Previous studies on bilingualism and aphasia have identified a similar pattern of verb-noun dissociation in single-word naming (i.e., lower accuracy for verbs than nouns) in both languages. However, ...whether a similar pattern of verb and noun dissociation emerges in discourse production remains unknown, particularly in typologically dissimilar languages.
This study investigated patterns of verb and noun impairment in both single-word naming and discourse production, and whether naming was associated with lexical retrieval in discourse production in Mandarin-English bilingual adults with aphasia (BWA).
Twelve Mandarin-English bilinguals with chronic aphasia completed standardized assessments on object and action naming, and three discourse tasks from the AphasiaBank (i.e., sequential pictures, single-picture, storytelling) in both L1 (Mandarin) and L2 (English). Item-level accuracy of object and action naming was fit into a generalized mixed-effects model to estimate single-word naming ability as a function of grammatical category. The proportion of verb and noun production and the number of verbs and nouns per utterance were fit into multivariate linear regression models to assess lexical retrieval in discourse. Finally, another linear regression was performed to examine the association between naming and lexical retrieval in discourse production.
The naming accuracy for verbs was lower than for nouns in both L1 and L2. Mandarin-English BWA also demonstrated less production of verbs than nouns in discourse. However, depending on the type of the task, the effect of word category was greater in L2 than in L1. This cross-linguistic difference of the verb-noun dissociation was diminished in individuals with lower aphasia severity. Our results further showed a direct relationship between naming and lexical retrieval in discourse, irrespective of the language.
Our findings suggest an overall similar pattern of verb and noun dissociation across different linguistic contexts. However, depending on the cognitive-linguistic demands of the task, the verb-noun dissociation may emerge in L1 and L2 to varying degrees in individuals with different levels of aphasia severity. This study facilitates better understanding of verb and noun retrieval in Mandarin-English BWA.
Researchers have sought to understand how language is processed in the brain, how brain damage affects language abilities, and what can be expected during the recovery period since the early 19th ...century. In this review, we first discuss mechanisms of damage and plasticity in the post-stroke brain, both in the acute and the chronic phase of recovery. We then review factors that are associated with recovery. First, we review organism intrinsic variables such as age, lesion volume and location and structural integrity that influence language recovery. Next, we review organism extrinsic factors such as treatment that influence language recovery. Here, we discuss recent advances in our understanding of language recovery and highlight recent work that emphasizes a network perspective of language recovery. Finally, we propose our interpretation of the principles of neuroplasticity, originally proposed by Kleim and Jones (1) in the context of extant literature in aphasia recovery and rehabilitation. Ultimately, we encourage researchers to propose sophisticated intervention studies that bring us closer to the goal of providing precision treatment for patients with aphasia and a better understanding of the neural mechanisms that underlie successful neuroplasticity.
Background: Bilingual persons with aphasia (BWA) may present different degrees and patterns of impairment in their two languages. Previous research suggests that prestroke proficiency may be amongst ...the factors determining poststroke language impairment in BWA; however, this relationship is not well understood.
Aims: The purpose of this study was to examine the relationship between prestroke proficiency and poststroke lexical-semantic performance in BWA and to identify common patterns of language impairment in this population.
Methods and procedures: Twenty-seven Spanish-English BWA (14 female, age range = 29-88 years) were administered a language use questionnaire (LUQ) to measure several aspects of their bilingual language history that contribute to their prestroke proficiency in both languages. They also underwent standardized language assessments tapping lexical-semantic performance in each language. A principal component analysis was first conducted on the LUQ metrics to determine the factors that contributed to prestroke proficiency in each language. Next, regression analyses allowed assessing the relationships between prestroke proficiency and poststroke lexical-semantic performance in both languages. Differences in proficiency and language performance across languages were contrasted prior and after stroke to identify profiles of impairment.
Outcomes and results: Prestroke proficiency in the native language was determined by daily use, educational history, lifetime exposure, and language ability rating. Prestroke proficiency in the second language was determined by age of acquisition, daily use, educational history, lifetime exposure, lifetime confidence, family proficiency, and language ability rating. Prestroke proficiency significantly predicted poststroke lexical-semantic performance in BWA in both languages. Twenty-two participants presented parallel impairment while only three presented differential impairment.
Conclusions: Our results confirm that prestroke language proficiency is a key predictor of poststroke language impairment in BWA. These findings have important implications for the assessment and diagnosis of aphasia in bilingual individuals.
