Comparative efficacy of different noninvasive brain stimulation protocols on upper-extremity motor function and activities of daily living after stroke: a systematic review and network meta-analysis

The objectives of the study were to systematically evaluate the rehabilitation effect of noninvasive brain stimulation (NIBS) on upper extremity motor function and activities of daily living in stroke patients and to prioritize various stimulation protocols for reliable evidence-based medical recommendations in patients with upper extremity motor dysfunction after stroke. Web of Science, PubMed, Embase, Cochrane Library, CNKI, Wanfang, VIP, and CBM were searched to collect all randomized controlled trials (RCTs) of NIBS to improve upper extremity motor function in stroke patients. The retrieval time was from the establishment of all databases to May 2023. According to the Cochrane system evaluation manual, the quality of the included studies was evaluated, and the data were extracted. Statistical analysis was carried out by using RevMan 5.3, R 4.3.0, and Stata 17.0 software. Finally, 94 RCTs were included, with a total of 5546 patients. Meta-analysis showed that NIBS improved the Fugl-Meyer assessment (FMA) score (mean difference (MD) = 6.51, 95% CI 6.20 ~ 6.82, P < 0.05), MBI score (MD = 7.69, 95% CI 6.57 ~ 8.81, P < 0.05), ARAT score (MD = 5.06, 95% CI 3.85 ~ 6.27, P < 0.05), and motor evoked potential (MEP) amplitude. The modified Ashworth scale score (MD =  - 0.37, 95% CI - 0.60 to - 0.14, P < 0.05), National Institutes of Health Stroke Scale score (MD =  - 2.17, 95% CI - 3.32 to - 1.11, P < 0.05), incubation period of MEP (MD =  - 0.72, 95% CI - 1.06 to - 0.38, P < 0.05), and central motor conduction time (MD =  - 0.90, 95% CI - 1.29 to - 0.50, P < 0.05) were decreased in stroke patients. Network meta-analysis showed that the order of interventions in improving FMA scores from high to low was anodal-transcranial direct current stimulation (tDCS) (surface under the cumulative ranking curve (SUCRA) = 83.7%) > cathodal-tDCS (SUCRA = 80.2%) > high-frequency (HF)-repetitive transcranial magnetic stimulation (rTMS) (SUCRA = 68.5%) > low-frequency (LF)-rTMS (SUCRA = 66.5%) > continuous theta burst stimulation (cTBS) (SUCRA = 54.2%) > bilateral-tDCS (SUCRA = 45.2%) > intermittent theta burst stimulation (iTBS) (SUCRA = 34.1%) > sham-NIBS (SUCRA = 16.0%) > CR (SUCRA = 1.6%). In terms of improving MBI scores, the order from high to low was anodal-tDCS (SUCRA = 88.7%) > cathodal-tDCS (SUCRA = 85.4%) > HF-rTMS (SUCRA = 63.4%) > bilateral-tDCS (SUCRA = 56.0%) > LF-rTMS (SUCRA = 54.2%) > iTBS (SUCRA = 32.4%) > sham-NIBS (SUCRA = 13.8%) > CR (SUCRA = 6.1%). NIBS can effectively improve upper extremity motor function and activities of daily living after stroke. Among the various NIBS protocols, anodal-tDCS demonstrated the most significant intervention effect, followed by cathodal-tDCS and HF-rTMS.

Effects of repetitive transcranial magnetic stimulation over the contralesional dorsal premotor cortex on upper limb function in severe ischaemic stroke: study protocol for a randomised controlled trial

INTRODUCTION

Repetitive transcranial magnetic stimulation (rTMS) is an evidence-based treatment widely recommended to promote hand motor recovery after ischaemic stroke. However, the therapeutic efficacy of rTMS over the motor cortex in stroke patients is currently restricted and heterogeneous. This study aimed to determine whether excitatory rTMS over the contralesional dorsal premotor cortex (cPMd) facilitates the functional recovery of the upper limbs during the postacute stage of severe ischaemic stroke.

METHODS AND ANALYSIS

This study will be conducted as a single-blind, controlled, randomised study, in which 44 patients with poststroke hemiplegia with a course of disease ranging from 1 week to 3 months and Fugl-Meyer upper limb score ≤22 will be enrolled. The study participants will be randomly assigned to groups A (n=22) and B (n=22). The two groups are based on routine rehabilitation training and drug treatment; group A will be treated with low-frequency (1 Hz) rTMS over the contralesional primary motor cortex (cM1), and group B will be treated with high-frequency (10 Hz) rTMS over cPMd. For 2 weeks, rTMS will be administered once a day, 5 days a week. The primary outcome is the Fugl-Meyer assessment of the upper limb. The secondary outcomes include the Arm Subscore of the Motricity Index, Hong Kong edition of Functional Test for the Hemiplegic Upper Extremity, Modified Barthel Index and Modified Ashworth Scale score of the paralysed pectoralis major and biceps brachii. Furthermore, data of diffusion tensor imaging and functional MRI will be collected. These outcomes will be assessed before and after the completion of the intervention.

ETHICS AND DISSEMINATION

This study has been approved by the Ethics Committee of the First Affiliated Hospital of Nanjing Medical University (2020 SR-266). The findings of this study will be spread through networks of scientists, professionals and the general public as well as peer-reviewed scientific papers and presentations at pertinent conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2000038049.

Applications of Repetitive Transcranial Magnetic Stimulation to Improve Upper Limb Motor Performance After Stroke: A Systematic Review

BACKGROUND

Noninvasive brain stimulation (NIBS) is a promising technique for improving upper limb motor performance post-stroke. Its application has been guided by the interhemispheric competition model and typically involves suppression of contralesional motor cortex. However, the bimodal balance recovery model prompts a more tailored application of NIBS based on ipsilesional corticomotor function.

OBJECTIVE

To review and assess the application of repetitive transcranial magnetic stimulation (rTMS) protocols that aimed to improve upper limb motor performance after stroke.

METHODS

A PubMed search was conducted for studies published between 1st January 2005 and 1st November 2022 using rTMS to improve upper limb motor performance of human adults after stroke. Studies were grouped according to whether facilitatory or suppressive rTMS was applied to the contralesional hemisphere.

RESULTS

Of the 492 studies identified, 70 were included in this review. Only 2 studies did not conform to the interhemispheric competition model, and facilitated the contralesional hemisphere. Only 21 out of 70 (30%) studies reported motor evoked potential (MEP) status as a biomarker of ipsilesional corticomotor function. Around half of the studies (37/70, 53%) checked whether rTMS had the expected effect by measuring corticomotor excitability (CME) after application.

CONCLUSION

The interhemispheric competition model dominates the application of rTMS post-stroke. The majority of recent and current studies do not consider bimodal balance recovery model for the application of rTMS. Evaluating CME after the application rTMS could confirm that the intervention had the intended neurophysiological effect. Future studies could select patients and apply rTMS protocols based on ipsilesional MEP status.

Evidence of rTMS for Motor or Cognitive Stroke Recovery: Hype or Hope?

BACKGROUND

Evidence of efficacy of repetitive transcranial magnetic stimulation (rTMS) for stroke recovery is hampered by an unexplained variability of reported effect sizes and an insufficient understanding of mechanisms of action. We aimed to (1) briefly summarize evidence of efficacy, (2) identify critical factors to explain the reported variation in effects, and (3) provide mechanism-based recommendations for future trials.

METHODS

We performed a systematic review of the literature according to Cochrane and PRISMA Protocols. We included trials with ≥10 patients per treatment group. We classified outcome measures according to the International Classification of Functioning, Disability, and Health. Meta-analysis was done when at least 3 trials were reported on the same construct. In case of significant summary effect sizes with significant heterogeneity, we used sensitivity analyses to test for correlations and differences between found individual effect sizes and possible effect modifiers such as patient-, repetitive transcranial magnetic stimulation-, and trial characteristics.

