuroimaging tools to examine behavioural deficit profiles and their lesion correlates and predictors in a large cohort of individuals with post-stroke aphasia. First, individuals with aphasia were clustered based on their behavioural deficit profiles using community detection analysis (CDA) and these clusters were compared with the traditional aphasia subtypes. Random forest classifiers were built to evaluate how well individual lesion profiles predict cluster membership. The results of the CDA analyses did not align with the traditional model of aphasia in either behavioural or neuroanatomical patterns. Instead, the results suggested that the primary distinction in aphasia (after severity) is between phonological and semantic processing rather than between production and comprehension. Further, lesion-based classification reached 75% accuracy for the CDA-based categories and only 60% for categories based on the traditional fluent/non-fluent aphasia distinction. The results of this study provide a data-driven basis for a new approach to classification of post-stroke aphasia subtypes in both research and clinical settings.

Facilitator Behaviors Leading to Engagement and Disengagement in Aphasia Conversation Groups.

Purpose Researchers have identified features of successful aphasia conversation groups and clinician behaviors leading to engagement and group cohesion. There has been less focus in the literature on facilitator behaviors that hinder participation or result in disengagement. This study aims to explore the behaviors of graduate student facilitators that contribute to and detract from engagement in aphasia conversation groups. Method Data were drawn from 4 conversation group sessions from 2 different university settings. Groups included 1 graduate student facilitator and 3 or more persons with aphasia. Sociolinguistic discourse analysis was applied to transcripts of group sessions. Results Three broad patterns detailing facilitator behaviors were identified. Several facilitator actions contributing to engagement were noted, including strategic use of topic elicitors, multimodal communication supports, and techniques to avoid interactional asymmetry. Behaviors associated with participant disengagement were also noted across sessions, including restricted discourse behaviors and difficulty managing the competing needs of participants. Engagement and disengagement were the product of several coordinating actions of the facilitator and group members that together influenced participation in conversation. Conclusion Results suggest that novice facilitators exhibit behaviors that contribute to and detract from participant engagement in aphasia conversation groups. Findings, discussed within the context of the literature on well-managed groups, highlight the skill required in managing the needs of participants with aphasia and knowing how and when to employ clinician-led strategies.

A Retrospective Study of Long-Term Improvement on the Boston Naming Test.

Purpose Lexical retrieval impairment is a universal characteristic of aphasia and a common treatment focus. Although naming improvement is well documented, there is limited information to shape expectations regarding long-term recovery. This was the motivation for a retrospective study of longitudinal data on the Boston Naming Test (BNT; Kaplan, Goodglass, & Weintraub, 1983, 2000). Method BNT scores were analyzed from a heterogeneous cohort of 42 individuals with anomia associated with a range of aphasia types. The data were collected over the course of 20 years from individuals who had participated in treatment and received at least 2 BNT administrations. A linear mixed model was implemented to evaluate effects of initial BNT score, time postonset, and demographic variables. For those over 55 years of age, BNT change was evaluated relative to data from the Mayo Clinic's Older Americans Normative Studies. Results There was a significant average improvement of +7.67 points on the BNT in individuals followed for an average of 2 years. Overall, the average rate of improvement was +5.84 points per year, in contrast to a decline of 0.23 points per year in a healthy adult cohort from the Mayo Clinic's Older Americans Normative Studies. Naming recovery was approximately linear, with significant main effects of initial BNT score (i.e., initial severity) and time postonset; the greatest changes were noted in those whose initial severity was moderate. Conclusions These findings indicate a positive prognosis for naming improvement over time regardless of demographic factors and provide estimates for clinical predictions for those who seek rehabilitation during the chronic phase.

Evaluating informative content and global coherence in fluent and non-fluent aphasia.

