The Methodological Quality of Short-Term/Working Memory Treatments in Poststroke Aphasia: A Systematic Review

Comparative Efficacy of Cognitive Training for Post-Stroke Aphasia: A Systematic Review and Network Meta-Analysis

BACKGROUND

Although cognitive training has shown potential for treating post-stroke aphasia (PSA), its efficacy varies across studies, and the optimal training approaches remain unclear.

OBJECTIVE

To evaluate and compare the effects of distinct cognitive training interventions, either combined with or independent of speech and language therapy (SLT), on language function in individuals with PSA.

METHODS

A systematic search encompassing PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, Wanfang, VIP, and Chinese Biomedical Databases was conducted for randomized controlled trials (RCTs). A network meta-analysis evaluated interventions, including computer-assisted cognitive training (CCT), conventional cognitive training (CT), virtual reality (VR)-based cognitive training (vrCT), telerehabilitation computer-assisted cognitive training (tCCT), working memory (WM) training, and attention training (AT).

RESULTS

Eleven RCTs comprising 501 participants were included. Individuals with PSA who underwent combined WM training with SLT led to significantly enhanced Western Aphasia Battery (WAB) Aphasia Quotient (AQ), as well as in spontaneous speech, auditory comprehension, repetition, and naming, compared to those receiving SLT alone. This combination was more effective than both CCT with SLT and tCCT with SLT in improving WAB AQ. Similarly, it outperformed both CCT with SLT and vrCT with SLT in enhancing WAB spontaneous speech. Additionally, both AT and CT combined with SLT were more effective than SLT alone in enhancing WAB spontaneous speech. Specifically, AT combined with SLT proved more effective than vrCT with SLT in this area. Moreover, vrCT combined with SLT significantly improved auditory comprehension compared with SLT alone.

CONCLUSIONS

Combining WM training and SLT and integrating vrCT with SLT both significantly enhance language function in individuals with PSA, compared with SLT alone. Our findings advocate for the use of these cognitive training approaches as promising strategies for language rehabilitation in this population. PROSPERO registration number: CRD42023462361.

Word Repetition Paired With Startling Stimuli Decreases Aphasia and Apraxia Severity in Severe-to-Moderate Stroke: A Stratified, Single-Blind, Randomized, Phase 1 Clinical Trial

PURPOSE

This prospective, single-blinded, parallel, stratified, randomized clinical trial via telehealth aimed to investigate the impact of Startle Adjuvant Rehabilitation Therapy (START) on aphasia, apraxia of speech (AOS), and quality of life in individuals with chronic stroke. The study hypothesized that START would have a greater effect on AOS-related measures and more severe individuals.

METHOD

Forty-two participants with poststroke aphasia, AOS, or both were randomly assigned to the START or control group. Both groups received 77-dB GET READY and GO cues during a word repetition task for three 1-hr sessions on consecutive days. The START group additionally received 105-dB white noise GO cues during one third of trials. The Western Aphasia Battery-Revised, Apraxia Battery for Adults, Stroke Impact Scale, and Communication Outcomes After Stroke scale were administered at Day 1, Day 5, and 1-month follow-up.

RESULTS

START improved performance on some subtests of the Western Aphasia Battery (Comprehension, Repetition, Reading) and measures of AOS (Diadochokinetic Rate, Increasing Word Length) in individuals with moderate/severe aphasia, whereas moderate/severe controls saw no changes. Individuals with mild aphasia receiving START had improved Reading, whereas mild controls saw improved Comprehension. The START group had increased mood and perceived communication recovery by Day 5, whereas controls saw no changes in quality of life.

CONCLUSIONS

This study is the first to evaluate the impact of training with startling acoustic stimuli on clinical measures of aphasia and AOS. Our findings suggest START can enhance both nontrained speech production and receptive speech tasks in moderate/severe aphasia, possibly by reducing poststroke cortical inhibition. Our findings should be considered carefully, as our limitations include small effect sizes, within-group variability, and low completion rates for quality-of-life assessments and follow-up visits. Future studies should explore a mechanism of action, conduct larger and longer Phase 2 clinical trials, and evaluate long-term retention.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24093519.

Targeted neurorehabilitation strategies in post-stroke aphasia

BACKGROUND

Aphasia is a debilitating language impairment, affecting millions of people worldwide. About 40% of stroke survivors develop chronic aphasia, resulting in life-long disability.

OBJECTIVE

This review examines extrinsic and intrinsic neuromodulation techniques, aimed at enhancing the effects of speech and language therapies in stroke survivors with aphasia.

METHODS

We discuss the available evidence supporting the use of transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation, and functional MRI (fMRI) real-time neurofeedback in aphasia rehabilitation.

RESULTS

This review systematically evaluates studies focusing on efficacy and implementation of specialized methods for post-treatment outcome optimization and transfer to functional skills. It considers stimulation target determination and various targeting approaches. The translation of neuromodulation interventions to clinical practice is explored, emphasizing generalization and functional communication. The review also covers real-time fMRI neurofeedback, discussing current evidence for efficacy and essential implementation parameters. Finally, we address future directions for neuromodulation research in aphasia.

CONCLUSIONS

This comprehensive review aims to serve as a resource for a broad audience of researchers and clinicians interested in incorporating neuromodulation for advancing aphasia care.

