Examining cortical tracking of the speech envelope in post-stroke aphasia.

Introduction: People with aphasia have been shown to benefit from rhythmic elements for language production during aphasia rehabilitation. However, it is unknown whether rhythmic processing is associated with such benefits. Cortical tracking of the speech envelope (CTenv) may provide a measure of encoding of speech rhythmic properties and serve as a predictor of candidacy for rhythm-based aphasia interventions. Methods: Electroencephalography was used to capture electrophysiological responses while Spanish speakers with aphasia (n = 9) listened to a continuous speech narrative (audiobook). The Temporal Response Function was used to estimate CTenv in the delta (associated with word- and phrase-level properties), theta (syllable-level properties), and alpha bands (attention-related properties). CTenv estimates were used to predict aphasia severity, performance in rhythmic perception and production tasks, and treatment response in a sentence-level rhythm-based intervention. Results: CTenv in delta and theta, but not alpha, predicted aphasia severity. Neither CTenv in delta, alpha, or theta bands predicted performance in rhythmic perception or production tasks. Some evidence supported that CTenv in theta could predict sentence-level learning in aphasia, but alpha and delta did not. Conclusion: CTenv of the syllable-level properties was relatively preserved in individuals with less language impairment. In contrast, higher encoding of word- and phrase-level properties was relatively impaired and was predictive of more severe language impairments. CTenv and treatment response to sentence-level rhythm-based interventions need to be further investigated.

Fatigue Influences Social Participation in Aphasia: A Cross-sectional and Retrospective Study Using Patient-Reported Measures.

OBJECTIVE: To examine associations between social participation, fatigue, and aphasia severity using patient-reported outcome measures and to examine associations between demographic/diagnostic variables and fatigue in people with aphasia. DESIGN: Retrospective analysis of patient-reported outcome measures using a Bayesian framework. SETTING: Urban rehabilitation research hospital. PARTICIPANTS: 67 participants (N=67) with chronic aphasia (mean age=54.1 years) as a consequence of stroke. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Ability to Participate in Social Roles and Activities, Fatigue, and Global Health Questionnaire scales from the Patient-Reported Outcomes Measurement Information System initiative and the Western Aphasia Battery-Revised. We hypothesized an association between social participation and fatigue in people with aphasia. RESULTS: People with aphasia with higher fatigue levels tended to report less social participation. Also, people with aphasia who were a longer time post-stroke tended to report higher social participation. People with aphasia who reported better physical health were more likely to report higher social participation. CONCLUSIONS: There is an association between fatigue and social participation in people with aphasia. Fatigue should be considered in clinical assessments and treatments for this population.

Reproducibility in Small-N Treatment Research: A Tutorial Using Examples From Aphasiology.

PURPOSE: Small-N studies are the dominant study design supporting evidence-based interventions in communication science and disorders, including treatments for aphasia and related disorders. However, there is little guidance for conducting reproducible analyses or selecting appropriate effect sizes in small-N studies, which has implications for scientific review, rigor, and replication. This tutorial aims to (a) demonstrate how to conduct reproducible analyses using effect sizes common to research in aphasia and related disorders and (b) provide a conceptual discussion to improve the reader's understanding of these effect sizes. METHOD: We provide a tutorial on reproducible analyses of small-N designs in the statistical programming language R using published data from Wambaugh et al. (2017). In addition, we discuss the strengths, weaknesses, reporting requirements, and impact of experimental design decisions on effect sizes common to this body of research. RESULTS: Reproducible code demonstrates implementation and comparison of within-case standardized mean difference, proportion of maximal gain, tau-U, and frequentist and Bayesian mixed-effects models. Data, code, and an interactive web application are available as a resource for researchers, clinicians, and students. CONCLUSIONS: Pursuing reproducible research is key to promoting transparency in small-N treatment research. Researchers and clinicians must understand the properties of common effect size measures to make informed decisions in order to select ideal effect size measures and act as informed consumers of small-N studies. Together, a commitment to reproducibility and a keen understanding of effect sizes can improve the scientific rigor and synthesis of the evidence supporting clinical services in aphasiology and in communication sciences and disorders more broadly. Supplemental Material and Open Science Form: https://doi.org/10.23641/asha.21699476.

On the Role of Neural Oscillations Across Timescales in Speech and Music Processing.

This mini review is aimed at a clinician-scientist seeking to understand the role of oscillations in neural processing and their functional relevance in speech and music perception. We present an overview of neural oscillations, methods used to study them, and their functional relevance with respect to music processing, aging, hearing loss, and disorders affecting speech and language. We first review the oscillatory frequency bands and their associations with speech and music processing. Next we describe commonly used metrics for quantifying neural oscillations, briefly touching upon the still-debated mechanisms underpinning oscillatory alignment. Following this, we highlight key findings from research on neural oscillations in speech and music perception, as well as contributions of this work to our understanding of disordered perception in clinical populations. Finally, we conclude with a look toward the future of oscillatory research in speech and music perception, including promising methods and potential avenues for future work. We note that the intention of this mini review is not to systematically review all literature on cortical tracking of speech and music. Rather, we seek to provide the clinician-scientist with foundational information that can be used to evaluate and design research studies targeting the functional role of oscillations in speech and music processing in typical and clinical populations.

