Transcranial direct current stimulation (tDCS) for improving aphasia in adults with aphasia after stroke

Neural mechanisms underlying improved new-word learning with high-density transcranial direct current stimulation

Neurobehavioral studies have provided evidence for the effectiveness of anodal tDCS on language production, by stimulation of the left Inferior Frontal Gyrus (IFG) or of left Temporo-Parietal Junction (TPJ). However, tDCS is currently not used in clinical practice outside of trials, because behavioral effects have been inconsistent and underlying neural effects unclear. Here, we propose to elucidate the neural correlates of verb and noun learning and to determine if they can be modulated with anodal high-definition (HD) tDCS stimulation. Thirty-six neurotypical participants were randomly allocated to anodal HD-tDCS over either the left IFG, the left TPJ, or sham stimulation. On day one, participants performed a naming task (pre-test). On day two, participants underwent a new-word learning task with rare nouns and verbs concurrently to HD-tDCS for 20 min. The third day consisted of a post-test of naming performance. EEG was recorded at rest and during naming on each day. Verb learning was significantly facilitated by left IFG stimulation. HD-tDCS over the left IFG enhanced functional connectivity between the left IFG and TPJ and this correlated with improved learning. HD-tDCS over the left TPJ enabled stronger local activation of the stimulated area (as indexed by greater alpha and beta-band power decrease) during naming, but this did not translate into better learning. Thus, tDCS can induce local activation or modulation of network interactions. Only the enhancement of network interactions, but not the increase in local activation, leads to robust improvement of word learning. This emphasizes the need to develop new neuromodulation methods influencing network interactions. Our study suggests that this may be achieved through behavioral activation of one area and concomitant activation of another area with HD-tDCS.

Combining computer-based rehabilitative approach with tDCS for recovering of aphasia: Implications from a single case study

We present a case of a single left hemisphere temporal-parietal stroke with subacute global aphasia and severe verbal apraxia and moderate dysphagia. The patient underwent a combined transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex (DLPFC) and language stimulation with Virtual Reality Rehabilitation System (VRRS). Patient was treated in a 1-h session, for 5 days a week, for 4 consecutive weeks. After treatment, evident improvements in the comprehension of oral and written language, swallowing abilities, and caregiver burden were detected. Power spectrum analysis of EEG data revealed significant enhancements of θ, α, and β waves from baseline to follow-up. These preliminary results seem to confirm the reliability of the tDCS translational application in conjunction with computer-based cognitive treatment for language disorders in a patient with stroke-induced aphasia.

Neurobiological Effects of Transcranial Direct Current Stimulation over the Inferior Frontal Gyrus: A Systematic Review on Cognitive Enhancement in Healthy and Neurological Adults

The neurobiological effects of transcranial direct current stimulation (tDCS) have still not been unequivocally clarified. Some studies have suggested that the application of tDCS over the inferior frontal gyrus (IFG) enhances different aspects of cognition in healthy and neurological individuals, exerting neural changes over the target area and its neural surroundings. In this systematic review, randomized sham-controlled trials in healthy and neurological adults were selected through a database search to explore whether tDCS over the IFG combined with cognitive training modulates functional connectivity or neural changes. Twenty studies were finally included, among which twelve measured tDCS effects through functional magnetic resonance (fMRI), two through functional near-infrared spectroscopy (fNIRS), and six through electroencephalography (EEG). Due to the high heterogeneity observed across studies, data were qualitatively described and compared to assess reliability. Overall, studies that combined fMRI and tDCS showed widespread changes in functional connectivity at both local and distant brain regions. The findings also suggested that tDCS may also modulate electrophysiological changes underlying the targeted area. However, these outcomes were not always accompanied by corresponding significant behavioral results. This work raises the question concerning the general efficacy of tDCS, the implications of which extend to the steadily increasing tDCS literature.

Neurostimulation for treatment of post-stroke impairments

Neurostimulation, the use of electrical stimulation to modulate the activity of the nervous system, is now commonly used for the treatment of chronic pain, movement disorders and epilepsy. Many neurostimulation techniques have now shown promise for the treatment of physical impairments in people with stroke. In 2021, vagus nerve stimulation was approved by the FDA as an adjunct to intensive rehabilitation therapy for the treatment of chronic upper extremity deficits after ischaemic stroke. In 2024, pharyngeal electrical stimulation was conditionally approved by the UK National Institute for Health and Care Excellence for neurogenic dysphagia in people with stroke who have a tracheostomy. Many other approaches have also been tested in pivotal device trials and a number of approaches are in early-phase study. Typically, neurostimulation techniques aim to increase neuroplasticity in response to training and rehabilitation, although the putative mechanisms of action differ and are not fully understood. Neurostimulation techniques offer a number of practical advantages for use after stroke, such as precise dosing and timing, but can be invasive and costly to implement. This Review focuses on neurostimulation techniques that are now in clinical use or that have reached the stage of pivotal trials and show considerable promise for the treatment of post-stroke impairments.

[Transcranial direct current stimulation to enhance training effectiveness in chronic poststroke aphasia-A challenge for recruiting participants]

INTRODUCTION/BACKGROUND

DC_TRAIN_APHASIA is an ongoing multicenter, randomized controlled trial, conducted since November 2019 under the lead of the University Medicine Greifswald (ClinicalTrials.gov Identifier: NCT03930121). The study seeks to determine whether adjuvant transcranial direct current stimulation (tDCS) can increase the effectiveness of a 3‑week treatment with intensive speech-language therapy in chronic post-stroke aphasia.

MATERIAL AND METHOD

Until the end of 2024, a total of 130 patients are to be included in Germany. Recruitment has been a challenge throughout the study and substantial efforts went into devising innovative recruiting approaches. Standard recruitment strategies were used, such as directly approaching people with aphasia in clinical settings, inpatient and outpatient language rehabilitation facilities, and patient support and advocacy groups, alongside more innovative techniques including radio commercials, dissemination of study information via national television and social media platforms.

PROVISIONAL RESULTS

Up until now, 110 patients have been included into the study. The largest short-term response was achieved via television and radio. The largest long-term response was obtained through recruitment via logopaedic and neurological facilities, patient support groups, and social media. Participants served as "testimonials", expressing that they were satisfied with the therapy and the tDCS application.

DISCUSSION

The multicenter study DC_TRAIN_APHASIA aims to provide evidence on tDCS as an adjuvant application to increase the effect size of intensive speech-language therapy in chronic post-stroke aphasia. The present review may guide future studies in recruiting samples that involve people with impaired communicative abilities.

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.

Functional neuroimaging and behavioral correlates of multisite tDCS as an add-on to language training in a person with post-stroke non-fluent aphasia: a year-long case study

Mary, who experienced non-fluent aphasia as a result of an ischemic stroke, received 10 years of personalized language training (LT), resulting in transient enhancements in speech and comprehension. To enhance these effects, multisite transcranial Direct Current Stimulation (tDCS) was added to her LT regimen for 15 sessions. Assessment using the Reliable Change Index showed that this combination improved her left inferior frontal connectivity and speech production for two months and significantly improved comprehension after one month. The results indicate that using multisite transcranial direct current stimulation (tDCS) can improve the effectiveness of language therapy (LT) for individuals with non-fluent aphasia.

