Factors predicting post-stroke aphasia recovery

From concept to practice: a scoping review of the application of AI to aphasia diagnosis and management

PURPOSE

Aphasia is an acquired communication disability resulting from impairments in language processing following brain injury, most commonly stroke. People with aphasia experience difficulties in all modalities of language that impact their quality of life. Therefore, researchers have investigated the use of Artificial Intelligence (AI) to deliver innovative solutions in Aphasia management and rehabilitation.

MATERIALS AND METHODS

We conducted a scoping review of the use of AI in aphasia research and rehabilitation to explore the evolution of AI applications to aphasia, the progression of technologies and applications. Furthermore, we aimed to identify gaps in the use of AI in Aphasia to highlight the potential areas where AI might add value. We analysed 77 studies to determine the research objectives, the history of AI techniques in Aphasia and their progression over time.

RESULTS

Most of the studies focus on automated assessment using AI, with recent studies focusing on AI for therapy and personalised assistive systems. Starting from prototypes and simulations, the use of AI has progressed to include supervised machine learning, unsupervised machine learning, natural language processing, fuzzy rules, and genetic programming.

CONCLUSION

Considerable scope remains to align AI technology with aphasia rehabilitation to empower patient-centred, customised rehabilitation and enhanced self-management.

Do social determinants influence post-stroke aphasia outcomes? A scoping review

PURPOSE

To conduct a scoping review on five individual social determinants of health (SDOHs): gender, education, ethnicity, socioeconomic status, and social support, in relation to post-stroke aphasia outcomes.

MATERIALS AND METHODS

A comprehensive search across five databases was conducted in 2020 and updated in 2022. Twenty-five studies (3363 participants) met the inclusion criteria. Data on SDOHs and aphasia outcomes were extracted and analysed descriptively.

RESULTS

Twenty studies provide information on SDOH and aphasia recovery outcomes. Five studies provide insights on SDOH and response to aphasia intervention. Research on SDOH and aphasia recovery has predominantly focussed solely on language outcomes (14 studies), with less research on the role of SDOH on activity, participation, and quality of life outcomes (6 studies). There is no evidence to support a role for gender or education on language outcomes in the first 3 months post stroke. SDOHs may influence aphasia outcomes at or beyond 12 months post onset.

CONCLUSIONS

Research on SDOHs and aphasia outcomes is in its infancy. Given SDOHs are modifiable and operate over a lifetime, and aphasia is a chronic condition, there is a pressing need to understand the role of SDOHs on aphasia outcomes in the long term.

Multilevel factors predict treatment response following semantic feature-based intervention in bilingual aphasia

Semantic feature-based treatments (SFTs) are effective rehabilitation strategies for word retrieval deficits in bilinguals with aphasia (BWA). However, few studies have prospectively evaluated the effects of key parameters of these interventions on treatment outcomes. This study examined the influence of intervention-level (i.e., treatment language and treatment sessions), individual-level (baseline naming severity and age), and stimulus-level (i.e., lexical frequency, phonological length, and phonological neighborhood density) factors on naming improvement in a treated and untreated language for 34 Spanish-English BWA who completed 40 hours of SFT. Results revealed significant improvement over time in both languages. In the treated language, individuals who received therapy in their L1 improved more. Additionally, higher pre-treatment naming scores predicted greater response to treatment. Finally, a frequency effect on baseline naming accuracy and phonological effects on accuracy over time were associated with differential treatment gains. These findings indicate that multilevel factors are influential predictors of bilingual treatment outcomes.

Early within therapy naming probes as a clinically-feasible predictor of anomia treatment response

This study investigated the relationship between early within-therapy probe naming performance and anomia therapy outcomes in individuals with aphasia. Thirty-four adults with chronic, post-stroke aphasia participated in the Aphasia Language Impairment and Functioning Therapy (Aphasia LIFT) programme, comprised of 48 h of comprehensive aphasia therapy. Sets of 30 treated and 30 untreated items identified at baseline were probed during impairment therapy which targeted word retrieval using a combined semantic feature analysis and phonological component analysis approach. Multiple regression models were computed to determine the relationship between baseline language and demographic variables, early within-therapy probe naming performance (measured after 3 h of impairment therapy) and anomia treatment outcomes. Early within-therapy probe naming performance emerged as the strongest predictor of anomia therapy gains at post-therapy and at 1-month follow-up. These findings have important clinical implications, as they suggest that an individual's performance after a brief period of anomia therapy may predict response to intervention. As such, early within-therapy probe naming may provide a quick and accessible tool for clinicians to identify potential response to anomia treatment.

The volume and the distribution of premorbid white matter hyperintensities: Impact on post-stroke aphasia

White matter hyperintensities (WMH) are a radiological manifestation of progressive white matter integrity loss. The total volume and distribution of WMH within the corpus callosum have been associated with pathological cognitive ageing processes but have not been considered in relation to post-stroke aphasia outcomes. We investigated the contribution of both the total volume of WMH, and the extent of WMH lesion load in the corpus callosum to the recovery of language after first-ever stroke. Behavioural and neuroimaging data from individuals (N = 37) with a left-hemisphere stroke were included at the early subacute stage of recovery. Spoken language comprehension and production abilities were assessed using word and sentence-level tasks. Neuroimaging data was used to derive stroke lesion variables (volume and lesion load to language critical regions) and WMH variables (WMH volume and lesion load to three callosal segments). WMH volume did not predict variance in language measures, when considered together with stroke lesion and demographic variables. However, WMH lesion load in the forceps minor segment of the corpus callosum explained variance in early subacute comprehension abilities (t = -2.59, p = .01) together with corrected stroke lesion volume and socio-demographic variables. Premorbid WMH lesions in the forceps minor were negatively associated with early subacute language comprehension after aphasic stroke. This negative impact of callosal WMH on language is consistent with converging evidence from pathological ageing suggesting that callosal WMH disrupt the neural networks supporting a range of cognitive functions.

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.

[Formula: see text] Post-stroke acquired childhood aphasia. A scoping review

Aphasia has a great impact on children's lives, with stroke being its most common and studied etiology. However, our knowledge about this disorder is limited, the studies on this topic are sparse, and a consensus regarding its definition is lacking. In particular, the interpretation of this condition varied over time: from the rigid description of the so-called "standard doctrine" to the adoption of adult models for post-stroke aphasia. Therefore, this review provides a critical overview of childhood aphasia after stroke, focusing on its epidemiology, definition, diagnosis, and clinical manifestation. The scoping review approach was adopted, following PRISMA-ScR guidelines. PubMed, Web of Science, and PsycInfo databases were searched for related peer-review papers in English. Forty-six records were identified; the majority were single cases and case series, only a few were reviews and observational studies. Epidemiologic data are scarce; a few studies report that aphasia affects about one-third of children post-stroke. Despite terminological differences, there is an overall agreement on the definition of post-stroke aphasia in children as a language disorder acquired after the age of two. Approaches for the diagnosis and evaluation vary widely, including both assessments for developmental language disorders and tests for aphasia in adults. The clinical manifestations described in children are numerous and varied, similar to those found in adults, in contrast with the "standard doctrine." This review highlights the need for further studies to improve the knowledge of this condition, develop validated and specific assessment tools, and standardize clinical management.