Applying adaptive distributed practice to self-managed computer-based anomia treatment: A single-case experimental design.

INTRODUCTION: There is a pressing need to improve computer-based treatments for aphasia to increase access to long-term effective evidence-based interventions. The current single case design incorporated two learning principles, adaptive distributed practice and stimuli variability, to promote acquisition, retention, and generalization of words in a self-managed computer-based anomia treatment. METHODS: Two participants with post-stroke aphasia completed a 12-week adaptive distributed practice naming intervention in a single-case experimental design. Stimuli variability was manipulated in three experimental conditions: high exemplar variability, low exemplar variability, and verbal description prompt balanced across 120 trained words. Outcomes were assessed at 1-week, 1-month, and 3-months post-treatment. Statistical comparisons and effect sizes measured in the number of words acquired, generalized, and retained were estimated using Bayesian generalized mixed-effect models. RESULTS: Participants showed large and robust acquisition, generalization, and retention effects. Out of 120 trained words, participant 1 acquired ∼77 words (trained picture exemplars) and ∼63 generalization words (untrained picture exemplars of treated words). Similarly, participant 2 acquired ∼57 trained words and ∼48 generalization words. There was no reliable change in untrained control words for either participant. Stimuli variability did not show practically meaningful effects. CONCLUSIONS: These case studies suggest that adaptive distributed practice is an effective method for re-training more words than typically targeted in anomia treatment research (∼47 words on average per Snell et al., 2010). Generalization across experimental conditions provided evidence for improved lexical access beyond what could be attributed to simple stimulus-response mapping. These effects were obtained using free, open-source flashcard software in a clinically feasible, asynchronous format, thereby minimizing clinical implementation barriers. Larger-scale clinical trials are required to replicate and extend these effects.

Get in Sync: Active Ingredients and Patient Profiles in Scripted-Sentence Learning in Spanish Speakers With Aphasia.

PURPOSE: Script training is a well-established treatment for aphasia, but its evidence comes almost exclusively from monolingual English speakers with aphasia. Furthermore, its active ingredients and profiles of people with aphasia (PWA) that respond to this treatment remain understudied. This study aimed to adapt a scripted-sentence learning protocol to Colombian Spanish speakers with aphasia, investigate speech entrainment (i.e., unison production of sentences) as an active ingredient for scripted-sentence learning, and identify patient profiles associated with better scripted-sentence learning. METHOD: Fourteen monolingual Spanish speakers with aphasia learned a set of 30 sentences. To examine speech entrainment as an active ingredient for scripted-sentence learning, we investigated whether sentences containing externally added rhythmic cues (involving stress-aligned vs. metronomic rhythmic cues) would result in better scripted-sentence learning compared with control sentences. Learning was measured via postsession probes and analyzed using mixed-effects logistic regression models. The relationship between scripted-sentence learning and baseline language and rhythmic processing measures was also examined. RESULTS: Significant scripted-sentence learning over time indicated a successful adaptation of a script-training protocol to Spanish. PWA learned significantly more scripted sentences in the rhythmically enhanced conditions compared with the control condition. There were no differences between rhythmically enhanced conditions (stress-aligned vs. metronomic). In terms of patient profiles, it was found that PWA with more severe aphasia demonstrated larger learning gains, but rhythmic processing showed little association with learning estimates. CONCLUSIONS: To our knowledge, this study provides the first adaptation of a scripted-sentence learning protocol for monolingual Spanish speakers with aphasia, demonstrating cross-linguistic benefits of script training interventions. Highlighting rhythmic features during speech entrainment facilitated scripted-sentence learning in Spanish speakers with aphasia, suggesting that speech entrainment may be an active ingredient for scripted-sentence learning. More severe aphasia was associated with better scripted-sentence learning, suggesting that more severely impaired individuals are likely to benefit most from this treatment. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.19241847.

Practice-Related Predictors of Semantic Feature Verification Treatment for Aphasia.

PURPOSE: Specifying the active ingredients in aphasia interventions can inform treatment theory and improve clinical implementation. This secondary analysis examined three practice-related predictors of treatment response in semantic feature verification (SFV) treatment. We hypothesized that (a) successful feature verification practice would be associated with naming outcomes if SFV operates similarly to standard feature generation semantic feature analysis and (b) successful retrieval practice would be associated with naming outcomes for treated, but not semantically related, untreated words if SFV operates via a retrieval practice-oriented lexical activation mechanism. METHOD: Item-level data from nine participants with poststroke aphasia who received SFV treatment reported in the work of Evans, Cavanaugh, Quique, et al. (2021) were analyzed using Bayesian generalized linear mixed-effects models. Models evaluated whether performance on three treatment components (facilitated retrieval, feature verification, and effortful retrieval) moderated treatment response for treated and semantically related, untreated words. RESULTS: There was no evidence for or against a relationship between successful feature verification practice and treatment response. In contrast, there was a robust relationship between the two retrieval practice components and treatment response for treated words only. DISCUSSION: Findings were consistent with the second hypothesis: Retrieval practice, but not feature verification practice, appears to be a practice-related predictor of treatment response in SFV. However, treatment components are likely interdependent, and feature verification may still be an active ingredient in SFV. Further research is needed to evaluate the causal role of treatment components on treatment outcomes in aphasia.