RESULTS

We included 57 articles (N=2595). Funnel plots showed no publication bias. We found significant effect sizes at the level of body function (upper limb synergies, muscle strength, language functioning, global cognitive functioning, visual/spatial inattention) with repetitive transcranial magnetic stimulation within or beyond 3 months after stroke. We also found significant effect sizes at the level of activities. We found no subgroup differences or significant correlations between individual summary effect sizes and any tested possible effect modifier.

CONCLUSIONS

Repetitive transcranial magnetic stimulation holds the potential to benefit a range of motor and cognitive outcomes after stroke, but the evidence of efficacy is challenged by unexplained heterogeneity across many small sampled trials. We propose large trials with the collection of individual patient data on baseline severity and brain network integrity with sufficiently powered subgroup analyses, as well as protocolized time-locked training of the target behavior. Additional neurophysiological and biomechanical data may help in understanding mechanisms and identifying biomarkers of treatment efficacy.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: CRD42022300330.

Non-invasive Brain Stimulation Techniques for the Improvement of Upper Limb Motor Function and Performance in Activities of Daily Living After Stroke: A Systematic Review and Network Meta-analysis

OBJECTIVE

To compare the efficacy of non-invasive brain stimulation (NiBS) such as transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), theta-burst stimulation (TBS), and transcutaneous vagus nerve stimulation (taVNS) in upper limb stroke rehabilitation.

DATA SOURCES

PubMed, Web of Science, and Cochrane databases were searched from January 2010 to June 2022.

DATA SELECTION

Randomized controlled trials (RCTs) assessing the effects of "tDCS", "rTMS", "TBS", or "taVNS" on upper limb motor function and performance in activities of daily livings (ADLs) after stroke.

DATA EXTRACTION

Data were extracted by 2 independent reviewers. Risk of bias was evaluated with the Cochrane Risk of Bias tool.

DATA SYNTHESIS

87 RCTs with 3750 participants were included. Pairwise meta-analysis showed that all NiBS except continuous TBS (cTBS) and cathodal tDCS were significantly more efficacious than sham stimulation for motor function (standardized mean difference [SMD] range 0.42-1.20), whereas taVNS, anodal tDCS, and both low and high frequency rTMS were significantly more efficacious than sham stimulation for ADLs (SMD range 0.54-0.99). NMA showed that taVNS was more effective than cTBS (SMD:1.00; 95% CI (0.02-2.02)), cathodal tDCS (SMD:1.07; 95% CI (0.21-1.92)), and Physical rehabilitation alone (SMD:1.46; 95% CI (0.59-2.33)) for improving motor function. P-score found that taVNS is best ranked treatment in improving motor function (SMD: 1.20; 95% CI (0.46-1.95)) and ADLs (SMD:1.20; 95% CI (0.45-1.94)) after stroke. After taVNS, excitatory stimulation protocols (intermittent TBS, anodal tDCS, and HF-rTMS) are most effective in improving motor function and ADLs after acute/sub-acute (SMD range 0.53-1.63) and chronic stroke (SMD range 0.39-1.16).

CONCLUSIONS

Evidence suggests that excitatory stimulation protocols are the most promising intervention in improving upper limb motor function and performance in ADLs. taVNS appeared to be a promising intervention for stroke patients, but further large RCTs are required to confirm its relative superiority.

Does noninvasive brain stimulation combined with other therapies improve upper extremity motor impairment, functional performance, and participation in activities of daily living after stroke? A systematic review and meta-analysis of randomized controlled trial

BACKGROUND

Several studies have investigated the effect of noninvasive brain stimulation (NIBS) on upper limb motor function in stroke, but the evidence so far is conflicting.

OBJECTIVE

We aimed to determine the effect of NIBS on upper limb motor impairment, functional performance, and participation in activities of daily living after stroke.

METHOD

Literature search was conducted for randomized controlled trials (RCTs) assessing the effect of "tDCS" or "rTMS" combined with other therapies on upper extremity motor recovery after stroke. The outcome measures were Fugl-Meyer Assessment of Upper Extremity (FMA-UE), Wolf Motor Function Test (WMFT), and Barthel Index (BI). The mean difference (MD) and 95%CI were estimated for motor outcomes. Cochrane risk of bias tool was used to assess the quality of evidence.

RESULT

Twenty-five RCTs involving 1102 participants were included in the review. Compared to sham stimulation, NIBS combined with other therapies has effectively improved FMA-UE (MD0.97 [95%CI, 0.09 to 1.86; p = .03]) and BI score (MD9.11 [95%CI, 2.27 to 15.95; p = .009]) in acute/sub-acute stroke (MD1.73 [95%CI, 0.61 to 2.85; p = .003]) but unable to modify FMA-UE score in chronic stroke (MD-0.31 [95%CI, -1.77 to 1.15; p = .68]). Only inhibitory (MD3.04 [95%CI, 1.76 to 4.31; I² = 82%, p < .001] protocol is associated with improved FMA-UE score. Twenty minutes of stimulation/session for ≥20 sessions was found to be effective in improving FMA-UE score (Stimulation time: ES0.45; p ≤ .001; Sessions: ES0.33; p ≤ .001). The NIBS did not produce any significant improvement in WMFT as compared to sham NIBS (MD0.91 [95% CI, -0.89 to 2.70; p = .32]).

CONCLUSION

Moderate to high-quality evidence suggested that NIBS combined with other therapies is effective in improving upper extremity motor impairment and participation in activities of daily living after acute/sub-acute stroke.

Do Higher Transcranial Direct Current Stimulation Doses Lead to Greater Gains in Upper Limb Motor Function in Post-Stroke Patients?

Objective: To investigate whether a higher number of transcranial direct current stimulation (tDCS) sessions results in a greater improvement in upper limb function in chronic post-stroke patients. Materials and methods: A randomized, sham-controlled, double-blind clinical trial was conducted in 57 chronic post-stroke patients (≥ 3 months after their injuries). The patients were allocated to receive sessions of tDCS combined with physiotherapy and divided into three groups (anodal, cathodal, and sham). The Fugl-Meyer Assessment of Upper Extremity (FMA-UE) was used to assess the sensorimotor impairment of the patients’ upper limbs before (baseline) and after five and ten sessions. The percentage of patients who achieved a clinically significant improvement (> five points on the FMA-UE) was also analyzed. Results: The FMA-UE score increased after five and ten sessions in both the anodal and cathodal tDCS groups, respectively, compared to the baseline. However, in the sham group, the FMA-UE score increased only after ten sessions. When compared to the sham group, the mean difference from the baseline after five sessions was higher in the anodal tDCS group. The percentage of individuals who achieved greater clinical improvement was higher in the stimulation groups than in the sham group and after ten sessions when compared to five sessions. Conclusions: Our results suggest that five tDCS sessions are sufficient to augment the effect of standard physiotherapy on upper limb function recovery in chronic post-stroke patients, and ten sessions resulted in greater gains.

Effects of repetitive transcranial magnetic stimulation on upper-limb and finger function in stroke patients: A systematic review and meta-analysis of randomized controlled trials

Background

Repetitive transcranial magnetic stimulation (rTMS) is a promising intervention for stroke rehabilitation. Several studies have demonstrated the effectiveness of rTMS in restoring motor function. This meta-analysis aimed to summarize the current evidence of the effect of rTMS in improving upper limb function and fine motor recovery in stroke patients.

Methods

Three online databases (Web of Science, PubMed, and Embase) were searched for relevant randomized controlled trials. A total of 45 studies (combined n = 2064) were included. Random effects model was used for meta-analysis and effect size was reported as standardized mean difference (SMD).

