Randomized trial of iReadMore word reading training and brain stimulation in central alexia

Can non-motor outcomes be improved in chronic stroke? A systematic review on the potential role of non-invasive brain stimulation

BACKGROUND

Non-invasive brain stimulation induces changes in spontaneous neural activity in the cerebral cortex through facilitatory or inhibitory mechanisms, relying on neuromodulation of neural excitability to impact brain plasticity. This systematic review assesses the state-of-the art and existing evidence regarding the effectiveness of NIBS in cognitive recovery among patients with chronic stroke.

MATERIALS AND METHODS

We conducted a systematic search, following PRISMA guidelines, for articles published from January 2010 through September 2023. We searched the following databases: PubMed, Embase, Cochrane Database of Systematic Reviews, PEDro, Rehab Data, and Web of Science.

RESULTS

Our electronic searches identified 109 papers. We assessed and included 61 studies based on their pertinence and relevance to the topic. After reading the full text of the selected publications and applying predefined inclusion criteria, we excluded 32 articles, leaving 28 articles for our qualitative analysis. We categorized our results into two sections as follows: (1) Cognitive and emotional domains (11 studies), (2) language and speech functions (16 studies).

CONCLUSION

Our findings highlight the potential of NIBS, such as tDCS and rTMS, in the cognitive, linguistic, and emotional recovery of post-stroke patients. Although it seems that NIBS may work as a complementary tool to enhance cognitive and communication abilities in patients with stroke -also in the chronic phase- evidence on behavioural outcomes is still poor. Future studies should focus on this important issue to confirm the effectiveness of neuromodulation in chronic neurological diseases. PROSPERO Registration: CRD42023458370.

Transcranial Direct Current Stimulation to Ameliorate Post-Stroke Cognitive Impairment

Post-stroke cognitive impairment is a common and disabling condition with few effective therapeutic options. After stroke, neural reorganization and other neuroplastic processes occur in response to ischemic injury, which can result in clinical improvement through spontaneous recovery. Neuromodulation through transcranial direct current stimulation (tDCS) is a promising intervention to augment underlying neuroplasticity in order to improve cognitive function. This form of neuromodulation leverages mechanisms of neuroplasticity post-stroke to optimize neural reorganization and improve function. In this review, we summarize the current state of cognitive neurorehabilitation post-stroke, the practical features of tDCS, its uses in stroke-related cognitive impairment across cognitive domains, and special considerations for the use of tDCS in the post-stroke patient population.

Dosage Frequency Effects on Treatment Outcomes Following Self-managed Digital Therapy: Retrospective Cohort Study

BACKGROUND

Although the efficacy of high-dose speech-language therapy (SLT) for individuals with poststroke aphasia has been established in the literature, there is a gap in translating these research findings to clinical practice. Therefore, patients continue to receive suboptimal amounts of SLT, with negative consequences for their functional communication recovery. Recent research has identified self-managed digital health technology as one way to close the dosage gap by enabling high-intensity therapy unrestricted by clinician availability or other practical constraints. However, there is limited empirical evidence available to rehabilitation professionals to guide dose prescriptions for self-managed SLT despite their increasing use in the COVID-19 era and likely beyond.

OBJECTIVE

This study aims to leverage real-world mobile health data to investigate the effects of varied dosage frequency on performance outcomes for individuals with poststroke speech, language, and cognitive deficits following a 10-week period of self-managed treatment via a commercially available digital health platform.

METHODS

Anonymized data from 2249 poststroke survivors who used the Constant Therapy app between late 2016 and 2019 were analyzed. The data included therapy tasks spanning 13 different language and cognitive skill domains. For each patient, the weekly therapy dosage was calculated based on the median number of days per week of app use over the 10-week therapy period, binned into groups of 1, 2, 3, 4, or ≥5 days per week. Linear mixed-effects models were run to examine change in performance over time as a function of dosage group, with post hoc comparisons of slopes to evaluate the performance gain associated with each additional day of practice.

RESULTS

Across all skill domains, linear mixed-effects model results showed that performance improvement was significantly greater for patients who practiced 2 (β=.001; t_15,355=2.37; P=.02), 3 (β=.003; t₉₇₃₈=5.21; P<.001), 4 (β=.005; t₉₂₈₉=7.82; P<.001), or ≥5 (β=.005; t₆₃₄₃=8.14; P<.001) days per week compared with those who only practiced for 1 day per week. Post hoc comparisons confirmed an incremental dosage effect accumulating with each day of practice (ie, 1 day vs 2 days, 2 days vs 3 days, and 3 days vs 4 days), apart from 4 days versus ≥5 days of practice per week. The result of greater improvement for higher versus lower dosage frequency groups was true not only across all domains but also within a majority of individual subdomains.