New approaches to recovery after stroke

After a stroke, several mechanisms of neural plasticity can be activated, which may lead to significant recovery. Rehabilitation therapies aim to restore surviving tissue over time and reorganize neural connections. With more patients surviving stroke with varying degrees of neurological impairment, new technologies have emerged as a promising option for better functional outcomes. This review explores restorative therapies based on brain-computer interfaces, robot-assisted and virtual reality, brain stimulation, and cell therapies. Brain-computer interfaces allow for the translation of brain signals into motor patterns. Robot-assisted and virtual reality therapies provide interactive interfaces that simulate real-life situations and physical support to compensate for lost motor function. Brain stimulation can modify the electrical activity of neurons in the affected cortex. Cell therapy may promote regeneration in damaged brain tissue. Taken together, these new approaches could substantially benefit specific deficits such as arm-motor control and cognitive impairment after stroke, and even the chronic phase of recovery, where traditional rehabilitation methods may be limited, and the window for repair is narrow.

Effects of Cerebellar Transcranial Direct Current Stimulation in Patients with Stroke: a Systematic Review

BACKGROUND

The cerebellum is involved in regulating motor, affective, and cognitive processes. It is a promising target for transcranial direct current stimulation (tDCS) intervention in stroke.

OBJECTIVES

To review the current evidence for cerebellar tDCS (ctDCS) in stroke, its problems, and its future directions.

METHODS

We searched the Web of Science, MEDLINE, CINAHL, EMBASE, Cochrane Library, and PubMed databases. Eligible studies were identified after a systematic literature review of the effects of ctDCS in stroke patients. The changes in assessment scale scores and objective indicators after stimulation were reviewed.

RESULTS

Eleven studies were included in the systematic review, comprising 169 stroke patients. Current evidence suggests that anode tDCS on the right cerebellar hemisphere does not appear to enhance language processing in stroke patients. Compared with the sham group, stroke patients showed a significant improvement in the verb generation task after cathodal ctDCS stimulation. However, with regard to naming, two studies came to the opposite conclusion. The contralesional anodal ctDCS is expected to improve standing balance but not motor learning in stroke patients. The bipolar bilateral ctDCS protocol to target dentate nuclei (PO10h and PO9h) had a positive effect on standing balance, goal-directed weight shifting, and postural control in stroke patients.

CONCLUSIONS

ctDCS appears to improve poststroke language and motor dysfunction (particularly gait). However, the evidence for these results was insufficient, and the quality of the relevant studies was low. ctDCS stimulation parameters and individual factors of participants may affect the therapeutic effect of ctDCS. Researchers need to take a more regulated approach in the future to conduct studies with large sample sizes. Overall, ctDCS remains a promising stroke intervention technique that could be used in the future.

Low-dose intravenous immunoglobulin for children with newly diagnosed immune thrombocytopenia: protocol of a systematic review and meta-analysis

INTRODUCTION

Intravenous immunoglobulin (IVIg) is a first-line treatment for children with newly diagnosed immune thrombocytopenia (ITP). However, the cost of IVIg is high. Higher doses of IVIg are associated with a more insupportable financial burden to paediatric patients' families and may produce more adverse reactions. Whether low-dose IVIg can quickly stop bleeding and induce a durable response in treating children with newly diagnosed ITP is not yet established.

METHODS AND ANALYSIS

We will extensively search five English databases (PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials, Cumulative Index of Nursing and Allied Health Literature) and three Chinese databases (CNKI, Wanfang and VIP). International Clinical Trials Registry Platform and ClinicalTrials.gov will also be searched as supplementary. Randomised controlled trials and prospective observational studies compared the efficacy of low-dose IVIg and high-dose or moderate-dose IVIg will be included. The primary outcome is the proportion of patients achieving durable response. Estimates of effect will be pooled with either a random-effect model or a fixed-effect model according to the heterogeneity of studies. If significant heterogeneity exists, we will conduct subgroup analysis and sensitivity analysis to explore the source of heterogeneity and evaluate the robustness of the results. Publication bias will also be assessed, if possible. The risk of bias will be assessed using the Risk of Bias 2 and Risk Of Bias In Non-randomised Studies of Interventions tools. The certainty of evidence will be evaluated using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system.

ETHICS AND DISSEMINATION

No ethical approval is required since this systematic review is based on previously published studies. The findings of this study will be presented at international conferences or published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022384604.

Effect and safety of C7 neurotomy at the intervertebral foramen in patients with chronic poststroke aphasia: a multicentre, randomised, controlled study protocol

INTRODUCTION

Aphasia affects many stroke survivors; therefore, effective treatments are urgently needed. Preliminary clinical findings have suggested an association between contralateral C7-C7 cross nerve transfer and recovery from chronic aphasia. Randomised controlled trials supporting the efficacy of C7 neurotomy (NC7) are lacking. This study will explore the efficacy of NC7 at the intervertebral foramen for improving chronic poststroke aphasia.

METHODS AND ANALYSIS

This study protocol reports a multicentre, randomised, assessor-blinded active-controlled trial. A total of 50 patients with chronic poststroke aphasia for over 1 year and with a aphasia quotient calculated by Western Aphasia Battery Aphasia Quotient (WAB-AQ) score below 93.8 will be recruited. Participants will be randomly assigned to 1 of 2 groups (25 individuals each) to receive NC7 plus intensive speech and language therapy (iSLT), or iSLT alone programme. The primary outcome is the change in Boston Naming Test score from baseline to the first follow-up after NC7 plus 3 weeks of iSLT or iSLT alone. The secondary outcomes include the changes in the WAB-AQ, Communication Activities of Daily Living-3, International Classification of Functioning, Disability and Health (ICF) speech language function, Barthel Index, Stroke Aphasic Depression Questionnaire-hospital version and sensorimotor assessments. The study will also collect functional imaging outcomes of naming and semantic violation tasks through functional MRI and electroencephalogram to evaluate the intervention-induced neuroplasticity.

ETHICS AND DISSEMINATION

This study was approved by the institutional review boards of Huashan Hospital, Fudan University, and all participating institutions. The study findings will be disseminated through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

ChiCTR2200057180.

Effect of Transcranial Direct Current Stimulation Combined with Donepezil on stroke patients with memory impairment

Objective

To investigate the therapeutic effect of transcranial direct current stimulation (TDCS) combined with donepezil on stroke patients with memory impairment.

Methods

The subjects of the study were 120 stroke patients with memory impairment admitted to the Rehabilitation Department of Tianjin Medical University General Hospital from July 2017 to March 2020. Enrolled patients were divided into Group-A (58 cases) and Group-B (62 cases) according to different treatment intervention methods. Patients in Group-A were treated with TDCS and those in Group-B received donepezil on the basis of TDCS. The changes in Montreal Cognitive Assessment (MoCA) memory index score, Barthel Index (MBI) score, cognitive function and cognitive potential were observed and compared between the two groups before and after treatment.

Results

The improvement of total MoCA score, a single score of memory, MBI score, cognitive function and P300 potential index in Group-B was significantly better than that in Group-A (p<0.05).

Conclusion

TDCS combined with donepezil can reduce or delay the cognitive impairment of stroke patients, improve their delayed memory ability, increase the neurotransmitter acetylcholine in the cerebral cortex, and further enhance their neural function. Findings in our study support that the proposed therapeutic method is worthy of clinical application.

Transcranial Direct-Current Stimulation in Subacute Aphasia: A Randomized Controlled Trial

BACKGROUND

Transcranial direct-current stimulation (tDCS) is a promising adjunct to therapy for chronic aphasia.

