Neuroplasticity of Language Networks in Aphasia: Advances, Updates, and Future Challenges

Self-Improved Language Production in Nonfluent Aphasia Through Automated Recursive Self-Feedback

BACKGROUND

Persons with nonfluent aphasia (PWNA) use feedback from external agents (e.g., speech-language pathologists) and self-feedback to improve their language production. The extent to which PWNA can improve their language production using their self-feedback alone is underexplored. In a proof-of-concept study, we developed an automated recursive self-feedback procedure to demonstrate the extent to which two PWNA who used self-feedback alone improved their production of sentences from trained and untrained scripts. In the current study, we use the Rehabilitation Response Specification System as a framework to replicate our initial findings.

METHOD

We tested the effects of two treatments: script production with recursive self-feedback and script production with external feedback in four persons with chronic nonfluent aphasia. We compared the effects of treatment by measuring percent script produced, speaking rate, and speech initiation latency of trained and untrained scripts. The participants received the treatments remotely through mini tablets using two versions of a mobile app we developed. All the participants received each treatment intensively for 14 sessions across 2-3 weeks. We estimated clinical improvements of production of sentences from trained and untrained scripts through nonoverlap of all pairs analysis of performance pretreatment and posttreatment.

RESULTS

Both treatments improved PWNA's language production. Recursive self-feedback improved speaking rate and speech initiation latency, which generalized to untrained scripts in all participants. External feedback treatment did not generalize to improvement in speaking rate in two participants.

CONCLUSIONS

Our findings confirm our initial evidence that PWNA can self-improve their sentence production from scripts through recursive self-feedback. This novel procedure enables PWNA to autonomously enhance their language production over time. Given the evidence and the mechanics of the procedure, we propose that its utility is not constrained by linguistic idiosyncrasies across cultures. Consequently, it has the potential to bypass linguistic barriers to aphasia care.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.27007060.

The value of action observation in speech and language rehabilitation: A systematic review and meta-analysis

In this systematic review and meta-analysis, our aim was to identify and quantify evidence of action observation therapy (AOT) efficacy in managing language deficits in patients with aphasia. This study conducts two quantitative investigations: firstly, comparing the effects of AOT and conventional control therapy in different groups, and secondly, analyzing within AOT group to explore potential moderators of AOT effectiveness. Four databases were searched up until August 2023 to find studies utilizing AOT for aphasia management. Seven eligible studies were included. The main analyses revealed moderate evidence of improvement in naming tasks, with a large effect size (Hedge's g = 1.27, 95 %CI [0.44; 2.09], p = 0.003, I2 < 25) following AOT compared to control interventions. Furthermore, to be efficient, AOT should focus on human actions (e.g., running, jumping) rather than non-human actions (e.g., meowing or barking). These findings indicate that AOT is a promising alternative complementary approach for patients with aphasia. Future research should confirm the potential benefits of AOT with more randomized controlled studies and aim to clarify the minimal dose necessary and the possibility of transfer to various language tasks.

Exercise and Language Performance in Healthy Aging, Stroke and Neurodegenerative Conditions: a Scoping Review

Background

While the benefits of exercise on cognitive functions have already been reviewed, little is known about the impact of exercise on language performance. This scoping review was conducted to identify existing evidence on exercise-induced changes in language performance in healthy aging individuals and adults with stroke or neurodegenerative conditions.

Methods & Results

Using the Arksey and O'Malley framework, 29 studies were included. Eleven studies in healthy aging indicated enhanced language performance, with 72.72% having significant improvement in semantic/phonological Verbal Fluency (VF) following exercise. Among 18 studies on older adults with stroke or neurodegenerative conditions, 11 reported better language performance, with 44.44% having significant improvement in picture naming/description and semantic/phonological VF by exercise. The seven remaining studies reported no significant change in language performance in persons with stroke or neurodegenerative conditions.

Conclusion

Overall, exercise interventions showed improvement in language performance in healthy aging, while selective enhancement was shown for language performance in persons with either stroke or neurodegenerative conditions.

Recovery of Verbal Working Memory Depends on Left Hemisphere White Matter Tracts

Researchers propose that the recovery of language function following stroke depends on the recruitment of perilesional regions in the left hemisphere and/or homologous regions in the right hemisphere (Kiran, 2012). Many investigations of recovery focus on changes in gray matter regions (e.g., Turkeltaub et al., 2011), whereas relatively few examine white matter tracts (e.g., Schlaug et al., 2009) and none address the role of these tracts in the recovery of verbal working memory (WM). The present study addressed these gaps, examining the role of left vs. right hemisphere tracts in the longitudinal recovery of phonological and semantic WM. For 24 individuals with left hemisphere stroke, we assessed WM performance within one week of stroke (acute timepoint) and at more than six months after stroke (chronic timepoint). To address whether recovery depends on the recruitment of left or right hemisphere tracts, we assessed whether changes in WM were related to the integrity of five white matter tracts in the left hemisphere which had been implicated previously in verbal WM and their right hemisphere analogues. Behavioral results showed significant improvement in semantic but not phonological WM from the acute to chronic timepoints. Improvements in semantic WM significantly correlated with tract integrity as measured by functional anisotropy in the left direct segment of the arcuate fasciculus, inferior fronto-occipital fasciculus and inferior longitudinal fasciculus. The results confirm the role of white matter tracts in language recovery and support the involvement of the left rather than right hemisphere in the recovery of semantic WM.

Targeting Phonology or Semantics to Improve Reading Aloud Response Times and Accuracy: A Case Series Investigation of Stroke Survivors With Aphasia

PURPOSE

Acquired reading deficits, or alexia, affect a significant proportion of individuals with aphasia. We sought to improve treatment for alexia by targeting specific cognitive information-processing components critical to reading (i.e., phonology or semantics).

METHOD

To target either phonological or semantic processing, we administered two anomia treatments, phonomotor treatment (PMT) and semantic feature analysis, modified to include a focus on reading throughout the therapy. Chronic left-hemisphere stroke survivors (N = 5) completed one or two 60-hr treatment rounds. Based on predictions from a computational reading model, three participants received the treatment recommended for their specific reading challenges (e.g., PMT for phonological deficits), while two participants had the nonrecommended treatment first, followed by the recommended model-matched treatment. Changes in reading aloud accuracy and response times (RTs) from before to after treatment were examined as a function of matching treatment to the deficit profile, type of treatment, therapy round, and word characteristics.

RESULTS

Participants' reading aloud accuracy improved after treatment relative to baseline with higher accuracy for high-frequency words and shorter words. After the first treatment round, participants' accuracy and RT improved, irrespective of whether treatment was matched to the deficit profile. Furthermore, participants who completed the second treatment round continued achieving accuracy gains. Following treatment, participants demonstrated enhanced reading efficiency and generalized improvements on the selected sections of the Woodcock Reading Mastery Test.

CONCLUSIONS

While larger studies are needed to test for the effects of matching treatment type to the deficit profile, we conclude that treatments targeting specific information-processing components can effectively improve reading. Doubling the treatment dose offers small but significant gains.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.26517319.

Self-reported longitudinal impacts of the COVID-19 pandemic on adults with acquired communication disorders

PURPOSE

Adults with acquired communication disorders are particularly vulnerable to potential negative effects from the changes that arose during the COVID-19 pandemic. In this longitudinal study, we asked: How did the self-perceived impacts of the pandemic on adults with acquired communication disorders change over time?

METHOD

We developed an online survey to investigate changes in day-to-day behaviours, psychosocial elements, and communication abilities among members of a community-based stroke recovery centre in the USA. Participants included adults with aphasia or other cognitive-communication disorder from stroke or brain injury. We compared survey responses from summer 2020 (n = 50) and summer 2021 (n = 24) using a concurrent mixed methods design.

RESULT

The impacts of the pandemic changed over time. By 2021, participants reported a more "normal" amount of time spent on in-person socialising and healthcare, improved quality of life and connectedness to others, and an improvement in overall communication ability. Across both years, participants shared comments regarding changes in routine, increased use of technology, and the positive benefit of therapy groups.

CONCLUSION

Self-perceived psychosocial elements and communication abilities among stroke and other brain injury survivors changed over the course of the pandemic. Clinicians and researchers should continue providing this population with support and opportunities for engagement.

Early Boost of Linguistic Skills? Individualized Non-Invasive Brain Stimulation in Early Postacute Aphasia

Non-invasive brain stimulation, such as transcranial direct current stimulation (tDCS), has been shown to increase the outcome of speech and language therapy (SLT) in chronic aphasia. Only a few studies have investigated the effect of add-on tDCS on SLT in the early stage of aphasia; this may be due to methodological reasons, in particular the influence of spontaneous remission and the difficulty of establishing stimulation protocols in clinical routines. Thirty-seven participants with subacute aphasia (PwA) after stroke (23 men, 14 women; mean age 62 ± 12 years; mean duration 49 ± 28 days) were included in two consecutive periods of treatment lasting two weeks each. During the first period (P1) the participants received 10 sessions of SLT, during the second period (P2) the aphasia therapy was supplemented by anodal left hemispheric 2 mA tDCS over the left hemisphere. Severity-specific language tests (Aachen Aphasia Test (AAT), n = 27 and Bielefeld Aphasia Screening-Reha (BIAS-R), n = 10) were administered before P1, between P1 and P2, and after P2. Where information was available, the results were corrected for spontaneous remission (AAT sample), and the therapy outcomes of P1 and P2 were compared. Participants' overall language abilities improved significantly during P1 and P2. However, improvement-as measured by the AAT profile level or the BIAS-R mean percentage value-during P2 (with tDCS) was significantly higher than during P1 (p < 0.001; AAT sample and p = 0.005; BIAS-R sample). Thus, tDCS protocols can be implemented in early aphasia rehabilitation. Despite the limitations of the research design, which are also discussed from an implementation science perspective, this is preliminary evidence that an individually tailored anodal tDCS can have a significant add-on effect on the outcome of behavioral aphasia therapy in subacute aphasia.