CONCLUSIONS

The findings from this study demonstrated that increased dosage frequency is associated with greater therapy gains over a 10-week treatment period of self-managed digital therapy. The use of real-world data maximizes the ecological validity of study results and makes the findings more generalizable to clinical settings. This study represents an important step toward the development of optimal dose recommendations for self-managed SLT.

Are People With Poststroke Aphasia Receptive to Transcranial Direct Current Stimulation? A Survey

PURPOSE

The objective of this study was to explore receptiveness of people with poststroke aphasia to receiving transcranial direct current stimulation (tDCS), including preferences for the treatment setting and schedule of tDCS delivery.

METHOD

An online survey was distributed via e-mail, flyers, social media, and online newsletters to reach people with aphasia. Fisher's exact test examined the relationship of self-reported tDCS receptiveness to demographic, clinical, and other factors.

RESULTS

Fifty-seven surveys were returned, and 50 complete surveys were analyzed. Twenty-eight percent of respondents had previously heard of tDCS. Sixty-six percent reported they would receive tDCS if it could help their aphasia, and only 6% reported that they definitely would not. There were statistically significant relationships between being receptive to tDCS and (a) not currently working, (b) being receptive to speech-language therapy, and (c) greater acceptance of potential temporary risks associated with tDCS. Most individuals (73%) who would consider tDCS were equivalently open to receiving it in the clinic or at home, yet the majority (64%) were open to more frequent sessions at home than in the clinic. Most respondents indicated that they would consider having tDCS "forever if it helped" (clinic: 51%; home: 68%).

CONCLUSIONS

This is the first study to query individuals with aphasia about their receptiveness to tDCS outside the context of an intervention study. Responses suggest that a large majority of people with poststroke aphasia might be open to receiving tDCS if it can ameliorate their aphasia. Limitations include the small sample size, which does not adequately represent the broader population of people with aphasia, and that the survey did not provide the level of tDCS education crucial to inform shared decision making and person-centered care. However, future work may benefit from considering the practical implications of research designs (e.g., high intensity treatment outside the home) that may not, in application, be widely acceptable to primary stakeholders.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19611777.

Noninvasive brain stimulation to augment language therapy for poststroke aphasia

Behavioral language treatment approaches represent the standard of care for persons with aphasia (PWA), but the benefits of these treatments are variable. Moreover, due to the logistic and financial limitations on the amount of behavioral therapy available to patients, it is often infeasible for PWA to receive behavioral interventions with the level of frequency, intensity, or duration that would provide significant and lasting benefit, underscoring the need for novel, effective treatment approaches. Noninvasive brain stimulation (NIBS) techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), have emerged as promising neurally-based tools to enhance language abilities for PWA following stroke. This chapter first provides an overview of the methods and physiologic basis motivating the use of NIBS to enhance aphasia recovery followed by a selective review of the growing evidence of its potential as a novel therapeutic tool. Subsequent sections discuss some of the principles that may prove most useful in guiding and optimizing the effects of NIBS on aphasia recovery, focusing on how the functional state of the brain at the time of stimulation interacts with the behavioral aftereffects of neuromodulation. We conclude with a discussion of current challenges and future directions for NIBS in aphasia treatment.

Assessment of language impairment and function

This chapter is written for the qualified neurologist or related professional working with persons who have had a stroke or other sudden brain injury. It is critical that the presence of aphasia is detected, no matter how mild the presentation, and to support that assertion, this chapter highlights the plight of persons with latent aphasia. At the individual level, the impact of aphasia is devastating, with overwhelming evidence that aphasia negatively impacts psychosocial outcomes. At the global level, sensitive detection and accurate diagnosis of aphasia are critical for accurate characterization and quantification of the global burden of aphasia. The word "LANGUAGE" is leveraged as an acronym to create a useful and memorable checklist to guide navigation of aphasia screening and assessment: it begins with the definition of language (L), followed by the definition and diagnostic criteria for aphasia (A). Then language abilities and characteristics to be considered in assessment are presented: naming (N); grammar and syntax (G); unintelligible words, jargon, and paraphasias (U); auditory comprehension and repetition (A); graphemic abilities-reading and writing (G); and everyday communication and discourse (E). Recommendations for improving procedural adherence are provided, and a list of potential brief assessment measures are introduced.

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.

