Neuroplasticity and aphasia treatments: new approaches for an old problem.

Given the profound impact of language impairment after stroke (aphasia), neuroplasticity research is garnering considerable attention as means for eventually improving aphasia treatments and how they are delivered. Functional and structural neuroimaging studies indicate that aphasia treatments can recruit both residual and new neural mechanisms to improve language function and that neuroimaging modalities may hold promise in predicting treatment outcome. In relatively small clinical trials, both non-invasive brain stimulation and behavioural manipulations targeting activation or suppression of specific cortices can improve aphasia treatment outcomes. Recent language interventions that employ principles consistent with inducing neuroplasticity also are showing improved performance for both trained and novel items and contexts. While knowledge is rapidly accumulating, larger trials emphasising how to select optimal paradigms for individualised aphasia treatment are needed. Finally, a model of how to incorporate the growing knowledge into clinical practice could help to focus future research.

Quality Appraisal of Systematic Reviews for Behavioral Treatments of Attention Disorders in Traumatic Brain Injury.

OBJECTIVE: This review appraised the quality of systematic reviews (SRs) and meta-analyses (MAs) to summarize research on behavioral interventions for attention disorders in persons with traumatic brain injury. METHODS: A search of 7 databases revealed 15 MAs/SRs reporting outcomes for attention treatments in traumatic brain injury. Two examiners independently coded the quality of reviews with the Critical Appraisal of Systematic Review or Meta-Analysis and the Evidence in Augmentative and Alternative Communication Systematic Review Scale. RESULTS: The findings of both scales were highly correlated. Four reviews were conducted with high methodologic rigor indicated by a score of 60% or greater on both scales. No other study scored above 45%. Among the well-conducted SRs/MAs, evidence for direct attention training effects was limited to basic attention exercises, with little generalization to functional activities. Strategy training for activities and tasks requiring attentional abilities had a stronger evidence base in 1 rigorous MA. CONCLUSIONS: This appraisal provides valuable practice information. The conclusions of 4 rigorous reviews suggest that there is only limited positive scientific support for the effects of attention treatments for traumatic brain injury. Future SRs/MAs would benefit from adherence to review guidelines.

Critical appraisal of systematic reviews of executive function treatments in TBI.

OBJECTIVE: To appraise the quality of systematic reviews (SRs) and meta-analyses (MAs) that summarize the treatment literature for executive function (EF) impairments following traumatic brain injury (TBI). METHODS: We used five data sources (PubMed; PsycINFO; ANCDS.org; Cochrane Collaboration; American Speech-Language-Hearing Association Compendium; Psychological Database for Brain Impairment Treatment Efficacy) and identified 19 reviews that met eligibility criteria (adults with TBI; behavioural treatments for EF impairments; no pharmacologic treatments). Two reviewers independently and reliably rated each paper using two appraisal tools (Critical Appraisal of Systematic Review or Meta-Analysis and Evidence in Augmentative and Alternative Communication systematic review scale). RESULTS: Five MAs received highest ratings. Four SRs also addressed the majority of SR criteria. Reviews were better at addressing SR criteria as outcome measures across studies varied considerably, posing a challenge to quantitatively synthesize TBI outcomes. The strongest research evidence favours compensatory treatments that train individuals with TBI to use strategies to circumvent EF impairments in daily activities. Smaller effects are reported for direct training approaches. CONCLUSIONS: Researchers need to identify core outcome measures to facilitate future rigorous MAs of the EF rehabilitation literature. SRs/MAs need to be conducted with thorough methods that are reported with detail.

Effectiveness of Transcranial Direct Current Stimulation as an Adjuvant to Aphasia Treatment Following Stroke: Evidence From Systematic Reviews and Meta-Analyses.