METHODS

This single-center, randomized, double-blind, sham-controlled efficacy trial tested the hypothesis that anodal tDCS augments language therapy in subacute aphasia. Secondarily, we compared the effect of tDCS on discourse measures and quality of life and compared the effects on naming to previous findings in chronic stroke. Right-handed English speakers with aphasia <3 months after left hemisphere ischemic stroke were included, unless they had prior neurological or psychiatric disease or injury or were taking certain medications (34 excluded; final sample, 58). Participants were randomized 1:1, controlling for age, aphasia type, and severity, to receive 20 minutes of tDCS (1 mA) or sham-tDCS in addition to fifteen 45-minute sessions of naming treatment (plus standard care). The primary outcome variable was change in naming accuracy of untrained pictures pretreatment to 1-week posttreatment.

RESULTS

Baseline characteristics were similar between the tDCS (N=30) and sham (N=28) groups: patients were 65 years old, 53% male, and 2 months from stroke onset on average. In intent-to-treat analysis, the adjusted mean change from baseline to 1-week posttreatment in picture naming was 22.3 (95% CI, 13.5-31.2) for tDCS and 18.5 (9.6-27.4) for sham and was not significantly different. Content and efficiency of picture description improved more with tDCS than sham. Groups did not differ in quality of life improvement. No patients were withdrawn due to adverse events.

CONCLUSIONS

tDCS did not improve recovery of picture naming but did improve recovery of discourse. Discourse skills are critical to participation. Future research should examine tDCS in a larger sample with richer functional outcomes.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02674490.

Long-term effects of transcranial direct current stimulation (tDCS) combined with speech language therapy (SLT) on post-stroke aphasia patients: A systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation tool for improving language performance in patients with aphasia after stroke. However, it remains unclear whether it has long-term effects. After consulting a large number of relevant studies, it was found that there are no definitive conclusions about the long-term effects of tDCS on post-stroke aphasia patients.

OBJECTIVE

To determine whether tDCS has long-term effects on post-stroke aphasia patients (PAPs) and which type of tDCS has the most beneficial treatment effects on language performance (especially naming ability).

METHODS

A network meta-analysis was conducted by searching for randomized controlled trials (RCTs) published until April 2023 in the following databases: Web of Science, Embase, Medline (from OVID and PubMed), PsycInfo and PsycARTICLES (from OVID). We only included RCTs published in English. PAPs treated by tDCS combined with speech-language therapy were selected. Sham tDCS was the control group. Naming ability or other language performance must be assessed at follow-up states. Two reviewers independently used checklists to assess the primary outcome (the long-term effects on naming ability) and the secondary outcome (other language performance, such as communication). Cochrane Collaboration guidelines were used to assess the risk of bias.

RESULTS

Seven studies with 249 patients were included for data synthesis. For primary outcomes (naming nous), there was no obvious evidence to show a difference between interventions (C-tDCS vs. S-tDCS SMD = 0.06, 95% CI = -1.01, 1.12; A-tDCS vs. S-tDCS SMD = 0.00, 95% CI = -0.66, 0.65; D-tDCS vs. S-tDCS SMD = 0.77, 95% CI = -0.71, 2.24; A-tDCS vs. C-tDCS SMD = -0.06, 95% CI = -1.31,1.19; D-tDCS vs. C-tDCS SMD = 0.71, 95% CI = -1.11,2.53; D-tDCS vs. A-tDCS SMD = 0.77, 95% CI = -0.84, 2.39). In addition, no evidence showed differences in communication ability (C-tDCS vs. S-tDCS SMD = 0.08 95% CI = -1.77, 1.92; A-tDCS vs. S-tDCS SMD = 1.23 95% CI = -1.89, 4.34; D-tDCS vs. S-tDCS SMD = 0.70; 95% CI = -1.93, 3.34; A-tDCS vs. C-tDCS SMD = 1.15 95% CI = -2.48, 4.77; D-tDCS vs. C-tDCS SMD = 0.62 95% CI = -2.59, 3.84; D-tDCS vs. A-tDCS SMD = -0.52 95% CI = -4.60, 3.56).

CONCLUSION

It seems that tDCS has no long-term effects on post-stroke aphasia patients in naming nouns and communication in terms of the results of our network meta-analysis. However, the results should be interpreted with caution. In the future, more RCTs with long follow-up times should be included in the research to conduct subgroup or meta-regression analyses to obtain a sufficient effect size.

Narrative Review of Noninvasive Brain Stimulation in Stroke Rehabilitation

Stroke is a disease with a high incidence and disability rate, resulting in changes in neural network and corticoid-subcortical excitability and various functional disabilities. The aim of the present study was to discuss the current status of research and limitations and potential direction in the application of noninvasive brain stimulation (NIBS) on post-stroke patients. This literature review focused on clinical studies and reviews. Literature retrieval was conducted in PubMed, Cochrane, Scopus, and CNKI, using the following keywords: Repeated transcranial magnetic stimulation, Transcranial direct current stimulation, Transcranial alternating current stimulation, Transcranial alternating current stimulation, Transcranial focused ultrasound, Noninvasive vagus nerve stimulation, Stroke, and Rehabilitation. We selected 200 relevant publications from 1985 to 2022. An overview of recent research on the use of NIBS on post-stroke patients, including its mechanism, therapeutic parameters, effects, and safety, is presented. It was found that NIBS has positive therapeutic effects on dysfunctions of motor, sensory, cognitive, speech, swallowing, and depression after stroke, but standardized stimulus programs are still lacking. The literature suggests that rTMS and tDCS are more beneficial to post-stroke patients, while tFUS and tVNS are currently less studied for post-stroke rehabilitation, but are also potential interventions.

Cognitive impairment, anxiety and depression: a map of Cochrane evidence relevant to rehabilitation for people with post COVID-19 condition

INTRODUCTION

Currently, no evidence exists on specific treatments for post COVID-19 condition (PCC). However, rehabilitation interventions that are effective for similar symptoms in other health conditions could be applied to people with PCC. With this overview of systematic reviews with mapping, we aimed to describe the Cochrane evidence on rehabilitation interventions proposed for cognitive impairment, anxiety and depression in different health conditions that can be relevant for PCC.

EVIDENCE ACQUISITION

We searched the last five years' Cochrane Systematic Review (CSRs) using the terms "cognitive impairment," "depressive disorder," "anxiety disorder," their synonyms and variants, and "rehabilitation" in the Cochrane Library. We extracted and summarized the available evidence using a map. We grouped the included CSRs for health conditions and interventions, indicating the effect and the quality of evidence.

EVIDENCE SYNTHESIS

We found 3596 CSRs published between 2016 and 2021, and we included 17 on cognitive impairment and 37 on anxiety and depression. For cognitive impairment, we found 7 CSRs on participants with stroke, 3 with cancer, 2 with Parkinson's disease, and one each for five other health conditions. Each intervention improved a different domain, and included exercises, cognitive and attention-specific training, and computerized cognition-based training (from very low to high-quality evidence). For anxiety and depression, we found 10 CSRs including participants with cancer, 8 with stroke, 3 with chronic obstructive pulmonary disease, and 2 or 1 each in 11 other health conditions. Exercise training, physical activity and yoga resulted effective in several pathologies (very low- to moderate-quality evidence). In specific diseases, we found effective acupuncture, animal-assisted therapy, aromatherapy, educational programs, home-based multidimensional survivorship programs, manual acupressure massage, memory rehabilitation, non-invasive brain stimulation, pulmonary rehabilitation, and telerehabilitation (very low- to moderate-quality evidence).

CONCLUSIONS

These results are the first step of indirect evidence able to generate helpful hypotheses for clinical practice and future research. They served as the basis for the three recommendations on treatments for these PCC symptoms published in the current WHO Guidelines for clinical practice.