Leukoaraiosis Is Not Associated With Recovery From Aphasia in the First Year After Stroke

After a stroke, individuals with aphasia often recover to a certain extent over time. This recovery process may be dependent on the health of surviving brain regions. Leukoaraiosis (white matter hyperintensities on MRI reflecting cerebral small vessel disease) is one indication of compromised brain health and is associated with cognitive and motor impairment. Previous studies have suggested that leukoaraiosis may be a clinically relevant predictor of aphasia outcomes and recovery, although findings have been inconsistent. We investigated the relationship between leukoaraiosis and aphasia in the first year after stroke. We recruited 267 patients with acute left hemispheric stroke and coincident fluid attenuated inversion recovery MRI. Patients were evaluated for aphasia within 5 days of stroke, and 174 patients presented with aphasia acutely. Of these, 84 patients were evaluated at ∼3 months post-stroke or later to assess longer-term speech and language outcomes. Multivariable regression models were fit to the data to identify any relationships between leukoaraiosis and initial aphasia severity, extent of recovery, or longer-term aphasia severity. We found that leukoaraiosis was present to varying degrees in 90% of patients. However, leukoaraiosis did not predict initial aphasia severity, aphasia recovery, or longer-term aphasia severity. The lack of any relationship between leukoaraiosis severity and aphasia recovery may reflect the anatomical distribution of cerebral small vessel disease, which is largely medial to the white matter pathways that are critical for speech and language function.

Therapies and Challenges in the Post-Stroke Aphasia Rehabilitation Arena: Current and Future Prospects

Aphasia is a serious consequence of stroke that results in a breakdown in communication. The course of aphasia recovery differs between afflicted individuals, and responsiveness to treatment cannot be predicted. Aphasiologists continue to investigate numerous behavioral treatment protocols that have shifted their focus to complimentary rehabilitation strategies. The aim of this study is threefold. First, to summarize the different categories of aphasia interventions post-stroke, considering their respective protocols, and present available evidence on the effectiveness of those protocols. Second, to document the challenges regarding the prediction of aphasia treatment response post-stroke in individual patients. Third, to report the challenges faced by researchers in recruiting people with aphasia (PWA) for treatment studies, and provide recommendations on how to increase participant recruitment and retention. This study provides up-to-date information on (i) effective therapies and aphasia recovery processes, and (ii) research recruitment hurdles together with potential strategies for overcoming them.

Novel participant-level meta-analytic evidence for AbSANT efficacy

The current study employed interrupted time series (ITS) models to analyze all available (published and unpublished) Abstract Semantic Associative Network Training (AbSANT) data. AbSANT is a semantically focused anomia treatment that targets not only concrete but abstract words, unique among existing anomia treatments. However, evidence to date for the positive effects of AbSANT comes only from small-sample, single-subject design studies, limiting the strength of this evidence and the inferences that can be drawn from it. The statistical power and greater representativeness afforded by this larger aggregated sample enabled us to look for group-level efficacy evidence for AbSANT, examine specific questions about AbSANT's direct training and generalization effects, and identify potential predictors and mechanisms of AbSANT treatment response. We found that across 33 participants from four different data sources, AbSANT appears to be a robust word retrieval therapy protocol, with overall direct training and generalization effects that were more meaningful than exposure effects. Similar to previous smaller-sample study conclusions, we found that in this large sample, training abstract words results not only in larger direct training effects than training concrete words, but also larger generalization effects, suggesting that while AbSANT successfully improves both abstract and concrete word retrieval, it may be better suited for training abstract words. In general, direct training effects were more persistent after treatment ended than generalization effects and effects for concrete words were more persistent than for abstract words. Additionally, the effects of generalization appear to be distinct from the effects of simple exposure to words, and generalization effects are consistent with AbSANT's hypothesized mechanism of action: spreading activation from directly trained concepts to related concepts. Also consistent with this mechanism, we found that milder aphasia and both conceptual and lexical semantic processing ability predicted both direct training and generalization gains, and that executive function was predictive of generalization effects. These factors are thus important to consider when evaluating the appropriateness of AbSANT for individual clients.

Comparison of the Effect of Four Transcranial Direct Current Stimulation Configurations on Picture-Naming Improvement in Non-Fluent Aphasia: A Randomized Clinical Trial

Background

Anomia is a language disorder that negatively affects communication abilities in people with aphasia (PWA). We aimed to compare the effect of transcranial direct current stimulation (tDCS) over the left and right inferior frontal gyrus (IFG) and superior temporal gyrus (STG) on the picture-naming accuracy and reaction time in PWA.

Methods

A randomized, single-blind, sham-controlled crossover trial was conducted in 2021 at Mobasher Kashani Clinic, Hamadan, Iran. Sixteen patients received both five days of real-tDCS (1 mA for 20 minutes) and five days of sham-tDCS with a seven-day washout period in between. Using the Persian aphasia naming test, picture-naming accuracy and reaction time on 50 images were assessed at baseline, real-tDCS, and sham-tDCS stages. The data were analyzed using STATA software, version 11.0. P<0.05 was considered statistically significant.

Results

Sixteen non-fluent PWA participated in the study. Of all patients, 64% benefited from tDCS over the STG and 18% over the IFG. The results showed that real-tDCS had a significant effect on the picture-naming accuracy (P=0.003) and the Persian-Western aphasia battery-one score (P=0.01), whereas sham-tDCS had no noticeable effects. Both the real- and sham-tDCS had no significant effect on the reaction time (P=0.28).

Conclusion

Five sessions of individualized tDCS protocol (1 mA for 20 minutes) were adequate to improve picture-naming accuracy in patients with chronic aphasia.

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.

The role of extracranial carotid duplex in predicting functional outcome in first time lacunae strokes

BACKGROUND

Stroke is the third largest cause of death both worldwide and in Taiwan. Among the various stroke subtypes, lacunae strokes account for 20 to 30% of the total stroke population. Through vigorous risk control factors, the effective prevention and the long-term functional outcome remains are yet to be investigated. Carotid duplex is a non-invasive neuroimaging modality that is routinely applied to stroke patients. In the current research, we correlate baseline carotid duplex examination parameters with functional outcome assessment in an attempt to ascertain important variables for early outcome prediction.

METHOD

We retrospectively recruited lacunae ischemic stroke patients from the Department of Neurology, Changhua Christian Hospital. Patient baseline demographics, biochemistry, neuroimaging, and outcome assessments were thoroughly evaluated via a modified Rankin Scale (mRS), NIHSS, and Barthel index scores, both prior and subsequent to patient discharge for a period of up to one year. Patients were divided into two groups based on their functional recovery status. This current study utilizes the Kaplan-Meier method to draw the survival curve and adopts the Cox proportional hazards model to estimate the hazard ratio between the two groups. The risk modeling method is also applied to formulate the best fit in seeking and identifying the variables, which has the most impact on determining theoutcome predictor. All statistical analyses were performed using R for Windows (version 3.6.3), with p < 0.05 meaning statistical significance and 0.05 < p < 0.1 denoting marginal statistical significance.

RESULTS

One hundred forty-one ischemic lacunae stroke patients are included in the study, of which the follow-ups of 69 patients showed no physical functionality improvement, whereas 72 patients demonstrated favorable functional outcomes. In terms of underlying diseases, more than 80% of the patients suffered from hyperlipidemia upon hospitalization and more than 40% of the patients suffered from diabetes mellitus and heart disease. There was a significant difference in pulmonary disease between improvement and non-improvement in disability (1.4% vs 10.1%, p = 0.034). The average age of the improved group was lower than that of the non-improved group (65.5 vs. 72, p = 0.014), and the WBC was higher (8 vs 6.95, p = 0.005); furthermore, higher NIHSS scores (6.5 vs 3, p = 0.001) and lower Barthel index scores (47.5 vs 80, p < 0.001) were also noted. The group with improved mRS required a longer hospital stay (with a median of 10 days), while their un-improved counterpart required 8 days (p < 0.05). The majority of patients were discharged within 30 days, and there was a slight difference between the two survival curves (marginal statistical significance, 0.05 < p < 0.1). The hazard ratio of the improved group was 0.7188. There was a difference in the end diastolic velocity (EDV) of common carotid artery (CCA) between the lesion and non-lesion sides of the patients (p < 0.05). Risk-stratifying models indicate that diabetes mellitus, peak systolic velocity (PSV) of the internal carotid artery (ICA) on the lesion side, the diameter of the ICA on the non-lesion side, and the pulsatility index (PI) of the ICA and external carotid artery (ECA) were selected as the most important factors affecting the end diastolic velocity (EDV) of the common carotid artery (CCA) in all four models.