Aberrant neural oscillations in poststroke aphasia

Neural oscillations are electrophysiological indicators of synchronous neuronal activity in the brain. Recent work suggests aberrant patterns of neuronal activity in patients with poststroke aphasia. Yet, there is a lack of systematic explorations of neural oscillations in poststroke aphasia. Investigating changes in the dynamics of neuronal activity after stroke may be helpful to identify neural markers of aphasia and language recovery and increase the current understanding of successful language rehabilitation. This review summarizes research on neural oscillations in poststroke aphasia and evaluates their potential as biomarkers for specific linguistic processes. We searched the literature through PubMed, Web of Science, and EBSCO, and selected 31 studies that met the inclusion criteria. Our analyses focused on neural oscillation activity in each frequency band, brain connectivity, and therapy-induced changes during language recovery. Our review highlights potential neurophysiological markers; however, the literature remains confounded, casting doubt on the reliability of these findings. Future research must address these confounds to confirm the robustness of cross-study findings on neural oscillations in poststroke aphasia.

A feasibility randomised waitlist-controlled trial of a personalised multi-level language treatment for people with aphasia: The remote LUNA study

BACKGROUND

Stroke survivors with aphasia want to improve their everyday talking (discourse). In current UK practice, 90% of speech and language therapists believe discourse assessment and treatment is part of their role but are hampered by barriers in resources, time and expertise. There is a clinical need for well-articulated discourse assessment and treatments. LUNA is a multi-level treatment targeting words, sentences and discourse macrostructure in personal stories that addresses this clinical need.

OBJECTIVES

This study aimed to assess the feasibility and acceptability of LUNA trial procedures in a randomised waitlist-controlled trial; and to evaluate preliminary efficacy.

METHODS

This paper reports a phase II, waitlist-controlled, proof-of-concept feasibility trial. Participants with chronic aphasia (n = 28) were recruited from the community and randomised to an Immediate (n = 14) or Delayed (n = 14) group. LUNA treatment was delivered twice weekly for 10 weeks via the videoconferencing technology, Zoom. Feasibility was assessed in terms of participant recruitment and retention, adherence, missing data, and treatment fidelity. Preliminary treatment efficacy was assessed in terms of between group differences in outcome measures relating to discourse, language, and psychosocial state.

RESULTS

The remote LUNA trial was feasible: 85% of those eligible consented to the trial; trial retention was 86%; 87% of treatment sessions were delivered as scheduled, and 79% of participants completed 80%+ of the treatment programme; data was missing only for participants who withdrew; treatment fidelity was high at 92% adherence; and only one clinical outcome measure demonstrated ceiling effects. ANCOVA analysis of the clinical outcome measures revealed group differences with medium and large effect sizes, indicating, improvements in the production of words, sentences, discourse macrostructure, overall language functioning (WAB-R), and psychosocial state (VAMS) following LUNA treatment. For most outcomes measured, similar treatment benefits were suggested in a secondary, non-parametric analysis.

CONCLUSIONS

Large-scale evaluation of the clinical efficacy and cost-effectiveness of LUNA is warranted and supported by these findings.

TRIAL REGISTRATION

Clinical trials registration: NCT05847023 (clinical trials.gov).

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

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

Understanding task "challenge" in stroke rehabilitation: an interdisciplinary concept analysis

PURPOSE

Rehabilitation plays a critical role in minimising disability after stroke, with the concept of "challenge" proposed to be essential to rehabilitation efficacy and outcomes. This review unpacks how challenge is conceptualised in stroke rehabilitation literature from the perspectives of physiotherapy, occupational therapy, speech-language therapy and people with stroke. A secondary purpose was to provide a definition of challenge that is applicable to stroke rehabilitation.

METHODS

Principle-based concept analysis was utilised to examine challenge within the stroke rehabilitation literature. Forty-two papers were included. Data analysis involved immersion, analytical questioning, coding and synthesis to elicit the conceptual components of challenge.

RESULTS

Challenge was understood as a multidimensional and dynamic concept with three facets: nominal, functional and perceived challenge. Functional and perceived challenge were integral to optimal challenge. Optimal challenge was central to enhancing the outcomes and experiences of people with stroke, in rehabilitation and everyday life.

CONCLUSIONS

Challenge is a key concept which, when carefully optimised to the person's ability and experience, may positively influence their learning, recovery and engagement after stroke. This review lays a conceptual foundation for better understanding, operationalisation and advancement of challenge, offering important implications for addressing the growing burden of stroke disability, through rehabilitation.

An exploration of anomia rehabilitation in drug-resistant temporal lobe epilepsy

Around 40% of patients who undergo a left temporal lobe epilepsy (LTLE) surgery suffer from anomia (word-finding difficulties), a condition that negatively impacts quality of life. Despite these observations, language rehabilitation is still understudied in LTLE. We assessed the effect of a four-week rehabilitation on four drug-resistant LTLE patients after their surgery. The anomia rehabilitation was based on cognitive descriptions of word finding deficits in LTLE. Its primary ingredients were psycholinguistic tasks and a psychoeducation approach to help patients cope with daily communication issues. We repeatedly assessed naming skills for trained and untrained words, before and during the therapy using an A-B design with follow-up and replication. Subjective anomia complaint and standardized language assessments were also collected. We demonstrated the effectiveness of the rehabilitation program for trained words despite the persistence of seizures. Furthermore, encouraging results were observed for untrained items. Variable changes in anomia complaint were observed. One patient who conducted the protocol as self-rehabilitation responded similarly to the others, despite the different manner of intervention. These results open promising avenues for helping epileptic patients suffering from anomia. For example, this post-operative program could easily be adapted to be conducted preoperatively.

A Meta-Analysis of Anomia Treatment in Bilingual Aphasia: Within- and Cross-Language Generalization and Predictors of the Treatment Outcomes

PURPOSE

The present meta-analysis investigated the efficacy of anomia treatment in bilingual and multilingual persons with aphasia (BPWAs) by assessing the magnitudes of six anomia treatment outcomes. Three of the treatment outcomes pertained to the "trained language": improvement of trained words (treatment effect [TE]), within-language generalization of semantically related untrained words (WLG-Related), and within-language generalization of unrelated words (WLG-Unrelated). Three treatment outcomes were for the "untrained language": improvement of translations of the trained words (cross-language generalization of trained words [CLG-Tx]), cross-language generalization of semantically related untrained words (CLG-Related), and cross-language generalization of unrelated untrained words (CLG-Unrelated). This study also examined participant- and treatment-related predictors of these treatment outcomes.

METHOD

This study is registered in the International Prospective Register of Systematic Reviews (PROSPERO) under the number CRD42023418147. Nine electronic databases were searched to identify word retrieval treatment studies of poststroke BPWAs of at least 6 months postonset. Pre- and posttreatment single-word naming scores were extracted for each eligible participant and used to calculate effect sizes (within-case Cohen's d) of the six treatment outcomes. Random-effects meta-analyses were conducted to assess weighted mean effect sizes of the treatment outcomes across studies. Multiple linear regression analyses were used to examine the effects of participant-related variables (pretreatment single-word naming and comprehension representing poststroke lexical processing abilities) and treatment-related variables (type, language, and duration). The methodological quality of eligible studies and the risk of bias in this meta-analysis were assessed.

RESULTS

A total of 17 published studies with 39 BPWAs were included in the meta-analysis. The methodological quality of the included studies ranged from fair (n = 4) to good (n = 13). Anomia treatment produced a medium effect size for TE (M = 8.36) and marginally small effect sizes for WLG-Related (M = 1.63), WLG-Unrelated (M = 0.68), and CLG-Tx (M = 1.56). Effect sizes were nonsignificant for CLG-Related and CLG-Unrelated. TE was significantly larger than the other five types of treatment outcomes. TE and WLG-Related effect sizes were larger for BPWAs with milder comprehension or naming impairments and for treatments of longer duration. WLG-Unrelated was larger when BPWAs received phonological treatment than semantic and mixed treatments. The overall risk of bias in the meta-analysis was low with a potential risk of bias present in the study identification process.

CONCLUSIONS

Current anomia treatment practices for bilingual speakers are efficacious in improving trained items but produce marginally small within-language generalization and cross-language generalization to translations of the trained items. These results highlight the need to provide treatment in each language of BPWAs and/or investigate other approaches to promote cross-language generalization. Furthermore, anomia treatment outcomes are influenced by BPWAs' poststroke single-word naming and comprehension abilities as well as treatment duration and the provision of phonological treatment.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25595712.