Neurotechnology’s Prospects for Bringing About Meaningful Reductions in Neurological Impairment

Here we report and comment on the magnitudes of post-stroke impairment reduction currently observed using new neurotechnologies. We argue that neurotechnology’s best use case is impairment reduction as this is neither the primary strength nor main goal of conventional rehabilitation, which is better at targeting the activity and participation levels of the ICF. The neurotechnologies discussed here can be divided into those that seek to be adjuncts for enhancing conventional rehabilitation, and those that seek to introduce a novel behavioral intervention altogether. Examples of the former include invasive and non-invasive brain stimulation. Examples of the latter include robotics and some forms of serious gaming. We argue that motor learning and training-related recovery are conceptually and mechanistically distinct. Based on our survey of recent results, we conclude that large reductions in impairment will need to begin with novel forms of high dose and high intensity behavioral intervention that are qualitatively different to conventional rehabilitation. Adjunct forms of neurotechnology, if they are going to be effective, will need to piggyback on these new behavioral interventions.

Transcranial direct current stimulation over the primary motor cortex improves speech production in post-stroke dysarthric speakers: A randomized pilot study

PURPOSE

The current study investigated the therapeutic potential of transcranial direct current stimulation (tDCS) on speech intelligibility, speech-related physiological and vocal functions among post-stroke dysarthric patients.

METHOD

Nine chronic post-stroke dysarthric patients were randomly assigned to the stimulation or sham group. The stimulation group received 2mA of anodal tDCS over the left inferior primary motor cortex for 15 minutes, while the sham group received 30s of stimulation under the same settings. All the participants received 10 daily 15 minutes of individualized speech therapy targeting their dominant phonological process or phonemes with the greatest difficulty. The outcome measures included (1) perceptual analysis of single words, passage reading and diadochokinetic rate, (2) acoustic analysis of a sustained vowel, and (3) kinematic analysis of rapid syllable repetitions and syllable production in sentence, conducted before and after the treatment.

RESULTS

The results revealed that both the stimulation and sham groups had improved perceptual speech intelligibility at the word level, reduced short rushes of speech during passage reading, improved rate during alternating motion rate, AMR-kha1, and improved articulatory kinematics in AMR-tha1 and syllables /tha1/ and /kha1/ production in sentence. Compared to the sham group, the stimulation group showed significant improvement in articulatory kinematics in AMR-kha1 and syllable /kha1/ production in sentence. The findings also showed that anodal stimulation led to reduced shimmer value in sustained vowel /a/ phonation, positive changes in articulatory kinematics in AMR-tha1 and syllables /pha1/ and /kha1/ production in sentence at the post treatment measure. In addition to positive effects on articulatory control, reduced perturbation of voice amplitude documented in the stimulation group post treatment suggests possible tDCS effects on the vocal function.

CONCLUSIONS

The current study documented the beneficial effects of anodal tDCS over the primary motor cortex on speech production and suggested that combined tDCS and speech therapy may promote recovery from post-stroke dysarthria.

Combined anodal transcranial direct current stimulation and behavioural naming treatment improves language performance in patients with post-stroke aphasia

PRIMARY OBJECTIVE

During the last decade, studies using anodal transcranial Direct Current Stimulation (atDCS) have yielded promising results in patients with aphasia. The main aim of the present pilot study was to assess the effects of combined atDCS over the left posterior perisylvian region and behavioral naming training on the behavioral outcomes of language comprehension and production of patients with post-stroke aphasia.

RESEARCH DESIGN

A 2 × 2 quasi-experimental design was conducted, optimal to compare changes after treatment in experimental versus control group.

METHODS AND PROCEDURES

Ten patients with post-stroke aphasia were enrolled in this study: half received atDCS on the left posterior perisylvian region while they underwent a 2-week behavioral naming training. The other half received sham stimulation. The outcomes were measured using the abbreviated form of the Boston Diagnostic Aphasia Examination and analyzed using ANOVAs.

MAIN OUTCOMES AND RESULTS

Both groups improved their performance in Oral comprehension, Narrative writing and Language Competence Index, but only those that received anodal tDCS presented better results in the Naming category after the treatment.

CONCLUSIONS

AtDCS on the left posterior perisylvian area seems to be a promising tool for boosting the outcomes of behavioral naming therapy in patients with post-stroke aphasia.

The efficacy and safety of acupuncture combined with language training for motor aphasia after stroke: study protocol for a multicenter randomized sham-controlled trial

BACKGROUND

Motor aphasia after stroke is a common and intractable complication of stroke. Acupuncture and language training may be an alternative and effective approach. However, the efficacy of acupuncture and language training for motor aphasia after stroke has not been confirmed. The main objectives of this trial are to evaluate the effectiveness and safety of acupuncture and low-intensity, low-dose language training in treating ischemic motor aphasia after stroke from 15 to 90 days.

METHODS

This is a multicenter randomized sham-controlled clinical trial. We will allocate 252 subjects aged between 45 and 75 years diagnosed with motor aphasia after stroke with an onset time ranging from 15 to 90 days into two groups randomly in a 1:1 ratio. Patients in the experimental group will be treated with "Xing-Nao Kai-Qiao" acupuncture therapy plus language training, and those in the control group will be treated with sham-acupoint (1 cun next to the acupoints) acupuncture therapy plus language training. All the patients will be given acupuncture and language training for 6 weeks, with a follow-up evaluation 6 weeks after the end of the treatment and 6 months after the onset time. The patients will mainly be evaluated using the Western Aphasia Battery and Chinese Functional Communication Profile, and the incidence of treatment-related adverse events at the 2nd, 4th, and 6th weeks of treatment will be recorded. The baseline characteristics of the patients will be summarized by group, the chi-squared test will be used to compare categorical variables, and repeated measures of analysis of variance or a linear mixed model will be applied to analyze the changes measured at different time points.

DISCUSSION

The present study is designed to investigate the effectiveness and safety of traditional acupuncture therapy and language training in ischemic motor aphasia after stroke and explore the correlation between the treatment time and clinical effect of acupuncture. We hope our results will help doctors understand and utilize acupuncture combined with language training.

TRIAL REGISTRATION

ChiCTR ChiCTR1900026740 . Registered on 20 October 2019.

The Progress of Functional Magnetic Resonance Imaging in Patients with Poststroke Aphasia

Aphasia after stroke is one of the common complications of cerebral infarction. Early diagnosis and treatment of aphasia after stroke is of great significance for the recovery of language function. At present, there are different views on the pathogenesis of aphasia after stroke. Functional magnetic resonance imaging (fMRI) can reflect the brain function, brain tissue metabolism, and the level of brain local blood flow. It has the advantages of noninvasive, high resolution and sensitivity, low price, and so on. It has been widely used in the study of sensory aphasia after stroke. This study focuses on the development of functional magnetic resonance imaging in patients with poststroke aphasia and summarizes the published studies on functional magnetic resonance imaging in patients with poststroke aphasia. Evidence acquisition: A literature search was conducted in PubMed, Hindawi, PLoS, IEEE, Wiley, ScienceDirect, Springer, EMBASE, and web of science, with the keywords of "stroke" and "Aphasia" and "functional magnetic resonance imaging", "RS fMRI", or "DTI", to review the research of functional magnetic resonance imaging in patients with aphasia after stroke. The results included clinical evaluation, diagnostic scale, and imaging analysis; the study design was a randomized controlled trial, case series and case report, and observational study. A total of 67 articles were identified in the first search and 43 after the second search. Based on the analysis of 43 selected articles, 19 articles were included, and 24 articles were excluded. The selected information is shown in Table 1. Eleven of them did not contain imaging-related data. Six articles are related review articles. Four studies were conducted on patients without poststroke aphasia. Three studies studied the effect of poststroke aphasia on patients' social participation.