PURPOSE: Transcranial direct current stimulation (tDCS) is a neuromodulation tool to amplify neural excitability and enhance outcomes associated with speech-language therapy (SLT). Stimulation currents to the left and right hemispheres vary in applying anodal (excitatory), cathodal (inhibitory), or bihemispheric signals. Several systematic reviews (SRs) and meta-analyses (MAs) have summarized the large literature examining tDCS for aphasia rehabilitation. The purpose of this project was to appraise the quality of SRs and MAs of tDCS for aphasia and examine the weight of the evidence for language outcomes in individuals with aphasia beyond SLT alone. METHOD: We searched four databases for SRs/MAs examining effects of tDCS for poststroke aphasia. We identified 16 reviews, with nine that incorporated MA to quantify results. Two reviewers reliably coded articles for methodological rigor using the AMSTAR 2 (A MeaSurement Tool to Assess Systematic Reviews, Version 2). We then summarized findings of the 16 reviews. RESULTS: The AMSTAR 2 appraisal criteria suggest that critical weaknesses were noted among all reviews except those by Elsner et al. (2015, 2019). Reviews summarized three to 48 studies, as some included only randomized crossover trials and others included all trial designs. All SRs and one MA reported improvements following tDCS stimulation for general aphasia abilities and measures of repetition and speech fluency. Five recent MAs reported significant naming improvements following tDCS using all stimulation arrays. No tDCS effects were noted for comprehension measures. CONCLUSIONS: As the tDCS literature matured, the conclusions of MAs merged with earlier SRs reporting statistically positive benefits over SLT alone. Most consistent results are reported for naming measures, leaving some to question the clinical significance of tDCS effects for functional measures of aphasia recovery. Although the tDCS literature is expansive, important questions remain before the technique can be confidently recommended for clinical practice.

Effectiveness of Constraint-Induced Language Therapy for Aphasia: Evidence From Systematic Reviews and Meta-Analyses.

PURPOSE: Constraint-induced language therapy (CILT) is an aphasia treatment that incorporates neuroplasticity principles of forced verbal use and high-intensity training to facilitate language recovery in individuals with stroke-induced aphasia (Pulvermüller et al., 2001). The burgeoning CILT literature has led to systematic reviews (SRs) that summarize treatment results. In this project, we appraised the quality and examined findings reported in several SRs to draw conclusions about the effectiveness of CILT. METHOD: We searched multiple databases for SRs that summarized CILT research for poststroke aphasia. We identified six SRs, among which three summarized findings qualitatively and three included meta-analysis (MA) to quantify results. We rated each SR for methodologic quality using the A MeaSurement Tool to Assess Systematic Reviews (AMSTAR 2; Shea et al., 2017) and extracted findings across the six SRs. RESULTS: Two reviewers reliably applied the AMSTAR 2 to the six SRs. Although the six SRs generally were conducted with satisfactory rigor, each was lacking two or more critical domains. Descriptive summaries in SRs reported positive effects of CILT for language and communication measures. However, the three MAs showed that effects of CILT often did not surpass those of comparison treatments for naming, comprehension, and repetition measures. MA findings were positive in a review that included all research designs and evaluated treatment effects for trained naming items. Generalized CILT effects for standardized language measures were limited in two other MAs. CONCLUSIONS: CILT led to improvements in a variety of language and communication measures. When compared with intensive multimodality treatments, CILT effects were similar, suggesting that training intensity may be the potent factor in CILT outcomes. Future SRs should be implemented with increased rigor across quality rating scale domains to increase confidence in conclusions.

Contrasting effects of errorless naming treatment and gestural facilitation for word retrieval in aphasia.

We compared the effects of two treatments for aphasic word retrieval impairments, errorless naming treatment (ENT) and gestural facilitation of naming (GES), within the same individuals, anticipating that the use of gesture would enhance the effect of treatment over errorless treatment alone. In addition to picture naming, we evaluated results for other outcome measures that were largely untested in earlier ENT studies. In a single participant crossover treatment design, we examined the effects of ENT and GES in eight individuals with stroke-induced aphasia and word retrieval impairments (three semantic anomia, five phonological anomia) in counterbalanced phases across participants. We evaluated effects of the two treatments for a daily picture naming/gesture production probe measure and in standardised aphasia tests and communication rating scales administered across phases of the experiment. Both treatments led to improvements in naming of trained words (small-to-large effect sizes) in individuals with semantic and phonological anomia. Small generalised naming improvements were noted for three individuals with phonological anomia. GES improved use of corresponding gestures for trained words (large effect sizes). Results were largely maintained at one month post-treatment completion. Increases in scores on standardised aphasia testing also occurred for both ENT and GES training. Both ENT and GES led to improvements in naming measures, with no clear difference between treatments. Increased use of gestures following GES provided a potential compensatory means of communication for those who did not improve verbal skills. Both treatments are considered to be effective methods to promote recovery of word retrieval and verbal production skills in individuals with aphasia.

Applying Appraisal Tools in Aphasia Systematic Reviews: A Tutorial.