Smartphone-Based Speech Therapy for Poststroke Dysarthria: Pilot Randomized Controlled Trial Evaluating Efficacy and Feasibility

BACKGROUND

Dysarthria is a common poststroke speech disorder affecting communication and psychological well-being. Traditional speech therapy is effective but often poses challenges in terms of accessibility and patient adherence. Emerging smartphone-based therapies may offer promising alternatives for the treatment of poststroke dysarthria.

OBJECTIVE

This study aimed to assess the efficacy and feasibility of smartphone-based speech therapy for improving speech intelligibility in patients with acute and early subacute poststroke dysarthria. This study also explored the impact of the intervention on psychological well-being, user experience, and overall feasibility in a clinical setting.

METHODS

Participants were divided into 2 groups for this randomized, evaluator-blinded trial. The intervention group used a smartphone-based speech therapy app for 1 hour per day, 5 days per week, for 4 weeks, with guideline-based standard stroke care. The control group received standard guideline-based stroke care and rehabilitation. Speech intelligibility, psychological well-being, quality of life, and user acceptance were assessed using repeated measures ANOVA.

RESULTS

In this study, 40 patients with poststroke dysarthria were enrolled, 32 of whom completed the trial (16 in each group). The intervention group showed significant improvements in speech intelligibility compared with the control group. This was evidenced by improvements from baseline (F1,30=34.35; P<.001), between-group differences (F1,30=6.18; P=.02), and notable time-by-group interactions (F1,30=6.91; P=.01). Regarding secondary outcomes, the intervention led to improvements in the percentage of correct consonants over time (F1,30=5.57; P=.03). In addition, significant reductions were noted in the severity of dysarthria in the intervention group over time (F1,30=21.18; P<.001), with a pronounced group effect (F1,30=5.52; P=.03) and time-by-group interaction (F1,30=5.29; P=.03). Regarding quality of life, significant improvements were observed as measured by the EQ-5D-3L questionnaire (F1,30=13.25; P<.001) and EQ-VAS (F1,30=7.74; P=.009) over time. The adherence rate to the smartphone-based app was 64%, with over half of the participants completing all the sessions. The usability of the app was rated high (system usability score 80.78). In addition, the intervention group reported increased self-efficacy in using the app compared with the control group (F1,30=10.81; P=.003).

CONCLUSIONS

The smartphone-based speech therapy app significantly improved speech intelligibility, articulation, and quality of life in patients with poststroke dysarthria. These findings indicate that smartphone-based speech therapy can be a useful assistant device in the management of poststroke dysarthria, particularly in the acute and early subacute stroke stages.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05146765; https://clinicaltrials.gov/ct2/show/NCT05146765.

Resting-state brain network connectivity is an independent predictor of responsiveness to language therapy in chronic post-stroke aphasia

Post-stroke aphasia recovery, especially in the chronic phase, is challenging to predict. Functional integrity of the brain and brain network topology have been suggested as biomarkers of language recovery. This study sought to investigate functional connectivity in four predefined brain networks (i.e., language, default mode, dorsal attention, and salience networks), in relation to aphasia severity and response to language therapy. Thirty patients with chronic post-stroke aphasia were recruited and received a treatment targeting word finding. Structural and functional brain scans were acquired at baseline and resting state functional connectivity for each network was calculated. Additionally, graph measures quantifying network properties were calculated for each network. These included global efficiency for all networks and average strength and clustering coefficient for the language network. Linear mixed effects models showed that mean functional connectivity in the default mode, dorsal attention, and salience networks as well as graph measures of all four networks are independent predictors of response to therapy. While greater mean functional connectivity and global efficiency of the dorsal attention and salience networks predicted greater treatment response, greater mean functional connectivity and global efficiency in the default mode network predicted poorer treatment response. Results for the language network were more nuanced with more efficient network configurations (as reflected in graph measures), but not mean functional connectivity, predicting greater treatment response. These findings highlight the prognostic value of resting-state functional connectivity in chronic treatment-induced aphasia recovery.

Disentangling neuroplasticity mechanisms in post-stroke language recovery

A major objective in post-stroke aphasia research is to gain a deeper understanding of neuroplastic mechanisms that drive language recovery, with the ultimate goal of enhancing treatment outcomes. Subsequent to recent advances in neuroimaging techniques, we now have the ability to examine more closely how neural activity patterns change after a stroke. However, the way these neural activity changes relate to language impairments and language recovery is still debated. The aim of this review is to provide a theoretical framework to better investigate and interpret neuroplasticity mechanisms underlying language recovery in post-stroke aphasia. We detail two sets of neuroplasticity mechanisms observed at the synaptic level that may explain functional neuroimaging findings in post-stroke aphasia recovery at the network level: feedback-based homeostatic plasticity and associative Hebbian plasticity. In conjunction with these plasticity mechanisms, higher-order cognitive control processes dynamically modulate neural activity in other regions to meet communication demands, despite reduced neural resources. This work provides a network-level neurobiological framework for understanding neural changes observed in post-stroke aphasia and can be used to define guidelines for personalized treatment development.

tDCS of right-hemispheric Wernicke's area homologue affects contextual learning of novel lexicon

Numerous studies have shown robust evidence of the right hemisphere's involvement in the language function, for instance in the processing of intonation, grammar, word meanings, metaphors, etc. However, its role in lexicon acquisition remains obscure. We applied transcranial direct current stimulation (tDCS) over the right-hemispheric homologue of Wernicke's area to assess its putative involvement in the processing of different types of novel semantics. After receiving 15 min of anodal, cathodal, or sham (placebo) tDCS, three groups of healthy participants learnt novel concrete and abstract words in the context of short stories. Learning outcomes were assessed using a battery of tests immediately after this contextual learning session and 24 h later. As a result, an inhibitory effect of cathodal tDCS and a facilitatory effect of anodal tDCS were found for abstract word acquisition only. We also found a significant drop in task performance on the second day of the assessment for both word types in all the stimulation groups, suggesting no significant influence of tDCS on the post-learning consolidation of new memory traces. The results suggest an involvement of Wernicke's right-hemispheric counterpart in initial encoding (but not consolidation) of abstract semantics, which may be explained either by the right hemispheres direct role in processing lexical semantics or by an indirect impact of tDCS on contralateral (left-hemispheric) cortical areas through cross-callosal connections.

Are pharmacotherapeutics effective for treating aphasia?

INTRODUCTION

Aphasia is a communication disorder resulting from stroke and/or neurodegenerative conditions which involve the left cerebral hemisphere. It is a debilitating disorder affecting a person's ability to speak, understand, read, and write. Its impact on daily life necessitates therapeutic strategies to aid patients with aphasia.

AREAS COVERED

In this special report, the authors speculate whether current pharmacotherapeutic strategies are effective in treating aphasia. The authors look at aphasia caused by different conditions and how this could impact therapy before providing the reader with their expert perspectives. The aim of this paper is for the reader to gain a clearer understanding of the efficacy of the current pharmacotherapeutic treatment paradigms as well as potential future developments.

EXPERT OPINION

The exploration of pharmacotherapy for aphasia in vascular brain disorders and neurodegenerative diseases has received much attention in recent years with various therapeutic strategies having been put forward. In terms of whether pharmacotherapy is effective for the treatment of aphasia, there is still no clear-cut answer. Further research is needed with more studies requiring a greater emphasis on language and communication deficits. Biomarkers may also help clinicians provide their patients with a more personalized treatment plan.

Functional neuroimaging and behavioral correlates of multisite tDCS as an add-on to language training in a person with post-stroke non-fluent aphasia: a year-long case study

Mary, who experienced non-fluent aphasia as a result of an ischemic stroke, received 10 years of personalized language training (LT), resulting in transient enhancements in speech and comprehension. To enhance these effects, multisite transcranial Direct Current Stimulation (tDCS) was added to her LT regimen for 15 sessions. Assessment using the Reliable Change Index showed that this combination improved her left inferior frontal connectivity and speech production for two months and significantly improved comprehension after one month. The results indicate that using multisite transcranial direct current stimulation (tDCS) can improve the effectiveness of language therapy (LT) for individuals with non-fluent aphasia.

Efficacy and feasibility of a digital speech therapy for post-stroke dysarthria: protocol for a randomized controlled trial

Background

Dysarthria is a motor speech disorder caused by various neurological diseases, particularly stroke. Individuals with post-stroke dysarthria experience impaired speech intelligibility, communication difficulties, and a reduced quality of life. However, studies on the treatment of post-stroke dysarthria are lacking. Digital speech therapy applications have the advantages of being personalized and easily accessible. However, evidence for their efficacy is not rigorous. Moreover, no studies have investigated both the acute to subacute, and chronic phases of stroke. This study aims to investigate the efficacy and feasibility of digital speech therapy applications in addressing these gaps in dysarthria treatment.

