Efficacy of Noninvasive Brain Stimulation on Unilateral Neglect After Stroke: A Systematic Review and Meta-analysis

Using mechanistic knowledge to appraise contemporary approaches to the rehabilitation of upper limb function following stroke

It is a paradox of neurological rehabilitation that, in an era in which preclinical models have produced significant advances in our mechanistic understanding of neural plasticity, there is inadequate support for many therapies recommended for use in clinical practice. When the goal is to estimate the probability that a specific form of therapy will have a positive clinical effect, the integration of mechanistic knowledge (concerning 'the structure or way of working of the parts in a natural system') may improve the quality of inference. This is illustrated by analysis of three contemporary approaches to the rehabilitation of lateralized dysfunction affecting people living with stroke: constraint-induced movement therapy; mental practice; and mirror therapy. Damage to 'cross-road' regions of the structural (white matter) brain connectome generates deficits that span multiple domains (motor, language, attention and verbal/spatial memory). The structural integrity of these regions determines not only the initial functional status, but also the response to therapy. As structural disconnection constrains the recovery of functional capability, 'disconnectome' modelling provides a basis for personalized prognosis and precision rehabilitation. It is now feasible to refer a lesion delineated using a standard clinical scan to a (dis)connectivity atlas derived from the brains of other stroke survivors. As the individual disconnection pattern thus obtained suggests the functional domains most likely be compromised, a therapeutic regimen can be tailored accordingly. Stroke is a complex disorder that burdens individuals with distinct constellations of brain damage. Mechanistic knowledge is indispensable when seeking to ameliorate the behavioural impairments to which such damage gives rise.

Modulation of initial leftward bias in visual search by parietal tDCS

Transcranial direct current stimulation (tDCS) has the potential to modulate spatial attention by enhancing the activity in one hemisphere relative to the other. This study aims to inform neurorehabilitation strategies for spatial attention disorders by investigating the impact of tDCS on the performance of healthy participants. Unlike prior research that focused on visual detection, we extended the investigation to visual search and visual imagery using computerized neuropsychological tests. Forty-eight participants had to actively search for targets in space (visual search) and notice differences between two mental images (visual imagery). Anodal stimulation was administered over the left parietal cortex for half of the participants and over the right parietal cortex for the other half. The results showed that tDCS modulated spatial attention in visual search but not in visual imagery. In the sham condition, visual search was characterized by a leftward bias in the selection of the first target and a left asymmetry in the overall spatial distribution of cancelled targets. Parietal tDCS modulated the initial leftward bias, enhancing it (more lateral) during right anodal stimulation and reducing it (more central) during left anodal stimulation. However, this effect was not reflected in the spatial distribution of the cancelled targets. The overall visual search performance marginally improved during right anodal stimulation, as evidenced by a greater percentage of cancelled targets compared to sham. Finally, the results revealed no left-right asymmetries in the visual imagery task, either after sham or anodal stimulation. The specific effect of parietal tDCS on the initiation of visual search offers a new perspective for targeted neurorehabilitation strategies and provides further insight into the different sensitivity of visual search measures classically used in brain-lesioned patients.

Short- and Long-Term Effects of Repetitive Transcranial Magnetic Stimulation on Poststroke Visuospatial Neglect: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

This systematic review and meta-analysis aimed to assess the effects of repetitive transcranial magnetic stimulation and select a suitable protocol for poststroke visuospatial neglect.

DESIGN

PubMed, Cochrane Library, and Embase databases were searched for relevant studies from the inception date to October 31, 2021. The inclusion criteria were (1) randomized controlled trials, (2) people with visuospatial neglect, (3) treatment with different repetitive transcranial magnetic stimulation protocols, (4) comparison with sham or blank control, and (5) reports of performance measurements.

RESULTS

Data were obtained from 11 randomized controlled trials. The effects of immediate and 1-mo postintervention were measured using line bisection test, cancellation test, and Catherine Bergego Scale. Results showed statistically significant improvement when applying low-frequency (0.5-1 Hz) repetitive transcranial magnetic stimulation or continuous theta burst stimulation to the left hemisphere on short- and long-term line bisection test (standardized mean difference = -1.10, 95% confidence interval = -1.84 to -0.37; standardized mean difference = -1.25, 95% confidence interval = -2.11 to -0.39) and cancellation test (standardized mean difference = 1.08, 95% confidence interval = 0.45 to 1.71; standardized mean difference = 1.45, 95% confidence interval = 0.42, 2.47).