CONCLUSION

In the current study, the most suitable length of stay in hospital for lacunae stroke patients to fully recuperate is ten days. Additionally, CCA EDV might be the key determinant, with baseline diabetes mellitus acting in a medium role, capable of altering long-term outcome functionality and recovery.

Depression Risk in Post-Stroke Aphasia Patients: A Nationwide Population-Based Cohort Study

INTRODUCTION

Depression and aphasia impair the quality of life after a stroke. Studies linking depression risk to post-stroke aphasia (PSA) lacked confirmation using a large database.

METHODS

Using Taiwan's National Health Insurance claims data, we identified ≥18-year-old patients hospitalized for stroke from 2005 to 2009, and those diagnosed with aphasia during hospitalization or within 3 months after discharge were selected to form the aphasic group. We estimated depression incidence by December 31, 2018, and used the Cox proportional hazards model to estimate aphasia group to non-aphasia group hazard ratios (HRs).

RESULTS

With a median follow-up period of 7.91 and 8.62 years for aphasia (n = 26,754) and non-aphasia groups (n = 139,102), respectively, the incidence of depression was higher in the aphasia group than in the non-aphasia group (9.02 vs. 8.13 per 1,000 person-years), with an adjusted HR (95% confidence intervals [CI]) of 1.21 (1.15-1.29) for depression. The adjusted HRs (95% CI) of depression were homogenous for females, 1.26 (1.15-1.37); for males, 1.18 (1.09-1.27); for hemorrhagic stroke, 1.22 (1.09-1.37); and for ischemic stroke, 1.21 (1.13-1.30). Results in analyzing 25,939 propensity score-matched pairs demonstrated an equivalent effect.

CONCLUSION

Patients with PSA are at an increased risk of developing depression, regardless of sex or stroke type.

Speech and Language Therapy for Acquired Central Dysgraphia in Neurological Patients: A Systematic Review to Describe and Identify Trainings for Clinical Practice

PURPOSE

Acquired central dysgraphia is a heterogeneous neurological disorder that usually co-occurs with other language disorders. Written language training is relevant to improve everyday skills and as a compensatory strategy to support limited oral communication. A systematic evaluation of existing writing treatments is thus needed.

METHOD

We performed a systematic review of speech and language therapies for acquired dysgraphia in studies of neurological diseases (PROSPERO: CRD42018084221), following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist with a search on several databases for articles written in English and published until August 31, 2021. Only methodological well-designed studies were included. Further assessment of methodological quality was conducted by means of a modified version of the Downs and Black checklist.

RESULTS

Eleven studies of 43 patients in total were included. For each study, we collected data on type of population, type of impairment, experimental design, type of treatment, and measured outcomes. The studies had a medium level of assessed methodological quality. An informative description of treatments and linkages to deficits is reported.

CONCLUSIONS

Although there is a need for further experimental evidence, most treatments showed good applicability and improvement of written skills in patients with dysgraphia. Lexical treatments appear to be more frequently adopted and more flexible in improving dysgraphia and communication, especially when a multimodal approach is used. Finally, the reported description of treatment modalities for dysgraphia in relation to patients' deficits may be important for providing tailored therapies in clinical management.

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.

Altered Spontaneous Brain Activity in Poststroke Aphasia: A Resting-State fMRI Study

PURPOSE

Brain areas frequently implicated in language recovery after stroke comprise perilesional sites in the left hemisphere and homotopic regions in the right hemisphere. However, the neuronal mechanisms underlying language restoration are still largely unclear.

METHODS AND MATERIALS

In the present study, we investigated the brain function in 15 patients with poststroke aphasia and 30 matched control subjects by combining the regional homogeneity (ReHo) and amplitudes of low-frequency fluctuation (ALFF) analysis methods based on resting-state fMRI.

RESULTS

Compared to the control subjects, the patients with aphasia exhibited increased ReHo and ALFF values in the ipsilateral perilesional areas and increased ReHo in the contralesional right middle frontal gyrus.

CONCLUSIONS

The increased spontaneous brain activity in patients with poststroke aphasia during the recovery period, specifically in the ipsilateral perilesional regions and the homologous language regions of the right hemisphere, has potential implications for the treatment of patients with aphasia.

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.

Sex/Gender Differences in Brain Lateralisation and Connectivity

There is now a significant body of literature concerning sex/gender differences in the human brain. This chapter will critically review and synthesise key findings from several studies that have investigated sex/gender differences in structural and functional lateralisation and connectivity. We argue that while small, relative sex/gender differences reliably exist in lateralisation and connectivity, there is considerable overlap between the sexes. Some inconsistencies exist, however, and this is likely due to considerable variability in the methodologies, tasks, measures, and sample compositions between studies. Moreover, research to date is limited in its consideration of sex/gender-related factors, such as sex hormones and gender roles, that can explain inter-and inter-individual differences in brain and behaviour better than sex/gender alone. We conclude that conceptualising the brain as 'sexually dimorphic' is incorrect, and the terms 'male brain' and 'female brain' should be avoided in the neuroscientific literature. However, this does not necessarily mean that sex/gender differences in the brain are trivial. Future research involving sex/gender should adopt a biopsychosocial approach whenever possible, to ensure that non-binary psychological, biological, and environmental/social factors related to sex/gender, and their interactions, are routinely accounted for.

Diffusion tensor imaging of dorsal stream language areas in patients with post-stroke aphasia

Background

Aphasia complicating stroke occurs due to language deficits that decrease communication abilities and functional independence. Our study aims to assess fractional anisotropy (FA) and mean diffusivity (MD) parameters of diffusion tensor imaging (DTI) of the dorsal stream language areas in patients with post-stroke aphasia. It was conducted on 27 patients with post-stroke aphasia and 27 age- and sex-matched controls who underwent DTI of the brain. FA and MD values of Broca's area (BA), Wernick's area (WA), superior longitudinal fasciculus (SLF), and arcuate fasciculus (AF), and number of tract fibers (TF) of AF and SLF were calculated. Results were correlated with National Institutes of Health Stroke Scale (NIHSS), Arabic version of Comprehensive Aphasia Test (Arabic CAT), and Mansoura Arabic Screening Aphasia Test (MASAT).

Results

FA of AF and SLF in patients was significantly lower (P = 0.001) than controls. MD of AF and SLF in patients was significantly higher (P = 0.001) than controls. The mean volume TF of AF and SLF in patients was significantly (P = 0.001) lower than the mean volume in controls for AF and SLF. FA cutoff for AF was 0.34 and for SLF, it was 0.35 with sensitivity, specificity, and accuracy (85.2%, 62.1%, 73.2%) for AF, (74.1%, 69%, 71.4%) for SLF, respectively. MD cutoff value for AF was 0.87, and 0.84 for SLF with sensitivity, specificity, and accuracy (63%, 72.4%, 67.8%) for AF, (81.5%, 79.3%, 80.4%) for SLF, respectively. Cutoff TF of AF was 1728 and for SLF it was 601 with sensitivity, specificity, and accuracy (88.9%, 72.4%, 80.4%) for AF and (85.2%, 85.2%, 78.6%) for SLF, respectively.