BACKGROUND: Discourse analysis is an important component of aphasia assessment because it can provide an insight into functional communication abilities. However, there are many unknowns regarding the levels of discourse breakdowns that occur across aphasia types. The purpose of the current study is to explore the possible differences in discourse-level communication in persons with fluent and non-fluent aphasia during picture description. AIMS: To examine if persons with fluent and non-fluent aphasia differ on utterance-level discourse measures when evaluating informative content and global coherence. Additionally, to evaluate and compare the types of global coherence violations made by each group. METHODS & PROCEDURES: Data from 31 people with aphasia was collected from AphasiaBank, which included 13 people with fluent aphasia and 18 people with non-fluent aphasia. Discourse samples from three picture descriptions were analysed. Discourse outcomes included utterances with new information (UNIs-relevant utterances containing new information) and global coherence (the extent to which each utterance maintained the overall discourse theme). Additionally, seven types of errors were identified to explore the nature of breakdowns in global coherence. OUTCOMES & RESULTS: People with fluent aphasia produced significantly higher proportions of UNIs and had significantly higher average global coherence ratings than those with non-fluent aphasia. Differences in global coherence violations were identified with people with fluent aphasia producing more non-specific, incorrect and off-topic utterances and people with non-fluent aphasia producing more incomplete utterances. One of the most common global coherence error types in both groups was commentary. CONCLUSIONS & IMPLICATIONS: Although people with fluent aphasia produced more types of global coherence errors, including incorrect, non-specific and off-topic utterances, the group was still rated significantly higher on utterance relevance and topic maintenance, indicating that the ability to produce a complete utterance plays an important role in some aspects of discourse production. Additionally, these findings provide an insight into potential targets for intervention.

Effect of Text-to-Speech Rate on Reading Comprehension by Adults With Aphasia.

Purpose Accessing auditory and written material simultaneously benefits people with aphasia; however, the extent of benefit as well as people's preferences and experiences may vary given different auditory presentation rates. This study's purpose was to determine how 3 text-to-speech rates affect comprehension when adults with aphasia access newspaper articles through combined modalities. Secondary aims included exploring time spent reviewing written texts after speech output cessation, rate preference, preference consistency, and participant rationales for preferences. Method Twenty-five adults with aphasia read and listened to passages presented at slow (113 words per minute [wpm]), medium (154 wpm), and fast (200 wpm) rates. Participants answered comprehension questions, selected most and least preferred rates following the 1st and 3rd experimental sessions and after receiving performance feedback, and explained rate preferences and reading and listening strategies. Results Comprehension accuracy did not vary significantly across presentation rates, but reviewing time after cessation of auditory content did. Visual data inspection revealed that, in particular, participants with substantial extra reviewing time took longer given fast than medium or slow presentation. Regardless of exposure amount or receipt of performance feedback, participants most preferred the medium rate and least preferred the fast rate; rationales centered on reading and listening synchronization, benefits to comprehension, and perceived normality of speaking rate. Conclusion As a group, people with aphasia most preferred and were most efficient given a text-to-speech rate around 150 wpm when processing dual modality content; individual differences existed, however, and mandate attention to personal preferences and processing strengths.

Speech Fluency in Acquired Apraxia of Speech During Narrative Discourse: Group Comparisons and Dual-Task Effects.

Purpose Slowed speech and interruptions to the flow of connected speech are common in aphasia. These features are also observed during dual-task performance for neurotypical adults. The purposes of this study were to determine (a) whether indices of fluency related to cognitive-linguistic versus motor processing would differ between speakers with aphasia plus apraxia of speech (AOS) and speakers with aphasia only and (b) whether cognitive load reduces fluency in speakers with aphasia with and without AOS. Method Fourteen speakers with aphasia (7 with AOS) and 7 neurotypical controls retold short stories alone (single task) and while simultaneously distinguishing between a high and a low tone (dual task). Their narrative samples were analyzed for speech fluency according to sample duration, speech rate, pause/fill time, and repetitions per syllable. Results As expected, both speaker groups with aphasia spoke slower and with more pauses than the neurotypical controls. The speakers with AOS produced more repetitions and longer samples than controls, but they did not differ on these measures from the speakers with aphasia without AOS. Relative to the single-task condition, the dual-task condition increased the duration of pauses and fillers for all groups but reduced speaking rate only for the control group. Sample duration and frequency of repetitions did not change in response to cognitive load. Conclusions Speech output in aphasia becomes less fluent when speakers have to engage in simultaneous tasks, as is typical in everyday conversation. Although AOS may lead to more sound and syllable repetitions than normal, speaking tasks other than narrative discourse might better capture this specific type of disfluency. Future research is needed to confirm and expand these preliminary findings. Supplemental Material https://doi.org/10.23641/asha.8847845.