PURPOSE: A systematic review (SR) represents a rigorous process of identifying and summarizing current research to answer specific clinical questions. Not all SRs present high-quality information, because they do not adhere to established standards of conduct or reporting. This tutorial aims to (a) describe two tools developed in epidemiology for reporting (PRISMA 2020; Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and appraising (AMSTAR 2; A MeaSurement Tool to Assess Systematic Reviews) SRs and (b) exemplify the use of AMSTAR 2. First, we describe the intents of PRISMA 2020 and AMSTAR 2 and compare the items on each checklist. Next, we apply the AMSTAR 2 list of domains to critically appraise methodological quality in two randomly selected SRs, which describe aphasia treatment. Appraisal results are reported, including the AMSTAR 2 ratings for overall confidence in the results of each review. For each SR, the overall rating was critically low, indicating that within the seven critical domains of AMSTAR 2, the SR had more than one critical weakness. CONCLUSIONS: While PRISMA 2020 is a tool to guide preparation of SRs, to examine SR quality, the AMSTAR 2 is the tool of choice. Applied to two current aphasia treatment SRs, the AMSTAR 2 demonstrates that although both SRs were thorough, thoughtful summaries of a body of aphasia treatment literature, they did not achieve high ratings for methodological quality. Clinicians reading SRs are advised to familiarize themselves with quality assessment tools to assure that an SR meets expected criteria to document internal and external validity of the SR process, so resulting findings can be confidently applied for patients with aphasia.

Intensity of aphasia therapy: evidence and efficacy.

Determining the optimal amount and intensity of treatment is essential to the design and implementation of any treatment program for aphasia. A growing body of evidence, both behavioral and biological, suggests that intensive therapy positively impacts outcomes. We update a systematic review of treatment studies that directly compares conditions of higher and lower intensity treatment for aphasia. We identify five studies published since 2006, review them for methodologic quality, and synthesize their findings with previous ones. For both acute and chronic aphasia, results at the language impairment and communication activity/participation levels tend to be more equivocal than previously demonstrated, with no clear differences between intensive and nonintensive treatment emerging across studies. Future research directions are discussed including research design, definitions of treatment intensity, and behavioral and biological measurement of short- and long-term changes following implementation of an intensive treatment.

Cognitive Assessments for Patients With Neurological Conditions: A Preliminary Survey of Speech-Language Pathology Practice Patterns.

Purpose Speech-language pathologists (SLPs) are often responsible for assessing cognitive disorders that affect communication for individuals with diagnosed or suspected acute or degenerative neurological conditions. However, consensus on appropriate assessment tools for various neurological disorders remains elusive. This preliminary survey was conducted to study current practices in the use of published and unpublished tools by SLPs when assessing cognitive-communication impairments across common neurologic conditions. Method An 18-item web-based survey was sent to SLPs through ASHA Communities and social media, asking them to select which cognitive assessment tools they use to evaluate the cognitive-communication status of individuals with Parkinson's disease, multiple sclerosis, dementia, stroke (i.e., cerebrovascular accident), and traumatic brain injury. The 100 SLPs who completed the online survey represent a spectrum of professionals seeing neurologic patients across the United States. Results Among the 100 responding SLPs, no unique pattern of assessment tool use was noted across neurologic disorders as indicated by a chi-square analysis. A common set of nonstandardized and observational assessment practices was reported most commonly, regardless of the neurologic condition. Conclusions This study shows consistent cognitive assessment practices by SLPs across various neurological conditions rather than unique protocols relevant to the patterns typical across disorders. However, the amount of clinical evaluations supported by informal observation and/or the completion of select subtests of standardized assessment tools is considerable. This preliminary information conflicts with principles of rigorous assessment and increases the risk of erroneous findings when identifying cognitive impairments. Further research into the decision-making process of clinician assessment selection is warranted to encourage consistent, evidence-based practice for persons with cognitive impairments. Better recognition of the limitations imposed by providing clinical services that impact the reliability and validity of cognitive assessments can drive future clinical practice policy and practice recommendations.

Executive Functions and Student Success During Physical Therapist Education: An Exploratory Study.