Does Right-Hemispheric Anodal tDCS Enhance the Impact of Script Training in Chronic Aphasia? A Single-Subject Experimental Study

Background: Script training is an aphasia treatment approach that has been demonstrated to have a positive effect on communication of individuals with aphasia; however, it is time intensive as a therapeutic modality. To augment therapy-induced neuroplasticity, transcranial direct current stimulation (tDCS) may be implemented. tDCS has been paired with other speech-language treatments, however, has not been investigated with script training.

Aims: The purpose of this study was to determine if tDCS improves communication proficiency when paired with script training, compared to script training alone.

Methods and Procedures: A single-subject experimental design was implemented with a participant with non-fluent aphasia, using two scripts across treatment conditions: script training with sham-tDCS, and script training with anodal-tDCS. Treatment sessions were 75 min long, administered three times weekly. Anodal tDCS was implemented for 20 min with a current of 1.5 mA over the right inferior frontal gyrus.

Results: Large effect sizes were obtained on script mastery for both stimulation conditions (anodal d₂ = 9.94; sham d₂ = 11.93). tDCS did not improve script accuracy, however, there was a significant improvement in the rate of change of script pace relative to baseline (3.99 seconds/day, p < 0.001) in the anodal tDCS condition.

Conclusion: Despite a null tDCS result on accuracy, the script training protocol increased script performance to a near-fluent level of communication. There is preliminary evidence to suggest that tDCS may alter the rate of script acquisition, however, further research to corroborate this finding is required. Implications for future studies are discussed.

A Method to Experimentally Estimate the Conductivity of Chronic Stroke Lesions: A Tool to Individualize Transcranial Electric Stimulation

The inconsistent response to transcranial electric stimulation in the stroke population is attributed to, among other factors, unknown effects of stroke lesion conductivity on stimulation strength at the targeted brain areas. Volume conduction models are promising tools to determine optimal stimulation settings. However, stroke lesion conductivity is often not considered in these models as a source of inter-subject variability. The goal of this study is to propose a method that combines MRI, EEG, and transcranial stimulation to estimate the conductivity of cortical stroke lesions experimentally. In this simulation study, lesion conductivity was estimated from scalp potentials during transcranial electric stimulation in 12 chronic stroke patients. To do so, first, we determined the stimulation configuration where scalp potentials are maximally affected by the lesion. Then, we calculated scalp potentials in a model with a fixed lesion conductivity and a model with a randomly assigned conductivity. To estimate the lesion conductivity, we minimized the error between the two models by varying the conductivity in the second model. Finally, to reflect realistic experimental conditions, we test the effect rotation of measurement electrode orientation and the effect of the number of electrodes used. We found that the algorithm converged to the correct lesion conductivity value when noise on the electrode positions was absent for all lesions. Conductivity estimation error was below 5% with realistic electrode coregistration errors of 0.1° for lesions larger than 50 ml. Higher lesion conductivities and lesion volumes were associated with smaller estimation errors. In conclusion, this method can experimentally estimate stroke lesion conductivity, improving the accuracy of volume conductor models of stroke patients and potentially leading to more effective transcranial electric stimulation configurations for this population.

Timing-Dependent Effects of Transcranial Direct Current Stimulation on Hand Motor Function in Healthy Individuals: A Randomized Controlled Study

The timing of transcranial direct current stimulation (tDCS) is essential for enhancing motor skill learning. Previously, tDCS, before or concurrently, with motor training was evaluated in healthy volunteers or elderly patients, but the optimal timing of stimulation has not been determined. In this study, we aimed to optimize the existing tDCS protocols by exploring the timing-dependent stimulation effects on finger movements in healthy individuals. We conducted a single-center, prospective, randomized controlled trial. The study participants (n = 39) were randomly assigned into three groups: tDCS concurrently with finger tapping training (CON), tDCS prior to finger tapping training (PRI), and SHAM-tDCS simultaneously with finger tapping training (SHAM). In all groups, the subjects participated in five 40-min training sessions for one week. Motor performance was measured before and after treatment using the finger-tapping task (FTT), the grooved pegboard test (GPT), and hand strength tests. tDCS treatment prior to finger tapping training significantly improved motor skill learning, as indicated by the GPT and hand strength measurements. In all groups, the treatment improved the FTT performance. Our results indicate that applying tDCS before training could be optimal for enhancing motor skill learning. Further research is required to confirm these findings.

Novel Advances to Post-Stroke Aphasia Pharmacology and Rehabilitation

Aphasia is one of the most common clinical features of functional impairment after a stroke. Approximately 21–40% of stroke patients sustain permanent aphasia, which progressively worsens one’s quality of life and rehabilitation outcomes. Post-stroke aphasia treatment strategies include speech language therapies, cognitive neurorehabilitation, telerehabilitation, computer-based management, experimental pharmacotherapy, and physical medicine. This review focuses on current evidence of the effectiveness of impairment-based aphasia therapies and communication-based therapies (as well as the timing and optimal treatment intensities for these interventions). Moreover, we present specific interventions, such as constraint-induced aphasia therapy (CIAT) and melodic intonation therapy (MIT). Accumulated data suggest that using transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) is safe and can be used to modulate cortical excitability. Therefore, we review clinical studies that present TMS and tDCS as (possible) promising therapies in speech and language recovery, stimulating neuroplasticity. Several drugs have been used in aphasia pharmacotherapy, but evidence from clinical studies suggest that only nootropic agents, donepezil and memantine, may improve the prognosis of aphasia. This article is an overview on the current state of knowledge related to post-stroke aphasia pharmacology, rehabilitation, and future trends.

An Exploratory Study of Cerebellar Transcranial Direct Current Stimulation in Individuals With Chronic Stroke Aphasia

BACKGROUND

Aphasia is a common, debilitating consequence of stroke, and speech therapy is often inadequate to achieve a satisfactory outcome. Neuromodulation techniques have emerged as a potential augmentative treatment for improving aphasia outcomes. Most studies have targeted the cerebrum, but there are theoretical and practical reasons that stimulation over the cerebral hemispheres might not be ideal. On the other hand, the right cerebellum is functionally and anatomically linked to major language areas in the left hemisphere, making it a promising alternative target site for stimulation.

OBJECTIVE

To provide preliminary effect sizes for the ability of a short course of anodal transcranial direct current stimulation (tDCS) targeted over the right cerebellum to enhance language processing in individuals with chronic poststroke aphasia.

METHOD

Ten individuals received five sessions of open-label anodal tDCS targeting the right cerebellum. The effects of the tDCS were compared with the effects of sham tDCS on 14 controls from a previous clinical trial. In total, 24 individuals with chronic poststroke aphasia participated in the study. Behavioral testing was conducted before treatment, immediately following treatment, and at the 3-month follow-up.

RESULTS

Cerebellar tDCS did not significantly enhance language processing measured either immediately following treatment or at the 3-month follow-up. The effect sizes of tDCS over sham treatment were generally nil or small, except for the mean length of utterance on the picture description task, for which medium to large effects were observed.

CONCLUSION

These results may provide guidance for investigators who are planning larger trials of tDCS for individuals with chronic poststroke aphasia.