Conclusions

DTI is a non-invasive promising method that can be used to assess language areas in patients with post-stroke aphasia.

The role of the hippocampus in statistical learning and language recovery in persons with post stroke aphasia

Although several studies have aimed for accurate predictions of language recovery in post stroke aphasia, individual language outcomes remain hard to predict. Large-scale prediction models are built using data from patients mainly in the chronic phase after stroke, although it is clinically more relevant to consider data from the acute phase. Previous research has mainly focused on deficits, i.e., behavioral deficits or specific brain damage, rather than compensatory mechanisms, i.e., intact cognitive skills or undamaged brain regions. One such unexplored brain region that might support language (re)learning in aphasia is the hippocampus, a region that has commonly been associated with an individual's learning potential, including statistical learning. This refers to a set of mechanisms upon which we rely heavily in daily life to learn a range of regularities across cognitive domains. Against this background, thirty-three patients with aphasia (22 males and 11 females, M = 69.76 years, SD = 10.57 years) were followed for 1 year in the acute (1-2 weeks), subacute (3-6 months) and chronic phase (9-12 months) post stroke. We evaluated the unique predictive value of early structural hippocampal measures for short-term and long-term language outcomes (measured by the ANELT). In addition, we investigated whether statistical learning abilities were intact in patients with aphasia using three different tasks: an auditory-linguistic and visual task based on the computation of transitional probabilities and a visuomotor serial reaction time task. Finally, we examined the association of individuals' statistical learning potential with acute measures of hippocampal gray and white matter. Using Bayesian statistics, we found moderate evidence for the contribution of left hippocampal gray matter in the acute phase to the prediction of long-term language outcomes, over and above information on the lesion and the initial language deficit (measured by the ScreeLing). Non-linguistic statistical learning in patients with aphasia, measured in the subacute phase, was intact at the group level compared to 23 healthy older controls (8 males and 15 females, M = 74.09 years, SD = 6.76 years). Visuomotor statistical learning correlated with acute hippocampal gray and white matter. These findings reveal that particularly left hippocampal gray matter in the acute phase is a potential marker of language recovery after stroke, possibly through its statistical learning ability.

Establishing reporting standards for participant characteristics in post-stroke aphasia research: An international e-Delphi exercise and consensus meeting

Objective

To establish international, multidisciplinary expert consensus on minimum participant characteristic reporting standards in aphasia research (DESCRIBE project).

Methods

An international, three-round e-Delphi exercise and consensus meeting, involving multidisciplinary researchers, clinicians and journal editors working academically or clinically in the field of aphasia.

Results

Round 1 of the DESCRIBE e-Delphi exercise ( n = 156) generated 113 items, 20 of which reached consensus by round 3. The final consensus meeting ( n = 19 participants) established DESCRIBE's 14 participant characteristics that should be reported in aphasia studies: age; years of education; biological sex; language of treatment/testing; primary language; languages used; history of condition(s) known to impact communication/cognition; history of previous stroke; lesion hemisphere; time since onset of aphasia; conditions arising from the neurological event; and, for communication partner participants, age, biological sex and relationship to person with aphasia. Each characteristic has been defined and matched with standard response options to enable consistent reporting.

Conclusion

Aphasia research studies should report the 14 DESCRIBE participant characteristics as a minimum. Consistent adherence to the DESCRIBE minimum reporting standard will reduce research wastage and facilitate evidence-based aphasia management by enabling replication and collation of research findings, and translation of evidence into practice.

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.

Better long-term speech outcomes in stroke survivors who received early clinical speech and language therapy: What's driving recovery?

Establishing whether speech and language therapy after stroke has beneficial effects on speaking ability is challenging because of the need to control for multiple non-therapy factors known to influence recovery. We investigated how speaking ability at three time points post-stroke differed in patients who received varying amounts of clinical therapy in the first month post-stroke. In contrast to prior studies, we factored out variance from: initial severity of speaking impairment, amount of later therapy, and left and right hemisphere lesion size and site. We found that speaking ability at one month post-stroke was significantly better in patients who received early therapy (n = 79), versus those who did not (n = 64), and the number of hours of early therapy was positively related to recovery at one year post-stroke. We offer two non-mutually exclusive interpretations of these data: (1) patients may benefit from the early provision of self-management strategies; (2) therapy is more likely to be provided to patients who have a better chance of recovery (e.g., poor physical and/or mental health may impact suitability for therapy and chance of recovery). Both interpretations have implications for future studies aiming to predict individual patients' speech outcomes after stroke, and their response to therapy.

French Phonological Component Analysis and aphasia recovery: A bilingual perspective on behavioral and structural data

Studies show bilingualism entails an advantage in cognitive control tasks. There is evidence of a bilingual advantage in the context of aphasia, resulting in better cognitive outcomes and recovery in bilingual persons with aphasia compared to monolingual peers. This bilingual advantage also results in structural changes in the right hemisphere gray matter. Very few studies have examined the so-called bilingual advantage by reference to specific anomia therapy efficacy. This study aims to compare the effect of French-Phonological Component Analysis (Fr-PCA) in monolinguals and bilingual persons with aphasia, both at the linguistic and cognitive control level, and to examine the structural impact of left hemisphere lesion location and right hemisphere structural data. Eight participants with chronic aphasia received Fr-PCA for a total of 15 h over 5 weeks. The results showed improved accuracy for treated words and generalization to untreated items and discourse in both groups, and improved Flanker task performance for some participants. Bilingual participants improved more than monolinguals for picture-naming tasks and narrative discourse. Damage to the left postcentral gyrus and the middle frontal gyrus was associated with less therapy-induced improvement. Additionally, left hemisphere damage to the inferior parietal gyrus and postcentral gyrus was associated with reduced cognitive control pre-therapy. Undamaged right hemisphere cortical thicknesses were significantly different between groups; the inferior frontal gyrus and the middle frontal gyrus were greater for the bilingual participants and correlated with cognitive control skills. These results suggest a bilingual advantage in anomia recovery following Fr-PCA, potentially resulting from enhanced cognitive control abilities that could be supported by right hemisphere neural reserve.

Language learning in aphasia: A narrative review and critical analysis of the literature with implications for language therapy

People with aphasia (PWA) present with language deficits including word retrieval difficulties after brain damage. Language learning is an essential life-long human capacity that may support treatment-induced language recovery after brain insult. This prospect has motivated a growing interest in the study of language learning in PWA during the last few decades. Here, we critically review the current literature on language learning ability in aphasia. The existing studies in this area indicate that (i) language learning can remain functional in some PWA, (ii) inter-individual variability in learning performance is large in PWA, (iii) language processing, short-term memory and lesion site are associated with learning ability, (iv) preliminary evidence suggests a relationship between learning ability and treatment outcomes in this population. Based on the reviewed evidence, we propose a potential account for the interplay between language and memory/learning systems to explain spared/impaired language learning and its relationship to language therapy in PWA. Finally, we indicate potential avenues for future research that may promote more cross-talk between cognitive neuroscience and aphasia rehabilitation.