Methods and design

This study is a multicenter, prospective, randomized, evaluator-blinded non-inferiority trial. We aim to recruit 76 participants with post-stroke dysarthria. Eligible participants will be stratified based on the onset period of stroke into acute to subacute, and chronic phases. Participants will be randomized in a 1:1 to receive either a personalized digital speech therapy application or conventional therapy with a workbook for 60 min daily, 5 days a week, for 4 weeks. The primary outcome is the improvement in speech intelligibility. This will be measured by how accurately independent listeners can transcribe passages read by the participants. Secondary outcomes, which include speech function, will be evaluated remotely by speech-language pathologists. This includes the maximum phonation time, oral diadochokinetic rate, and percentage of consonants correct. Participants' psychological well-being will also be assessed using self-report questionnaires, such as depressive symptoms (Patient Health Questionnaire-9) and quality of life (Quality of Life in the Dysarthric Speaker scale). The trial will also assess the feasibility, participant adherence, and usability of the application. Rigorous data collection and monitoring will be implemented to ensure patient safety.

Conclusion

This trial aims to investigate the efficacy and feasibility of digital speech therapy applications for treating post-stroke dysarthria. The results could establish foundational evidence for future clinical trials with larger sample sizes.

Clinical trial registration

Clinicaltrials.gov, identifier: NCT05865106.

Integrating EEG and Machine Learning to Analyze Brain Changes during the Rehabilitation of Broca's Aphasia

The fusion of electroencephalography (EEG) with machine learning is transforming rehabilitation. Our study introduces a neural network model proficient in distinguishing pre- and post-rehabilitation states in patients with Broca's aphasia, based on brain connectivity metrics derived from EEG recordings during verbal and spatial working memory tasks. The Granger causality (GC), phase-locking value (PLV), weighted phase-lag index (wPLI), mutual information (MI), and complex Pearson correlation coefficient (CPCC) across the delta, theta, and low- and high-gamma bands were used (excluding GC, which spanned the entire frequency spectrum). Across eight participants, employing leave-one-out validation for each, we evaluated the intersubject prediction accuracy across all connectivity methods and frequency bands. GC, MI theta, and PLV low-gamma emerged as the top performers, achieving 89.4%, 85.8%, and 82.7% accuracy in classifying verbal working memory task data. Intriguingly, measures designed to eliminate volume conduction exhibited the poorest performance in predicting rehabilitation-induced brain changes. This observation, coupled with variations in model performance across frequency bands, implies that different connectivity measures capture distinct brain processes involved in rehabilitation. The results of this paper contribute to current knowledge by presenting a clear strategy of utilizing limited data to achieve valid and meaningful results of machine learning on post-stroke rehabilitation EEG data, and they show that the differences in classification accuracy likely reflect distinct brain processes underlying rehabilitation after stroke.

Acceptability, feasibility and preliminary efficacy of low-moderate intensity Constraint Induced Aphasia Therapy and Multi-Modality Aphasia Therapy in chronic aphasia after stroke

BACKGROUND

High-intensity Constraint-Induced Aphasia Therapy Plus (CIAT-Plus) and Multi-Modality Aphasia Therapy (M-MAT) are effective interventions for chronic post-stroke aphasia but challenging to provide in clinical practice. Providing these interventions may be more feasible at lower intensities, but comparative evidence is lacking. We therefore explored feasibility, acceptability, and preliminary efficacy of the treatments at a lower intensity.

METHODS

A multisite, single-blinded, randomized Phase II trial was conducted within the Phase III COMPARE trial. Groups of participants with chronic aphasia from the usual care arm of the COMPARE trial were randomized to M-MAT or CIAT-Plus, delivered at the same dose as the COMPARE trial but at lower intensity (6 hours/week × 5 weeks rather than 15 hours/week × 2 weeks). Blinded assessors measured aphasia severity (Western Aphasia Battery-Revised Aphasia Quotient), word retrieval, connected speech, multimodal communication, functional communication, and quality of life immediately post interventions and after 12 weeks. Feasibility and acceptability were explored.

RESULTS

Of 70 eligible participants, 77% consented to the trial; 78% of randomized participants completed intervention and 98% of assessment visits were conducted. Fatigue and distress ratings were low with no related withdrawals. Adverse events related to the trial (n = 4) were mild in severity. Statistically significant treatment effects were demonstrated on word retrieval and functional communication and both interventions were equally effective.

CONCLUSIONS

Low-moderateintensity CIAT-Plus and M-MAT were feasible and acceptable. Both interventions show preliminary efficacy at a low-moderate intensity. These results support a powered trial investigating these interventions at a low-moderate intensity.

Investigating Aphasia Recovery: Demographic and Clinical Factors

Post-stroke language recovery remains one of the main unresolved topics in the field of aphasia. In recent years, there have been efforts to identify specific factors that could potentially lead to improved language recovery. However, the exact relationship between the recovery of particular language functions and possible predictors, such as demographic or lesion variables, is yet to be fully understood. In the present study, we attempted to investigate such relationships in 42 patients with aphasia after left hemisphere stroke, focusing on three language domains: auditory comprehension, naming and speech fluency. Structural imaging data were also obtained for the identification of the lesion sites. According to our findings, patients demonstrated an overall improvement in all three language domains, while no demographic factor significantly contributed to aphasia recovery. Interestingly, specific lesion loci seemed to have a differential effect on language performance, depending on the time of testing (i.e., acute/subacute vs. chronic phase). We argue that this variability concerning lesion-deficit associations reflects the dynamic nature of aphasia and further discuss possible explanations in the framework of neuroplastic changes during aphasia recovery.

Multimodal measures of sentence comprehension in agrammatism

Agrammatic or asyntactic comprehension is a common language impairment in aphasia. We considered three possible hypotheses about the underlying cause of this deficit, namely problems in syntactic processing, over-reliance on semantics, and a deficit in cognitive control. We tested four individuals showing asyntactic comprehension on their comprehension of syntax-semantics conflict sentences (e.g., The robber handcuffed the cop), where semantic cues pushed towards a different interpretation from syntax. Two of the four participants performed above chance on such sentences indicating that not all agrammatic individuals are impaired in structure-based interpretation. We collected additional eyetracking measures from the other two participants, who performed at chance on the conflict sentences. These measures suggested distinct underlying processing profiles in the two individuals. Cognitive assessments further suggested that one participant might have performed poorly due to a linguistic cognitive control impairment while the other had difficulty due to over-reliance on semantics. Together, the results highlight the importance of multimodal measures for teasing apart aphasic individuals' underlying deficits. They corroborate findings from neurotypical adults by showing that semantics can strongly influence comprehension and that cognitive control could be relevant for choosing between competing sentence interpretations. They extend previous findings by demonstrating variability between individuals with aphasia-cognitive control might be especially relevant for patients who are not overly reliant on semantics. Clinically, the identification of distinct underlying problems in different individuals suggests that different treatment paths might be warranted for cases who might look similar on behavioral assessments.

Bridging the Divide: Brain and Behavior in Developmental Language Disorder

Developmental language disorder (DLD) is a heterogenous neurodevelopmental disorder that affects a child's ability to comprehend and/or produce spoken and/or written language, yet it cannot be attributed to hearing loss or overt neurological damage. It is widely believed that some combination of genetic, biological, and environmental factors influences brain and language development in this population, but it has been difficult to bridge theoretical accounts of DLD with neuroimaging findings, due to heterogeneity in language impairment profiles across individuals and inconsistent neuroimaging findings. Therefore, the purpose of this overview is two-fold: (1) to summarize the neuroimaging literature (while drawing on findings from other language-impaired populations, where appropriate); and (2) to briefly review the theoretical accounts of language impairment patterns in DLD, with the goal of bridging the disparate findings. As will be demonstrated with this overview, the current state of the field suggests that children with DLD have atypical brain volume, laterality, and activation/connectivity patterns in key language regions that likely contribute to language difficulties. However, the precise nature of these differences and the underlying neural mechanisms contributing to them remain an open area of investigation.

Mechanisms of brain activation following naming therapy in aphasia: A systematic review on task-based fMRI studies

The pattern of brain neuroplasticity after naming therapies in patients with aphasia can be evaluated using task-based fMRI. This article aims to review studies investigating brain reorganization after semantic and phonological-based anomia therapy that used picture-naming fMRI tasks. We searched for those articles that compared the activation of brain areas before and after aphasia therapies in the PubMed and the EMBASE databases from 1993 up to April 2020. All studies (single-cases or group designs) on anomia treatment in individuals with acquired aphasia were reviewed. Data were synthesized descriptively through tables to allow the facilitated comparison of the studies. A total of 14 studies were selected and reviewed. The results of the reviewed studies demonstrated that the naming improvement is associated with changes in the activation of cortical and subcortical brain areas. This review highlights the need for a more systematic investigation of the association between decreased and increased activation of brain areas related to anomia therapy. Also, more detailed information about factors influencing brain reorganization is required to elucidate the neural mechanisms of anomia therapy. Overall, regarding the theoretical and clinical aspects, the number of studies that used intensive protocol is growing, and based on the positive potential of these treatments, they could be suitable for the rehabilitation of people with aphasia.