Purpose: This paper reviews several studies whose aim was to understand the nature of language recovery in chronic aphasia and identify predictors of how people may recover their language functions ...after a brain injury.
Method: Several studies that mostly draw from data collected within the Centre for Neurobiology of Language Recovery were reviewed and categorised in four aspects of language impairment and recovery in aphasia: (a) neural markers for language impairment and recovery, (b) language and cognitive markers for language impairment and recovery, (c) effective treatments and (d) predictive modelling of treatment-induced rehabilitation.
Result: Language impairment and recovery in stroke-induced aphasia is multi-factorial, including patient-specific and treatment-specific factors. A combination of these factors may help us predict treatment responsiveness even before treatment begins.
Conclusion: Continued work on this topic will lead to a better understanding of the mechanisms that underly language impairment and treatment-induced recovery in aphasia, and, consequently, use this information to predict each person's recovery profile trajectory and provide optimal prescriptions regarding the type and dosage of treatment.
This study aimed to improve verb retrieval ability in Mandarin-English bilinguals with aphasia by adapting the Verb Network Strengthening Treatment (VNeST) into Mandarin Chinese. Two Mandarin-English ...bilingual patients with chronic post-stroke aphasia participated in this study via online conferencing system following a multiple-baseline design. Both of them completed a 10-week of Mandarin VNeST treatment, and were probed on verb retrieval ability in a sentence context in both languages. Response accuracy was analysed to investigate the treatment acquisition, within-language generalization, and cross-language generalization effects. Standardized language assessments in both languages were administered pre- and post-treatment to further examine generalization to other linguistic tasks. Error analysis was conducted to investigate the evolution of within- and cross-language errors. Both patients improved after training in Mandarin VNeST, and showed different patterns of within-language and cross-language generalizations. They also improved in a variety of standardized language tasks. Error analysis showed a decline in semantic errors over the course of treatment in both patients, with cross-linguistic errors showing a decrease during Mandarin probes and an increase during English probes in one of the patients. This study contributes to our current understanding of theories of bilingual verb processing, and provides treatment guidance in Mandarin-English bilinguals with aphasia.
Predicting language therapy outcomes in bilinguals with aphasia (BWA) remains challenging due to the multiple pre- and poststroke factors that determine the deficits and recovery of their two ...languages. Computational models that simulate language impairment and treatment outcomes in BWA can help predict therapy response and identify the optimal language for treatment. Here we used the BiLex computational model to simulate the behavioral profile of language deficits and treatment response of a retrospective sample of 13 Spanish-English BWA who received therapy in one of their languages. Specifically, we simulated their prestroke naming ability and poststroke naming impairment in each language, and their treatment response in the treated and the untreated language. BiLex predicted treatment effects accurately and robustly in the treated language and captured different degrees of cross-language generalization in the untreated language in BWA. Our cross-validation approach further demonstrated that BiLex generalizes to predict treatment response for patients whose data were not used in model training. These findings support the potential of BiLex to predict therapy outcomes for BWA and suggest that computational modeling may be helpful to guide individually tailored rehabilitation plans for this population.
For stroke, traumatic brain injury (TBI), and other neurologic conditions associated with speech-language disorders, speech and language therapy is the standard of care for promoting recovery. ...However, barriers such as clinician time constraints and insurance reimbursement can inhibit a patient's ability to receive the support needed to optimize functional gain. Although digital rehabilitation has the potential to increase access to therapy by allowing patients to practice at home, the clinical and demographic characteristics that impact a patient's level of engagement with technology-based therapy are currently unknown.
This study aimed to evaluate whether the level of engagement with digital therapy differs by various patient characteristics, including age, gender, diagnosis, time from disease onset, and geographic location (urban vs rural).
Data for patients with stroke or TBI that initiated the use of Constant Therapy, a remotely delivered, cloud-based rehabilitation program for patients with speech-language disorders, were retrospectively analyzed. Only data from therapeutic sessions completed at home were included. The following three activity metrics were evaluated: (1) the number of active weeks of therapy, (2) the average number of active therapy days per week, and (3) the total number of therapeutic sessions completed during the first 20 weeks of program access. An active day or week was defined as having at least one completed therapeutic session. Separate multiple linear regression models were performed with each activity measure as the dependent variable and all available patient demographics as model covariates.