Results

rTMS was effective in improving fine motor function in stroke patients (SMD, 0.38; 95% CI 0.19–0.58; P = 0). On subgroup analyses, for post-stroke functional improvement of the upper extremity, bilateral hemisphere stimulation was more effective than unilateral stimulation during the acute phase of stroke, and a regimen of 20 rTMS sessions produced greater improvement than <20 sessions. In the subacute phase of stroke, affected hemispheric stimulation with a 40-session rTMS regimen was superior to unaffected hemispheric stimulation or bilateral hemispheric stimulation with <40 sessions. Unaffected site stimulation with a 10-session rTMS regimen produced significant improvement in the chronic phase compared to affected side stimulation and bilateral stimulation with >10 rTMS sessions. For the rTMS stimulation method, both TBS and rTMS were found to be significantly more effective in the acute phase of stroke, but TBS was more effective than rTMS. However, rTMS was found to be more effective than TBS stimulation in patients in the subacute and chronic phases of stroke. rTMS significantly improved upper limb and fine function in the short term (0–1-month post-intervention) and medium term (2–5 months), but not for upper limb function in the long term (6 months+). The results should be interpreted with caution due to significant heterogeneity.

Conclusions

This updated meta-analysis provides robust evidence of the efficacy of rTMS treatment in improving upper extremity and fine function during various phases of stroke.

Systematic Review Registration

https://inplasy.com/inplasy-2022-5-0121/, identifier: INPLASY202250121.

Rehabilitation Interventions Combined with Noninvasive Brain Stimulation on Upper Limb Motor Function in Stroke Patients

(1) Background: This systematic review aimed to focus on the effects of rehabilitation interventions combined with noninvasive brain stimulation on upper limb motor function in stroke patients. (2) Methods: PubMed, MEDLINE, and CINAHL were used for the literature research. Articles were searched using the following terms: "Stroke OR CVA OR cerebrovascular accident" AND "upper limb OR upper extremity" AND "NIBS OR Non-Invasive Brain Stimulation" OR "rTMS" OR "repetitive transcranial magnetic stimulation" OR "tDCS" OR "transcranial direct current stimulation" AND "RCT" OR randomized control trial." In total, 12 studies were included in the final analysis. (3) Results: Analysis using the Physiotherapy Evidence Database scale for qualitative evaluation of the literature rated eight articles as "excellent" and four as "good." Combined rehabilitation interventions included robotic therapy, motor imagery using brain-computer interaction, sensory control, occupational therapy, physiotherapy, task-oriented approach, task-oriented mirror therapy, neuromuscular electrical stimulation, and behavior observation therapy. (4) Conclusions: Although it is difficult to estimate the recovery of upper limb motor function in stroke patients treated with noninvasive brain stimulation alone, a combination of a task-oriented approach, occupational therapy, action observation, wrist robot-assisted rehabilitation, and physical therapy can be effective.

Effects of high frequency rTMS of contralesional dorsal premotor cortex in severe subcortical chronic stroke: protocol of a randomized controlled trial with multimodal neuroimaging assessments

Background

Previous studies have revealed that low frequency repeated transcranial magnetic stimulation (rTMS) on the contralesional primary motor cortex (cM1) is less effective in severe stroke patients with poor neural structural reserve than in patients with highly reserved descending motor pathway. This may be attributed to the fact that secondary motor cortex, especially contralesional dorsal premotor cortex (cPMd), might play an important compensatory role in the motor function recovery of severely affected upper extremity. The main purpose of this study is to compare the effectiveness of low frequency rTMS on cM1 and high frequency rTMS on cPMd in subcortical chronic stroke patients with severe hemiplegia. By longitudinal analysis of multimodal neuroimaging data, we hope to elucidate the possible mechanism of brain reorganization following different treatment regimens of rTMS therapy, and to determine the cut-off of stimulation strategy selection based on the degree of neural structural reserve.

Methods/design

The study will be a single-blinded randomized controlled trial involving a total of 60 subcortical chronic stroke patients with severe upper limb motor impairments. All patients will receive 3 weeks of conventional rehabilitation treatment, while they will be divided into three groups and receive different rTMS treatments: cM1 low frequency rTMS (n = 20), cPMd high frequency rTMS (n = 20), and sham stimulation group (n = 20). Clinical functional assessment, multimodal functional MRI (fMRI) scanning, and electrophysiological measurement will be performed before intervention, 3 weeks after intervention, and 4 weeks after the treatment, respectively.

Discussion

This will be the first study to compare the effects of low-frequency rTMS of cM1 and high-frequency rTMS of cPMd. The outcome of this study will provide a theoretical basis for clarifying the bimodal balance-recovery model of stroke, and provide a strategy for individualized rTMS treatment for stroke in future studies and clinical practice.

Trial registration

Chinese Clinical Trial Registry, ChiCTR1900027399. Registered on 12 Nov 2019, http://www.chictr.org.cn/showproj.aspx?proj=43686.

Low-Frequency rTMS over Contralesional M1 Increases Ipsilesional Cortical Excitability and Motor Function with Decreased Interhemispheric Asymmetry in Subacute Stroke: A Randomized Controlled Study

Objective

To determine the long-term effects of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) over the contralesional M1 preceding motor task practice on the interhemispheric asymmetry of the cortical excitability and the functional recovery in subacute stroke patients with mild to moderate arm paresis.

Methods

Twenty-four subacute stroke patients were randomly allocated to either the experimental or control group. The experimental group underwent rTMS over the contralesional M1 (1 Hz), immediately followed by 30 minutes of motor task practice (10 sessions within 2 weeks). The controls received sham rTMS and the same task practice. Following the 2-week intervention period, the task practice was continued twice weekly for another 10 weeks in both groups. Outcomes were evaluated at baseline (T0), at the end of the 2-week stimulation period (T1), and at 12-week follow-up (T2).

Results

The MEP (paretic hand) and interhemispheric asymmetry, Fugl-Meyer motor assessment, Action Research Arm Test, and box and block test scores improved more in the experimental group than controls at T1 (p < 0.05). The beneficial effects were largely maintained at T2.

Conclusion

LF-rTMS over the contralesional M1 preceding motor task practice was effective in enhancing the ipsilesional cortical excitability and upper limb function with reducing interhemispheric asymmetry in subacute stroke patients with mild to moderate arm paresis. Significance. Adding LF-rTMS prior to motor task practice may reduce interhemispheric asymmetry of cortical excitabilities and promote upper limb function recovery in subacute stroke with mild to moderate arm paresis.

Resting motor threshold in the course of hand motor recovery after stroke: a systematic review

Background

Resting motor threshold is an objective measure of cortical excitability. Numerous studies indicate that the success of motor recovery after stroke is significantly determined by the direction and extent of cortical excitability changes. A better understanding of this topic (particularly with regard to the level of motor impairment and the contribution of either cortical hemisphere) may contribute to the development of effective therapeutical strategies in this cohort.

Objectives

This systematic review collects and analyses the available evidence on resting motor threshold and hand motor recovery in stroke patients.

Methods

PubMed was searched from its inception through to 31/10/2020 on studies investigating resting motor threshold of the affected and/or the non-affected hemisphere and motor function of the affected hand in stroke cohorts.

Results

Overall, 92 appropriate studies (including 1978 stroke patients and 377 healthy controls) were identified. The analysis of the data indicates that severe hand impairment is associated with suppressed cortical excitability within both hemispheres and with great between-hemispheric imbalance of cortical excitability. Favorable motor recovery is associated with an increase of ipsilesional motor cortex excitability and reduction of between-hemispheric imbalance. The direction of change of contralesional motor cortex excitability depends on the amount of hand motor impairment. Severely disabled patients show an increase of contralesional motor cortex excitability during motor recovery. In contrast, recovery of moderate to mild hand motor impairment is associated with a decrease of contralesional motor cortex excitability.

Conclusions

This data encourages a differential use of rehabilitation strategies to modulate cortical excitability. Facilitation of the ipsilesional hemisphere may support recovery in general, whereas facilitation and inhibition of the contralesional hemisphere may enhance recovery in severe and less severely impaired patients, respectively.