Transcranial direct current stimulation with multiple oral re-reading therapy for pure alexia without agraphia: a case report

Pure alexia without agraphia is characterized by impaired reading due to damage to the occipitotemporal cortex with preserved writing skills. In this case report, we investigate the effect of multiple oral re-reading (MOR) therapy adjunct with transcranial direct current stimulation (tDCS) in improving reading recovery of a 64-year-old patient with pure alexia without agraphia following a stroke. His MRI revealed an area of infarct with microhemorrhages at the left occipitotemporal region. The patient was blinded to each therapy and underwent seven consecutive sessions of sham tDCS followed by seven consecutive sessions of real tDCS, coupled with 1-hour MOR therapy during each session. Western Aphasia Battery (WAB) was performed at baseline, before sham and real-tDCS, and 6 weeks after completing tDCS therapy. The patient showed improvement using both sham and real-tDCS with better reading comprehension, average reading time, and word per minute after real-tDCS. This study suggests that MOR, coupled with tDCS therapy may accelerate the reading recovery in patients with pure alexia.

The cost to see the Wizard: buy-ins and trade-offs in neurological rehabilitation

This scientific commentary refers to ‘A decision-neuroscientific intervention to improve cognitive recovery after stroke’ by Studer et al. (doi:10.1093/brain/awab128).

Treatment of post-stroke aphasia: A narrative review for stroke neurologists

This review is intended to help physicians guide patients to optimal management of post-stroke aphasia. We review literature on post-stroke aphasia treatment, focusing on: (1) when and for whom language therapy is most effective, (2) the variety of approaches that can be effective for different individuals, and (3) the extent to which behavioral therapy might be augmented by non-invasive brain stimulation and/or medications.

Rehabilitation of visual disorders

While there is a long history of rehabilitation for motor deficits following cerebral lesions, less is known about our ability to improve visual deficits. Vision therapy, prisms, occluders, and filters have been advocated for patients with mild traumatic brain injury, on the premise that some of their symptoms may reflect abnormal visual or ocular motor function, but the evidence for their efficacy is modest. For hemianopia, attempts to restore vision have had unimpressive results, though it appears possible to generate blindsight through training. Strategic approaches that train more efficient use of visual search in hemianopia have shown consistent benefit in visual function, while prism aids may help some patients. There are many varieties of alexia. Strategic adaptation of saccades can improve hemianopic alexia, but there has been less work and mixed results for pure alexia, neglect dyslexia, attentional dyslexia, and the central dyslexias. A number of approaches have been tried in prosopagnosia, with recent studies of small groups suggesting that face perception of prosopagnosic subjects can be enhanced through perceptual learning.

Adjunctive Approaches to Aphasia Rehabilitation: A Review on Efficacy and Safety

Aphasia is one of the most socially disabling post-stroke deficits. Although traditional therapies have been shown to induce adequate clinical improvement, aphasic symptoms often persist. Therefore, unconventional rehabilitation techniques which act as a substitute or as an adjunct to traditional approaches are urgently needed. The present review provides an overview of the efficacy and safety of the principal approaches which have been proposed over the last twenty years. First, we examined the effectiveness of the pharmacological approach, principally used as an adjunct to language therapy, reporting the mechanism of action of each single drug for the recovery of aphasia. Results are conflicting but promising. Secondly, we discussed the application of Virtual Reality (VR) which has been proven to be useful since it potentiates the ecological validity of the language therapy by using virtual contexts which simulate real-life everyday contexts. Finally, we focused on the use of Transcranial Direct Current Stimulation (tDCS), both discussing its applications at the cortical level and highlighting a new perspective, which considers the possibility to extend the use of tDCS over the motor regions. Although the review reveals an extraordinary variability among the different studies, substantial agreement has been reached on some general principles, such as the necessity to consider tDCS only as an adjunct to traditional language therapy.

Efficacy of spoken word comprehension therapy in patients with chronic aphasia: a cross-over randomised controlled trial with structural imaging

OBJECTIVE

The efficacy of spoken language comprehension therapies for persons with aphasia remains equivocal. We investigated the efficacy of a self-led therapy app, 'Listen-In', and examined the relation between brain structure and therapy response.

METHODS

A cross-over randomised repeated measures trial with five testing time points (12-week intervals), conducted at the university or participants' homes, captured baseline (T1), therapy (T2-T4) and maintenance (T5) effects. Participants with chronic poststroke aphasia and spoken language comprehension impairments completed consecutive Listen-In and standard care blocks (both 12 weeks with order randomised). Repeated measures analyses of variance compared change in spoken language comprehension on two co-primary outcomes over therapy versus standard care. Three structural MRI scans (T2-T4) for each participant (subgroup, n=25) were analysed using cross-sectional and longitudinal voxel-based morphometry.