Current Approaches to the Treatment of Post-Stroke Aphasia

Aphasia, impairment of language after stroke or other neurological insult, is a common and often devastating condition that affects nearly every social activity and interaction. Behavioral speech and language therapy is the mainstay of treatment, although other interventions have been introduced to augment the effects of the behavioral therapy. In this narrative review, we discuss advances in aphasia therapy in the last 5 years and focus primarily on properly powered, randomized, controlled trials of both behavioral therapies and interventions to augment therapy for post-stroke aphasia. These trials include evaluation of behavioral therapies and computer-delivered language therapies. We also discuss outcome prediction trials as well as interventional trials that have employed noninvasive brain stimulation, or medications to augment language therapy. Supported by evidence from Phase III trials and large meta-analyses, it is now generally accepted that aphasia therapy can improve language processing for many patients. Not all patients respond similarly to aphasia therapy with the most severe patients being the least likely responders. Nevertheless, it is imperative that all patients, regardless of severity, receive aphasia management focused on direct therapy of language deficits, counseling, or both. Emerging evidence from Phase II trials suggests transcranial brain stimulation is a promising method to boost aphasia therapy outcomes.

Extended fMRI-Guided Anodal and Cathodal Transcranial Direct Current Stimulation Targeting Perilesional Areas in Post-Stroke Aphasia: A Pilot Randomized Clinical Trial

Transcranial direct current stimulation (tDCS) may enhance speech and language treatment (SLT) for stroke survivors with aphasia; however, to date, there is no standard protocol for the application of tDCS in post-stroke aphasia. We explored the safety and efficacy of fMRI-guided tDCS on functional language and cortical activity when delivered to the lesioned left hemisphere concurrently with SLT across an extended, six-week treatment period. Twelve persons with chronic, nonfluent aphasia following a single left-hemisphere stroke participated in the three-arm (anodal vs. cathodal vs. sham) single-blind, parallel, pilot trial. No serious adverse events occurred during 30 treatment sessions or in the following six weeks. All groups demonstrated functional language gains following intensive treatment; however, active tDCS resulted in greater gains in standardized, probe, and caregiver-reported measures of functional language than sham. Evidence declaring one polarity as superior for inducing language recovery was mixed. However, cathodal stimulation to the lesioned left hemisphere, expected to have a down-regulating effect, resulted in increased areas of cortical activation across both hemispheres, and specifically perilesionally. Generalization of these preliminary findings is limited; however, results are nevertheless compelling that tDCS combined with SLT can be safely applied across extended durations, with the potential to enhance functional language and cortical activation for persons with aphasia.

Tractography Alterations in the Arcuate and Uncinate Fasciculi in Post-Stroke Aphasia

Fiber tractography based on diffuse tensor imaging (DTI) can reveal three-dimensional white matter connectivity of the human brain. Tractography is a non-invasive method of visualizing cerebral white matter structures in vivo, including neural pathways surrounding the ischemic area. DTI may be useful for elucidating alterations in brain connectivity resulting from neuroplasticity after stroke. We present a case of a male patient who developed significant mixed aphasia following ischemic stroke. The patient had been treated by mechanical thrombectomy followed by an early rehabilitation, in conjunction with transcranial direct current stimulation (tDCS). DTI was used to examine the arcuate fasciculus and uncinate fasciculus upon admission and again at three months post-stroke. Results showed an improvement in the patient’s symptoms of aphasia, which was associated with changes in the volume and numbers of tracts in the uncinate fasciculus and the arcuate fasciculus.

HD-tDCS as a neurorehabilitation technique for a case of post-anoxic leukoencephalopathy

Post-anoxic leukoencephalopathy is a rare event that causes global demyelination secondary to anoxic injury. Given the nature and extent of the damage, cognitive and functional deficits are typically chronic even after standard therapies. Here, we describe a novel treatment approach that used high definition transcranial direct-current stimulation (HD-tDCS) with a 62-year-old male who was 5 years post-anoxic leukoencephalopathy secondary to an accidental drug overdose. HD-tDCS was administered over the left lateral prefrontal cortex across 29 daily sessions at 2 mA (20 min/session) in order to address dysexecutive behaviors. Results demonstrated improved delayed memory and trends for improved visuospatial and semantic fluency performance as well as improved insight and daily functioning, all of which returned to baseline by the end of a 10 week no-contact follow up period. Resting state fMRI connectivity results mirrored these changes by showing increased dorsal attention and cingulo-opercular but reduced ventral attention network connectivity after session 29, all of which returned to baseline at follow-up. These findings suggest HD-tDCS may benefit functioning even following serious and pervasive anoxic injury. Findings also suggest the need for continued HD-tDCS for maintenance purposes, though future work is needed to identify optimal dose-response information.

High definition transcranial direct current stimulation modulates abnormal neurophysiological activity in post-stroke aphasia

Recent findings indicate that measures derived from resting-state magnetoencephalography (rsMEG) are sensitive to cortical dysfunction in post-stroke aphasia. Spectral power and multiscale entropy (MSE) measures show that left-hemispheric areas surrounding the stroke lesion (perilesional) exhibit pathological oscillatory slowing and alterations in signal complexity. In the current study, we tested whether individually-targeted high-definition transcranial direct current stimulation (HD-tDCS) can reduce MEG abnormalities and transiently improve language performance. In eleven chronic aphasia survivors, we devised a method to localize perilesional areas exhibiting peak MSE abnormalities, and subsequently targeted these areas with excitatory/anodal-tDCS, or targeted the contralateral homolog areas with inhibitory/cathodal-tDCS, based on prominent theories of stroke recovery. Pathological MEG slowing in these patients was correlated with aphasia severity. Sentence/phrase repetition accuracy was assessed before and after tDCS. A delayed word reading task was administered inside MEG to assess tDCS-induced neurophysiological changes in relative power and MSE computed on the pre-stimulus and delay task time windows. Results indicated increases in repetition accuracy, decreases in contralateral theta (4–7 Hz) and coarse-scale MSE (slow activity), and increases in perilesional low-gamma (25–50 Hz) and fine-scale MSE (fast activity) after anodal-tDCS, indicating reversal of pathological abnormalities. RsMEG may be a sensitive measure for guiding therapeutic tDCS.

Enhancing Brain Plasticity to Promote Stroke Recovery

Stroke disturbs both the structural and functional integrity of the brain. The understanding of stroke pathophysiology has improved greatly in the past several decades. However, effective therapy is still limited, especially for patients who are in the subacute or chronic phase. Multiple novel therapies have been developed to improve clinical outcomes by improving brain plasticity. These approaches either focus on improving brain remodeling and restoration or on constructing a neural bypass to avoid brain injury. This review describes emerging therapies, including modern rehabilitation, brain stimulation, cell therapy, brain-computer interfaces, and peripheral nervous transfer, and highlights treatment-induced plasticity. Key evidence from basic studies on the underlying mechanisms is also briefly discussed. These insights should lead to a deeper understanding of the overall neural circuit changes, the clinical relevance of these changes in stroke, and stroke treatment progress, which will assist in the development of future approaches to enhance brain function after stroke.

Clinical Feasibility of Combining Transcranial Direct Current Stimulation with Standard Aphasia Therapy

Background

Transcranial direct current stimulation (tDCS) is a safe, portable, and inexpensive form of noninvasive brain stimulation that appears to augment the effects of concurrent therapy. However, several methodological issues in existing studies distance tDCS from current clinical practice. In this study, we offered (and administered) tDCS to individuals seeking typical behavioral aphasia therapy on an outpatient basis.