Medidas de Calidad de Vida en Personas con Afasia. Revisión Sistemática

La afasia después de un daño cerebral y sus diferentes condiciones negativas derivadas, afectan a la calidad de vida (CdV) de la persona. El objetivo de este estudio es describir y analizar la literatura de los años comprendidos entre 2016 y 2020 para identificar y cuantificar aspectos relevantes de la CdV y su evaluación en personas con afasia (PWA). Para lo anterior, se consultaron tres bases de datos (PsycINFO, Medline y Psicodoc). Se incluyeron 38 estudios. Se codificaron y analizaron las características de los estudios y se evaluó la calidad de los trabajos siguiendo las pautas marcadas por la STROBE y la NIH. Los resultados muestran que la prueba de evaluación de CdV más utilizada fue la Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39) (n= 19, 50.00%). En la mayoría de los estudios, independientemente de las pruebas de evaluación, las PWA presentan una baja CdV. Los estudios seleccionados presentan una calidad metodológica media-alta. Como conclusión cabe destacar que, además de limitar aspectos de la comunicación y el lenguaje, la afasia afecta negativamente a la CdV de forma global de la persona que la padece. El desarrollo de pruebas de evaluación de la CdV puede ayudar a los profesionales a planificar una intervención adecuada.

Motivation as a Predictor of Aphasia Treatment Outcomes: A Scoping Review

PURPOSE

Motivation is a complex phenomenon that can influence a person's ability to make progress in treatment. We sought to understand how motivation is currently measured and utilized in aphasia rehabilitation by identifying treatment studies that (1) include measurement of motivation and (2) use motivation to predict treatment response.

METHOD

A scoping review was conducted by systematically searching PubMed, CINAHL, EBSCO, Ovid MEDLINE, and APA PsycInfo using the following search terms: (measurement OR treatment OR rehabilitation OR predict*) AND (motiv* OR engagement OR adherence OR compliance) AND (aphasia OR dysphasia).

RESULTS

Two studies met our inclusion criteria. Motivation was measured differently across studies. No studies used motivation to predict treatment outcomes.

DISCUSSION/CONCLUSIONS

Despite the importance of motivation in aphasia rehabilitation success, studies that include its measurement are sparse. Additional research is needed and should include development of measurement tools and evaluation of the predictive value of motivation on treatment outcomes.

Structural Integrity and Functional Neural Activity Associated with Oral Language Function after Stroke

(1) Background: The impairment of language function after a stroke is common. It is unclear how the brain reorganizes for language function after cerebral infarction. The aim of this observational study is to investigate the association of structural integrity and functional neural activity with language function in aphasic patients with middle cerebral artery infarction. (2) Methods: Magnetic resonance images and scores from the Western Aphasia Battery on 20 patients were retrieved from medical records. A Voxel-wise linear regression analysis was performed using fractional anisotropy maps or the fractional amplitude of low-frequency fluctuation maps as dependent variables and scores of oral language function as independent variables while controlling for age and time elapsed after stroke. (3) Results: Spontaneous speech was positively associated with fractional anisotropy in the left dorsal stream and the right posterior corpus callosum and with the fractional amplitude of the low-frequency fluctuation of cranial nuclei in the pontomedullary junction. Comprehension was positively associated with the left ventral stream. Naming was positively associated with the left ventral stream and the bilateral occipitofrontal fasciculus, as well as with the fractional amplitude of low-frequency fluctuation of the supramarginal gyrus in the left hemisphere. (4) Conclusions: The dorsal and ventral streams are important for articulation and meaning after the reorganization of neural circuits following stroke. Subdomains of oral language function with a visual component are dependent on the visual association areas located in the right hemisphere.

Swallowing Ability in Stroke Patients: A Case Study in Tasikmalaya Hospital, Indonesia

BACKGROUND: Dysphagia is one of the problems that stroke patients often experience. Stroke patients who experience dysphagia often do not get attention because of the lack of early screening, which will cause delays in treatment. To overcome this, nurses have an essential role from the initial screening phase to independent nursing interventions. In screening for dysphagia, nurses can use various methods: Gugging Swallowing Screen (GUSS). AIM: The purpose of the study was to identify and explain association between respondent characteristics and the GUSS method of swallowing ability scores in stroke patients. METHODS: This research was a descriptive study, with a total sample of 20 people. The sampling technique used was consecutive sampling. RESULTS: The results showed that based on the results of the screening test for swallowing ability using the GUSS method, it was found that most of the respondents (75%) belonged to the category of severe dysphagia. Dysphagia was associated with age (p < 0.001), gender (p = 0.000), type of stroke (p < 0.001), comorbidities (p < 0.001), and the frequency of stroke attacks (p < 0.001). CONCLUSION: This study concludes that there is association between respondent characteristics: Age, gender, type of stroke, comorbidities, and frequency of attacks with the score of swallowing ability of stroke patients.

Prognostication in Poststroke Aphasia: Perspectives of Significant Others of People With Aphasia on Receiving Information About Recovery

PURPOSE

Knowing what to expect poststroke is important for many significant others of people with aphasia, yet an understanding of their perceptions and preferences in receiving prognostic information is limited. This knowledge is needed to inform the formulation and delivery of aphasia prognoses as conversations about prognosis can be harmful or helpful depending on their alignment with key stakeholder perspectives. Our preliminary study sought insight into the perspectives of significant others of people with aphasia on receiving prognostic information, with an aim toward informing evidence-based practice in aphasia prognostication.

METHOD

We interviewed seven significant others of people with aphasia, 3-12 months poststroke. The interviews were semistructured, conducted one-to-one, and analyzed qualitatively using reflexive thematic analysis.

RESULTS

Five themes were drawn from the interviews: (a) You don't know what you don't know. (b) Having them alive is the best you can ask for. (c) Recovery in the eye of the beholder. (d) Outcomes don't matter unless they help me help them. (e) It's my prognosis too if I'm living with aphasia.

CONCLUSIONS

A significant other's prognosis-related perceptions and preferences are products of their poststroke reality and may inadvertently shape that of the person with aphasia. In order to facilitate recovery, prognostication practices need to consider the needs of significant others both as providers of care and as requiring care themselves for their first-hand experiences of third-party disability.

Deep Learning Approach Using Diffusion-Weighted Imaging to Estimate the Severity of Aphasia in Stroke Patients

Background and Purpose

This study aimed to investigate the applicability of deep learning (DL) model using diffusion-weighted imaging (DWI) data to predict the severity of aphasia at an early stage in acute stroke patients.

Methods

We retrospectively analyzed consecutive patients with aphasia caused by acute ischemic stroke in the left middle cerebral artery territory, who visited Asan Medical Center between 2011 and 2013. To implement the DL model to predict the severity of post-stroke aphasia, we designed a deep feed-forward network and utilized the lesion occupying ratio from DWI data and established clinical variables to estimate the aphasia quotient (AQ) score (range, 0 to 100) of the Korean version of the Western Aphasia Battery. To evaluate the performance of the DL model, we analyzed Cohen’s weighted kappa with linear weights for the categorized AQ score (0–25, very severe; 26–50, severe; 51–75, moderate; ≥76, mild) and Pearson’s correlation coefficient for continuous values.

Results

We identified 225 post-stroke aphasia patients, of whom 176 were included and analyzed. For the categorized AQ score, Cohen’s weighted kappa coefficient was 0.59 (95% confidence interval [CI], 0.42 to 0.76; P<0.001). For continuous AQ score, the correlation coefficient between true AQ scores and model-estimated values was 0.72 (95% CI, 0.55 to 0.83; P<0.001).

Conclusions

DL approaches using DWI data may be feasible and useful for estimating the severity of aphasia in the early stage of stroke.