Interrater Reliability and Concurrent Validity for the Apraxia of Speech Rating Scale 3.0: Application With Persons With Acquired Apraxia of Speech and Aphasia.

Purpose This investigation was designed to provide interrater reliability data for the Apraxia of Speech Rating Scale 3.0 (ASRS 3.0; Strand, Duffy, Clark, & Josephs, 2014 ). Importantly, ratings were completed by investigators who were not involved with the ASRS development. Another aim was to evaluate the relationship of the ASRS 3.0 total score to word intelligibility. Method Two investigators independently completed ASRS 3.0 ratings for 28 participants with chronic apraxia of speech and aphasia. Intelligibility scores were obtained for all participants. Results Consistency of ratings for each feature and total score of the ASRS 3.0 was measured using intraclass correlation coefficients. Twelve of 13 intraclass correlation coefficients for feature ratings reached significance; clinical meaningfulness ranged from poor to excellent. Interrater reliability for the total scores was excellent. Similarly, absolute difference of ratings was minimal for the total scores, but varied across the 13 feature ratings. Correlations between the intelligibility scores and ASRS 3.0 total score were moderate to strong. Conclusion The total ASRS 3.0 score may be viewed as a reliable indicator of prevalence of apraxia of speech features. Although there was good to acceptable correspondence in ratings of the majority of the individual features, additional operationalization of rating procedures may be needed to improve interrater reliability for a few features.

Correlación neurorradiológica de las afasias. Mapa cortico-subcortical del lenguaje / Neuroradiologic correlation with aphasias. Cortico-subcortical map of language

La afasia es una alteración adquirida del lenguaje debida a una lesión cerebral, que se caracteriza por errores en la producción, la denominación o la comprensión del lenguaje. Aunque la mayoría de las afasias suelen ser mixtas, desde un punto de vista práctico se clasifican en diferentes tipos según sus rasgos clínicos principales: afasia de Broca, afasia de Wernicke, afasia de conducción, afasia transcortical y alexia con o sin agrafia. Presentamos los hallazgos clínicos de los principales subtipos representándolos con casos radiológicos, y proporcionamos una revisión actualizada de la red del lenguaje con imágenes de resonancia funcional y de tractografía

Aphasia is an acquired language disorder due to a cerebral lesion; it is characterized by errors in production, denomination, or comprehension of language. Although most aphasias are mixed, from a practical point of view they are classified into different types according to their main clinical features: Broca's aphasia, Wernicke's aphasia, conduction aphasia, transcortical aphasia, and alexia with or without agraphia. We present the clinical findings for the main subtypes of aphasia, illustrating them with imaging cases, and we provide an up-to-date review of the language network with images from functional magnetic resonance imaging and tractography

José Ingenieros y las amusias, sobre los orígenes de la neuropsicología argentina / José Ingenieros and the amusias: the beginning of the neuropsychology in Argentina

La escuela neuropsicológica argentina nace de la mano de la escuela europea y forma parte del inicio de la psicología experimental. En 1896, Horacio Pinero crea la primera cátedra de psicología de la Universidad de Buenos Aires, y en 1898 se anexa el primer laboratorio de psicología experimental. José Ingenieros, psiquiatra, neurólogo, político y, sobre todo, sociólogo publica en Francia su trabajo sobre afasias musicales, el primer estudio neuropsicológico argentino con trascendencia internacional. En él redime a Charcot y no a Knoblauch como el primero en describir la amusia, habla de una inteligencia y no de un lenguaje musical, y propone una clasificación y una metodología de evaluación con una perspectiva integradora neurológica-psiquiátrica. Este artículo dio origen a su libro en francés sobre el lenguaje musical y sus alteraciones histéricas, premiado por la Academia de Medicina de París

The Argentine neuropsychological school is born of the hand of the European school and is part of the beginning of the Experimental Psychology. In 1896 Horacio Pinero creates the first Department of Psychology at the University of Buenos Aires and in 1898 the first laboratory of Experimental Psychology is annexed. José Ingeniero, psychiatrist, neurologist, politician and above all sociologist publishes in France his work about the musical aphasia, the first neuropsychological work with international significance. In the same redeems to Charcot instead of to Knoblauch like the first one to describe the amusias, it speaks of an intelligence instead of a musical language and proposes a new classification and a methodology of assessment with a neurological-psychiatric integrative perspective. This article gave rise to this book in French on the musical language and its hysterical alterations awarded by the Academy of Medicine of Paris

Characterization of aphasia in aneurysmal subarachnoid hemorrhage. / Caracterização das afasias na hemorragia subaracnóidea aneurismática.