Placebo effect of rTMS on post-stroke motor rehabilitation: a meta-analysis

Previous studies have shown that placebo repetitive transcranial magnetic stimulation (rTMS) was effective on post-stroke motor rehabilitation. However, the placebo effect has not been systematically assessed. Therefore, this meta-analysis was conducted to resolve this issue and explore potential influencing factors further. PubMed, Embase, web of science and the Cochrane Library were searched for published randomised controlled trials (RCTs) with placebo rTMS treatment of stroke recovery until May 2019. The placebo effect size (Hedges' g) was estimated using the motor outcome of pre- and post- placebo rTMS treatment. Meta-regression analysis was also performed to explore potential influencing factors for the placebo effect. Twenty-six placebo-controlled trials (including 381 patients in placebo group) were selected. Effect size results (Hedges' g = 0.466, 95% CI 0.207-0.726; P < 0.05) showed a medium and significant placebo rTMS effect on improving post-stroke motor recovery. The mean ratio of the effect size of sham to real stimulation was 56%. Meta-regression analysis did not find significant result except for the treatment sessions, which was significantly correlated with the placebo effect size (r = 0.465, p = 0.031). In the follow-up observations (1, 2 and 3 months), the sham rTMS groups manifested gradually increased motor improvement, which was similar to the real group, but the amplitude was lower, which was sustained for at least 3 months. Placebo effect of rTMS on post-stroke motor recovery was medium but significant. Regarding different sham styles, the number of stimulation sessions had an impact on the effect.

Canadian Platform for Trials in Noninvasive Brain Stimulation (CanStim) Consensus Recommendations for Repetitive Transcranial Magnetic Stimulation in Upper Extremity Motor Stroke Rehabilitation Trials

Objective. To develop consensus recommendations for the use of repetitive transcranial magnetic stimulation (rTMS) as an adjunct intervention for upper extremity motor recovery in stroke rehabilitation clinical trials. Participants. The Canadian Platform for Trials in Non-Invasive Brain Stimulation (CanStim) convened a multidisciplinary team of clinicians and researchers from institutions across Canada to form the CanStim Consensus Expert Working Group. Consensus Process. Four consensus themes were identified: (1) patient population, (2) rehabilitation interventions, (3) outcome measures, and (4) stimulation parameters. Theme leaders conducted comprehensive evidence reviews for each theme, and during a 2-day Consensus Meeting, the Expert Working Group used a weighted dot-voting consensus procedure to achieve consensus on recommendations for the use of rTMS as an adjunct intervention in motor stroke recovery rehabilitation clinical trials. Results. Based on best available evidence, consensus was achieved for recommendations identifying the target poststroke population, rehabilitation intervention, objective and subjective outcomes, and specific rTMS parameters for rehabilitation trials evaluating the efficacy of rTMS as an adjunct therapy for upper extremity motor stroke recovery. Conclusions. The establishment of the CanStim platform and development of these consensus recommendations is a first step toward the translation of noninvasive brain stimulation technologies from the laboratory to clinic to enhance stroke recovery.

Low-Frequency Repetitive Transcranial Magnetic Stimulation Over Contralesional Motor Cortex for Motor Recovery in Subacute Ischemic Stroke: A Randomized Sham-Controlled Trial

BACKGROUND

Low-frequency repetitive transcranial magnetic stimulation (rTMS) over the contralesional motor cortex (M1) has demonstrated beneficial effects on motor recovery, but evidence among patients with subacute stroke is lacking. We aimed to investigate whether 1-Hz rTMS over the contralesional M1 versus sham rTMS could improve arm function in patients with subacute ischemic stroke when combined with rehabilitative motor training.

METHODS

In total, 77 patients who were within 90 days after their first-ever ischemic stroke were enrolled and randomly allocated to either real (n = 40) or sham rTMS (n = 37). We delivered 1-Hz 30-minute active or sham rTMS before each daily 30-minute occupational therapy sessions over a 2-week period. The primary endpoint was changes in the Box and Block Test (BBT) score immediately after the end of treatment (EOT). Secondary analyses assessed changes in Fugl-Meyer assessment, Finger Tapping Test (FTT), Brunnstrom stage, and grip strength.

CLINICAL TRIAL REGISTRATION

ClinialTrials.gov (NCT02082015).

RESULTS

Changes in BBT immediately after the end of treatment did not differ significantly between the 2 groups (P = .267). Subgroup analysis according to cortical involvement revealed that real rTMS resulted in improvements in BBT at 1 month after EOT (17.4 ± 9.8 real vs 10.9 ± 10.3 sham; P = .023) and Brunnstrom stage of the hand immediately after EOT (0.6 ± 0.5 real vs 0.2 ± 0.5 sham; P = .023), only in the group without cortical involvement.

CONCLUSION

The effects of real and sham rTMS did not differ significantly among patients within 3 months poststroke. The location of stroke lesions should be considered for future clinical trials.

Pragmatic Solutions for Stroke Recovery and Improved Quality of Life in Low- and Middle-Income Countries-A Systematic Review

Background: Given the limited healthcare resources in low and middle income countries (LMICs), effective rehabilitation strategies that can be realistically adopted in such settings are required. Objective: A systematic review of literature was conducted to identify pragmatic solutions and outcomes capable of enhancing stroke recovery and quality of life of stroke survivors for low- and middle- income countries. Methods: PubMed, HINARI, and Directory of Open Access Journals databases were searched for published Randomized Controlled Trials (RCTs) till November 2018. Only completed trials published in English with non-pharmacological interventions on adult stroke survivors were included in the review while published protocols, pilot studies and feasibility analysis of trials were excluded. Obtained data were synthesized thematically and descriptively analyzed. Results: One thousand nine hundred and ninety six studies were identified while 347 (65.22% high quality) RCTs were found to be eligible for the review. The most commonly assessed variables (and outcome measure utility) were activities of daily living [75.79% of the studies, with Barthel Index (37.02%)], motor function [66.57%; with Fugl Meyer scale (71.88%)], and gait [31.12%; with 6 min walk test (38.67%)]. Majority of the innovatively high technology interventions such as robot therapy (95.24%), virtual reality (94.44%), transcranial direct current stimulation (78.95%), transcranial magnetic stimulation (88.0%) and functional electrical stimulation (85.00%) were conducted in high income countries. Several traditional and low-cost interventions such as constraint-induced movement therapy (CIMT), resistant and aerobic exercises (R&AE), task oriented therapy (TOT), body weight supported treadmill training (BWSTT) were reported to significantly contribute to the recovery of motor function, activity, participation, and improvement of quality of life after stroke. Conclusion: Several pragmatic, in terms of affordability, accessibility and utility, stroke rehabilitation solutions, and outcome measures that can be used in resource-limited settings were found to be effective in facilitating and enhancing post-stroke recovery and quality of life.

Efficacy of Low-Frequency Repetitive Transcranial Magnetic Stimulation in Ischemic Stroke: A Double-Blind Randomized Controlled Trial

OBJECTIVE

To investigate the role of low-frequency repetitive transcranial magnetic stimulation (rTMS) along with conventional physiotherapy in the functional recovery of patients with subacute ischemic stroke.

DESIGN

Double-blind, parallel group, randomized controlled trial.

SETTING

The outpatient department of a tertiary hospital participants: first ever ischemic stroke patients (N=96) in the previous 15 days were recruited and were randomized after a run-in period of 75±7 days into real rTMS (n=47) and sham rTMS (n=49) groups.

INTERVENTION

Conventional physical therapy was given to both the groups for 90±7 days postrecruitment. Total 10 sessions of low-frequency rTMS on contralesional premotor cortex was administered to real rTMS group (n=47) over a period of 2 weeks followed by physiotherapy regime for 45-50 minutes.

MAIN OUTCOME MEASURES

The primary efficacy outcomes were change in modified Barthel Index (mBI) score (pre- to postscore) and proportion of participants with mBI score more than 90, measured at 90±7 days postrecruitment. The secondary outcomes were change in Fugl-Meyer Assessment-upper extremity, Fugl-Meyer Assessment-lower extremity, Hamilton Depression Scale, modified Rankin Scale, and National Institute of Health and Stroke Scale (pre- to post-rTMS) scores at 90±7 days post recruitment.

RESULTS

Modified intention to treat analysis showed a significant increase in the mBI score from pre- to post-rTMS in real rTMS group (4.96±4.06) versus sham rTMS group (2.65±3.25). There was no significant difference in proportion of patients with mBI>90 (55% vs 59%; P=.86) at 3 months between the groups.