CONCLUSIONS

Repetitive transcranial magnetic stimulation may be considered a treatment option for poststroke visuospatial neglect. This review proves that a decrease in neuronal excitation in the left hemisphere, which restores the interhemispheric balance, benefits poststroke visuospatial neglect.

Noninvasive Brain Stimulation for Neurorehabilitation in Post-Stroke Patients

Characterized by high morbidity, mortality, and disability, stroke usually causes symptoms of cerebral hypoxia due to a sudden blockage or rupture of brain vessels, and it seriously threatens human life and health. Rehabilitation is the essential treatment for post-stroke patients suffering from functional impairments, through which hemiparesis, aphasia, dysphagia, unilateral neglect, depression, and cognitive dysfunction can be restored to various degrees. Noninvasive brain stimulation (NIBS) is a popular neuromodulatory technology of rehabilitation focusing on the local cerebral cortex, which can improve clinical functions by regulating the excitability of corresponding neurons. Increasing evidence has been obtained from the clinical application of NIBS, especially repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS). However, without a standardized protocol, existing studies on NIBS show a wide variation in terms of stimulation site, frequency, intensity, dosage, and other parameters. Its application for neurorehabilitation in post-stroke patients is still limited. With advances in neuronavigation technologies, functional near-infrared spectroscopy, and functional MRI, specific brain regions can be precisely located for stimulation. On the basis of our further understanding on neural circuits, neuromodulation in post-stroke rehabilitation has also evolved from single-target stimulation to co-stimulation of two or more targets, even circuits and the network. The present study aims to review the findings of current research, discuss future directions of NIBS application, and finally promote the use of NIBS in post-stroke rehabilitation.

Repetitive Transcranial Magnetic Stimulation Combined with Cognitive Training for Cognitive Function and Activities of Daily Living in Patients with Post-Stroke Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Despite the potential effect of repetitive transcranial magnetic stimulation (rTMS) combined with cognitive training for post-stroke cognitive impairment (PSCI), there is uncertainty regarding rTMS combined with cognitive training for PSCI.

OBJECTIVE

To determine the effectiveness of rTMS combined with cognitive training for improving global cognitive function, specific domains of cognitive function and activities of daily living (ADL) in patients with PSCI.

METHODS

Databases including Cochrane Central, EMBASE (Ovid SP), CHINAL, APA PsycINFO, EBSCO, Medline, Web of science and other sources were systematically searched on March 23, 2022, and updated on December 5, 2022. All randomized controlled trials (RCTs) applied rTMS + cognitive training for patients with PSCI were screened for inclusion.

RESULTS

A total of 8 trials was finally included and 336 participants provided data for meta-analyses. Large effects were found for rTMS + cognitive training on global cognition (g = 0.780, 95% CI = 0.477 to 1.083), executive function (g = 0.769, 95% CI = 0.291 to 1.247), working memory (g = 0.609, 95% CI = 0.158-1.061) and medium improvement on ADL (g = 0.418, 95% CI = 0.058 to 0.778) were seen. While, no effects were found on memory or attention. Subgroup analyses showed that combinations of phase of stroke onset, rTMS frequency, stimulation site and stimulation sessions were potent factors that modulate the effects of rTMS + cognitive training for cognitive function.

CONCLUSIONS

The pooled data showed more positive effects of rTMS + cognitive training for global cognition, executive function, working memory and ADL in patients with PSCI. While, robust evidence of rTMS + cognitive training for global cognition, executive function, working memory and ADL from the Grade recommendations is lacking. Further, rTMS + cognitive training did not show no better effects on memory. Future definitive trials are needed to determine the benefits of rTMS + cognitive training for cognitive function and ADL in the field of PSCI.

Unilateral Spatial Neglect Recovery Poststroke

Unilateral spatial neglect (USN) is a common and disabling cognitive consequence of stroke wherein individuals demonstrate decreased response to contralesional information. Here, we provide an updated narrative review of studies that shed light on the neural mechanisms and predictors of recovery of USN. Additionally, we report a rapid review of randomized controlled trials focusing on USN intervention, both nonpharmacological and pharmacological, published in the last 5 years. Randomized controlled trials are reviewed within the context of systematic reviews and meta-analyses of USN interventions published within the same time frame. The quality of randomized controlled trials of treatment is higher compared to quality reported in previous reviews and meta-analyses. However, remaining weaknesses in participant demographic reporting, as well as small, heterogenous samples, render generalizability and cross-study interpretation a challenge. Nevertheless, evidence regarding neural mechanisms underlying USN recovery and regarding the effectiveness of targeted USN interventions is accumulating and strengthening, setting the foundation for future investigations into patient-specific factors that may influence treatment response. We identify gaps and provide suggestions for future USN intervention research.