RESULTS

Thirty-five participants completed, on average, 85 hours (IQR=70-100) of Listen-In (therapy first, n=18). The first study-specific co-primary outcome (Auditory Comprehension Test (ACT)) showed large and significant improvements for trained spoken words over therapy versus standard care (11%, Cohen's d=1.12). Gains were largely maintained at 12 and 24 weeks. There were no therapy effects on the second standardised co-primary outcome (Comprehensive Aphasia Test: Spoken Words and Sentences). Change on ACT trained words was associated with volume of pretherapy right hemisphere white matter and post-therapy grey matter tissue density changes in bilateral temporal lobes.

CONCLUSIONS

Individuals with chronic aphasia can improve their spoken word comprehension many years after stroke. Results contribute to hemispheric debates implicating the right hemisphere in therapy-driven language recovery. Listen-In will soon be available on GooglePlay.

TRIAL REGISTRATION NUMBER

NCT02540889.

Is Aphasia Treatment Beneficial for the Elderly? A Review of Recent Evidence

Purpose

We review recent literature regarding aphasia therapy in the elderly. Relevant articles from the last 5 years were identified to determine whether or not there is evidence to support that various therapeutic approaches can have a positive effect on post-stroke aphasia in the elderly.

Recent findings

There were no studies examining the effects of aphasia therapy specifically in the elderly within the timeframe searched. Therefore, we briefly summarize findings from 50 relevant studies that included large proportions of participants with post-stroke aphasia above the age of 65. A variety of behavioral and neuromodulation therapies are reported.

Summary

We found ample evidence suggesting that a variety of behavioral and neuromodulatory therapeutic approaches can benefit elderly individuals with post-stroke aphasia.

The management of subacute and chronic vascular aphasia: an updated review

Background

Post-stroke aphasia (PSA) is an impairment of the generation or comprehension of language due to acute cerebrovascular lesions. Subacute phase span the 7th day to 24 weeks post-onset while > 6 months is termed chronic phase. Language recovery does not arise immediately in chronic PSA, unlike the acute phase. The majority of the treatment modalities in these two PSA phases are still in the infancy stage, facing dilemmas and considered experimental requiring constant updates. Hence, we aimed to upgrade the existing literature regarding available PSA management options, advances, and drawbacks pertaining to subacute and chronic phases.

Main text

In this review, we analyzed the management options for subacute and chronic vascular aphasia. MEDLINE, through PubMed, ScienceDirect, and Google Scholar were explored for English studies by utilizing the terms “stroke aphasia” Plus “vascular aphasia”; 160,753 articles were retrieved. The latest studies, published from 2016 to July 2020, were selected. Article headings and abstracts were analyzed for relevance and filtered; eventually, 92 articles were included in this review. Various management options were extracted as follows: noninvasive brain stimulation (NIBS), technology-based therapies, speech-language therapy (SLT), pharmacotherapy, music-based therapies, and psychosocial interventions.

Conclusion

The PSA therapy evolves towards more intense SLT therapy, yet the optimal dosage of the emerging high-intensity therapies is controversial. As spinal and cerebellar NIBS, Telespeech, and E-mental health mark PSA's future, distinct pharmacological options remain a dilemma. Across the continuum of care, PSA–depression comorbidity and inadequate PSA post-discharge education to patient’s families are the significant therapeutic challenges. Future therapeutic mechanisms, optimal dose/timing, and tolerability/safety exploration are obliged.

A Review of Biological Interventions in Chronic Aphasia

Aphasia is a common and debilitating condition following stroke. While the gold standard for aphasia treatment is behavioral speech-language therapy, benefits remain modest in chronic stages of recovery. This limitation motivates the pursuit of novel interventions for chronic aphasia. Here, we review biological approaches that have been used (or proposed for use, in the case of regenerative and genetic therapies) to treat chronic aphasia. These techniques aim to ameliorate the deficits of aphasia by directly manipulating brain function, rather than training lost or compensatory functions, although many have been used to augment effects of behavioral therapy. Specifically, we explore the most robust designs of transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and pharmacotherapy that have been applied in chronic (≥6 months) post-stroke aphasia. We also consider less investigated approaches including epidural cortical stimulation and photobiomodulation. All methods are currently in nascent phases and restricted to experimental studies and clinical trials. Although the evidence base remains limited, such interventions may ultimately improve language function and quality of life for those living with chronic aphasia. However, it is crucial that application of these methods consider the effects of concomitant speech-language therapy, as biological interventions combined with behaviorally induced experience-dependent plasticity will likely yield the most beneficial and durable outcomes.