CONCLUSION

In patients with subacute ischemic stroke, 1-Hz low-frequency rTMS on contralesional premotor cortex along with conventional physical therapy resulted in significant change in mBI score.

Synergistic Effects of Scalp Acupuncture and Repetitive Transcranial Magnetic Stimulation on Cerebral Infarction: A Randomized Controlled Pilot Trial

This study investigated the synergistic effects of scalp acupuncture (SA) and repetitive transcranial magnetic stimulation (rTMS), known to be effective for cerebral infarction. This outcome-assessor-blinded, randomized controlled clinical trial included a per-protocol analysis to compare the efficacy of SA and electromagnetic convergence stimulation (SAEM-CS) and single or no stimulation. The trial was conducted with 42 cerebral infarction patients (control group, 12; SA group, 11; rTMS group, 8; SAEM-CS group, 11). All patient groups underwent two sessions of CSRT per day. SA, rTMS, and SAEM-CS were conducted once per day, 5 days per week, for 3 weeks. The primary outcome was evaluated using the Fugl–Mayer assessment (FMA). FMA Upper Extremity, FMA total, MBI, and FIM scores significantly increased in the rTMS group compared with the control group. Additionally, FMA Upper Extremity, FMA total, MBI and FIM scores significantly increased in the rTMS group compared with the SAEM-CS group. However, there were no significant changes in the SA or SAEM-CS groups. In conclusion, low-frequency rTMS in the contralesional hemisphere may have long-term therapeutic effects on upper extremity motor function recovery and improvements in activities of daily living. SAEM-CS did not show positive synergistic effects of SA and rTMS.

Ipsilateral primary motor cortex and behavioral compensation after stroke: a case series study

Arm motor recovery after stroke is mainly attributed to reorganization of the primary motor cortex (M1). While M1 contralateral to the paretic arm (cM1) is critical for recovery, the role of ipsilateral M1 (iM1) is still inconclusive. Whether iM1 activity is related to recovery, behavioral compensation, or both is still far from settled. We hypothesized that the magnitude of iM1 activity in chronic stroke survivors will increase or decrease in direct proportion to the degree that movements of the paretic arm are compensated. Movement kinematics (VICON, Oxford Metrics) and functional MRI data (3T MR system) were collected in 11 patients before and after a 4-week training designed to improve motor control of the paretic arm and decrease compensatory trunk recruitment. Twelve matched controls underwent similar evaluations and training. Relationships between iM1 activity and trunk motion were analyzed. At baseline, patients exhibited increased iM1 activity (p = 0.001) and relied more on trunk movement (p = 0.02) than controls. These two variables were directly and significantly related in patients (r = 0.74, p = 0.01) but not in controls (r = 0.28, p = 0.4). After training, patients displayed a significant reduction in iM1 activity (p = 0.008) and a trend toward decreased trunk use (p = 0.1). The relationship between these two variables remained significant (r = 0.66, p = 0.03) and different from controls (r = 0.26, p = 0.4). Our preliminary results suggest that iM1 may play a role in compensating for brain damage rather than directly gaining control of the paretic arm. However, we recommend caution in interpreting these results until more work is completed.

Treatments for Poststroke Motor Deficits and Mood Disorders: A Systematic Review for the 2019 U.S. Department of Veterans Affairs and U.S. Department of Defense Guidelines for Stroke Rehabilitation

BACKGROUND

Early rehabilitation after stroke is essential to help reduce disability.

PURPOSE

To summarize evidence on the benefits and harms of nonpharmacologic and pharmacologic treatments for motor deficits and mood disorders in adults who have had stroke.

DATA SOURCES

English-language searches of multiple electronic databases from April 2009 through July 2018; targeted searches to December 2018 for studies of selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors.

STUDY SELECTION

19 systematic reviews and 37 randomized controlled trials addressing therapies for motor deficits or mood disorders in adults with stroke.

DATA EXTRACTION

One investigator abstracted the data, and quality and GRADE assessment were checked by a second investigator.

DATA SYNTHESIS

Most interventions (for example, SSRIs, mental practice, mirror therapy) did not improve motor function. High-quality evidence did not support use of fluoxetine to improve motor function. Moderate-quality evidence supported use of cardiorespiratory training to improve maximum walking speed and repetitive task training or transcranial direct current stimulation to improve activities of daily living (ADLs). Low-quality evidence supported use of robotic arm training to improve ADLs. Low-quality evidence indicated that antidepressants may reduce depression, whereas the frequency and severity of antidepressant-related adverse effects was unclear. Low-quality evidence suggested that cognitive behavioral therapy and exercise, including mind-body exercise, may reduce symptoms of depression and anxiety.

LIMITATION

Studies were of poor quality, interventions and comparators were heterogeneous, and evidence on harms was scarce.

CONCLUSION

Cardiorespiratory training, repetitive task training, and transcranial direct current stimulation may improve ADLs in adults with stroke. Cognitive behavioral therapy, exercise, and SSRIs may reduce symptoms of poststroke depression, but use of SSRIs to prevent depression or improve motor function was not supported.

PRIMARY FUNDING SOURCE

U.S. Department of Veterans Affairs, Veterans Health Administration.

Timing of Repetitive Transcranial Magnetic Stimulation Onset for Upper Limb Function After Stroke: A Systematic Review and Meta-Analysis

Background: Repetitive transcranial magnetic stimulation (rTMS) is a promising intervention to promote upper limb recovery after stroke. We aimed to identify differences in the efficacy of rTMS treatment on upper limb function depending on the onset time post-stroke.

Methods: We searched PubMed, Embase, and the Cochrane Library to identify relevant RCTs from their inception to February 2018. RCTs on the effects of rTMS on upper limb function in adult patients with stroke were included. Study quality and risk of bias were assessed independently by two authors. Meta-analyses were performed for outcomes on individual upper limb outcome measures (function or activity) and for function and activity measures jointly, categorized by timing of treatment initiation. Timing of treatment initiation post-stroke was categorized as follows: acute to early subacute (<1 month), early subacute (1–3 months), late subacute (3–6 months), and chronic (>6 months).

Results: We included 38 studies involving 1,074 stroke patients. Subgroup analysis demonstrated benefit of rTMS applied within the first month post-stroke [MD = 9.31; 95% confidence interval (6.27–12.34); P < 0.0001], but not in the early subacute phase (1–3 months post-stroke) [MD = 1.14; 95% confidence interval (−5.32 to 7.59), P = 0.73) or chronic phase (>6 months post-stroke) [MD = 1.79; 95% confidence interval (−2.00 to 5.59]; P = 0.35), when assessed with a function test [Fugl-Meyer Arm test (FMA)]. There were no studies within the late subacute phase (3–6 months post-stroke) that used the FMA. Tests at the level of function revealed improved upper limb function after rTMS [SMD = 0.43; 95% confidence interval (0.02–0.75); P = 0.0001], but tests at the level of activity did not, independent of rTMS onset post-stroke [SMD = 0.17; 95% confidence interval (−0.09 to 0.44); P = 0.19]. Heterogeneities in the results of the individual studies included in the main analyses were large, as suggested by funnel plot asymmetry.

Conclusions: Based on the FMA, rTMS seems more beneficial only when started in the first month post-stroke. Tests at the level of function are likely more sensitive to detect beneficial rTMS effects on upper limb function than tests at the level of activity. However, heterogeneities in treatment designs and outcomes are high. Future rTMS trials should include the FMA and work toward a core set of outcome measures.