Reversing the Ruin: Rehabilitation, Recovery, and Restoration After Stroke

PURPOSE OF REVIEW

Stroke is a common cause of disability in aging adults. A given individual's needs after stroke vary as a function of the stroke extent and location. The purpose of this review was to discuss recent clinical investigations addressing rehabilitation of an array of overlapping functional domains.

RECENT FINDINGS

Research is ongoing in the domains of movement, cognition, attention, speech, language, swallowing, and mental health. To best assist patients' recovery, innovative research has sought to develop and evaluate behavioral approaches, identify and refine synergistic approaches that augment the response to behavioral therapy, and integrate technology where appropriate, particularly to introduce and titrate real-world complexity and improve the overall experience of therapy. Recent and ongoing trials have increasingly adopted a multidisciplinary nature - augmenting refined behavioral therapy approaches with methods for increasing their potency, such as pharmaceutical or electrical interventions. The integration of virtual reality, robotics, and other technological advancements has generated immense excitement, but has not resulted in consistent improvements over more universally accessible, lower technology therapy.

Transcranial direct current stimulation in neglect rehabilitation after stroke: a systematic review

Hemispatial neglect is one of the most frequent attention disorders after stroke. The presence of neglect is associated with longer hospital stays, extended rehabilitation periods, and poorer functional recovery. Transcranial direct current stimulation (tDCS) is a new technique with promising results in neglect rehabilitation; therefore, the objective of this systematic review, performed following the PRISMA guidelines, is to evaluate the effectiveness of tDCS on neglect recovery after stroke. The search was done in MEDLINE (PubMed), Web of Science, Scopus, Cochrane Library, and BioMed Central databases. A total of 311 articles were found; only 11 met the inclusion criteria, including 152 post-stroke patients in total. Methodological quality and risk of bias were assessed for all the studies, and methodological characteristics of the studies, sample sizes, methods, main results, and other relevant data were extracted. tDCS intervention ranged from one to twenty sessions distributed in 1 day to 4 weeks, with intensity ranged from 1 to 2 mA. We found moderate evidence for the efficacy of tDCS in the rehabilitation of hemispatial neglect after a stroke, being more effective in combination with other interventions. Nonetheless, the limited number of studies and some studies' design characteristics makes it risky to draw categorical conclusions. Since scientific evidence is still scarce, further research is needed to determine the advantage of this treatment in acute, sub-acute and chronic stroke patients. Future studies should include larger samples, longer follow-ups, and broader neurophysiological assessments, with the final aim of establishing the appropriate use of tDCS as an adjuvant intervention in neurorehabilitation settings.

Rehabilitation interventions of unilateral spatial neglect based on the functional outcome measure: A systematic review and meta-analysis

ABSTRACTThis review aimed to examine the bottom-up and top-down rehabilitation intervention effectiveness based on the functional outcome measure as immediate effect and long-term effect for unilateral spatial neglect conditions. The RCT studies were collected by searching in three databases J-Stage, PubMed, and PEDro from 2008 through 2018. The studies which used the following instruments: BI, CBS, FMA, and FIM, as the functional outcome with the PEDro score of six and above, were eligible for inclusion. A total of 492 participants in 13 studies included from 291 studies initially identified. The meta-analysis for overall ES revealed that BI and CBS had a significant mean of SMD = 0.65 (95% CI, 0.23-1.07; p = 0.003; I2 = 65%), and SMD = -0.23 (95% CI, -0.45 to -0.01; p = 0.04; I2 = 35%) respectively, while FMA and FIM had an insignificant mean of SMD = 0.14 (95% CI, -0.08-0.37; p = 0.22; I2 = 0%), and SMD = -0.22 (95% CI, -0.69-0.25; p = 0.37; I2 = 0%) respectively. Based on the results, although indicated the heterogeneity representation across studies, it showed that the top-down intervention approach of high-frequency rTMS was more effective in enhancing the functional abilities and ADL of unilateral spatial neglect patients on the immediate effects but not necessarily in the long-term effects.

Non-invasive brain stimulation in rehabilitation

Non-invasive brain stimulation (NIBS) has been seen more common in rehabilitation settings. It can be used for the treatment of stroke, spinal cord injury, traumatic brain injury and multiple sclerosis, as well as for some diagnostic neurophysiological measurements. Two major modalities of NIBS are transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). As an add-on therapy to conventional rehabilitative treatments, the main goal of NIBS is to create neuromodulation by inhibiting or activating neural activity in the targeted cortical region. Indications for therapeutic NIBS in neurorehabilitation are motor recovery, aphasia, neglect, dysphagia, cognitive disorders, spasticity, and central pain. The NIBS can be regarded a safe technique with appropriate patient selection and defined treatment parameters. This review provides an overview on NIBS modalities, specifically TMS and tDCS, the working mechanisms, the stimulation techniques, areas of use, neuronavigation systems and safety considerations.