BACKGROUND: Clinical reasoning relies on executive functions (EFs) that manage attention, inhibition, organization, and decision-making. Assessment of EFs may help identify students who excel at clinical reasoning, yet data showing this relationship in physical therapy (PT) education programs are lacking. The primary purpose of this exploratory study was to examine EFs in relationship to success in PT educational programs. METHODS: Thirteen third-year PT graduate students completed two EF tests which were compared to culminating scores in the program and admissions scores. RESULTS: A relationship existed between National Physical Therapy Examination (NPTE) and comprehensive exam results and one EF test score; comprehensive exams and NPTE scores related to the other EF test. CONCLUSIONS: EF measures may provide insights into student successes, especially as they pertain to outcomes requiring clinical reasoning.

Translational research in aphasia: from neuroscience to neurorehabilitation.

PURPOSE: In this article, the authors encapsulate discussions of the Language Work Group that took place as part of the Workshop in Plasticity/NeuroRehabilitation Research at the University of Florida in April 2005. METHOD: In this narrative review, they define neuroplasticity and review studies that demonstrate neural changes associated with aphasia recovery and treatment. The authors then summarize basic science evidence from animals, human cognition, and computational neuroscience that is relevant to aphasia treatment research. They then turn to the aphasia treatment literature in which evidence exists to support several of the neuroscience principles. CONCLUSION: Despite the extant aphasia treatment literature, many questions remain regarding how neuroscience principles can be manipulated to maximize aphasia recovery and treatment. They propose a framework, incorporating some of these principles, that may serve as a potential roadmap for future investigations of aphasia treatment and recovery. In addition to translational investigations from basic to clinical science, the authors propose several areas in which translation can occur from clinical to basic science to contribute to the fundamental knowledge base of neurorehabilitation. This article is intended to reinvigorate interest in delineating the factors influencing successful recovery from aphasia through basic, translational, and clinical research.

Treatment of adynamia in aphasia.

Transcortical motor aphasia (TCMA) is an acquired impairment of language expression that occurs following neurologic damage that affects left frontal cortex and spares perisylvian regions. In some individuals with TCMA, verbal expression is rendered nonfluent due to difficulty spontaneously initiating and elaborating upon verbal messages. Nonfluency arises from impaired activation of intended messages and inhibition of competing verbal expressions. This impairment of the intentional aspects of language expression can be termed 'adynamia.' Because adynamic forms of TCMA occur infrequently, few systematic treatment investigations have been reported for this condition. Behavioral treatments have been proposed to engage intact frontal regions to improve the ability to initiate spontaneous verbal expression. Some data suggest that nonsymbolic limb movements performed in the context of speaking activities, a form of what Luria termed gestural reorganization, may improve the adynamic verbal expression. (1) In addition, the influence of pharmacologic treatment with bromocriptine, a dopaminergic agonist, has been considered for its effects on verbal nonfluency in aphasia. Individuals classified as TCMA are more likely to benefit than those with other forms of nonfluent aphasia, suggesting an influence of bromocriptine on circuits necessary to activate spontaneous language. Additional studies are warranted that contrast behavioral and pharmacologic interventions to determine optimal conditions to improve verbal expression in adynamic forms of aphasia.

Management of anomia.

Anomia is a complex, commonly occurring symptom of aphasia with different underlying causes. A number of behavioral approaches to rehabilitation of anomia have been described. Some are restitutive in nature and attempt to reactivate lexical-semantic or phonological representations to improve word retrieval. Others are intended to reorganize language functions by engaging alternative cognitive systems to mediate word retrieval or by exploiting residual abilities to circumvent the impairment. A better appreciation of the characteristics of an individual's naming deficit may assist the clinician in selecting appropriate interventions for restitution or substitution of function in the management of this disorder.

A comparison of intention and pantomime gesture treatment for noun retrieval in people with aphasia.

PURPOSE: The effects of intention gesture treatment (IGT) and pantomime gesture treatment (PGT) on word retrieval were compared in people with aphasia. METHOD: Four individuals with aphasia and word retrieval impairments subsequent to left-hemisphere stroke participated in a single-participant crossover treatment design. Each participant viewed target nouns on a computer screen in 2 counterbalanced training phases. Training included paired verbal + gesture treatment strategies to elicit verbal and/or gestural productions of target nouns. Treatment effects were measured using daily picture-naming probes for verbal naming and gesture productions for trained and untrained words as well as pre-/posttreatment standardized aphasia tests. Outcomes and Results IGT resulted in immediate effects on the verbal productions of 2 participants but lacked carryover to untrained words. PGT resulted in improved verbal production for 2 participants and immediate effects on the gesture productions of 3 participants, with carryover of gesture production to untrained words in 1 participant. Improvements on standardized aphasia tests were evident in 2 participants. CONCLUSION: IGT and PGT had positive treatment effects, but for contrasting communication modalities. Two individuals with mild-moderate aphasia improved verbal production with both IGT and PGT, and 2 individuals with severe aphasia improved gesture use with PGT.