Representation in Aphasia Research: An Examination of U.S. Treatment Studies Published Between 2009 and 2019.

PURPOSE: The external validity of aphasia treatment research relies on diverse and representative participants. The purposes of this study were (a) to examine whether reporting of patient-reported age, sex, and race/ethnicity has improved since Ellis (2009) and (b) to evaluate whether these demographic variables were consistent with population-level estimates of stroke survivor demographics in the United States. METHOD: A scoping review examined U.S.-based aphasia treatment studies published between 2009 and 2019 and characterized the percentage of studies reporting age, sex, and race/ethnicity. Summary statistics for these variables were calculated and compared statistically with a population-based study of stroke survivors. RESULTS: It was found out that 97.1% of studies reported age, 93.5% reported sex, and 28.1% reported race and/or ethnicity. Within reporting studies, participant mean age was 58.04 years, 61.6% of participants were men, and 38.4% were women; 86.5% of participants were White, 11.0% were Black, 2.0% were Hispanic/Latino, and 0.5% fell in other racial categories. All three variables were statistically different from the study of Kissela et al. (2012). DISCUSSION: Despite being highlighted as an issue by Ellis (2009), less than 30% of recent aphasia treatment studies reported race or ethnicity, and participants do not appear to be demographically representative compared with estimates of stroke survivors living in the United States. These issues may negatively impact the ecological validity of aphasia treatment research. Aphasia researchers should more consistently report participant race and ethnicity and follow current guidelines for increasing the demographic representation of women and minorities.

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.

Understanding Speed-Accuracy Processing Dynamics in Aphasia Using Response Time Modeling.

People with aphasia demonstrate language impairments evident in both performance accuracy and processing speed, but the direct relationship between accuracy and speed requires further consideration. This article describes two recent attempts to make quantitative progress in this domain using response time modeling: the diffusion model (Ratcliff, 1978) applied to two-choice tasks and a multinomial ex-Gaussian model applied to picture naming. The diffusion model may be used to characterize core linguistic processing efficiency and speed-accuracy tradeoffs independently, and research suggests that maladaptive speed-accuracy tradeoffs lead to performance impairments in at least some people with aphasia. The multinomial ex-Gaussian response time model of picture naming provides a simple and straightforward way to estimate the optimal response time cutoffs for individual people with aphasia (i.e., the cutoff where additional time is unlikely to lead to a correct response). While response time modeling applied to aphasia research is at an early stage of development, both the diffusion model and multinomial ex-Gaussian response time model of picture naming show promise and should be further developed in future work. This article also provides preliminary recommendations for clinicians regarding how to conceptualize, identify, and potentially address maladaptive speed-accuracy tradeoffs for people with aphasia.

Acquisition and Generalization Responses in Aphasia Naming Treatment: A Meta-Analysis of Semantic Feature Analysis Outcomes.

Purpose This meta-analysis synthesizes results from published studies that used semantic feature analysis (SFA) treatment to improve naming for people with aphasia. It examines how both person- and treatment-related variables affected the likelihood of correct naming responses in individual probe sessions for both acquisition (treated) and generalization (untreated) stimuli. Method The meta-analysis compiled data from 12 studies analyzing a total of 35 participants with aphasia. It used mixed-effects models as a novel statistical tool to examine the effects of 2 sets of variables on naming performance: treatment-related variables, including treatment phase (baseline vs. treatment), dosage (number of treatment sessions), and stimulus type (treated vs. untreated, semantically related vs. unrelated items), and person-specific variables, including degree of language impairment and demographic variables (age, time poststroke). Results Results of the meta-analysis revealed that SFA intervention promoted increased naming accuracy during naming probes when comparing baseline and treatment phases. In addition, increased dosages of SFA were associated with increased naming accuracy, and treatment-related gains were larger for acquisition (treated) than generalization (untreated) stimuli, likewise for related versus unrelated generalization stimuli. Furthermore, a subset of person-specific variables was predictive of SFA-related gains: Language impairment variables were related to treatment-related changes in naming performance, but demographic variables were not. Conclusion These results provide group-level evidence for the efficacy of SFA as well as preliminary estimates of how much naming performance benefit is engendered by varying dosages of SFA. The results also provide promising and previously unobserved evidence of potential person-level predictors of SFA treatment response.