Low-intensity contralesional electrical theta burst stimulation modulates ipsilesional excitability and enhances stroke recovery

Targeting interhemispheric inhibition using brain stimulation has shown potential for enhancing stroke recovery. Following stroke, increased inhibition originating from the contralesional hemisphere impairs motor activation in ipsilesional areas. We have previously reported that low-intensity electrical theta burst stimulation (TBS) applied to an implanted electrode in the contralesional rat motor cortex reduces interhemispheric inhibition, and improves functional recovery when commenced three days after cortical injury. Here we apply this approach at more clinically relevant later time points and measure recovery from photothrombotic stroke, following three weeks of low-intensity intermittent TBS (iTBS), continuous TBS (cTBS) or sham stimulation applied to the contralesional motor cortex. Interhemispheric inhibition and cellular excitability were measured in the same rats from single pyramidal neurons in the peri-infarct area, using in vivo intracellular recording. A minimal dose of iTBS did not enhance motor function when applied beginning one month after stroke. However both a high and a low dose of iTBS improved recovery to a similar degree when applied 10 days after stroke, with the degree of recovery positively correlated with ipsilesional excitability. The final level of interhemispheric inhibition was negatively correlated with excitability, but did not independently correlate with functional recovery. In contrast, contralesional cTBS left recovery unaltered, but decreased ipsilesional excitability. These data support focal contralesional iTBS and not cTBS as an intervention for enhancing stroke recovery and suggest that there is a complex relationship between functional recovery and interhemispheric inhibition, with both independently associated with ipsilesional excitability.

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.

Optogenetic Stimulation Enhanced Neuronal Plasticities in Motor Recovery after Ischemic Stroke

Motor capability recovery after ischemic stroke involves dynamic remodeling processes of neural connectomes in the nervous system. Various neuromodulatory strategies combining direct stimulating interventions with behavioral trainings for motor recovery after ischemic stroke have been developed. However, the effectiveness of these interventions varies widely due to unspecific activation or inhibition of undefined neuronal subtypes. Optogenetics is a functional and structural connection-based approach that can selectively activate or inhibit specific subtype neurons with a higher precision, and it has been widely applied to build up neuronal plasticities of the nervous system, which shows a great potential in restoring motor functions in stroke animal models. Here, we reviewed neurobiological mechanisms of enhanced brain plasticities underlying motor recovery through the optogenetic stimulation after ischemic stroke. Several brain sites and neural circuits that have been previously proven effective for motor function rehabilitation were identified, which would be helpful for a more schematic understanding of effective neuronal connectomes in the motor function recovery after ischemic stroke.

Repetitive Transcranial Magnetic Stimulation for Upper Extremity Motor Recovery: Does It Help?

PURPOSE OF REVIEW

Repetitive transcranial magnetic stimulation (rTMS) noninvasively modulates brain excitability in humans and influences mediators of plasticity in animals. When applied in humans in the months to years after stroke, potentiation of motor recovery has been limited. Recently, investigators have shifted rTMS administration into the early weeks following stroke, when injury-induced plasticity could be maximally engaged. This article provides an overview of basic mechanisms of rTMS, consideration of its interaction with various forms of neuroplasticity, and a summary of the highest quality clinical evidence for rTMS given early after stroke.

RECENT FINDINGS

Studies of repetitive magnetic stimulation in vitro and in vivo have found modulation of excitatory and inhibitory neurotransmission and induction of cellular mechanisms supporting plasticity. A handful of clinical studies have shown sustained improvements in grip strength and UE motor impairment when rTMS is delivered in the first weeks after stroke. Though in its infancy, recent research suggests a plasticity-enhancing influence and modest motor recovery potentiation when rTMS is delivered early after stroke.

Low-Frequency Repetitive Transcranial Magnetic Stimulation for Stroke-Induced Upper Limb Motor Deficit: A Meta-Analysis

Background and Purpose

This meta-analysis aimed to evaluate the therapeutic potential of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) over the contralesional hemisphere on upper limb motor recovery and cortex plasticity after stroke.

Methods

Databases of PubMed, Medline, ScienceDirect, Cochrane, and Embase were searched for randomized controlled trials published before Jun 31, 2017. The effect size was evaluated by using the standardized mean difference (SMD) and a 95% confidence interval (CI). Resting motor threshold (rMT) and motor-evoked potential (MEP) were also examined.

Results

Twenty-two studies of 1 Hz LF-rTMS over the contralesional hemisphere were included. Significant efficacy was found on finger flexibility (SMD = 0.75), hand strength (SMD = 0.49), and activity dexterity (SMD = 0.32), but not on body function (SMD = 0.29). The positive changes of rMT (SMD = 0.38 for the affected hemisphere and SMD = −0.83 for the unaffected hemisphere) and MEP (SMD = −1.00 for the affected hemisphere and SMD = 0.57 for the unaffected hemisphere) were also significant.

Conclusions

LF-rTMS as an add-on therapy significantly improved upper limb functional recovery especially the hand after stroke, probably through rebalanced cortical excitability of both hemispheres. Future studies should determine if LF-rTMS alone or in conjunction with practice/training would be more effective.

Clinical Trial Registration Information

This trial is registered with unique identifier CRD42016042181.

The Use of Repetitive Transcranial Magnetic Stimulation for Stroke Rehabilitation: A Systematic Review

OBJECTIVES

Stroke is a leading cause of disability. Alternative and more effective techniques for stroke rehabilitation have been sought to overcome limitations of conventional therapies. Repetitive transcranial magnetic stimulation (rTMS) arises as a promising tool in this context. This systematic review aims to provide a state of the art on the application of rTMS in stroke patients and to assess its effectiveness in clinical rehabilitation of motor function.

METHODS

Studies included in this review were identified by searching PubMed and ISI Web of Science. The search terms were (rTMS OR "repetitive transcranial magnetic stimulation") AND (stroke OR "cerebrovascular accident" OR CVA) AND (rehab OR rehabilitation OR recover*). The retrieved records were assessed for eligibility and the most relevant features extracted to a summary table.

RESULTS

Seventy out of 691 records were deemed eligible, according to the selection criteria. The majority of the articles report rTMS showing potential in improving motor function, although some negative reports, all from randomized controlled trials, contradict this claim. Future studies are needed because there is a possibility that a bias for non-publication of negative results may be present.

CONCLUSIONS

rTMS has been shown to be a promising tool for stroke rehabilitation, in spite of the lack of standard operational procedures and harmonization. Efforts should be devoted to provide a greater understanding of the underlying mechanisms and protocol standardization.

Neurorestoration after stroke

Recent advancements in stem cell biology and neuromodulation have ushered in a battery of new neurorestorative therapies for ischemic stroke. While the understanding of stroke pathophysiology has matured, the ability to restore patients' quality of life remains inadequate. New therapeutic approaches, including cell transplantation and neurostimulation, focus on reestablishing the circuits disrupted by ischemia through multidimensional mechanisms to improve neuroplasticity and remodeling. The authors provide a broad overview of stroke pathophysiology and existing therapies to highlight the scientific and clinical implications of neurorestorative therapies for stroke.

Short- and Long-term Effects of Repetitive Transcranial Magnetic Stimulation on Upper Limb Motor Function after Stroke: a Systematic Review and Meta-Analysis

Objective:

The aim of this study was to evaluate the short- and long-term effects as well as other parameters of repetitive transcranial magnetic stimulation (rTMS) on upper limb motor functional recovery after stroke.

Data sources:

The databases of PubMed, Medline, Science Direct, Cochrane, and Embase were searched for randomized controlled studies reporting effects of rTMS on upper limb motor recovery published before October 30, 2016.

Review methods:

The short- and long-term mean effect sizes as well as the effect size of rTMS frequency of pulse, post-stroke onset, and theta burst stimulation patterns were summarized by calculating the standardized mean difference (SMD) and the 95% confidence interval using fixed/random effect models as appropriate.

Results:

Thirty-four studies with 904 participants were included in this systematic review. Pooled estimates show that rTMS significantly improved short-term (SMD, 0.43; P < 0.001) and long-term (SMD, 0.49; P < 0.001) manual dexterity. More pronounced effects were found for rTMS administered in the acute phase of stroke (SMD, 0.69), subcortical stroke (SMD, 0.66), 5-session rTMS treatment (SMD, 0.67) and intermittent theta burst stimulation (SMD, 0.60). Only three studies reported mild adverse events such as headache and increased anxiety .