Neuroprotection by Transcranial Direct Current Stimulation in Rodent Models of Focal Ischemic Stroke: A Meta-Analysis

Infarct size is associated with stroke severity in clinical studies, so reducing it has become an important target and research hotspot in the treatment of ischemic stroke. Some preclinical studies have shown transcranial direct current stimulation (tDCS) reduced infarct size and improved neurological deficit, but others have not found beneficial effects. Besides, the optimal pattern of tDCS for ischemic stroke remains largely unknown. To shed light on the current circumstance and future research directions, the systematic review evaluated the effect of different tDCS paradigms in reducing infarct size and improving neurological deficit in rodent models of ischemic stroke and assessed the methodological quality of current literature. We searched the MEDLINE (via PubMed), EMBASE, Web of Science, and Scopus from their inception to August 18, 2021, to identify studies evaluating the effects of tDCS in rodent models of ischemic stroke. Eight studies were included, of which seven studies were included in the meta-analysis. The results showed cathodal tDCS, rather than anodal tDCS, reduced infarct size mainly measured by tetrazolium chloride and magnetic resonance imaging (standardized mean difference: -1.13; 95% CI: -1.72, -0.53; p = 0.0002) and improved neurological deficit assessed by a modified neurological severity score (standardized mean difference: -2.10; 95% CI: -3.78, -0.42; p = 0.01) in an early stage of focal ischemic stroke in rodent models. Subgroup analyses showed effects of cathodal tDCS on infarct size were not varied by ischemia duration (ischemia for 1, 1.5, and 2 h or permanent ischemia) and anesthesia (involving isoflurane and ketamine). The overall quality of studies included was low, thus the results must be interpreted cautiously. Published studies suggest that cathodal tDCS may be a promising avenue to explore for augmenting rehabilitation from focal ischemic stroke. Considering the methodological limitations, it is unreliable to blindly extrapolate the animal data to the clinical practice. Future research is needed to investigate the mechanism of tDCS in a randomized and blinded fashion in clinically relevant stroke models, such as elderly animals, female animals, and animals with comorbidities, to find an optimal treatment protocol.

Non-invasive, non-pharmacological/bio-technological interventions towards neurorestoration upshot after ischemic stroke, in adults-systematic, synthetic, literature review

Considering its marked life-threatening and (not seldom: severe and/or permanent) disabling, potential, plus the overall medico-psycho-socio-economic tough burden it represents for the affected persons, their families and the community, the cerebrovascular accident (CVA)-including with the, by far more frequent, ischemic type-is subject to considerable scientific research efforts that aim (if possible) at eliminating the stroke induced lesions, and consist, as well, in ambitious-but still poorly transferable into medical practice-goals such as brain neuroregeneration and/or repair, within related corollary/upshot of neurorestoration. We have conducted, in this respect, a systematic and synthetic literature review, following the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)" concept. Accordingly, we have interrogated five internationally renowned medical data bases: Elsevier, NCBI/PubMed, NCBI/PMC, PEDro, and ISI Web of Knowledge/Science (the last one to check whether the initially identified articles are published in ISI indexed journals), based on a large (details in the body text) number of most appropriate, to our knowledge, key word combinations/"syntaxes"-used contextually-and subsequently fulfilling the related, on five steps, filtering/selection methodology. We have thereby selected 114 fully eligible (of which contributive: 83-see further) papers; at the same time, additionally, we have enhanced our documentation-basically, but not exclusively, for the introductive part of this work (see further)-with bibliographic resources, overall connected to our subject, identified in the literature within a non-standardized search. It appears that the opportunity window for morph-functional recovery after stroke is larger than previously thought, actually being considered that brain neurorestoration/repair could occur, and therefore be expected, in later stages than in earlier ones, although, in this context, the number of cases possibly benefitting (for instance after physical and/or cognitive rehabilitation-including with magnetic or direct current transcranial stimulation) is quite small and with more or less conflicting, related outcomes, in the literature. Moreover, applying especially high intense, solicitating, rehabilitation interventions, in early stages post (including ischemic) stroke could even worsen the functional evolution. Accordingly, for clarifications and validation of more unitary points of view, continuing and boosting research efforts in this complex, interdisciplinary domain, is necessary. Until finding (if ever) effective modalities to cure the lesions of the central nervous system (CNS)-including post ischemic stroke-it is reasonable and recommendable-based on rigorous methodologies-the avail of combined ways: physiatric, pharmacologic, possibly also bio-technologic. On a different note, but however connected to our subject: periodic related systematic, synthetic literature reviews reappraisals are warranted and welcome.