Impact of Combined Transcranial Direct Current Stimulation and Speech-language Therapy on Spontaneous Speech in Aphasia: A Randomized Controlled Double-blind Study

OBJECTIVE

Aphasia recovery depends on neural reorganization, which can be enhanced by speech-language therapy and noninvasive brain stimulation. Several studies suggested that transcranial direct current stimulation (tDCS) associated with speech-language therapy may improve verbal performance evaluated by analytic tests, but none focused on spontaneous speech. We explored the effect of bihemispheric tDCS on spontaneous speech in patients with poststroke aphasia.

METHODS

In this multicentric controlled randomized cross-over double-blind study, we included 10 patients with poststroke aphasia (4 had aphasia >6 months and 6 with aphasia <6 months). We combined the sessions of speech-language therapy and bihemispheric tDCS (2 mA, 20 min). After three baseline speech evaluations (1/week), two different conditions were randomly consecutively proposed: active and sham tDCS over 3 weeks with 1 week of washout in between. The main outcome measure was the number of different nouns used in 2 min to answer the question "what is your job."

RESULTS

There was no significant difference between conditions concerning the main outcome measure (p = .47) nor in the number of verbs, adjectives, adverbs, pronouns, repetitions, blank ideas, ideas, utterances with grammatical errors or paraphasias used. Other cognitive functions (verbal working memory, neglect, or verbal fluency) were not significantly improved in the tDCS group. No adverse events occurred.

CONCLUSION

Our results differed from previous studies using tDCS to improve naming in patients with poststroke aphasia possibly due to bihemispheric stimulation, rarely used previously. The duration of the rehabilitation period was short given the linguistic complexity of the measure. This negative result should be confirmed by larger studies with ecological measures.

How Does iReadMore Therapy Change the Reading Network of Patients with Central Alexia?

Central alexia (CA) is an acquired reading disorder co-occurring with a generalized language deficit (aphasia). The roles of perilesional and ipsilesional tissue in recovery from poststroke aphasia are unclear. We investigated the impact of reading training (using iReadMore, a therapy app) on the connections within and between the right and left hemisphere of the reading network of patients with CA. In patients with pure alexia, iReadMore increased feedback from left inferior frontal gyrus (IFG) region to the left occipital (OCC) region. We aimed to identify whether iReadMore therapy was effective through a similar mechanism in patients with CA. Participants with chronic poststroke CA (n = 23) completed 35 h of iReadMore training over 4 weeks. Reading accuracy for trained and untrained words was assessed before and after therapy. The neural response to reading trained and untrained words in the left and right OCC, ventral occipitotemporal, and IFG regions was examined using event-related magnetoencephalography. The training-related modulation in effective connectivity between regions was modeled at the group level with dynamic causal modeling. iReadMore training improved participants' reading accuracy by an average of 8.4% (range, -2.77 to 31.66) while accuracy for untrained words was stable. Training increased regional sensitivity in bilateral frontal and occipital regions, and strengthened feedforward connections within the left hemisphere. Our data suggest that iReadMore training in these patients modulates lower-order visual representations, as opposed to higher-order, more abstract representations, to improve word-reading accuracy.SIGNIFICANCE STATEMENT This is the first study to conduct a network-level analysis of therapy effects in participants with poststroke central alexia. When patients trained with iReadMore (a multimodal, behavioral, mass practice, computer-based therapy), reading accuracy improved by an average 8.4% on trained items. A network analysis of the magnetoencephalography data associated with this improvement revealed an increase in regional sensitivity in bilateral frontal and occipital regions and strengthening of feedforward connections within the left hemisphere. This indicates that in patients with CA iReadMore engages lower-order, intact resources within the left hemisphere (posterior to their lesion locations) to improve word reading. This provides a foundation for future research to investigate reading network modulation in different CA subtypes, or for sentence-level therapy.

Aphasia Recovery: When, How and Who to Treat?

PURPOSE OF REVIEW

We now know that speech and language therapy (SALT) is effective in the rehabilitation of aphasia; however, there remains much individual variability in the response to interventions. So, what works for whom, when and how?

RECENT FINDINGS

This review evaluates the current evidence for the efficacy of predominantly impairment-focused aphasia interventions with respect to optimal dose, intensity, timing and distribution or spacing of treatment. We conclude that sufficient dose of treatment is required to enable clinical gains and that e-therapies are a promising and practical way to achieve this goal. In addition, aphasia can be associated with other cognitive deficits and may lead to secondary effects such as low mood and social isolation. In order to personalise individual treatments to optimise recovery, we need to develop a greater understanding of the interactions between these factors.