Unraveling the Thread of Aphasia Rehabilitation: A Translational Cognitive Perspective

Translational neuroscience is a multidisciplinary field that aims to bridge the gap between basic science and clinical practice. Regarding aphasia rehabilitation, there are still several unresolved issues related to the neural mechanisms that optimize language treatment. Although there are studies providing indications toward a translational approach to the remediation of acquired language disorders, the incorporation of fundamental neuroplasticity principles into this field is still in progress. From that aspect, in this narrative review, we discuss some key neuroplasticity principles, which have been elucidated through animal studies and which could eventually be applied in the context of aphasia treatment. This translational approach could be further strengthened by the implementation of intervention strategies that incorporate the idea that language is supported by domain-general mechanisms, which highlights the impact of non-linguistic factors in post-stroke language recovery. Here, we highlight that translational research in aphasia has the potential to advance our knowledge of brain-language relationships. We further argue that advances in this field could lead to improvement in the remediation of acquired language disturbances by remodeling the rationale of aphasia-therapy approaches. Arguably, the complex anatomy and phenomenology of aphasia dictate the need for a multidisciplinary approach with one of its main pillars being translational research.

Cerebral Small Vessel Disease Burden: An Independent Biomarker for Anomia Treatment Responsiveness in Chronic Stroke Patients With Aphasia

OBJECTIVE

To determine whether MRI-based cerebral small vessel disease (cSVD) burden predicts treatment-induced aphasia recovery in chronic stroke patients above and beyond initial aphasia severity and stroke-lesion volume.

DESIGN

Retrospective. Four cSVD neuroimaging markers were rated using validated visual scales: white matter hyperintensities, enlarged perivascular spaces, lacunes, and global cortical atrophy. We also calculated a cSVD total score. We employed linear regression models to model treatment response as a function of cSVD burden. We also ran correlation analyses to determine the association among cSVD burden and pre-treatment linguistic and non-linguistic cognition.

SETTING

Research clinic.

PARTICIPANTS

The study includes data from 30 chronic stroke patients with aphasia who received treatment for word finding difficulties and completed additional pre-treatment neuroimaging and behavioral assessments (N=30).

INTERVENTIONS

120-minute sessions of anomia treatment 2 times per week for up to 12 weeks.

MAIN OUTCOME MEASURES

Change in accuracy on the treatment probes measured as a percentage (ie, change in accuracy percentage score=post-treatment accuracy percentage minus pre-treatment accuracy percentage).

RESULTS

Baseline cSVD burden predicted response to anomia treatment independently from demographic and stroke-related factors. Patients with lower cSVD burden exhibited enhanced rehabilitation response compared with those with higher cSVD burden (β=-6.816e-02, P=.019). cSVD burden was highly associated with nonverbal executive function at baseline (r=-0.49, P=.005): patients with lower cSVD burden exhibited higher performance on nonverbal executive function tasks compared with participants with higher cSVD burden. No association was observed among cSVD burden and performance on language tasks at the baseline.

CONCLUSIONS

cSVD, a marker of brain reserve and a robust risk factor for post-stroke dementia, may be used as a biomarker for distinguishing patients who are more likely to respond to anomia therapy from those who are less likely to do so and for individualizing treatment parameters (eg, targeting both linguistic and nonlinguistic cognition in severe cSVD).

Cognitive training incorporating temporal information processing improves linguistic and non-linguistic functions in people with aphasia

People with aphasia (PWA) often present deficits in non-linguistic cognitive functions, such as executive functions, working memory, and temporal information processing (TIP), which intensify the associated speech difficulties and hinder the rehabilitation process. Therefore, training targeting non-linguistic cognitive function deficiencies may be useful in the treatment of aphasia. The present study compared the effects of the novel Dr. Neuronowski® training method (experimental training), which particularly emphasizes TIP, with the linguistic training commonly applied in clinical practice (control training). Thirty four PWA underwent linguistic and non-linguistic assessments before and after the training as well as a follow-up assessment. Patients were randomly assigned to either experimental (n = 18) or control groups (n = 16). The experimental training improved both non-linguistic functions (TIP and verbal short-term and working memory) and linguistic functions: phoneme discrimination, sentence comprehension, grammar comprehension, verbal fluency, and naming. In contrast, the control training improved only grammar comprehension and naming. The follow-up assessment confirmed the stability of the effects of both trainings over time. Thus, in PWA, Dr. Neuronowski® training appears to have broader benefits for linguistic and non-linguistic functions than does linguistic training. This provides evidence that Dr. Neuronowski® may be considered a novel tool with potential clinical applications.

Methodologies for task-fMRI based prognostic biomarkers in response to aphasia treatment

With the diversity in aphasia coupled with diminished gains at the chronic phase, it is imperative to deliver effective rehabilitation plans. Treatment outcomes have therefore been predicted using lesion-to-symptom mapping, but this method lacks holistic functional information about the language-network. This study, therefore, aims to develop whole-brain task-fMRI multivariate analysis to neurobiologically inspect lesion impacts on the language-network and predict behavioral outcomes in persons with aphasia (PWA) undergoing language therapy. In 14 chronic PWA, semantic fluency task-fMRI and behavioral measures were collected to develop prediction methodologies for post-treatment outcomes. Then, a recently developed imaging-based multivariate method to predict behavior (i.e., LESYMAP) was optimized to intake whole-brain task-fMRI data, and systematically tested for reliability with mass univariate methods. We also accounted for lesion size in both methods. Results showed that both mass univariate and multivariate methods identified unique biomarkers for semantic fluency improvements from baseline to 2-weeks post-treatment. Additionally, both methods demonstrated reliable spatial overlap in task-specific areas including the right middle frontal gyrus when identifying biomarkers of language discourse. Thus whole-brain task-fMRI multivariate analysis has the potential to identify functionally meaningful prognostic biomarkers even for relatively small sample sizes. In sum, our task-fMRI based multivariate approach holistically estimates post-treatment response for both word and sentence production and may serve as a complementary tool to mass univariate analysis in developing brain-behavior relationships for improved personalization of aphasia rehabilitation regimens.

Recursive Self-feedback Improved Speech Fluency in Two Patients with Chronic Nonfluent Aphasia

Background

Previous studies have demonstrated that people with nonfluent aphasia (PWNA) improve their language production after repeating personalized scripts, modeled by speech-language pathologists (SLPs). If PWNA could improve by using their own self-feedback, relying less on external feedback, barriers to aphasia treatment, such as a dearth of clinicians and mobility issues, can be overcome. Here we examine whether PWNA improve their language production through an automated procedure that exposes them to playbacks of their own speech, which are updated recursively, without any feedback from SLPs.

Method

We tested if recursive self-feedback could improve speech fluency in two persons with chronic nonfluent aphasia. We compared two treatments: script production with recursive self-feedback (a new technique) and a non-self-feedback training. We administered the treatments remotely to the participants through their smartphones using two versions of a mobile app we developed. Each participant engaged in each treatment for about three weeks. We estimated clinical improvements of script production through a quantitative trend analysis and nonoverlap of all pairs.

Results

Recursive self-feedback improved speaking rate and speech initiation latency of trained and untrained scripts in both participants. The control (non-self-feedback) training was also effective, but it induced a somewhat weaker improvement in speaking rate, and improved speech initiation latency in only one participant.

Conclusion

Our findings provide preliminary evidence that PWNA can improve their speaking rate and speech initiation latency during production of scripts via fully automated recursive self-feedback. The beneficial effects of recursive self-feedback training suggest that speech unison and repeated exposures to written scripts may be optional ingredients of script-based treatments for aphasia.

Turning the Spotlight to Cholinergic Pharmacotherapy of the Human Language System

Even though language is essential in human communication, research on pharmacological therapies for language deficits in highly prevalent neurodegenerative and vascular brain diseases has received little attention. Emerging scientific evidence suggests that disruption of the cholinergic system may play an essential role in language deficits associated with Alzheimer's disease and vascular cognitive impairment, including post-stroke aphasia. Therefore, current models of cognitive processing are beginning to appraise the implications of the brain modulator acetylcholine in human language functions. Future work should be directed further to analyze the interplay between the cholinergic system and language, focusing on identifying brain regions receiving cholinergic innervation susceptible to modulation with pharmacotherapy to improve affected language domains. The evaluation of language deficits in pharmacological cholinergic trials for Alzheimer's disease and vascular cognitive impairment has thus far been limited to coarse-grained methods. More precise, fine-grained language testing is needed to refine patient selection for pharmacotherapy to detect subtle deficits in the initial phases of cognitive decline. Additionally, noninvasive biomarkers can help identify cholinergic depletion. However, despite the investigation of cholinergic treatment for language deficits in Alzheimer's disease and vascular cognitive impairment, data on its effectiveness are insufficient and controversial. In the case of post-stroke aphasia, cholinergic agents are showing promise, particularly when combined with speech-language therapy to promote trained-dependent neural plasticity. Future research should explore the potential benefits of cholinergic pharmacotherapy in language deficits and investigate optimal strategies for combining these agents with other therapeutic approaches.