Conclusions:

Five-session rTMS treatment could best improve stroke-induced upper limb dyskinesia acutely and in a long-lasting manner. Intermittent theta burst stimulation is more beneficial than continuous theta burst stimulation. rTMS applied in the acute phase of stroke is more effective than rTMS applied in the chronic phase. Subcortical lesion benefit more from rTMS than other lesion site.

A Framework for Combining rTMS with Behavioral Therapy

Upon its inception, repetitive transcranial magnetic stimulation (rTMS) was delivered at rest, without regard to the potential impact of activity occurring during or around the time of stimulation. rTMS was considered an experimental intervention imposed on the brain; therefore, the myriad features that might suppress or enhance its desired effects had not yet been explored. The field of rTMS has since grown substantially and therapeutic benefits have been reported, albeit with modest and inconsistent improvements. Work in this field accelerated following approval of a psychiatric application (depression), and it is now expanding to other applications and disciplines. In the last decade, experimental enquiry has sought new ways to improve the therapeutic benefits of rTMS, intended to enhance underlying brain reorganization and functional recovery by combining it with behavioral therapy. This concept is appealing, but poorly defined and requires clarity. We provide an overview of how combined rTMS and behavioral therapy has been delineated in the literature, highlighting the diversity of approaches. We outline a framework for study design and reporting such that the effects of this emerging method can be better understood.

Stimulation targeting higher motor areas in stroke rehabilitation: A proof-of-concept, randomized, double-blinded placebo-controlled study of effectiveness and underlying mechanisms

PURPOSE

To demonstrate, in a proof-of-concept study, whether potentiating ipsilesional higher motor areas (premotor cortex and supplementary motor area) augments and accelerates recovery associated with constraint induced movement.

METHODS

In a randomized, double-blinded pilot clinical study, 12 patients with chronic stroke were assigned to receive anodal transcranial direct current stimulation (tDCS) (n = 6) or sham (n = 6) to the ipsilesional higher motor areas during constraint-induced movement therapy. We assessed functional and neurophysiologic outcomes before and after 5 weeks of therapy.

RESULTS

Only patients receiving tDCS demonstrated gains in function and dexterity. Gains were accompanied by an increase in excitability of the contralesional rather than the ipsilesional hemisphere.

CONCLUSIONS

Our proof-of-concept study provides early evidence that stimulating higher motor areas can help recruit the contralesional hemisphere in an adaptive role in cases of greater ipsilesional injury. Whether this early evidence of promise translates to remarkable gains in functional recovery compared to existing approaches of stimulation remains to be confirmed in large-scale clinical studies that can reasonably dissociate stimulation of higher motor areas from that of the traditional primary motor cortices.

Models to Tailor Brain Stimulation Therapies in Stroke

A great challenge facing stroke rehabilitation is the lack of information on how to derive targeted therapies. As such, techniques once considered promising, such as brain stimulation, have demonstrated mixed efficacy across heterogeneous samples in clinical studies. Here, we explain reasons, citing its one-type-suits-all approach as the primary cause of variable efficacy. We present evidence supporting the role of alternate substrates, which can be targeted instead in patients with greater damage and deficit. Building on this groundwork, this review will also discuss different frameworks on how to tailor brain stimulation therapies. To the best of our knowledge, our report is the first instance that enumerates and compares across theoretical models from upper limb recovery and conditions like aphasia and depression. Here, we explain how different models capture heterogeneity across patients and how they can be used to predict which patients would best respond to what treatments to develop targeted, individualized brain stimulation therapies. Our intent is to weigh pros and cons of testing each type of model so brain stimulation is successfully tailored to maximize upper limb recovery in stroke.

Challenges in Recruitment for the Study of Noninvasive Brain Stimulation in Stroke: Lessons from Deep Brain Stimulation

OBJECTIVE

Noninvasive brain stimulation (NIBS) can augment functional recovery following stroke; however, the technique lacks regulatory approval. Low enrollment in NIBS clinical trials is a key roadblock. Here, we pursued evidence to support the prevailing opinion that enrollment in trials of NIBS is even lower than enrollment in trials of invasive, deep brain stimulation (DBS).

METHODS

We compared 2 clinical trials in stroke conducted within a single urban hospital system, one employing NIBS and the other using DBS, (1) to identify specific criteria that generate low enrollment rates for NIBS and (2) to devise strategies to increase recruitment with guidance from DBS.

RESULTS

Notably, we found that enrollment in the NIBS case study was 5 times lower (2.8%) than the DBS trial (14.5%) (χ(2) = 20.815, P < .0001). Although the number of candidates who met the inclusion criteria was not different (χ(2) = .04, P < .841), exclusion rates differed significantly between the 2 studies (χ(2) = 21.354, P < .0001). Beyond lack of interest, higher exclusion rates in the NIBS study were largely due to exclusion criteria that were not present in the DBS study, including restrictions for recurrent strokes, seizures, and medications.

CONCLUSIONS

Based on our findings, we conclude and suggest that by (1) establishing criteria specific to each NIBS modality, (2) adjusting exclusion criteria based on guidance from DBS, and (3) including patients with common contraindications based on a probability of risk, we may increase enrollment and hence significantly impact the feasibility and generalizability of NIBS paradigms, particularly in stroke.

Ipsilesional motor-evoked potential absence in pediatric hemiparesis impacts tracking accuracy of the less affected hand

This study analyzed the relationship between electrophysiological responses to transcranial magnetic stimulation (TMS), finger tracking accuracy, and volume of neural substrate in children with congenital hemiparesis. Nineteen participants demonstrating an ipsilesional motor-evoked potential (MEP) were compared with eleven participants showing an absent ipsilesional MEP response. Comparisons of finger tracking accuracy from the affected and less affected hands and ipsilesional/contralesional (I/C) volume ratio for the primary motor cortex (M1) and posterior limb of internal capsule (PLIC) were done using two-sample t-tests. Participants showing an ipsilesional MEP response demonstrated superior tracking performance from the less affected hand (p=0.016) and significantly higher I/C volume ratios for M1 (p=0.028) and PLIC (p=0.005) compared to participants without an ipsilesional MEP response. Group differences in finger tracking accuracy from the affected hand were not significant. These results highlight differentiating factors amongst children with congenital hemiparesis showing contrasting MEP responses: less affected hand performance and preserved M1 and PLIC volume. Along with MEP status, these factors pose important clinical implications in pediatric stroke rehabilitation. These findings may also reflect competitive developmental processes associated with the preservation of affected hand function at the expense of some function in the less affected hand.

Effects of adjustment of transcranial direct current stimulation on motor function of the upper extremity in stroke patients

[Purpose] The purpose of this study was to examine the effects of transcranial direct current stimulation (tDCS) applied to the cerebral cortex motor area on the upper extremity functions of hemiplegic patients. [Subjects and Methods] Twenty four Patients with hemiplegia resulting from a stroke were divided into two groups: a tDCS group that received tDCS and physical therapy and a control group that received only physical therapy. A functional evaluation of the two groups was performed, and an electrophysiological evaluation was conducted before and after the experiment. Statistical analyses were performed to verify differences before and after the experiment. All statistical significance levels were set at 0.05. [Results] The results showed that functional evaluation scores for the elbow joint and hand increased after the treatment in both the experimental group and the control group, and the increases were statistically significantly different. [Conclusion] tDCS was effective in improving the upper extremity motor function of stroke patients. Additional research is warranted on the usefulness of tDCS in the rehabilitation of stroke patients in the clinical field.