Methods

We approached clients (n = 10) planning to receive standard aphasia therapy at a university clinic. Following a brief description of tDCS, we offered to provide stimulation during their therapy. Those interested and without contraindications participated in a double-blind, sham-controlled crossover study of tDCS paired with speech-language therapy provided twice weekly. Participants received active (2 mA) or sham tDCS during two eight-week therapy phases (separated by ten weeks) with the anode over Broca's area and the cathode on the contralateral forehead. Stimulation was provided for the first 20 minutes of each one-hour session. Prior to and following each phase, participants were video recorded telling the Cinderella narrative. Recordings were transcribed and analyzed for correct information units (CIUs).

Results

Seven individuals (70%) were interested in and eligible for tDCS. Data from four participants who completed the study indicated a large effect size favoring active over sham tDCS (Cohen's d = 1.32). The participant with the most severe deficits did not benefit from therapy in either condition.

Conclusion

There is potential for tDCS to enhance meaningful communication outcomes in standard clinical practice. Further investigation is needed to replicate findings and determine individual characteristics predictive of treatment response.

Transcranial direct current stimulation for post-stroke dysphagia: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Transcranial direct current stimulation (tDCS) has been investigated as a tool for dysphagia recovery after stroke in several single-center randomized controlled trials (RCT).

OBJECTIVE

The aim of this investigation was to quantitatively evaluate the effect of tDCS on dysphagia recovery after a stroke utilizing a systematic review and meta-analysis.

METHODS

Major databases were searched through October 2019 using a pre-defined set of criteria. Any RCT investigating the efficacy of tDCS in post-stroke dysphagia using a standardized dysphagia scale as outcome measure was included. Studies were assessed for risk of bias and quality using the Physiotherapy Evidence Database (PEDro) scale. Effect sizes were calculated from extracted data and entered into a random effects analysis to obtain pooled estimates of the effect.

RESULTS

Seven RCTs with a total sample size of 217 patients fulfilled the criteria and were included in the analysis. The overall results revealed a small but statistically significant pooled effect size (0.31; CI 0.03, 0.59; p = 0.03). The subgroup which explored the stimulation intensity yielded a moderately significant effect size for the low-intensity stimulation group (g = 0.44; CI = 0.08, 0.81 vs. g = 0.15, CI - 0.30, 0.61). For the other subgroup analyses, neither comparisons of affected vs. unaffected hemisphere or acute vs. chronic stroke phase revealed a significant result.

CONCLUSION

This meta-analysis demonstrates a modest but significant beneficial effect of tDCS on improving post-stroke dysphagia. Whether benefits from this intervention are more pronounced in certain patient subgroups and with specific stimulation protocols requires further investigation.

Transcranial direct current stimulation (tDCS) for improving aphasia after stroke: a systematic review with network meta-analysis of randomized controlled trials

BACKGROUND

Transcranial Direct Current Stimulation (tDCS) is an emerging approach for improving aphasia after stroke. However, it remains unclear what type of tDCS stimulation is most effective. Our aim was to give an overview of the evidence network regarding the efficacy and safety of tDCS and to estimate the effectiveness of the different stimulation types.

METHODS

This is a systematic review of randomized controlled trials with network meta-analysis (NMA). We searched the following databases until 4 February 2020: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, AMED, Web of Science, and four other databases. We included studies with adult people with stroke. We compared any kind of active tDCS (anodal, cathodal, or dual, that is applying anodal and cathodal tDCS concurrently) regarding improvement of our primary outcome of functional communication, versus control, after stroke.

PROSPERO ID

CRD42019135696.

RESULTS

We included 25 studies with 471 participants. Our NMA showed that tDCS did not improve our primary outcome, that of functional communication. There was evidence of an effect of anodal tDCS, particularly over the left inferior frontal gyrus, in improving our secondary outcome, that of performance in naming nouns (SMD = 0.51; 95% CI 0.11 to 0.90). There was no difference in safety between tDCS and its control interventions, measured by the number of dropouts and adverse events.

CONCLUSION

Comparing different application/protocols of tDCS shows that the anodal application, particularly over the left inferior frontal gyrus, seems to be the most promising tDCS treatment option to improve performance in naming in people with stroke.

Non-invasive brain stimulation as add-on therapy for subacute post-stroke aphasia: a randomized trial (NORTHSTAR)

Introduction

Non-invasive brain stimulation (NIBS) with speech therapy might improve recovery from post-stroke aphasia. This three-armed sham-controlled blinded prospective proof-of-concept study tested 1 Hz subthreshold repetitive transcranial magnetic stimulation (rTMS) and 2-mA cathodal transcranial direct current stimulation (ctDCS) on the right pars triangularis in subacute post-stroke aphasia.

Patients and methods

Sixty-three patients with left middle cerebral artery infarcts were recruited in five hospitals (Canada/United States/Germany, 01-2014/03-2018) and randomized to receive rTMS (N = 20), ctDCS (N = 24) or sham stimulation (N = 19) with ST for 10 days. Primary outcome variables were Z-score changes in naming, semantic fluency and comprehension tests and adverse event frequency. Secondary outcome variable was the percent change in the Unified Aphasia Score. Intention-to-treat analyses tested between-group effects at days 1 and 30 post-treatment with a pre-planned subgroup analysis for lesion location (affecting Broca's area or not).

Results

Naming was significantly improved by rTMS (median = 1.91/interquartile range = 0.77/p = .01) at 30 days versus ctDCS (median = 1.11/interquartile range = 1.51) and sham stimulation (median = 1.02/interquartile range = 1.71). All other primary results were non-significant. The rTMS effect was driven by the patient subgroup with intact Broca's area where NIBS tended to improve UnAS (median = 33.2%/interquartile range = 46.7%/p = .062) versus sham stimulation (median = 12.5%/interquartile range = 7.9%) at day 30. Conversely, in patients with infarcted Broca's area, UnAS tended to improve more with sham stimulation (median = 75.0%/interquartile range = 86.9%/p = .053) versus NIBS (median = 12.7%/interquartile range = 31.7).Conclusion: We found a delayed positive effect of low-frequency rTMS targeting the right pars triangularis on the recovery of naming performance in subacute post-stroke aphasia. This intervention may be beneficial only in patients with morphologically intact Broca's area.

Neuromodulation in post-stroke aphasia treatment

PURPOSE OF REVIEW

This paper aims to review non-invasive brain stimulation (NIBS) methods to augment speech and language therapy (SLT) for patients with post-stroke aphasia.

RECENT FINDINGS

In the past five years there have been more than 30 published studies assessing the effect of transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) for improving aphasia in people who have had a stroke. Different approaches to NIBS treatment have been used in post-stroke aphasia treatment including different stimulation locations, stimulation intensity, number of treatment sessions, outcome measures, type of aphasia treatment, and time post-stroke.

SUMMARY

This review of NIBS for post-stroke aphasia shows that both tDCS and TMS can be beneficial for improving speech and language outcomes for patients with stroke. Prior to translating NIBS to clinical practice, further studies are needed to determine optimal tDCS and TMS parameters as well as the mechanisms underlying tDCS and TMS treatment outcomes.

Developments in treating the nonmotor symptoms of stroke

INTRODUCTION

Stroke is among the most common causes of disability worldwide. Nonmotor symptoms of stroke are common and disabling. Many are treatable, and intervention improves the quality of life for stroke survivors.

AREAS COVERED

Here the author summarizes the evidence-based treatment of depression and other mood disorders, aphasia, hemispatial neglect, impairments of emotional communication and empathy, deficits in memory and other cognitive functions, sleep disorders, pain, fatigue, and seizures resulting from stroke. The author focuses on treatments supported by randomized controlled trials (RCTs), from the literature cited in Google Scholar, Embase, and Pubmed.