Efficacy and safety of transcranial direct current stimulation for post-stroke spasticity: A meta-analysis of randomised controlled trials

OBJECTIVES

To evaluate the efficacy and safety of transcranial direct current stimulation for post-stroke spasticity and to assess its evidence using a meta-analysis.

METHODS

We searched the Cochrane Library, EMBASE, MEDLINE (via PubMed), PEDro, CBM, CNKI and Wan Fang Data from their inception to June 2021 for randomised clinical trials published in English or Chinese, which aimed to explore the effects of transcranial direct current stimulation on post-stroke spasticity. Two reviewers independently extracted the data and evaluated the methodological quality and overall evidence quality.

RESULTS

Thirteen randomised clinical trials comprising 924 patients were included, 12 of which were included in the meta-analysis. The results showed that anodal stimulation (standard mean difference = -0.91; [95% CI; -1.63 to -0.19]) combined with other therapies was more effective in improving upper limb spasticity. More than 20 minutes of stimulation were found to be effective in improving spasticity. Transcranial direct current stimulation was superior to the control treatments for subacute (standard mean difference = -1.16; -1.75 to -0.57) and chronic stroke (standard mean difference = -0.68; -1.13 to -0.22) patients aged under 60 (standard mean difference = -1.07; -1.54 to -0.60). No severe adverse events were reported in any of the included studies.

CONCLUSIONS

Low-quality evidence demonstrates that anodal transcranial direct current stimulation as an adjunct is effective and safe in reducing upper limb post-stroke spasticity when applied for more than 20 minutes in subacute and chronic stroke survivors aged under 60. Further high-quality studies are needed to explore its long-term efficacy and safety.

Blinding in electric current stimulation in subacute neglect patients with current densities of 0.8 A/m2: a cross-over pilot study

Objective

Neglect after stroke is a disabling disorder and its rehabilitation is a major challenge. Transcranial direct current stimulation (tDCS) seems to be a promising adjuvant technique to improve standard care neglect therapy. Since electric fields are influenced by age-related factors, higher current densities are probably needed for effective treatment in aged stroke patients. Validation of treatment efficacy requires sham-controlled experiments, but increased current densities might comprise blinding. Therefore, a pilot study was conducted to test sham adequacy when using current density of 0.8 A/m². Whether especially neglect patients who mainly suffer from perceptual and attentional deficits are able to differentiate beyond chance active from sham tDCS was investigated in a randomized cross-over design (active/sham stimulation) in 12 early subacute patients with left-sided hemineglect. Stimulation (0.8 A/m²) was performed simultaneous to standard care neglect therapy.

Results

Odds ratio of correct guessing an atDCS condition compared to wrongly judge an atDCS condition as sham was 10.00 (95%CI 0.65–154.40, p = 0.099). However, given the small sample size and high OR, although likely somewhat overestimated, results require careful interpretation and blinding success in neglect studies with current densities of 0.8 A/m² should be further confirmed.

Influence of Static Magnetic Field Stimulation on the Accuracy of Tachystoscopically Presented Line Bisection

Transcranial static magnetic stimulation (tSMS) has been known to reduce human cortical excitability. Here, we investigated whether tSMS would modulate visuo-spatial cognition in healthy humans. Subjects performed a visuo-spatial task requiring judgements about the symmetry of pre-bisected lines. Visual stimuli consisted of symmetrically or asymmetrically transected lines, tachystoscopically presented for 150 ms on a computer monitor. Task performance was examined before, immediately after, and 10 min after tSMS/sham stimulation of 20 min over the posterior parietal cortex (PPC: P4 from the international 10-20 system) or superior temporal gyrus (STG: C6). Nine out of 16 subjects misjudged pre-bisected lines by consistently underestimating the length of the right-side segment (judging lines to be exactly pre-bisected when the transector was located to the left of the midpoint, or judging the left-side segment to be longer when the transector was located at the midpoint). In these subjects showing a leftward bias, tSMS over the right STG reduced the magnitude of the leftward bias. This did not occur with tSMS over the right PPC or sham stimulation. In the remaining right-biased subjects, no intervention effect was observed with any stimulation. Our findings indicate that application of tSMS over the right STG modulates visuo-spatial cognition in healthy adults.