Behavioral interventions for poststroke aphasia

There is a long history of behavioral interventions for poststroke aphasia with hundreds of studies supporting the benefits of aphasia treatment. However, interventions for aphasia are complex with many interacting components, and no one treatment is appropriate for all persons with aphasia. We present a novel, simple framework for classifying aphasia interventions. The framework is incorporated within the overarching International Classification of Functioning, Disability, and Health (ICF) model and is consistent with the commonly-held definition that aphasia is a multimodality disorder that impairs, in varying degrees, the understanding and expression of both oral and written language modalities. Furthermore, within the language impairment level, it distinguishes between the linguistic areas of phonology, semantics, and syntax that may be impaired individually or in combination. We define the terminology of the proposed framework and then categorize some common examples of behavioral interventions for post-stroke aphasia. We describe some of these interventions in greater detail to illustrate the extensive toolbox of evidence-based treatments for aphasia. We address some key issues that clinicians, usually speech-language pathologists, consider when selecting interventions for their specific patients with aphasia, including dose. Finally, we address various models of service delivery for persons with aphasia such as Intensive Comprehensive Aphasia Programs (ICAPs) and Aphasia Centers.

Multimodal Neural and Behavioral Data Predict Response to Rehabilitation in Chronic Poststroke Aphasia

BACKGROUND

Poststroke recovery depends on multiple factors and varies greatly across individuals. Using machine learning models, this study investigated the independent and complementary prognostic role of different patient-related factors in predicting response to language rehabilitation after a stroke.

METHODS

Fifty-five individuals with chronic poststroke aphasia underwent a battery of standardized assessments and structural and functional magnetic resonance imaging scans, and received 12 weeks of language treatment. Support vector machine and random forest models were constructed to predict responsiveness to treatment using pretreatment behavioral, demographic, and structural and functional neuroimaging data.

RESULTS

The best prediction performance was achieved by a support vector machine model trained on aphasia severity, demographics, measures of anatomic integrity and resting-state functional connectivity (F1=0.94). This model resulted in a significantly superior prediction performance compared with support vector machine models trained on all feature sets (F1=0.82, P<0.001) or a single feature set (F1 range=0.68-0.84, P<0.001). Across random forest models, training on resting-state functional magnetic resonance imaging connectivity data yielded the best F1 score (F1=0.87).

CONCLUSIONS

While behavioral, multimodal neuroimaging data and demographic information carry complementary information in predicting response to rehabilitation in chronic poststroke aphasia, functional connectivity of the brain at rest after stroke is a particularly important predictor of responsiveness to treatment, both alone and combined with other patient-related factors.

Low-Frequency vs. Theta Burst Transcranial Magnetic Stimulation for the Treatment of Chronic Non-fluent Aphasia in Stroke: A Proof-of-Concept Study

BACKGROUND

Although low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) has shown promise in the treatment of poststroke aphasia, the efficacy of high-frequency rTMS (HF-rTMS) has yet to be determined.

PURPOSE

We investigated the efficacy of intermittent theta burst stimulation (iTBS) in ameliorating chronic non-fluent aphasia and compared it with that of LF-rTMS.

METHODS

We randomly assigned patients with poststroke non-fluent aphasia to an ipsilesional iTBS (n = 29), contralesional 1-Hz rTMS (n = 27), or sham (n = 29) group. Each group received the rTMS protocol executed in 10 daily sessions over 2 weeks. We evaluated language function before and after the intervention by using the Concise Chinese Aphasia Test (CCAT).

RESULTS

Compared with the sham group, the iTBS group exhibited significant improvements in conversation, description, and expression scores (P = 0.0004-0.031), which characterize verbal production, as well as in auditory comprehension, reading comprehension, and matching scores (P < 0.01), which characterize language perception. The 1-Hz group exhibited superior improvements in expression, reading comprehension, and imitation writing scores compared with the sham group (P < 0.05). The iTBS group had significantly superior results in CCAT total score, matching and auditory comprehension (P < 0.05) relative to the 1-Hz group.

CONCLUSION

Our study findings contribute to a growing body of evidence that ipsilesional iTBS enhances the language recovery of patients with non-fluent aphasia after a chronic stroke. Auditory comprehension was more preferentially enhanced by iTBS compared with the 1-Hz protocol. Our findings highlight the importance of ipsilesional modulation through excitatory rTMS for the recovery of non-fluent aphasia in patients with chronic stroke.

CLINICAL TRIAL REGISTRATION

[www.ClinicalTrials.gov], identifier [NCT03059225].

Thalamic Aphasia: a Review

PURPOSE OF REVIEW

Thalamic aphasia is a rare language disorder resulting from lesions to the thalamus. While most patients exhibit mild symptoms with a predominance of lexical-semantic difficulties, variations in phenotype have been described. Overall, the exact mechanisms of thalamic aphasia await empirical research. The article reviews recent findings regarding phenotypes and possible underlying mechanisms of thalamic aphasia.

RECENT FINDINGS

Variations in phenotype of thalamic aphasia may be related to different lesion locations. Overall, the thalamus' role in language is thought to be due to its involvement in cortico-thalamic language networks with lesioning of certain nuclei resulting in the diachisis of otherwise interconnected areas. Its possible monitoring function in such a network might be due to its different cellular firing modes. However, no specific evidence has been collected to date. While recent findings show a more distinct understanding of thalamic aphasia phenotypes and possible underlying mechanisms, further research is needed. Additionally, as standard language testing might oftentimes not pick up on its subtle symptoms, thalamic aphasia might be underdiagnosed.

Transcranial Direct-Current Stimulation and Behavioral Training, a Promising Tool for a Tailor-Made Post-stroke Aphasia Rehabilitation: A Review

Aphasia is an acquired language disorder resulting from damage to portions of the brain which are responsible for language comprehension and formulation. This disorder can involve different levels of language processing with impairments in both oral and written comprehension and production. Over the last years, different rehabilitation and therapeutic interventions have been developed, especially non-invasive brain stimulation (NIBS) techniques. One of the most used NIBS techniques in aphasia rehabilitation is the Transcranial Direct-Current Stimulation (tDCS). It has been proven to be effective in promoting a successful recovery both in the short and the long term after a brain injury. The main strength of tDCS is its feasibility associated with relatively minor side effects, if safely and properly administered. TDCS requires two electrodes, an anode and a cathode, which are generally placed on the scalp. The electrode montage can be either unipolar or bipolar. The main aim of this review is to give an overview of the state of the art of tDCS for the treatment of aphasia. The studies described included patients with different types of language impairments, especially with non-fluent aphasia and in several cases anomia. The effects of tDCS are variable and depend on several factors, such as electrode size and montage, duration of the stimulation, current density and characteristics of the brain tissue underneath the electrodes. Generally, tDCS has led to promising results in rehabilitating patients with acquired aphasia, especially if combined with different language and communication therapies. The selection of the appropriate approach depends on the patients treated and their impaired language function. When used in combination with treatments such as Speech and Language Therapy, Constraint Induced Aphasia Therapy or Intensive Action Treatment, tDCS has generally promoted a better recovery of the impaired functions. In addition to these rehabilitation protocols, Action Observation Therapy, such as IMITAF, appeared to contribute to the reduction of post-stroke anomia. The potential of combining such techniques with tDCS would would therefore be a possibility for further improvement, also providing the clinician with a new action and intervention tool. The association of a tDCS protocol with a dedicated rehabilitation training would favor a generalized long-term improvement of the different components of language.

Acquired Brain Injury in Adults: A Review of Pathophysiology, Recovery, and Rehabilitation

Purpose

To summarize existing literature from a range of fields (i.e., neurology, neuropsychology, neuroscience, neuroimaging, rehabilitation, speech-language pathology) that is relevant to the development and/or revision of cognitive rehabilitation programs for individuals with acquired brain injury (ABI) and in particular, for young adults.