Understanding recovery of language after stroke: insights from neurovascular MRI studies

Stroke causes a disruption in blood flow to the brain that can lead to profound language impairments. Understanding the mechanisms of language recovery after stroke is crucial for the prognosis and effective rehabilitation of people with aphasia. While the role of injured brain structures and disruptions in functional connectivity have been extensively explored, the relationship between neurovascular measures and language recovery in both early and later stages has not received sufficient attention in the field. Fully functioning healthy brain tissue requires oxygen and nutrients to be delivered promptly via its blood supply. Persistent decreases in blood flow after a stroke to the remaining non-lesioned tissue have been shown to contribute to poor language recovery. The goal of the current paper is to critically examine stroke studies looking at the relationship between different neurovascular measures and language deficits and mechanisms of language recovery via changes in neurovascular metrics. Measures of perfusion or cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) provide complementary approaches to understanding neurovascular mechanisms post stroke by capturing both cerebral metabolic demands and mechanical vascular properties. While CBF measures indicate the amount of blood delivered to a certain region and serve as a proxy for metabolic demands of that area, CVR indices reflect the ability of the vasculature to recruit blood flow in response to a shortage of oxygen, such as when one is holding their breath. Increases in CBF during recovery beyond the site of the lesion have been shown to promote language gains. Similarly, CVR changes, when collateral vessels are recruited to help reorganize the flow of blood in hypoperfused regions, have been related to functional recovery post stroke. In the current review, we highlight the main findings in the literature investigating neurovascular changes in stroke recovery with a particular emphasis on how language abilities can be affected by changes in CBF and CVR. We conclude by summarizing existing methodological challenges and knowledge gaps that need to be addressed in future work in this area, outlining a promising avenue of research.

Research hotspots and frontiers of post-stroke aphasia rehabilitation: a bibliometric study and visualization analysis

Background

Aphasia is a common complication of stroke and is associated with high morbidity and mortality rates. Rehabilitation plays a crucial role in the comprehensive management of post-stroke aphasia and its consequences. However, bibliometric analysis in the field of post-stroke aphasia rehabilitation is still lacking. This study aimed to comprehensively identify assistance networks, analyze research trends, focus on hot and cutting-edge health topics related to post-stroke aphasia rehabilitation, and inform future research guidelines.

Methods

The Web of Science Core Collection (WoSCC) electronic database was searched from inception to January 4, 2023 to identify studies related to post-stroke aphasia rehabilitation. Bibliometric analysis and visualization of country, institution, journal, author, reference, and keywords were performed using CiteSpace and VOSviewer software.

Results

A total of 2,325 papers were included in the analysis, with a progressive increase in the number of articles published each year. The USA was the country with the most publications (809 articles), and the University of Queensland was the institution with the most publications (137 articles). The subject area of post-stroke aphasia rehabilitation is dominated by clinical neurology (882 articles). Aphasiology was the journal with the most publications (254 articles) and the most cited journal (6,893 citations). Worrall L was the most prolific author (51 publications), and Frideriksson J was the most cited author (804 citations).

Conclusion

By using bibliometrics, we provided a comprehensive review of studies related to post-stroke aphasia rehabilitation. Future research hotspots on topics related to post-stroke aphasia rehabilitation will mainly focus on the plasticity mechanisms of neurolinguistics networks, language function assessment, language rehabilitation modalities, and patients' rehabilitation needs and participation experiences in post-stroke aphasia. This paper provides systematic information that is worth exploring in the future.

The right uncinate fasciculus supports verbal short-term memory in aphasia

Verbal short-term memory (STM) deficits are associated with language processing impairments in people with aphasia. Importantly, the integrity of STM can predict word learning ability and anomia therapy gains in aphasia. While the recruitment of perilesional and contralesional homologous brain regions has been proposed as a possible mechanism for aphasia recovery, little is known about the white-matter pathways that support verbal STM in post-stroke aphasia. Here, we investigated the relationships between the language-related white matter tracts and verbal STM ability in aphasia. Nineteen participants with post-stroke chronic aphasia completed a subset of verbal STM subtests of the TALSA battery including nonword repetition (phonological STM), pointing span (lexical-semantic STM without language output) and repetition span tasks (lexical-semantic STM with language output). Using a manual deterministic tractography approach, we investigated the micro- and macrostructural properties of the structural language network. Next, we assessed the relationships between individually extracted tract values and verbal STM scores. We found significant correlations between volume measures of the right Uncinate Fasciculus and all three verbal STM scores, with the association between the right UF volume and nonword repetition being the strongest one. These findings suggest that the integrity of the right UF is associated with phonological and lexical-semantic verbal STM ability in aphasia and highlight the potential compensatory role of right-sided ventral white matter language tracts in supporting verbal STM after aphasia-inducing left hemisphere insult.

Pharmacotherapy for post-stroke aphasia: what are the options?

INTRODUCTION

Aphasia is a common, long-lasting aftermath of stroke lesions. There is an increased integration of pharmacotherapy as an adjunctive strategy to speech and language therapy (SLT) for post-stroke aphasia (PSA). Nevertheless, more research in pharmacotherapy for acute and chronic PSA is necessary, including the election of drugs that target different neurotransmitter systems and deficits in specific language domains.

AREAS COVERED

This article updates the role of pharmacotherapy for PSA, focusing the spotlight on some already investigated drugs and candidate agents deserving of future research. Refining the precision of drug election would require using multimodal biomarkers to develop personalized treatment approaches. There is a solid need to devise feasible randomized controlled trials adapted to the particularities of the PSA population. The emergent role of multimodal interventions combining one or two drugs with noninvasive brain stimulation to augment SLT is emphasized.

EXPERT OPINION

Pharmacotherapy can improve language deficits not fully alleviated by SLT. In addition, the 'drug-only' approach can also be adopted when administering SLT is not possible. The primary goal of pharmacotherapy is reducing the overall aphasia severity, although targeting language-specific deficits (i.e. naming, spoken output) also contributes to improving functional communication. Unfortunately, there is still little information for recommending a drug for specific language deficits.

Early Subacute White Matter Hyperintensities and Recovery of Language After Stroke

BACKGROUND

White matter hyperintensities (WMH) are considered to contribute to diminished brain reserve, negatively impacting on stroke recovery. While WMH identified in the chronic phase after stroke have been associated with post-stroke aphasia, the contribution of premorbid WMH to the early recovery of language across production and comprehension has not been investigated.

OBJECTIVE

To investigate the relationship between premorbid WMH severity and longitudinal comprehension and production outcomes in aphasia, after controlling for stroke lesion variables.

METHODS

Longitudinal behavioral data from individuals with a left-hemisphere stroke were included at the early subacute (n = 37) and chronic (n = 28) stage. Spoken language comprehension and production abilities were assessed at both timepoints using word and sentence-level tasks. Magnetic resonance imaging (MRI) was performed at the early subacute stage to derive stroke lesion variables (volume and proportion damage to critical regions) and WMH severity rating.

RESULTS

The presence of severe WMH explained an additional 18% and 25% variance in early subacute (t = -3.00, p = .004) and chronic (t = -3.60, P = .001) language comprehension abilities respectively, after controlling for stroke lesion variables. WMH did not predict additional variance of language production scores.

CONCLUSIONS

Subacute clinical MRI can be used to improve prognoses of recovery of aphasia after stroke. We demonstrate that severe early subacute WMH add to the prediction of impaired longitudinal language recovery in comprehension, but not production. This emphasizes the need to consider different domains of language when investigating novel neurobiological predictors of aphasia recovery.

Possible Effects of Acupuncture in Poststroke Aphasia

Neural plasticity promotes the reorganization of language networks and is an essential recovery mechanism for poststroke aphasia (PSA). Neuroplasticity may be a pivotal bridge to elucidate the potential recovery mechanisms of acupuncture for aphasia. Therefore, understanding the neuroplasticity mechanism of acupuncture in PSA is crucial. However, the underlying therapeutic mechanism of neuroplasticity in PSA after acupuncture needs to be explored. Excitotoxicity after brain injury affects the activity of neurotransmitters and disrupts the transmission of normal neuron information. Thus, a helpful strategy of acupuncture might be to improve PSA by affecting the availability of these neurotransmitters and glutamate receptors at synapses. In addition, the regulation of neuroplasticity by acupuncture may also be related to the regulation of astrocytes. Considering the guiding significance of acupuncture for clinical treatment, it is necessary to carry out further study about the influence of acupuncture on the recovery of aphasia after stroke. This study summarizes the current research on the neural mechanism of acupuncture in treating PSA. It seeks to elucidate the potential effect of acupuncture on the recovery of PSA from the perspective of synaptic plasticity and integrity of gray and white matter.

Point-light display: a new tool to improve verb recovery in patients with aphasia? A pilot study

Some studies have demonstrated that Action Observation (AO) could help patients with aphasia to recover use of verbs. However, the role of kinematics in this effect has remained unknown. The main aim was to assess the effectiveness of a complementary intervention based on the observation of action kinematics in patients with aphasia. Seven aphasic patients (3 males, 4 females) aged between 55 and 88 years participated in the studies. All patients received a classical intervention and an additional, specific intervention based on action observation. This consisted in visualizing a static image or a point-light sequence representing a human action and in trying to name the verb representing the action. In each session, 57 actions were visualized: 19 represented by a static drawing, 19 by a non-focalized point-light sequence, i.e., a point-light display with all dots in white, and 19 by a focalized point-light sequence, i.e., a point-light display (PLD) with the dots corresponding to the main limbs in yellow. Before (pre-test) and after (post-test) the intervention, each patient performed the same denomination task, in which all actions were presented in photographs. The results showed a significant improvement in performance between pre and post-test, but only when the actions were presented in focalized and non-focalized point-light sequences during the intervention. The presentation of action kinematics seems crucial in the recovery of verbs in patients with aphasia. This should be considered by speech therapists in their interventions.