Impact of Startling Acoustic Stimuli on Word Repetition in Individuals With Aphasia and Apraxia of Speech Following Stroke

PURPOSE

The StartReact effect, whereby movements are elicited by loud, startling acoustic stimuli (SAS), allows the evaluation of movements when initiated through involuntary circuitry, before auditory feedback. When StartReact is applied during poststroke upper extremity movements, individuals exhibit increased muscle recruitment, reaction times, and reaching distances. StartReact releases unimpaired speech with similar increases in muscle recruitment and reaction time. However, as poststroke communication disorders have divergent neural circuitry from upper extremity tasks, it is unclear if StartReact will enhance speech poststroke. Our objective is to determine if (a) StartReact is present in individuals with poststroke aphasia and apraxia and (b) SAS exposure enhances speech intelligibility.

METHOD

We remotely delivered startling, 105-dB white noise bursts (SAS) and quiet, non-SAS cues to 15 individuals with poststroke aphasia and apraxia during repetition of six words. We evaluated average word intensity, pitch, pitch trajectories, vowel formants F1 and F2 (first and second formants), phonemic error rate, and percent incidence of each SAS versus non-SAS-elicited phoneme produced under each cue type.

RESULTS

For SAS trials compared to non-SAS, speech intensity increased (∆ + 0.6 dB), speech pitch increased (∆ + 22.7 Hz), and formants (F1 and F2) changed, resulting in a smaller vowel space after SAS. SAS affected pitch trajectories for some, but not all, words. Non-SAS trials had more stops (∆ + 4.7 utterances) while SAS trials had more sustained phonemes (fricatives, glides, affricates, liquids; ∆ + 5.4 utterances). SAS trials had fewer distortion errors but no change in substitution errors or overall error rate compared to non-SAS trials.

CONCLUSIONS

We show that stroke-impaired speech is susceptible to StartReact, evidenced by decreased intelligibility due to altered formants, pitch trajectories, and articulation, including increased incidence of sounds that could not be produced without SAS. Future studies should examine the impact of SAS on voluntary speech intelligibility and clinical measures of aphasia and apraxia.

Cognitive Training to Enhance Aphasia Therapy (Co-TrEAT): A Feasibility Study

Persons with aphasia (PWA) often have deficits in cognitive domains such as working memory (WM), which are negatively correlated with recovery, and studies have targeted WM deficits in aphasia therapy. To our knowledge, however, no study has examined the efficacy of multi-modal training which includes both WM training and targeted language therapy. This pilot project examined the feasibility and preliminary efficacy of combining WM training and naming therapy to treat post-stroke PWA. Chronic PWA were randomly assigned to either the a) Phonological Components Analysis (PCA) and WM intervention (WMI) condition (i.e., a computerized adaptive dual n-back task), or b) PCA and active control condition (WMC). Participants received face-to-face PCA therapy 3 times/week for 5 weeks, and simultaneously engaged in WM training or the active control condition five times/week, independently at home. Six PWA were enrolled, 3 in each condition. Feasibility metrics were excellent for protocol compliance, retention rate and lack of adverse events. Recruitment was less successful, with insufficient participants for group analyses. Participants in the WMI (but not the WMC) condition demonstrated a clinically significant (i.e., > 5 points) improvement on the Western Aphasia Battery- Aphasia Quotient (WAB-R AQ) and Boston Naming Test after therapy. Given the small sample size, the performance of two individuals, matched on age, education, naming accuracy pre-treatment, WAB-R AQ and WM abilities was compared. Participant WMI-3 demonstrated a notable increase in WM training performance over the course of therapy; WMC-2 was the matched control. After therapy, WMI-3's naming accuracy for the treated words improved from 30 to 90% (compared to 30–50% for WMC-2) with a 7-point WAB-R AQ increase (compared to 3 for WMC-2). Improvements were also found for WMI-3 but not for WMC-2 on ratings of communicative effectiveness, confidence and some conversation parameters in discourse. This feasibility study demonstrated excellent results for most aspects of Co-TrEAT. Recruitment rate, hampered by limited resources, must be addressed in future trials; remotely delivered aphasia therapy may be a possible solution. Although no firm conclusions can be drawn, the case studies suggest that WM training has the potential to improve language and communication outcomes when combined with aphasia therapy.

Verbal Working Memory as Emergent from Language Comprehension and Production

This article reviews current models of verbal working memory and considers the role of language comprehension and long-term memory in the ability to maintain and order verbal information for short periods of time. While all models of verbal working memory posit some interaction with long-term memory, few have considered the character of these long-term representations or how they might affect performance on verbal working memory tasks. Similarly, few models have considered how comprehension processes and production processes might affect performance in verbal working memory tasks. Modern theories of comprehension emphasize that people learn a vast web of correlated information about the language and the world and must activate that information from long-term memory to cope with the demands of language input. To date, there has been little consideration in theories of verbal working memory for how this rich input from comprehension would affect the nature of temporary memory. There has also been relatively little attention to the degree to which language production processes naturally manage serial order of verbal information. The authors argue for an emergent model of verbal working memory supported by a rich, distributed long-term memory for language. On this view, comprehension processes provide encoding in verbal working memory tasks, and production processes maintenance, serial ordering, and recall. Moreover, the computational capacity to maintain and order information varies with language experience. Implications for theories of working memory, comprehension, and production are considered.