PURPOSE: Characterize the profile of aphasic syndromes determined by aneurysmal subarachnoid hemorrhage (aSAH) of the left middle cerebral artery (LMCA). METHODS: An analytical, retrospective, cross-sectional study was conducted using a database of cognitive assessments of 193 patients with aSAH admitted to Hospital da Restauração between March 2007 and November 2009. Of these, a total of 26 patients with aSAH in the LMCA territory confirmed by digital angiography were selected. Aphasia was assessed through the Montreal-Toulouse Language Assessment Alpha Version Protocol (Alpha Version) and the CERAD Neuropsychological Test Battery (Verbal fluency). RESULTS: Language and verbal fluency impairments were identified in patients with aSAH in the LMCA territory when compared with the control population (50 individuals). Of the 26 patients with aSAH, 11 presented aphasic characteristics preoperatively. CONCLUSION: The results of this research corroborate the literature, showing that the aSAH frame causes cognitive impairments even in the preoperative phase for aneurysm occlusion. Considering the observed aspects, the predominant aphasic syndromes characterize comprehension aphasia due to sequels in the posterior cerebral artery territory.

OBJETIVO: Caracterizar o perfil dos quadros afásicos determinados pela hemorragia subaracnóidea aneurismática (HSA) da artéria cerebral média esquerda. MÉTODO: Estudo analítico, retrospectivo, transversal, tendo como banco de dados as avaliações cognitivas de 193 pacientes do Hospital da Restauração com HSA aneurismática no período de março de 2007 a novembro de 2009. Destes, foram selecionados 26 pacientes com HSA em território da ACM-E, confirmada por angiografia digital. Os quadros afásicos foram classificados através do desempenho da linguagem dos pacientes através do Protocolo Montreal Toulose - Versão Alpha e a tarefa de fluência verbal da bateria CERAD. A pesquisa foi realizada no período de junho a agosto de 2015. RESULTADOS: Foi identificado comprometimento da linguagem e fluência verbal nos pacientes com HSA em território de ACM­E quando comparados com a população controle (50 indivíduos). Dos 26 pacientes com HSA, 11 apresentaram quadros afásicos ainda no período pré-operatório. CONCLUSÃO: Os resultados da pesquisa corroboram com a literatura, mostrando que o quadro da HSA promove comprometimentos cognitivos ainda na fase pré-operatória para oclusão de aneurisma. Tendo em vista os aspectos observados, os quadros afásicos predominantes caracterizam afasia de compreensão por sequelas nas áreas cerebrais posteriores.

Caracterização das afasias na hemorragia subaracnóidea aneurismática / Characterization of aphasia in aneurysmal subarachnoid hemorrhage

RESUMO Objetivo Caracterizar o perfil dos quadros afásicos determinados pela hemorragia subaracnóidea aneurismática (HSA) da artéria cerebral média esquerda. Método Estudo analítico, retrospectivo, transversal, tendo como banco de dados as avaliações cognitivas de 193 pacientes do Hospital da Restauração com HSA aneurismática no período de março de 2007 a novembro de 2009. Destes, foram selecionados 26 pacientes com HSA em território da ACM-E, confirmada por angiografia digital. Os quadros afásicos foram classificados através do desempenho da linguagem dos pacientes através do Protocolo Montreal Toulose - Versão Alpha e a tarefa de fluência verbal da bateria CERAD. A pesquisa foi realizada no período de junho a agosto de 2015. Resultados Foi identificado comprometimento da linguagem e fluência verbal nos pacientes com HSA em território de ACM-E quando comparados com a população controle (50 indivíduos). Dos 26 pacientes com HSA, 11 apresentaram quadros afásicos ainda no período pré-operatório. Conclusão Os resultados da pesquisa corroboram com a literatura, mostrando que o quadro da HSA promove comprometimentos cognitivos ainda na fase pré-operatória para oclusão de aneurisma. Tendo em vista os aspectos observados, os quadros afásicos predominantes caracterizam afasia de compreensão por sequelas nas áreas cerebrais posteriores.