Transcranial direct current stimulation (tDCS) for improving activities of daily living, and physical and cognitive functioning, in people after stroke

BACKGROUND

Stroke is one of the leading causes of disability worldwide. Functional impairment, resulting in poor performance in activities of daily living (ADL) among stroke survivors is common. Current rehabilitation approaches have limited effectiveness in improving ADL performance, function, muscle strength, and cognitive abilities (including spatial neglect) after stroke, with improving cognition being the number one research priority in this field. A possible adjunct to stroke rehabilitation might be non-invasive brain stimulation by transcranial direct current stimulation (tDCS) to modulate cortical excitability, and hence to improve these outcomes in people after stroke.

OBJECTIVES

To assess the effects of tDCS on ADL, arm and leg function, muscle strength and cognitive abilities (including spatial neglect), dropouts and adverse events in people after stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register, CENTRAL, MEDLINE, Embase and seven other databases in January 2019. In an effort to identify further published, unpublished, and ongoing trials, we also searched trials registers and reference lists, handsearched conference proceedings, and contacted authors and equipment manufacturers.

SELECTION CRITERIA

This is the update of an existing review. In the previous version of this review, we focused on the effects of tDCS on ADL and function. In this update, we broadened our inclusion criteria to compare any kind of active tDCS for improving ADL, function, muscle strength and cognitive abilities (including spatial neglect) versus any kind of placebo or control intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and risk of bias, extracted data, and applied GRADE criteria. If necessary, we contacted study authors to ask for additional information. We collected information on dropouts and adverse events from the trial reports.

MAIN RESULTS

We included 67 studies involving a total of 1729 patients after stroke. We also identified 116 ongoing studies. The risk of bias did not differ substantially for different comparisons and outcomes. The majority of participants had ischaemic stroke, with mean age between 43 and 75 years, in the acute, postacute, and chronic phase after stroke, and level of impairment ranged from severe to less severe. Included studies differed in terms of type, location and duration of stimulation, amount of current delivered, electrode size and positioning, as well as type and location of stroke. We found 23 studies with 781 participants examining the effects of tDCS versus sham tDCS (or any other passive intervention) on our primary outcome measure, ADL after stroke. Nineteen studies with 686 participants reported absolute values and showed evidence of effect regarding ADL performance at the end of the intervention period (standardised mean difference (SMD) 0.28, 95% confidence interval (CI) 0.13 to 0.44; random-effects model; moderate-quality evidence). Four studies with 95 participants reported change scores, and showed an effect (SMD 0.48, 95% CI 0.02 to 0.95; moderate-quality evidence). Six studies with 269 participants assessed the effects of tDCS on ADL at the end of follow-up and provided absolute values, and found improved ADL (SMD 0.31, 95% CI 0.01 to 0.62; moderate-quality evidence). One study with 16 participants provided change scores and found no effect (SMD -0.64, 95% CI -1.66 to 0.37; low-quality evidence). However, the results did not persist in a sensitivity analysis that included only trials with proper allocation concealment. Thirty-four trials with a total of 985 participants measured upper extremity function at the end of the intervention period. Twenty-four studies with 792 participants that presented absolute values found no effect in favour of tDCS (SMD 0.17, 95% CI -0.05 to 0.38; moderate-quality evidence). Ten studies with 193 participants that presented change values also found no effect (SMD 0.33, 95% CI -0.12 to 0.79; low-quality evidence). Regarding the effects of tDCS on upper extremity function at the end of follow-up, we identified five studies with a total of 211 participants (absolute values) without an effect (SMD -0.00, 95% CI -0.39 to 0.39; moderate-quality evidence). Three studies with 72 participants presenting change scores found an effect (SMD 1.07; 95% CI 0.04 to 2.11; low-quality evidence). Twelve studies with 258 participants reported outcome data for lower extremity function and 18 studies with 553 participants reported outcome data on muscle strength at the end of the intervention period, but there was no effect (high-quality evidence). Three studies with 156 participants reported outcome data on muscle strength at follow-up, but there was no evidence of an effect (moderate-quality evidence). Two studies with 56 participants found no evidence of effect of tDCS on cognitive abilities (low-quality evidence), but one study with 30 participants found evidence of effect of tDCS for improving spatial neglect (very low-quality evidence). In 47 studies with 1330 participants, the proportions of dropouts and adverse events were comparable between groups (risk ratio (RR) 1.25, 95% CI 0.74 to 2.13; random-effects model; moderate-quality evidence).  AUTHORS' CONCLUSIONS: There is evidence of very low to moderate quality on the effectiveness of tDCS versus control (sham intervention or any other intervention) for improving ADL outcomes after stroke. However, the results did not persist in a sensitivity analyses including only trials with proper allocation concealment. Evidence of low to high quality suggests that there is no effect of tDCS on arm function and leg function, muscle strength, and cognitive abilities in people after stroke. Evidence of very low quality suggests that there is an effect on hemispatial neglect. There was moderate-quality evidence that adverse events and numbers of people discontinuing the treatment are not increased. Future studies should particularly engage with patients who may benefit the most from tDCS after stroke, but also should investigate the effects in routine application. Therefore, further large-scale randomised controlled trials with a parallel-group design and sample size estimation for tDCS are needed.