Semantic-phonologic treatment for noun and verb retrieval impairments in aphasia.

Nouns and verbs differ in their neural and psycholinguistic attributes. It is not known whether these differences lead to distinct patterns of response to treatment for individuals with word retrieval impairments associated with aphasia. Eight participants with naming disorders induced by left hemisphere strokes were treated with a semantic-phonologic treatment protocol for nouns and verbs using a single participant multiple baseline design. We measured treatment gains in a picture naming measure and other secondary language and communication measures. Treatment led to improved picture naming for trained nouns and verbs in five of eight patients, with no difference evident between nouns and verbs. Improvements for untrained words were minimal. Improvement in verb retrieval was associated with increases on a functional measure of communicative effectiveness. Improvement for nouns and verbs was associated with severity of word retrieval impairment at onset. Although distinct in neural and psycholinguistic attributes, nouns and verbs were affected by treatment in a similar pattern in this group of individuals. Training-specific effects suggest the need for careful selection of training words to have potential for functional benefit in daily communication.

Functional MRI of language in aphasia: a review of the literature and the methodological challenges.

Animal analogue studies show that damaged adult brains reorganize to accommodate compromised functions. In the human arena, functional magnetic resonance imaging (fMRI) and other functional neuroimaging techniques have been used to study reorganization of language substrates in aphasia. The resulting controversy regarding whether the right or the left hemisphere supports language recovery and treatment progress must be reframed. A more appropriate question is when left-hemisphere mechanisms and when right-hemisphere mechanisms support recovery of language functions. Small lesions generally lead to good recoveries supported by left-hemisphere mechanisms. However, when too much language eloquent cortex is damaged, right-hemisphere structures may provide the better substrate for recovery of language. Some studies suggest that recovery is particularly supported by homologues of damaged left-hemisphere structures. Evidence also suggests that under some circumstances, activity in both the left and right hemispheres can interfere with recovery of function. Further research will be needed to address these issues. However, daunting methodological problems must be managed to maximize the yield of future fMRI research in aphasia, especially in the area of language production. In this review, we cover six challenges for imaging language functions in aphasia with fMRI, with an emphasis on language production: (1) selection of a baseline task, (2) structure of language production trials, (3) mitigation of motion-related artifacts, (4) the use of stimulus onset versus response onset in fMRI analyses, (5) use of trials with correct responses and errors in analyses, and (6) reliability and stability of fMRI images across sessions. However, this list of methodological challenges is not exhaustive. Once methodology is advanced, knowledge from conceptually driven fMRI studies can be used to develop theoretically driven, mechanism-based treatments that will result in more effective therapy and to identify the best patient candidates for specific treatments. While the promise of fMRI in the study of aphasia is great, there is much work to be done before this technique will be a useful clinical tool.

Effects of gesture+verbal treatment for noun and verb retrieval in aphasia.

Links between verbs and gesture knowledge suggest that verb retrieval may be particularly amenable to gesture+verbal training (GVT) in aphasia compared to noun retrieval. This study examines effects of GVT for noun and verb retrieval in nine individuals with aphasia subsequent to left hemisphere stroke. Participants presented an array of noun and verb retrieval deficits, including impairments of semantic and/or phonologic processing. In a single-participant experimental design, we investigated effects of GVT for noun and verb retrieval in two counterbalanced treatment phases. Effects were evaluated in spoken naming and gesture production to pictured objects and actions. Spoken naming improvements associated with large effect sizes were noted for trained nouns (5/9) and verbs (5/9); no improvements were evident for untrained words. Gesture production improved for trained nouns (8/9) and verbs (6/9), and for untrained nouns (2/9) and verbs (2/9). No significant differences were evident between nouns and verbs in spoken naming or gesture production. Improvements were evident across individuals with varied sources of word retrieval impairments. GVT has the potential to improve communication by increasing spoken word retrieval of trained nouns and verbs and by promoting use of gesture as a means to communicate when word retrieval fails.