ABSTRACT Purpose Characterize the profile of aphasic syndromes determined by aneurysmal subarachnoid hemorrhage (aSAH) of the left middle cerebral artery (LMCA). Methods An analytical, retrospective, cross-sectional study was conducted using a database of cognitive assessments of 193 patients with aSAH admitted to Hospital da Restauração between March 2007 and November 2009. Of these, a total of 26 patients with aSAH in the LMCA territory confirmed by digital angiography were selected. Aphasia was assessed through the Montreal-Toulouse Language Assessment Alpha Version Protocol (Alpha Version) and the CERAD Neuropsychological Test Battery (Verbal fluency). Results Language and verbal fluency impairments were identified in patients with aSAH in the LMCA territory when compared with the control population (50 individuals). Of the 26 patients with aSAH, 11 presented aphasic characteristics preoperatively. Conclusion The results of this research corroborate the literature, showing that the aSAH frame causes cognitive impairments even in the preoperative phase for aneurysm occlusion. Considering the observed aspects, the predominant aphasic syndromes characterize comprehension aphasia due to sequels in the posterior cerebral artery territory.

[Networks involved in motor cognition : Physiology and pathophysiology of apraxia]. / Netzwerke für motorische Kognition : Physiologie und Pathophysiologie der Apraxie.

Apraxia is an umbrella term for different disorders of higher motor abilities that are not explained by elementary sensorimotor deficits (e. g. paresis or ataxia). Characteristic features of apraxia that are easy to recognize in clinical practice are difficulties in pantomimed or actual use of tools as well as in imitation of meaningless gestures. Apraxia is bilateral, explaining the cognitive motor disorders and occurs frequently (but not exclusively) after left hemispheric lesions, as well as in neurodegenerative diseases, such as corticobasal syndrome and Alzheimer's disease. Apraxic deficits can seriously impair activities of daily living, which is why the appropriate diagnosis is of great relevance. At the functional anatomical level, different cognitive motor skills rely on at least partly different brain networks, namely, a ventral processing pathway for semantic components, such as tool-action associations, a ventro-dorsal pathway for sensorimotor representations of learnt motor acts, as well as a dorso-dorsal pathway for on-line motor control and, probably, imitation of meaningless gestures. While these networks partially overlap with language-relevant regions, more clear cut dissociations are found between apraxia deficits and disorders of spatial attention. In addition to behavioral interventions, noninvasive neuromodulation approaches, as well as human-computer interface assistance systems are a growing focus of interest for the treatment of apraxia.

Different Cognitive Profiles of Patients with Severe Aphasia.

Cognitive dysfunction frequently occurs in aphasic patients and primarily compromises linguistic skills. However, patients suffering from severe aphasia show heterogeneous performance in basic cognition. Our aim was to characterize the cognitive profiles of patients with severe aphasia and to determine whether they also differ as to residual linguistic abilities. We examined 189 patients with severe aphasia with standard language tests and with the CoBaGA (Cognitive Test Battery for Global Aphasia), a battery of nonverbal tests that assesses a wide range of cognitive domains such as attention, executive functions, intelligence, memory, visual-auditory recognition, and visual-spatial abilities. Twenty patients were also followed longitudinally in order to assess their improvement in cognitive skills after speech therapy. Three different subgroups of patients with different types and severity of cognitive impairment were evidenced. Subgroups differed as to residual linguistic skills, in particular comprehension and reading-writing abilities. Attention, reasoning, and executive functions improved after language rehabilitation. This study highlights the importance of an extensive evaluation of cognitive functions in patients with severe aphasia.

Motor recovery in post-stroke patients with aphasia: the role of specific linguistic abilities.