EXPERT OPINION

While behavioral rehabilitation is the most common intervention for many of the sequelae of stroke, relatively small RCTs support the use of noninvasive brain stimulation (transcranial direct current stimulation and transcranial direct current stimulation) and medications that facilitate neural plasticity and recovery. These noninvasive brain stimulation methods remain investigational for post-stroke symptoms. The strongest evidence for pharmacological intervention is in the domains of post-stroke mood disorders and epilepsy, but additional RCTs are needed to confirm the efficacy of selective serotonin reuptake inhibitors and other medications for improving recovery of cognition, language, and energy after stroke.

Developing, Implementing, and Improving Assessment and Treatment Fidelity in Clinical Aphasia Research

Purpose The purpose of this study was to describe the development and implementation of a fidelity program for an ongoing, multifacility, aphasia intervention study and to explain how initial fidelity measures are being used to improve study integrity. Method A Clinical Core team developed and incorporated a fidelity plan in this study. The aims of the Clinical Core team were to (a) supervise data collection and data management at each clinical site, (b) optimize and monitor assessment fidelity, and (c) optimize and monitor treatment fidelity. Preliminary data are being used to guide ongoing efforts to preserve and improve the fidelity of this intervention study. Results Preliminary results show that specific recruitment strategies help to improve appropriate referrals and that accommodations to participants and their families help to maintain excellent retention. A streamlined and centralized training program assures the reliability of assessors and raters for the study's assessment and treatment protocols. Ongoing monitoring of both assessment and treatment tasks helps to maintain study integrity. Less-than-optimal interrater reliability data for the raters of some of the discourse measures guided the Clinical Core team to address the training and coding inconsistencies in a timely manner. Conclusions The creation of a Clinical Core team is instrumental in developing and implementing a fidelity plan for improved assessment and treatment fidelity. Intentional planning and assignment of study staff to implement and monitor ongoing fidelity measures assures that clinical data are reliable and valid. Ongoing review of the plan shows areas of strengths and weaknesses for continuing adjustments and improvement of study fidelity.

Anodal tDCS over left parietal cortex expedites recovery from stroke-induced apraxic imitation deficits: a pilot study

Background

To date, specific therapeutic approaches to expedite recovery from apraxic deficits after left hemisphere (LH) stroke remain sparse. Thus, in this pilot study we evaluated the effect of anodal transcranial direct current stimulation (tDCS) in addition to a standardized motor training on apraxic imitation deficits.

Methods

In a rehabilitation hospital, we assessed apraxic, aphasic, and motor deficits in 30 LH stroke patients before and after a five-day standard programme of motor training combined with either anodal (10 min, 2 mA; n = 14) or sham (10 min, 0 mA, n = 16) tDCS applied in a double-blind fashion over left posterior parietal cortex (PPC). Where appropriate, data were analyzed with either t-test, Fisher’s exact test, or univariate/ repeated measures ANOVA.

Results

Compared to sham tDCS, five sessions of anodal tDCS expedited recovery from apraxic imitation deficits (p < 0.05): Already after 5 days, the anodal tDCS group showed levels of imitation performance that were achieved in the sham tDCS group after 3 months. However, the primary outcome of the study (i.e., anodal tDCS induced improvement of the total apraxia score) failed significance, and there was no significant tDCS effect on apraxia after 3 months. Anodal tDCS improved grip force (of the contra-lesional, i.e., right hand), but had no effect on aphasia.

Conclusions

Data from this pilot study show that repetitive, anodal tDCS over left PPC combined with a standardized motor training expedites recovery from imitation deficits in LH stroke patients with apraxia (relative to sham stimulation). Results suggest that in patients suffering from apraxic imitation deficits a randomized controlled trial (RCT) is warranted that investigates the effects of tDCS applied over PPC in addition to a standardized motor training.

Transcranial Direct Current Stimulation to Enhance Training Effectiveness in Chronic Post-Stroke Aphasia: A Randomized Controlled Trial Protocol

Background: Intensive speech-language therapy (SLT) can promote recovery from chronic post-stroke aphasia, a major consequence of stroke. However, effect sizes of intensive SLT are moderate, potentially reflecting a physiological limit of training-induced progress. Transcranial direct current stimulation (tDCS) is an easy-to-use, well-tolerated and low-cost approach that may enhance effectiveness of intensive SLT. In a recent phase-II randomized controlled trial, 26 individuals with chronic post-stroke aphasia received intensive SLT combined with anodal-tDCS of the left primary motor cortex (M1), resulting in improved naming and proxy-rated communication ability, with medium-to-large effect sizes.

Aims: The proposed protocol seeks to establish the incremental benefit from anodal-tDCS of M1 in a phase-III randomized controlled trial with adequate power, ecologically valid outcomes, and evidence-based SLT.

Methods: The planned study is a prospective randomized placebo-controlled (using sham-tDCS), parallel-group, double-blind, multi-center, phase-III superiority trial. A sample of 130 individuals with aphasia at least 6 months post-stroke will be recruited in more than 18 in- and outpatient rehabilitation centers.

Outcomes: The primary outcome focuses on communication ability in chronic post-stroke aphasia, as revealed by changes on the Amsterdam-Nijmegen Everyday Language Test (A-scale; primary endpoint: 6-month follow-up; secondary endpoints: immediately after treatment, and 12-month follow-up). Secondary outcomes include measures assessing linguistic-executive skills, attention, memory, emotional well-being, quality of life, health economic costs, and adverse events (endpoints: 6-month follow-up, immediately after treatment, and 12-month follow-up).

Discussion: Positive results will increase the quality of life for persons with aphasia and their families while reducing societal costs. After trial completion, a workshop with relevant stakeholders will ensure transfer into best-practice guidelines and successful integration within clinical routine.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT03930121.

Characterising neural plasticity at the single patient level using connectivity fingerprints

The occurrence of wide-scale neuroplasticity in the injured human brain raises hopes for biomarkers to guide personalised treatment. At the individual level, functional reorganisation has proven challenging to quantify using current techniques that are optimised for population-based analyses. In this cross-sectional study, we acquired functional MRI scans in 44 patients (22 men, 22 women, mean age: 39.4 ± 14 years) with a language-dominant hemisphere brain tumour prior to surgery and 23 healthy volunteers (11 men, 12 women, mean age: 36.3 ± 10.9 years) during performance of a verbal fluency task. We applied a recently developed approach to characterise the normal range of functional connectivity patterns during task performance in healthy controls. Next, we statistically quantified differences from the normal in individual patients and evaluated factors driving these differences. We show that the functional connectivity of brain regions involved in language fluency identifies “fingerprints” of brain plasticity in individual patients, not detected using standard task-evoked analyses. In contrast to healthy controls, patients with a tumour in their language dominant hemisphere showed highly variable fingerprints that uniquely distinguished individuals. Atypical fingerprints were influenced by tumour grade and tumour location relative to the typical fluency-activated network. Our findings show how alterations in brain networks can be visualised and statistically quantified from connectivity fingerprints in individual brains. We propose that connectivity fingerprints offer a statistical metric of individually-specific network organisation through which behaviourally-relevant adaptations could be formally quantified and monitored across individuals, treatments and time.

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Personalised treatment awaits individualised measures of brain adaptation.

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Connectivity patterns from FMRI offer unique “fingerprints” of brain networks.

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Individual brain tumours disrupt the language fluency network in unique ways.

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By fingerprint matching, networks can be tested and visualised in single patients.