A Review of Transcranial Magnetic Stimulation and Multimodal Neuroimaging to Characterize Post-Stroke Neuroplasticity

Following stroke, the brain undergoes various stages of recovery where the central nervous system can reorganize neural circuitry (neuroplasticity) both spontaneously and with the aid of behavioral rehabilitation and non-invasive brain stimulation. Multiple neuroimaging techniques can characterize common structural and functional stroke-related deficits, and importantly, help predict recovery of function. Diffusion tensor imaging (DTI) typically reveals increased overall diffusivity throughout the brain following stroke, and is capable of indexing the extent of white matter damage. Magnetic resonance spectroscopy (MRS) provides an index of metabolic changes in surviving neural tissue after stroke, serving as a marker of brain function. The neural correlates of altered brain activity after stroke have been demonstrated by abnormal activation of sensorimotor cortices during task performance, and at rest, using functional magnetic resonance imaging (fMRI). Electroencephalography (EEG) has been used to characterize motor dysfunction in terms of increased cortical amplitude in the sensorimotor regions when performing upper limb movement, indicating abnormally increased cognitive effort and planning in individuals with stroke. Transcranial magnetic stimulation (TMS) work reveals changes in ipsilesional and contralesional cortical excitability in the sensorimotor cortices. The severity of motor deficits indexed using TMS has been linked to the magnitude of activity imbalance between the sensorimotor cortices. In this paper, we will provide a narrative review of data from studies utilizing DTI, MRS, fMRI, EEG, and brain stimulation techniques focusing on TMS and its combination with uni- and multimodal neuroimaging methods to assess recovery after stroke. Approaches that delineate the best measures with which to predict or positively alter outcomes will be highlighted.

Tailoring Brain Stimulation to the Nature of Rehabilitative Therapies in Stroke: A Conceptual Framework Based on their Unique Mechanisms of Recovery

Despite showing early promise, several recent clinical trials of noninvasive brain stimulation (NIBS) failed to augment rehabilitative outcomes of the paretic upper limb. This article addresses why pairing NIBS with unilateral approaches is weakly generalizable to patients in all ranges of impairments. The article also addresses whether alternate therapies are better suited for the more impaired patients, where they may be more feasible and offer neurophysiologic advantages not offered with unilateral therapies. The article concludes by providing insight on how to create NIBS paradigms that are tailored to distinctly augment the effects of therapies across patients with varying degrees of impairment.

Motor priming in neurorehabilitation

Priming is a type of implicit learning wherein a stimulus prompts a change in behavior. Priming has been long studied in the field of psychology. More recently, rehabilitation researchers have studied motor priming as a possible way to facilitate motor learning. For example, priming of the motor cortex is associated with changes in neuroplasticity that are associated with improvements in motor performance. Of the numerous motor priming paradigms under investigation, only a few are practical for the current clinical environment, and the optimal priming modalities for specific clinical presentations are not known. Accordingly, developing an understanding of the various types of motor priming paradigms and their underlying neural mechanisms is an important step for therapists in neurorehabilitation. Most importantly, an understanding of the methods and their underlying mechanisms is essential for optimizing rehabilitation outcomes. The future of neurorehabilitation is likely to include these priming methods, which are delivered prior to or in conjunction with primary neurorehabilitation therapies. In this Special Interest article, we discuss those priming paradigms that are supported by the greatest amount of evidence, including (i) stimulation-based priming, (ii) motor imagery and action observation, (iii) sensory priming, (iv) movement-based priming, and (v) pharmacological priming.Video Abstract available. (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A86) for more insights from the authors.

Primary Motor Cortex Excitability During Recovery After Stroke: Implications for Neuromodulation

BACKGROUND

Non-invasive brain stimulation techniques may be useful adjuvants to promote recovery after stroke. They are typically used to facilitate ipsilesional cortical excitability directly, or indirectly by suppressing contralesional cortical excitability and reducing interhemispheric inhibition from the contralesional to ipsilesional hemisphere. However, most of the evidence for this approach comes from studies of patients at the chronic stage of recovery.

HYPOTHESIS

We hypothesized that corticomotor excitability and interhemispheric inhibition would initially be asymmetric, with greater interhemispheric inhibition from contralesional to ipsilesional M1. We also hypothesized that balancing of corticomotor excitability and interhemispheric inhibition would be associated with greater improvements in paretic upper-limb impairment and function.

METHODS

We conducted a retrospective analysis of longitudinal data collected from 46 patients during the first six months after stroke. Transcranial magnetic stimulation was used to measure rest motor threshold, stimulus-response curves, and ipsilateral silent periods from the extensor carpi radialis muscles of both upper limbs. Analyses of variance and linear regression modeling were used to evaluate the effect of time on corticomotor excitability and interhemispheric inhibition in both hemispheres, and associations between these effects and improvements in paretic upper-limb impairment and function.

RESULTS

All participants had subcortical damage and only two had motor cortex involvement. As expected, ipsilesional corticomotor excitability was initially suppressed and increased over time, and this increase was associated with improved upper-limb impairment and function. However, interhemispheric inhibition was symmetrical and stable over time, and there was no evidence for a decrease in contralesional corticomotor excitability.

CONCLUSIONS

Neuromodulation interventions applied during spontaneous recovery may be more beneficial if they facilitate ipsilesional corticomotor excitability directly.

Combinations of stroke neurorehabilitation to facilitate motor recovery: perspectives on Hebbian plasticity and homeostatic metaplasticity

Motor recovery after stroke involves developing new neural connections, acquiring new functions, and compensating for impairments. These processes are related to neural plasticity. Various novel stroke rehabilitation techniques based on basic science and clinical studies of neural plasticity have been developed to aid motor recovery. Current research aims to determine whether using combinations of these techniques can synergistically improve motor recovery. When different stroke neurorehabilitation therapies are combined, the timing of each therapeutic program must be considered to enable optimal neural plasticity. Synchronizing stroke rehabilitation with voluntary neural and/or muscle activity can lead to motor recovery by targeting Hebbian plasticity. This reinforces the neural connections between paretic muscles and the residual motor area. Homeostatic metaplasticity, which stabilizes the activity of neurons and neural circuits, can either augment or reduce the synergic effect depending on the timing of combination therapy and types of neurorehabilitation that are used. Moreover, the possibility that the threshold and degree of induced plasticity can be altered after stroke should be noted. This review focuses on the mechanisms underlying combinations of neurorehabilitation approaches and their future clinical applications. We suggest therapeutic approaches for cortical reorganization and maximal functional gain in patients with stroke, based on the processes of Hebbian plasticity and homeostatic metaplasticity. Few of the possible combinations of stroke neurorehabilitation have been tested experimentally; therefore, further studies are required to determine the appropriate combination for motor recovery.

A Comparison of Primed Low-frequency Repetitive Transcranial Magnetic Stimulation Treatments in Chronic Stroke

BACKGROUND

Preceding low-frequency repetitive transcranial magnetic stimulation (rTMS) with a bout of high-frequency rTMS called priming potentiates the after-effects of the former in healthy adults. The utility of primed rTMS in stroke remains under-explored despite its theoretical benefits in enhancing cortical excitability and motor function.

OBJECTIVE

To ascertain the efficacy of priming in chronic stroke by comparing changes in cortical excitability and paretic hand function following three types of primed low-frequency rTMS treatments.

METHODS

Eleven individuals with chronic stroke participated in this repeated-measures study receiving three treatments to the contralesional primary motor cortex in randomized order: 6 Hz primed 1 Hz rTMS, 1 Hz primed 1 Hz rTMS, and sham 6 Hz primed active 1 Hz rTMS. Within- and between-treatment differences from baseline in cortical excitability and paretic hand function from baseline were analyzed using mixed effects linear models.

RESULTS

6 Hz primed 1 Hz rTMS produced significant within-treatment differences from baseline in ipsilesional cortical silent period (CSP) duration and short-interval intracortical inhibition. Compared to 1 Hz priming and sham 6 Hz priming of 1 Hz rTMS, active 6 Hz priming generated significantly greater decreases in ipsilesional CSP duration. These heightened effects were not observed for intracortical facilitation or interhemispheric inhibition excitability measures.

CONCLUSION

Our findings demonstrate the efficacy of 6 Hz primed 1 Hz rTMS in probing homeostatic plasticity mechanisms in the stroke brain as best demonstrated by differences CSP duration and SICI from baseline. Though 6 Hz priming did not universally enhance cortical excitability across measures, our findings pose important implications in non-invasive brain stimulation application in stroke rehabilitation.