BACKGROUND: Aphasia is a serious consequence of stroke but aphasics patients have been routinely excluded from participation in some areas of stroke research. OBJECTIVE: To assess the role of specific linguistic and non-verbal cognitive abilities on the short-term motor recovery of patients with aphasia due to first-ever stroke to the left hemisphere after an intensive rehabilitation treatment. METHODS: 48 post-acute aphasic patients, who underwent physiotherapy and speech language therapy, were enrolled for this retrospective cohort-study. Four types of possible predictive factors were taken into account: clinical variables, functional status, language and non-verbal cognitive abilities. The motor FIM at discharge was used as the main dependent variable. RESULTS: Patients were classified as follows: 6 amnestic, 9 Broca's, 7 Wernicke's, and 26 global aphasics. Motor FIM at admission (p = 0.003) and at discharge (p = 0.042), all linguistic subtests of Aachener AphasieTest (p = 0.001), and non-verbal reasoning abilities (Raven's CPM, p = 0.006) resulted significantly different across different types of aphasia. Post-hoc analyses showed differences only between global aphasia and the other groups. A Multiple Linear Regression shows that admission motor FIM (p = 0.001) and Token test (p = 0.040), adjusted for clinical, language, and non-verbal reasoning variables, resulted as independent predictors of motor FIM scores at discharge, while Raven's CPM resulted close to statistical significance. CONCLUSIONS: Motor function at admission resulted as the variable that most affects the motor recovery of post-stroke patients with aphasia after rehabilitation. A linguistic test requiring also non-linguistic abilities, including attention and working memory (i.e. Token test) is an independent predictor as well.

Bilingualism delays the onset of behavioral but not aphasic forms of frontotemporal dementia.

Bilingualism has been found to delay onset of dementia and this has been attributed to an advantage in executive control in bilinguals. However, the relationship between bilingualism and cognition is complex, with costs as well as benefits to language functions. To further explore the cognitive consequences of bilingualism, the study used Frontotemporal dementia (FTD) syndromes, to examine whether bilingualism modifies the age at onset of behavioral and language variants of Frontotemporal dementia (FTD) differently. Case records of 193 patients presenting with FTD (121 of them bilingual) were examined and the age at onset of the first symptoms were compared between monolinguals and bilinguals. A significant effect of bilingualism delaying the age at onset of dementia was found in behavioral variant FTD (5.7 years) but not in progressive nonfluent aphasia (0.7 years), semantic dementia (0.5 years), corticobasal syndrome (0.4 years), progressive supranuclear palsy (4.3 years) and FTD-motor neuron disease (3 years). On dividing all patients predominantly behavioral and predominantly aphasic groups, age at onset in the bilingual behavioral group (62.6) was over 6 years higher than in the monolingual patients (56.5, p=0.006), while there was no difference in the aphasic FTD group (60.9 vs. 60.6 years, p=0.851). The bilingual effect on age of bvFTD onset was shown independently of other potential confounding factors such as education, gender, occupation, and urban vs rural dwelling of subjects. To conclude, bilingualism delays the age at onset in the behavioral but not in the aphasic variants of FTD. The results are in line with similar findings based on research in stroke and with the current views of the interaction between bilingualism and cognition, pointing to advantages in executive functions and disadvantages in lexical tasks.

Delivering communication strategy training for people with aphasia: what is current clinical practice?

BACKGROUND: Communication strategy training (CST) is a recognized part of UK speech and language therapists' (SLTs) role when working with a person with aphasia. Multiple CST interventions have been published but, to date, there are no published studies exploring clinical practice in this area. AIMS: To investigate UK SLTs' current CST practices. METHODS & PROCEDURES: Thirty-seven UK SLTs completed an online questionnaire, eight of whom attended a follow-up focus group. A clinical consistency scale was applied to the questionnaire data and tasks that were most consistently used were explored in the focus group and analyzed using a primarily deductive thematic data analysis approach. OUTCOMES & RESULTS: Three key CST findings arose: (1) the rarity with which SLTs focus equally and explicitly on both communication partners' strategies; (2) SLTs' differing understandings of CST terminologies and concepts and underuse of formal assessment; and (3) the absence of video feedback. CONCLUSION & IMPLICATIONS: This study's survey findings suggest that conversation partners not only receive half the amount of CST given to people with aphasia but also play a more passive learning role when they are present. This is an interesting point to consider when the current evidence base contains stronger evidence for the effectiveness of conversation partner CST over other CST approaches, it being described as an effective method that may be maintained over time.