Neuropsychological rehabilitation of acquired, non-progressive cognitive-behavioral disorders in evidence-based clinical recommendations

Introduction: Neuropsychological rehabilitation is an important area of neurological rehabilitation. Its techniques are studied in terms of effectiveness and subjected to collective analyses in order to identify the best interventions. Objective: The purpose of the article is to present current clinical recommendations for neuropsychological rehabilitation among adult patients with acquired, non-progressive brain damage usually caused by a stroke or head injury. Data sources: The recommendations are based on the latest scientific papers containing systematic reviews and meta-analysis of studies on the rehabilitation of patients with cognitive dysfunctions and/or behavioral abnormalities. Conclusions: To date, the highest recommendation and the status of practice standards in neuropsychological rehabilitation have been achieved by therapeutic techniques of 5 post-stroke disorders (attention deficits, mild memory deficits, left-sided visual neglect, aphasia, global decline in cognitive-behavioral functioning) and 5 post-traumatic disorders (attention deficits, mild memory deficits, mild and moderate executive dysfunctions, abnormalities in social functioning and interpersonal communication, global decline in cognitive-behavioral functioning). These techniques may be used independently or introduced in combination with interventions of a lower recommendation level, classified as practice guidelines or practice options. The use of lower grade recommendations should also be considered in situations where there are no standard techniques for specific forms of disorders. In the case of deficits for which no recommendations have yet been made, further research is necessary. This applies to agnosia, profound memory disorders and amnesia, as well as profound executive dysfunctions.

Transcranial electric stimulation optimizes the balance of visual attention across space

OBJECTIVE

Transcranial direct current stimulation (tDCS) provides a way to modulate spatial attention by enhancing the ratio of neural activity between the left and right hemispheres, with a potential benefit for the rehabilitation of visual neglect.

METHODS

We tested the effect of bilateral tDCS in healthy individuals performing a visual detection task. This protocol consists in the positioning of the anode and cathode on mirror positions over the left and right parietal areas. The stimulation was repeated over three days to maximize the chance to observe a bias to the hemispace controlateral to the anode.

RESULTS

Compared to a sham treatment, left anodal - right cathodal stimulation enhanced attention across the full range of space, since the first day with no build-up effect on the next days, and modified the balance of left-right omissions when stimuli appeared at the same time.

CONCLUSION

Bilateral tDCS improved detection in both visual fields, with no privileged processing of one side, except when concurrent stimuli were presented. The results provide partial support to the hemispheric rivalry hypothesis.

SIGNIFICANCE

The technique has the potential to boost attention in neglect patients but should be used as an adjuvant rather than as an alternative to functional rehabilitation.

Noninvasive Brain Stimulation and Noninvasive Peripheral Stimulation for Neglect Syndrome Following Acquired Brain Injury

OBJECTIVE

Hemispatial neglect is a frequent condition usually following nondominant hemispheric brain injury. It strongly affects rehabilitation strategies and everyday life activities. It is associated with behavioral and cognitive disability with a strong impact on patient's life.

METHODS

We reviewed the published literature on the use of noninvasive brain stimulation, including repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), and of noninvasive peripheral muscle stimulation, as therapeutic strategies for rehabilitation of neglect after acquired brain injury, such as in stroke or in traumatic injuries. The studies were grouped as controlled or uncontrolled studies in each stimulation techniques.

RESULTS

Thirty-four studies were identified and 16 on rTMS, 10 on tDCS, and 8 on vibration. All studies were conducted in adult patients who suffered a stroke, except for one that was conducted in a patient suffering traumatic acquired brain injury and another that was conducted in a patient with brain tumor. In spite of significant variability in treatment protocols, patients' features and assessment of neglect, improvement was reported in almost all studies with no side-effects.

CONCLUSIONS

Noninvasive brain stimulation and neuromuscular vibration are promising therapeutic neuromodulatory approaches for neglect. Further randomized-controlled studies are needed to corroborate their effectiveness as separate and combined techniques.