Method

This paper reviews a range of ABI-associated topics including: 1) mechanisms of injury; 2) biological, individual-specific, and behavioral drivers of recovery; and 3) current methods of cognitive rehabilitation. It then narrows focus to young adults, a frequently affected and growing population to sustain ABI. The paper concludes by providing: 1) suggestions for key components of cognitive rehabilitation for young adults with ABI; 2) an example from our own research providing intensive academically-focused cognitive rehabilitation for young adults with ABI pursuing college; and 3) recommendations for future behavioral and neuroimaging studies in this area.

Conclusions

ABI is on the rise in the United States. Young adults have been sustaining ABI at higher rates over the past several decades. These injuries occur when they would otherwise be advancing their academic and career goals, making the cognitive deficits that often accompany ABI especially devastating for this group. Review of existing literature suggests cognitive rehabilitation programs that combine aspects of restorative, comprehensive, and contextualized approaches could promote recovery for young adults with ABI. Future intervention studies may benefit from including both behavioral and neural outcomes to best understand how principles of neuroplasticity- naturally embedded within many cognitive rehabilitation approaches-could be manipulated to promote cognitive recovery and long-lasting brain reorganization in this group.

Treatment of Underlying Forms: A Bayesian Meta-Analysis of the Effects of Treatment and Person-Related Variables on Treatment Response

Purpose This meta-analysis synthesizes published studies using "treatment of underlying forms" (TUF) for sentence-level deficits in people with aphasia (PWA). The study aims were to examine group-level evidence for TUF efficacy, to characterize the effects of treatment-related variables (sentence structural family and complexity; treatment dose) in relation to the Complexity Account of Treatment Efficacy (CATE) hypothesis, and to examine the effects of person-level variables (aphasia severity, sentence comprehension impairment, and time postonset of aphasia) on TUF response. Method Data from 13 single-subject, multiple-baseline TUF studies, including 46 PWA, were analyzed. Bayesian generalized linear mixed-effects interrupted time series models were used to assess the effect of treatment-related variables on probe accuracy during baseline and treatment. The moderating influence of person-level variables on TUF response was also investigated. Results The results provide group-level evidence for TUF efficacy demonstrating increased probe accuracy during treatment compared with baseline phases. Greater amounts of TUF were associated with larger increases in accuracy, with greater gains for treated than untreated sentences. The findings revealed generalization effects for sentences that were of the same family but less complex than treated sentences. Aphasia severity may moderate TUF response, with people with milder aphasia demonstrating greater gains compared with people with more severe aphasia. Sentence comprehension performance did not moderate TUF response. Greater time postonset of aphasia was associated with smaller improvements for treated sentences but not for untreated sentences. Conclusions Our results provide generalizable group-level evidence of TUF efficacy. Treatment and generalization responses were consistent with the CATE hypothesis. Model results also identified person-level moderators of TUF (aphasia severity, time postonset of aphasia) and preliminary estimates of the effects of varying amounts of TUF for treated and untreated sentences. Taken together, these findings add to the TUF evidence and may guide future TUF treatment-candidate selection. Supplemental Material https://doi.org/10.23641/asha.16828630.

Resting-State Functional Connectivity following Phonological Component Analysis: The Combined Action of Phonology and Visual Orthographic Cues

Anomia is the most frequent and pervasive symptom for people with aphasia (PWA). Phonological component analysis (PCA) is a therapy incorporating phonological cues to treat anomia. Investigations of neural correlates supporting improvements following PCA remain scarce. Resting-state functional connectivity (rsFC) as a marker of therapy-induced neuroplasticity has been reported by our team. The present study explores the efficacy of PCA in French and associated therapy-induced neuroplasticity using whole-brain rsFC analysis. Ten PWA participated in a pre-/post-PCA fMRI study with cognitive linguistic assessments. PCA was delivered in French following the standard procedure. PCA led to significant improvement with trained and untrained items. PCA also led to changes in rsFC between distributed ROIs in the semantic network, visual network, and sub-cortical areas. Changes in rsFC can be interpreted within the frame of the visual and phonological nature of PCA. Behavioral and rsFC data changes associated with PCA in French highlight its efficacy and point to the importance of phonological and orthographic cues to consolidate the word-retrieval strategy, contributing to generalization to untrained words.

Topological signal processing and inference of event-related potential response

BACKGROUND

Topological signal processing is a novel approach for decoding multiscale features of signals recorded through electroencephalography (EEG) based on topological data analysis (TDA). New method: We establish stability properties of the TDA descriptor persistence landscape (PL) in event-related potential (ERP) across multi-trial EEG signals, state algorithms for computing PL, and propose an exact inference framework on persistence and PLs.

RESULTS

We apply the topological signal processing and inference framework to compare ERPs between individuals with post-stroke aphasia and healthy controls under a speech altered auditory feedback (AAF) paradigm. Results show significant PL difference in the ERP response of aphasic individuals and healthy controls over the parietal-occipital and occipital regions with respect to speech onset, and no significant PL difference in any regions with respect to the two pitch-shift stimuli. Comparison with existing methods: In comparison, spatial patterns of difference between aphasic individuals and healthy controls by persistence, local variance, and spectral powers are much more diffuse than the PL patterns. In simulation results, the exact test on persistence and PLs has more robust performance than the baseline tests on local variance and spectral powers.

CONCLUSIONS

Persistence features provide a more robust EEG marker than local variance, and spectral powers. It could be a potentially powerful tool for comparing electrophysiological correlates in neurological disorders.

Dysfunctional Tissue Correlates of Unrelated Naming Errors in Acute Left Hemisphere Stroke

Most naming error lesion-symptom mapping (LSM) studies have focused on semantic and/or phonological errors. Anomic individuals also produce unrelated word errors, which may be linked to semantic or modality-independent lexical deficits. To investigate the neural underpinnings of rarely-studied unrelated errors, we conducted LSM analyses in 100 individuals hospitalized with a left hemisphere stroke who completed imaging protocols and language assessments. We used least absolute shrinkage and selection operator regression to capture relationships between naming errors and dysfunctional brain tissue metrics (regional damage or hypoperfusion in vascular territories) in two groups: participants with and without impaired single-word auditory comprehension. Hypoperfusion-particularly within the parietal lobe-was an important error predictor, especially for the unimpaired group. In both groups, higher unrelated error proportions were associated with primarily ventral stream damage, the language route critical for processing meaning. Nonetheless, brain metrics implicated in unrelated errors were distinct from semantic error correlates.

Auditory Comprehension Deficits in Post-stroke Aphasia: Neurologic and Demographic Correlates of Outcome and Recovery

Introduction: One of the most challenging symptoms of aphasia is an impairment in auditory comprehension. The inability to understand others has a direct impact on a person's quality of life and ability to benefit from treatment. Despite its importance, limited research has examined the recovery pattern of auditory comprehension and instead has focused on aphasia recovery more generally. Thus, little is known about the time frame for auditory comprehension recovery following stroke, and whether specific neurologic and demographic variables contribute to recovery and outcome.

Methods: This study included 168 left hemisphere chronic stroke patients stroke patients with auditory comprehension impairments ranging from mild to severe. Univariate and multivariate lesion-symptom mapping (LSM) was used to identify brain regions associated with auditory comprehension outcomes on three different tasks: Single-word comprehension, yes/no sentence comprehension, and comprehension of sequential commands. Demographic variables (age, gender, and education) were also examined for their role in these outcomes. In a subset of patients who completed language testing at two or more time points, we also analyzed the trajectory of recovery in auditory comprehension using survival curve-based time compression.