Predicting Outcomes of Language Rehabilitation: Prognostic Factors for Immediate and Long-Term Outcomes After Aphasia Therapy

BACKGROUND

Aphasia therapy is an effective approach to improve language function in chronic aphasia. However, it remains unclear what prognostic factors facilitate therapy response at the individual level. Here, we utilized data from the POLAR (Predicting Outcomes of Language Rehabilitation in Aphasia) trial to (a) determine therapy-induced change in confrontation naming and long-term maintenance of naming gains and (b) examine the extent to which aphasia severity, age, education, time postonset, and cognitive reserve predict naming gains at 1 week, 1 month, and 6 months posttherapy.

METHOD

A total of 107 participants with chronic (≥ 12 months poststroke) aphasia underwent extensive case history, cognitive-linguistic testing, and a neuroimaging workup prior to receiving 6 weeks of impairment-based language therapy. Therapy-induced change in naming performance (measured as raw change on the 175-item Philadelphia Naming Test [PNT]) was assessed 1 week after therapy and at follow-up time points 1 month and 6 months after therapy completion. Change in naming performance over time was evaluated using paired t tests, and linear mixed-effects models were constructed to examine the association between prognostic factors and therapy outcomes.

RESULTS

Naming performance was improved by 5.9 PNT items (Cohen's d = 0.56, p < .001) 1 week after therapy and by 6.4 (d = 0.66, p < .001) and 7.5 (d = 0.65, p < .001) PNT items at 1 month and 6 months after therapy completion, respectively. Aphasia severity emerged as the strongest predictor of naming improvement recovery across time points; mild (ß = 5.85-9.02) and moderate (ß = 9.65-11.54) impairment predicted better recovery than severe (ß = 1.31-3.37) and very severe (ß = 0.20-0.32) aphasia. Age was an emergent prognostic factor for recovery 1 month (ß = -0.14) and 6 months (ß = -0.20) after therapy, and time postonset (ß = -0.05) was associated with retention of naming gains at 6 months posttherapy.

CONCLUSIONS

These results suggest that therapy-induced naming improvement is predictable based on several easily measurable prognostic factors. Broadly speaking, these results suggest that prognostication procedures in aphasia therapy can be improved and indicate that personalization of therapy is a realistic goal in the near future.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22141829.

Treatment-induced neural reorganization in aphasia is language-domain specific: Evidence from a large-scale fMRI study

Studies investigating the effects of language intervention on the re-organization of language networks in chronic aphasia have resulted in mixed findings, likely related to-among other factors-the language function targeted during treatment. The present study investigated the effects of the type of treatment provided on neural reorganization. Seventy individuals with chronic stroke-induced aphasia, recruited from three research laboratories and meeting criteria for agrammatism, anomia or dysgraphia were assigned to either treatment (N = 51) or control (N = 19) groups. Participants in the treatment group received 12-weeks of language intervention targeting sentence comprehension/production, naming, or spelling. At baseline and post-testing, all participants performed an fMRI story comprehension task, with blocks of auditorily-presented stories alternated with blocks of reversed speech. Participants in the treatment, but not control, group significantly improved in the treated language domain. FMRI region-of-interest (ROI) analyses, conducted within regions that were either active (or homologous to active) regions in a group of 22 healthy participants on the story comprehension task, revealed a significant increase in activation from pre-to post-treatment in right-hemisphere homologues of these regions for participants in the sentence and spelling, but not naming, treatment groups, not predicted by left-hemisphere lesion size. For the sentence (but not the spelling) treatment group, activation changes within right-hemisphere homologues of language regions were positively associated with changes in measures of verb and sentence comprehension. These findings support previous research pointing to recruitment of right hemisphere tissue as a viable route for language recovery and suggest that sentence-level treatment may promote greater neuroplasticity on naturalistic, language comprehension tasks, compared to word-level treatment.

The effect of musicality on language recovery after awake glioma surgery

Introduction

Awake craniotomy is increasingly used to resect intrinsic brain tumors while preserving language. The level of musical training might affect the speed and extend of postoperative language recovery, as increased white matter connectivity in the corpus callosum is described in musicians compared to non-musicians.

Methods

In this cohort study, we included adult patients undergoing treatment for glioma with an awake resection procedure at two neurosurgical centers and assessed language preoperatively (T1) and postoperatively at three months (T2) and one year (T3) with the Diagnostic Instrument for Mild Aphasia (DIMA), transferred to z-scores. Moreover, patients' musicality was divided into three groups based on the Musical Expertise Criterion (MEC) and automated volumetric measures of the corpus callosum were conducted.

Results

We enrolled forty-six patients, between June 2015 and September 2021, and divided in: group A (non-musicians, n = 19, 41.3%), group B (amateur musicians, n = 17, 36.9%) and group C (trained musicians, n = 10, 21.7%). No significant differences on postoperative language course between the three musicality groups were observed in the main analyses. However, a trend towards less deterioration of language (mean/SD z-scores) was observed within the first three months on the phonological domain (A: -0.425/0.951 vs. B: -0.00100/1.14 vs. C: 0.0289/0.566, p-value = 0.19) with a significant effect between non-musicians vs. instrumentalists (A: -0.425/0.951 vs. B + C: 0.201/0.699, p = 0.04). Moreover, a non-significant trend towards a larger volume (mean/SD cm³) of the corpus callosum was observed between the three musicality groups (A: 6.67/1.35 vs. B: 7.09/1.07 vs. C: 8.30/2.30, p = 0.13), with the largest difference of size in the anterior corpus callosum in non-musicians compared to trained musicians (A: 3.28/0.621 vs. C: 4.90/1.41, p = 0.02).

Conclusion

With first study on this topic, we support that musicality contributes to language recovery after awake glioma surgery, possibly attributed to a higher white matter connectivity at the anterior part of the corpus callosum. Our conclusion should be handled with caution and interpreted as hypothesis generating only, as most of our results were not significant. Future studies with larger sample sizes are needed to confirm our hypothesis.

Preoperative language tract integrity is a limiting factor in recovery from aphasia after glioma surgery

Aphasia can occur in a broad range of pathological conditions that affect cortical or subcortical structures. Here we test the hypothesis that white matter integrity of language pathways assessed by preoperative diffusion tensor imaging (DTI) is associated with language performance and its recovery after glioma resection. 27 patients with preoperative DTI were included. Segmentation of the arcuate fascicle (AF), the inferior fronto-occipital fascicle (IFOF), the inferior longitudinal fascicle (ILF), the superior longitudinal fascicle (SLF), and the uncinate fascicle (UF) was performed with a fully-connected neural network (FCNN, TractSeg). Median fractional anisotropy (FA) was extracted from the resulting volumes as surrogate marker for white matter integrity and tested for correlation with clinical parameters. After correction for demographic data and multiple testing, preoperative white matter integrity of the IFOF, the ILF, and the UF in the left hemisphere were independently and significantly associated with aphasia three months after surgery. Comparison between patients with and without aphasia three months after surgery revealed significant differences in preoperative white matter integrity of the left AF (p = 0.021), left IFOF (p = 0.015), left ILF (p = 0.003), left SLF (p = 0.001, p = 0.021, p = 0.043 for respective sub-bundles 1-3), left UF (p = 0.041) and the right AF (p = 0.027). Preoperative assessment of white matter integrity of the language network by time-efficient MRI protocols and FCNN-driven segmentation may assist in the evaluation of postoperative rehabilitation potential in glioma patients.

Longitudinal changes in functional connectivity in speech motor networks in apraxia of speech after stroke

Objective

The cerebral substrates of apraxia of speech (AOS) recovery remain unclear. Resting state fMRI post stroke can inform on altered functional connectivity (FC) within cortical language networks. Some initial studies report reduced FC between bilateral premotor cortices in patients with AOS, with lowest FC in patients with the most severe AOS. However, longitudinal FC studies in stroke are lacking. The aims of the present longitudinal study in early post stroke patients with AOS were (i) to compare connectivity strength in AOS patients to that in left hemisphere (LH) lesioned stroke patients without a speech-language impairment, (ii) to investigate the relation between FC and severity of AOS, aphasia and non-verbal oral apraxia (NVOA) and (iii) to investigate longitudinal changes in FC, from the subacute phase to the chronic phase to identify predictors of AOS recovery.

Methods

Functional connectivity measures and comprehensive speech-language assessments were obtained at 4 weeks and 6 months after stroke in nine patients with AOS after a LH stroke and in six LH lesioned stroke patients without speech-language impairment. Functional connectivity was investigated in a network for speech production: inferior frontal gyrus (IFG), anterior insula (aINS), and ventral premotor cortex (vPMC), all bilaterally to investigate signs of adaptive or maladaptive changes in both hemispheres.

Results

Interhemispheric vPMC connectivity was significantly reduced in patients with AOS compared to LH lesioned patients without speech-language impairment. At 6 months, the AOS severity was associated with interhemispheric aINS and vPMC connectivity. Longitudinal changes in FC were found in individuals, whereas no significant longitudinal change in FC was found at the group level. Degree of longitudinal AOS recovery was strongly associated with interhemispheric IFG connectivity strength at 4 weeks.

Conclusion

Early interhemispheric IFG connectivity may be a strong predictor of AOS recovery. The results support the importance of interhemispheric vPMC connection in speech motor planning and severity of AOS and suggest that also bilateral aINS connectivity may have an impact on AOS severity. These findings need to be validated in larger cohorts.