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

BACKGROUND: Given the integral role that verbs play in sentence production, understanding verb deficits is critical to clinical practice. Difficulties in sentence production are often directly related to an inability to retrieve argument structure information which, according to most theoretical accounts, is specified at a lexical level as part of the semantic representation of the verb. The presence of an argument complexity effect when retrieving verbs in isolation, i.e. increased difficulty with increasing number of arguments required by the verb, is considered evidence of the integral link between verbs and the ensuing structure. Recent reports, however, of relatively intact verb retrieval and impaired argument structure suggest that difficulties with verbs and argument structure may not always co-occur. One explanation for this is that lexical-syntactic information may be stored separately to lexical-semantic information at the lemma level and then differentially impaired. AIMS: To determine whether the presence of difficulties creating argument structure in a group of people with aphasia with verb-retrieval deficits consistently aligned with the underlying nature of their impairment, where semantic involvement resulted in argument structure difficulties and post-semantic impairment resulted in intact argument structure. This would provide evidence either to support or to challenge the view that argument structure is lexically specified. The presence of an argument complexity effect within the participants' single verb naming was also investigated to examine the relationship between verb argument information and any subsequent difficulties creating argument structure for sentence production. METHODS & PROCEDURES: Verb retrieval and argument structure production were investigated in 12 people with aphasia with verb-retrieval deficits on single-word and sentence-production measures. OUTCOMES & RESULTS: Eight of the 12 participants presented with a semantic verb deficit (five semantic and three mixed semantic and phonological) and had difficulties in creating argument structure. Four participants presented with a phonological verb deficit. Of these, two had intact argument structure while two had impaired argument structure. An argument complexity effect in verb naming was seen in both groups. CONCLUSIONS & IMPLICATIONS: Semantic verb-retrieval deficits consistently resulted in argument structure production difficulties, supporting the view that syntactic information is stored within the lemma. The presence of argument structure difficulties in two participants with phonological deficits; however, lends support for the separate coding of lexical-syntactic from lexical-semantic information at the lemma level, a factor that has both theoretical and clinical implications with respect to diagnosis and management.

The unbridged gap between clinical diagnosis and contemporary research on aphasia: A short discussion on the validity and clinical utility of taxonomic categories.

Even if the traditional aphasia classification is continuously questioned by many scholars, it remains widely accepted among clinicians and included in textbooks as the gold standard. The present study aims to investigate the validity and clinical utility of this taxonomy. For this purpose, 65 left-hemisphere stroke patients were assessed and classified with respect to aphasia type based on performance on a Greek adaptation of the Boston Diagnostic Aphasia Examination. MRI and/or CT scans were obtained for each patient and lesions were identified and coded according to location. Results indicate that 26.5% of the aphasic profiles remained unclassified. More importantly, we failed to confirm the traditional lesion-to-syndrome correspondence for 63.5% of patients. Overall, our findings elucidate crucial vulnerabilities of the neo-associationist classification, and further support a deficit-rather than a syndrome-based approach. The issue of unclassifiable patients is also discussed.

Algorithmic Classification of Five Characteristic Types of Paraphasias.

Purpose: This study was intended to evaluate a series of algorithms developed to perform automatic classification of paraphasic errors (formal, semantic, mixed, neologistic, and unrelated errors). Method: We analyzed 7,111 paraphasias from the Moss Aphasia Psycholinguistics Project Database (Mirman et al., 2010) and evaluated the classification accuracy of 3 automated tools. First, we used frequency norms from the SUBTLEXus database (Brysbaert & New, 2009) to differentiate nonword errors and real-word productions. Then we implemented a phonological-similarity algorithm to identify phonologically related real-word errors. Last, we assessed the performance of a semantic-similarity criterion that was based on word2vec (Mikolov, Yih, & Zweig, 2013). Results: Overall, the algorithmic classification replicated human scoring for the major categories of paraphasias studied with high accuracy. The tool that was based on the SUBTLEXus frequency norms was more than 97% accurate in making lexicality judgments. The phonological-similarity criterion was approximately 91% accurate, and the overall classification accuracy of the semantic classifier ranged from 86% to 90%. Conclusion: Overall, the results highlight the potential of tools from the field of natural language processing for the development of highly reliable, cost-effective diagnostic tools suitable for collecting high-quality measurement data for research and clinical purposes.