Repetitive transcranial magnetic stimulation in stroke rehabilitation: review of the current evidence and pitfalls

Acute brain ischemia causes changes in several neural networks and related cortico-subcortical excitability, both in the affected area and in the apparently spared contralateral hemisphere. The modulation of these processes through modern techniques of noninvasive brain stimulation, namely repetitive transcranial magnetic stimulation (rTMS), has been proposed as a viable intervention that could promote post-stroke clinical recovery and functional independence. This review provides a comprehensive summary of the current evidence from the literature on the efficacy of rTMS applied to different clinical and rehabilitative aspects of stroke patients. A total of 32 meta-analyses published until July 2019 were selected, focusing on the effects on motor function, manual dexterity, walking and balance, spasticity, dysphagia, aphasia, unilateral neglect, depression, and cognitive function after a stroke. Only conventional rTMS protocols were considered in this review, and meta-analyses focusing on theta burst stimulation only were excluded. Overall, both HF-rTMS and LF-rTMS have been shown to be safe and well-tolerated. In addition, the current literature converges on the positive effect of rTMS in the rehabilitation of all clinical manifestations of stroke, except for spasticity and cognitive impairment, where definitive evidence of efficacy cannot be drawn. However, routine use of a specific paradigm of stimulation cannot be recommended yet due to a significant level of heterogeneity of the studies in terms of protocols to be set and outcome measures that have to be used. Future studies need to preliminarily evaluate the most promising protocols before going on to multicenter studies with large cohorts of patients in order to achieve a definitive translation into daily clinical practice.

Repetitive transcranial magnetic stimulation in stroke rehabilitation: review of the current evidence and pitfalls

Acute brain ischemia causes changes in several neural networks and related cortico-subcortical excitability, both in the affected area and in the apparently spared contralateral hemisphere. The modulation of these processes through modern techniques of noninvasive brain stimulation, namely repetitive transcranial magnetic stimulation (rTMS), has been proposed as a viable intervention that could promote post-stroke clinical recovery and functional independence. This review provides a comprehensive summary of the current evidence from the literature on the efficacy of rTMS applied to different clinical and rehabilitative aspects of stroke patients. A total of 32 meta-analyses published until July 2019 were selected, focusing on the effects on motor function, manual dexterity, walking and balance, spasticity, dysphagia, aphasia, unilateral neglect, depression, and cognitive function after a stroke. Only conventional rTMS protocols were considered in this review, and meta-analyses focusing on theta burst stimulation only were excluded. Overall, both HF-rTMS and LF-rTMS have been shown to be safe and well-tolerated. In addition, the current literature converges on the positive effect of rTMS in the rehabilitation of all clinical manifestations of stroke, except for spasticity and cognitive impairment, where definitive evidence of efficacy cannot be drawn. However, routine use of a specific paradigm of stimulation cannot be recommended yet due to a significant level of heterogeneity of the studies in terms of protocols to be set and outcome measures that have to be used. Future studies need to preliminarily evaluate the most promising protocols before going on to multicenter studies with large cohorts of patients in order to achieve a definitive translation into daily clinical practice.

The effect of theta-burst stimulation on unilateral spatial neglect following stroke: a systematic review

OBJECTIVE:

To evaluate the effectiveness of theta-burst stimulation for the treatment of stroke-induced unilateral spatial neglect.

DATA SOURCES:

A systematic literature search was conducted from the inception of each database to 30 June 2018 using CINAHL, EMBASE, PubMed, PsycINFO, and Scopus.

REVIEW METHODS:

Articles were included if theta-burst stimulation was used to treat neglect following a stroke. The additional a priori inclusion criteria were as follows: (1) ⩾3 adult (⩾18 years) participants, (2) ⩾50% stroke population, and (3) peer-reviewed journal articles published in English. Extracted data included study and treatment characteristics, results, and adverse events.

RESULTS:

Nine studies met the inclusion criteria, generating a total of 148 participants. Eight studies evaluated a continuous stimulation protocol and one study investigated an intermittent stimulation protocol. Overall, both protocols significantly improved neglect severity when compared against placebo or active controls ( P < 0.05). Adding smooth pursuit training to theta-burst stimulation did not improve neglect relative to when the stimulation was delivered alone ( P > 0.05). There was inconsistent reporting of neglect terminology, outcome measures, and adverse events. The treatment characteristics were heterogeneous among the trials.

CONCLUSION:

This systematic review found that theta-burst stimulation seems to improve post-stroke unilateral spatial neglect, but because the evidence is limited to a few small studies with varied and inconsistent protocols and use of terminology, no firm conclusion on effectiveness can be drawn.