Early white matter connectivity and plasticity in post stroke aphasia recovery

A disruption of white matter connectivity is negatively associated with language (recovery) in patients with aphasia after stroke, and behavioral gains have been shown to coincide with white matter neuroplasticity. However, most brain-behavior studies have been carried out in the chronic phase after stroke, with limited generalizability to earlier phases. Furthermore, few studies have investigated neuroplasticity patterns during spontaneous recovery (i.e., not related to a specific treatment) in the first months after stroke, hindering the investigation of potential early compensatory mechanisms. Finally, the majority of previous research has focused on damaged left hemisphere pathways, while neglecting the potential protective value of their right hemisphere counterparts for language recovery. To address these outstanding issues, we present a longitudinal study of thirty-two patients with aphasia (21 males and 11 females, M = 69.47 years, SD = 10.60 years) who were followed up for a period of 1 year with test moments in the acute (1-2 weeks), subacute (3-6 months) and chronic phase (9-12 months) after stroke. Constrained Spherical Deconvolution-based tractography was performed in the acute and subacute phase to measure Fiber Bundle Capacity (FBC), a quantitative connectivity measure that is valid in crossing fiber regions, in the bilateral dorsal arcuate fasciculus (AF) and the bilateral ventral inferior fronto-occipital fasciculus (IFOF). First, concurrent analyses revealed positive associations between the left AF and phonology, and between the bilateral IFOF and semantics in the acute - but not subacute - phase, supporting the dual-stream language model. Second, neuroplasticity analyses revealed a decrease in connection density of the bilateral AF - but not the IFOF - from the acute to the subacute phase, possibly reflecting post stroke white matter degeneration in areas adjacent to the lesion. Third, predictive analyses revealed no contribution of acute FBC measures to the prediction of later language outcomes over and above the initial language scores, suggesting no added value ofthe diffusion measures for languageprediction. Our study provides new insights on (changes in) connectivity of damaged and undamaged language pathways in patients with aphasia in the first months after stroke, as well as if/how such measures are related to language outcomes at different stages of recovery. Individual results are discussed in the light of current frameworks of language processing and aphasia recovery.

Motivation Theory and Practice in Aphasia Rehabilitation: A Scoping Review

PURPOSE

In the aphasia literature, motivation has been described as potentially influencing rehabilitation outcomes, and there are reports that researchers and clinicians have acted to promote it. However, studies directly investigating the range of beliefs and practices surrounding motivation do not exist currently. The purpose of this scoping review is to develop themes related to the beliefs and practices appearing in the recent aphasia literature.

METHOD

Four databases (CINAHL, PsycINFO, PubMed, and Google Scholar) were searched using keywords aphasia and motivation (including derivatives such as motiv*) for articles published between 2009 and 2020. Searches returned 19,731 articles; after deleting duplicates and applying inclusionary criteria, 365 articles remained. In each article, text surrounding the term motivation was highlighted and thematic analysis was applied to these quotations.

RESULTS

Sixteen themes were developed through thematic analysis and placed into two groups. The first group contained five themes suggesting that researchers believed that motivation should be studied and recognized the value of motivation in person(s) with aphasia when participating in research or clinical activities. The second group contained 11 themes reporting diverse beliefs and practices in how motivation is incorporated in research and clinical activities.

CONCLUSIONS

Results from this scoping review suggest that aphasia researchers, clinicians, and persons with aphasia hold beliefs about motivation that can influence clinical and research decisions. In general, beliefs and decisions related to motivation appeared to be guided by intuition rather than theories of motivation. These themes are discussed within the context of three psychological needs proposed by self-determination theory: competency, autonomy, and relatedness. Applying theories of motivation to future study in aphasia rehabilitation will guide work that can provide empirical support for these beliefs.

Time course of right-hemisphere recruitment during word production following left-hemisphere damage: A single case of young stroke

Our understanding of post-stroke language function is largely based on older age groups, who show increasing age-related brain pathology and neural reorganisation. To illustrate language outcomes in the young-adult brain, we present the case of J., a 23-year-old woman with chronic aphasia from a left-hemisphere stroke affecting the temporal lobe. Diffusion MRI-based tractography indicated that J.'s language-relevant white-matter structures were severely damaged. Employing magnetoencephalography (MEG), we explored J.'s conceptual preparation and word planning abilities using context-driven and bare picture-naming tasks. These revealed naming deficits, manifesting as word-finding difficulties and semantic paraphasias about half of the time. Naming was however facilitated by semantically constraining lead-in sentences. Altogether, this pattern indicates disrupted lexical-semantic and phonological retrieval abilities. MEG revealed that J.'s conceptual and naming-related neural responses were supported by the right hemisphere, compared to the typical left-lateralised brain response of a matched control. Differential recruitment of right-hemisphere structures (330-440 ms post-picture onset) was found concurrently during successful naming (right mid-to-posterior temporal lobe) and word-finding attempts (right inferior frontal gyrus). Disconnection of the temporal lobes via corpus callosum was not critical for recruitment of the right hemisphere in visually guided naming, possibly due to neural activity right lateralising from the outset. Although J.'s right hemisphere responded in a timely manner during word planning, its lexical and phonological retrieval abilities remained modest.

Structural disconnections associated with language impairments in chronic post-stroke aphasia using disconnectome maps

Inconsistent findings have been reported about the impact of structural disconnections on language function in post-stroke aphasia. This study investigated patterns of structural disconnections associated with chronic language impairments using disconnectome maps. Seventy-six individuals with post-stroke aphasia underwent a battery of language assessments and a structural MRI scan. Support-vector regression disconnectome-symptom mapping analyses were performed to examine the correlations between disconnectome maps, representing the probability of disconnection at each white matter voxel and different language scores. To further understand whether significant disconnections were primarily representing focal damage or a more extended network of seemingly preserved but disconnected areas beyond the lesion site, results were qualitatively compared to support-vector regression lesion-symptom mapping analyses. Part of the left white matter perisylvian network was similarly disconnected in 90% of the individuals with aphasia. Surrounding this common left perisylvian disconnectome, specific structural disconnections in the left fronto-temporo-parietal network were significantly associated with aphasia severity and with lower performance in auditory comprehension, syntactic comprehension, syntactic production, repetition and naming tasks. Auditory comprehension, repetition and syntactic processing deficits were related to disconnections in areas that overlapped with and extended beyond lesion sites significant in SVR-LSM analyses. In contrast, overall language abilities as measured by aphasia severity and naming seemed to be mostly explained by focal damage at the level of the insular and central opercular cortices, given the high overlap between SVR-DSM and SVR-LSM results for these scores. While focal damage seems to be sufficient to explain broad measures of language performance, the structural disconnections between language areas provide additional information on the neural basis of specific and persistent language impairments at the chronic stage beyond lesion volume. Leveraging routinely available clinical data, disconnectome mapping furthers our understanding of anatomical connectivity constraints that may limit the recovery of some language abilities in chronic post-stroke aphasia.

Leveraging manifold learning techniques to explore white matter anomalies: An application of the TractLearn pipeline in epilepsy

An accurate description of brain white matter anatomy in vivo remains a challenge. However, technical progress allows us to analyze structural variations in an increasingly sophisticated way. Current methods of processing diffusion MRI data now make it possible to correct some limiting biases. In addition, the development of statistical learning algorithms offers the opportunity to analyze the data from a new perspective. We applied newly developed tractography models to extract quantitative white matter parameters in a group of patients with chronic temporal lobe epilepsy. Furthermore, we implemented a statistical learning workflow optimized for the MRI diffusion data - the TractLearn pipeline - to model inter-individual variability and predict structural changes in patients. Finally, we interpreted white matter abnormalities in the context of several other parameters reflecting clinical status, as well as neuronal and cognitive functioning for these patients. Overall, we show the relevance of such a diffusion data processing pipeline for the evaluation of clinical populations. The "global to fine scale" funnel statistical approach proposed in this study also contributes to the understanding of neuroplasticity mechanisms involved in refractory epilepsy, thus enriching previous findings.

The longitudinal neural dynamics changes of whole brain connectome during natural recovery from poststroke aphasia

Poststroke aphasia is one of the most dramatic functional deficits that results from direct damage of focal brain regions and dysfunction of large-scale brain networks. The reconstruction of language function depends on the hierarchical whole-brain dynamic reorganization. However, investigations into the longitudinal neural changes of large-scale brain networks for poststroke aphasia remain scarce. Here we characterize large-scale brain dynamics in left-frontal-stroke aphasia through energy landscape analysis. Using fMRI during an auditory comprehension task, we find that aphasia patients suffer serious whole-brain dynamics perturbation in the acute and subacute stages after stroke, in which the brains were restricted into two major activity patterns. Following spontaneous recovery process, the brain flexibility improved in the chronic stage. Critically, we demonstrated that the abnormal neural dynamics are correlated with the aberrant brain network coordination. Taken together, the energy landscape analysis exhibited that the acute poststroke aphasia has a constrained, low dimensional brain dynamics, which were replaced by less constrained and high dimensional dynamics at chronic aphasia. Our study provides a new perspective to profoundly understand the pathological mechanisms of poststroke aphasia.