Results: LSM analyses revealed that poor single-word auditory comprehension was associated with lesions involving the left mid- to posterior middle temporal gyrus, and portions of the angular and inferior-middle occipital gyri. Poor yes/no sentence comprehension was associated almost exclusively with the left mid-posterior middle temporal gyrus. Poor comprehension of sequential commands was associated with lesions in the left posterior middle temporal gyrus. There was a small region of convergence between the three comprehension tasks, in the very posterior portion of the left middle temporal gyrus. The recovery analysis revealed that auditory comprehension scores continued to improve beyond the first year post-stroke. Higher education was associated with better outcome on all auditory comprehension tasks. Age and gender were not associated with outcome or recovery slopes.

Conclusions: The current findings suggest a critical role for the posterior left middle temporal gyrus in the recovery of auditory comprehension following stroke, and that spontaneous recovery of auditory comprehension can continue well beyond the first year post-stroke.

The role and use of event-related potentials in aphasia: A scoping review

Event-related potentials (ERPs) can provide important insights into underlying language processes in both unimpaired and neurologically impaired populations and may be particularly useful in aphasia. This scoping review was conducted to provide a comprehensive summary of how ERPs have been used with people with aphasia (PWA), with the goal of exploring the potential clinical application of ERPs in aphasia assessment and treatment. We identified 117 studies that met inclusionary criteria, reflecting six thematic domains of inquiry that relate to understanding both unimpaired and aphasic language processing and the use of ERPs with PWA. In these studies, a wide variety of ERP components were reported. Inconsistencies in reporting of participant characteristics and study protocols limit our ability to generalize beyond the individual studies and understand implications for clinical applicability. We discuss the potential roles of ERPs in aphasia management and make recommendations for further developing ERPs for clinical utility in PWA.

Effect of Repetitive Transcranial Magnetic Stimulation on Post-stroke Non-fluent Aphasia in Relation with Broca's Area

This study investigated the differences in the effect of repetitive transcranial magnetic stimulation (rTMS) between patients with and without the involvement of Broca's area (IBA). The medical records of 20 stroke patients treated with rTMS for non-fluent aphasia were reviewed. Patients completed the Korean version of the Western Aphasia Battery (K-WAB) pre- and post-rTMS. Magnetic resonance T1-weighted images of the brain were analyzed using SPM12 software. Montreal Neurological Institute templates and Talairach coordinates were used to determine Broca's area involvement and segregate patients into 2 groups: IBA and non-IBA (NBA) groups. All statistical analyses were performed using the SPSS software. Twenty subjects were included in the study. The K-WAB scores revealed improvements in the total subjects and IBA and NBA groups. There were no statistical differences between the IBA and NBA groups in the ΔK-WAB scores of aphasia quotient, fluency, comprehension, repetition, and naming. The rTMS was positive for non-fluent aphasia patients, but there was no significant difference in effectiveness depending on the IBA. Further research with a larger number of patients is needed to identify the differences in the effect of rTMS on the IBA.

Similarities between Cognitive Models of Language Production and Everyday Functioning: Implications for Development of Interventions for Functional Difficulties

The loss of the ability to independently complete activities of daily living, such as meal preparation and household chores, is a defining characteristic of clinical dementia; however, minor difficulties in completing everyday activities emerge in the mild cognitive impairment stage, and even healthy older adults exhibit subtle functional difficulties compared to younger adults. These functional difficulties are associated with an array of negative outcomes, including decreased quality of life, higher costs of care, and increased frustration, depression, caregiver burden, and institutionalization. While cognitive models have been proposed to explain the functional deficits seen in dementia and subtler forms of cognitive decline, in contrast to other cognitive disorders such as aphasia, there are essentially no theoretically motivated interventions to address difficulties in everyday functioning. Proposed models of functional impairment share features with cognitive processing models of language, including hierarchical organization of representations and interactive, spreading activation; thus, an examination of aphasia interventions has the potential to inform the development of theoretically motivated interventions for everyday activities. This review first addresses the shared characteristics of cognitive models of everyday function and language, with a focus on linguistic production. Next, we will present aphasia interventions that target single-word production, sentence production, short-term memory, and semantics, and discuss their implications for everyday functioning interventions. We conclude with a discussion of limitations of the language-everyday functioning comparison as well as areas of future research.

Stroke Recurrence and Its Relationship With Language Abilities

Purpose Many factors influence poststroke language recovery, yet little is known about the influence of previous stroke(s) on language after left hemisphere stroke. In this prospective longitudinal study, we investigated the role of prior stroke on language abilities following an acute left hemisphere ischemic stroke, while controlling for demographic and stroke-related factors, and examined if earlier stroke impacted language recovery at a chronic time point. Method Participants (n = 122) with acute left hemisphere ischemic stroke completed language evaluation and clinical neuroimaging. They were divided into two groups: single stroke (SS; n = 79) or recurrent stroke (RS; n = 43). A subset of participants (n = 31) completed chronic-stage re-evaluation. Factors studied included age, education, diabetes and hypertension diagnoses, lesion volume and broad location, group status, aphasia prevalence, and language scores. Results Groups did not differ in language performance across time points. The only significant group differences were that participants with RS were older, had smaller acute lesions, and were less educated. Stroke group membership (SS vs. RS) was not associated with language performance at either time point. In patients with prior stroke, large acute lesion volumes were associated with acute language performance, whereas both large acute and chronic volumes influenced recovery. Conclusions History of prior stroke in itself may not significantly influence language impairment after an additional acute left hemisphere stroke, unless it contributes substantially to the total volume of infarcted brain tissue. Chronic and acute lesion volumes should be accounted for in studies investigating poststroke language performance and recovery. Supplemental Material https://doi.org/10.23641/asha.14669715.

Predicting language treatment response in bilingual aphasia using neural network-based patient models

Predicting language therapy outcomes in bilinguals with aphasia (BWA) remains challenging due to the multiple pre- and poststroke factors that determine the deficits and recovery of their two languages. Computational models that simulate language impairment and treatment outcomes in BWA can help predict therapy response and identify the optimal language for treatment. Here we used the BiLex computational model to simulate the behavioral profile of language deficits and treatment response of a retrospective sample of 13 Spanish-English BWA who received therapy in one of their languages. Specifically, we simulated their prestroke naming ability and poststroke naming impairment in each language, and their treatment response in the treated and the untreated language. BiLex predicted treatment effects accurately and robustly in the treated language and captured different degrees of cross-language generalization in the untreated language in BWA. Our cross-validation approach further demonstrated that BiLex generalizes to predict treatment response for patients whose data were not used in model training. These findings support the potential of BiLex to predict therapy outcomes for BWA and suggest that computational modeling may be helpful to guide individually tailored rehabilitation plans for this population.

Predicting language recovery in post-stroke aphasia using behavior and functional MRI

Language outcomes after speech and language therapy in post-stroke aphasia are challenging to predict. This study examines behavioral language measures and resting state fMRI (rsfMRI) as predictors of treatment outcome. Fifty-seven patients with chronic aphasia were recruited and treated for one of three aphasia impairments: anomia, agrammatism, or dysgraphia. Treatment effect was measured by performance on a treatment-specific language measure, assessed before and after three months of language therapy. Each patient also underwent an additional 27 language assessments and a rsfMRI scan at baseline. Patient scans were decomposed into 20 components by group independent component analysis, and the fractional amplitude of low-frequency fluctuations (fALFF) was calculated for each component time series. Post-treatment performance was modelled with elastic net regression, using pre-treatment performance and either behavioral language measures or fALFF imaging predictors. Analysis showed strong performance for behavioral measures in anomia (R² = 0.948, n = 28) and for fALFF predictors in agrammatism (R² = 0.876, n = 11) and dysgraphia (R² = 0.822, n = 18). Models of language outcomes after treatment trained using rsfMRI features may outperform models trained using behavioral language measures in some patient populations. This suggests that rsfMRI may have prognostic value for aphasia therapy outcomes.