Data for 2850 patients with stroke or TBI were analyzed, with the average patient completing 8.6 weeks of therapy at a frequency of 1.5 days per week. Contrary to known barriers to technological adoption, older patients were more active during their first 20 weeks of program access, with those aged 51 to 70 years completing 5.01 more sessions than patients aged 50 years or younger (P=.04). Similarly, patients living in a rural area, who face greater barriers to clinic access, were more digitally engaged than their urban counterparts, with rural patients completing 11.54 more (P=.001) sessions during their first 20 weeks of access, after controlling for other model covariates.
An evaluation of real-world data demonstrated that patients with stroke and TBI use digital therapy frequently for cognitive and language rehabilitation at home. Usage was higher in areas with limited access to clinical services and was unaffected by typical barriers to technological adoption, such as age. These findings will help guide the direction of future research in digital rehabilitation therapy, including the impact of demographics on recovery outcomes and the design of large, randomized controlled trials.
This commentary responds to Ping Li and Qihui Xu's article "Computational Modeling of Bilingual Language Learning: Current Models and Future Directions" (Language Learning, 73(S2), 17-64).
Background: Lexical access in bilinguals can be influenced by the demands that different interactional contexts pose on cognitive control processes. However, how varying cognitive control demands ...impact lexical access in bilingual persons with aphasia (BPWA) remains unclear. Verbal fluency tasks may provide valuable insights into the interplay between cognitive control and lexical access in BPWA by addressing word generation abilities in language contexts that exert varying degrees of cognitive control effort.
Aims: The present study aimed to examine the performance of BPWA on a semantic category generation task that required word retrieval in single and dual-language contexts under varying cognitive control demands and a traditional letter fluency task conducted in single-language contexts. We also examined the associations between verbal fluency performance and (i) bilingual language history, and (ii) performance on standardized language assessments in both BPWA and healthy bilinguals.
Methods and Procedures: Thirteen Spanish-English BPWA and twenty-two Spanish-English healthy bilinguals completed a language use questionnaire, verbal fluency testing and standardized language assessments in each language. The semantic category generation task included four conditions: two conditions examined word retrieval in the first-acquired (L1) and second-acquired language (L2) in single language contexts (No Switch-L1 and No Switch-L2) and two conditions elicited word retrieval in dual-language contexts (Self-Switch and Forced-Switch) with low and high cognitive control demands by allowing or restricting switching across languages. The letter fluency task was administered in single language contexts only (F, A, S for English and P, M, R for Spanish). Verbal fluency performance was compared across conditions and groups using multivariate analyses. Further, correlational analyses were used to examine associations between verbal fluency tasks and bilingual language history, language assessments, and cognitive function.
Outcomes and Results: Overall, the healthy bilinguals produced a higher proportion of accurate words in both verbal fluency tasks relative to the BPWA. Results indicate that BPWA were more sensitive to the effects of increased cognitive control on lexical access relative to healthy bilinguals. BPWA and healthy bilinguals' performance on both verbal fluency tasks was associated with metrics of bilingual language history and standardized language assessments. Additionally, for BPWA, L2 letter fluency performance was associated with cognitive function.
Conclusion: Our findings suggest that verbal fluency tasks can help characterize the impact of cognitive control on lexical access in BPWA in single and mixed language contexts with important clinical implications.
This study investigated the effects of typicality-based semantic feature analysis (SFA) treatment on generalisation across three levels: untrained related items, semantic/phonological processing ...tasks, and measures of global language function. Using a single-subject design with group-level analyses, 27 persons with aphasia (PWA) received typicality-based SFA to improve their naming of atypical and/or typical exemplars. Progress on trained, untrained, and monitored items was measured weekly. Pre- and post-treatment assessments were administered to evaluate semantic/phonological processing and overall language ability. Ten PWA served as controls. For the treatment participants, the likelihood of naming trained items accurately was significantly higher than for monitored items over time. When features of atypical items were trained, the likelihood of naming untrained typical items accurately was significantly higher than for untrained atypical items over time. Significant gains were observed on semantic/phonological processing tasks and standardised assessments after therapy. Different patterns of near and far transfer were seen across treatment response groups. Performance was also compared between responders and controls. Responders demonstrated significantly more improvement on a semantic processing task than controls, but no other significant change score differences were found between groups. In addition to positive treatment effects, typicality-based SFA naming therapy resulted in generalisation across multiple levels.
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