Cerebellar Theta-Burst Stimulation Combined With Physiotherapy in Subacute and Chronic Stroke Patients: A Pilot Randomized Controlled Trial

The effect and optimal parameters of repetitive transcranial magnetic stimulation on lower extremity motor function in stroke patient: a systematic review and meta-analysis

PURPOSE

This study aimed to evaluate the efficacy of repetitive transcranial magnetic stimulation (rTMS) in treating lower limb motor dysfunction after stroke and explore the optimal stimulation parameters.

METHODS

PubMed, Embase, Cochrane Library, and other relevant databases were systematically queried for randomised controlled trials (RCTs) investigating the efficacy of rTMS in addressing lower limb motor dysfunction post-stroke. The search encompassed records from inception to July 2022. The assessed outcomes encompassed parameters such as the Fugl-Meyer motor function score for lower limbs, balance function, and Barthel index (BI). Three independent researchers were responsible for research selection, data extraction, and quality assessment. Study screening, data extraction, and bias evaluation were performed independently by two reviewers. Data synthesis was undertaken using Review Manager 5.3, while Stata version 14.0 software was employed for generating the funnel plot.

RESULTS

A total of 13 studies and 428 patients were included. The meta-analysis indicated that rTMS had a positive effect on the BI (MD = 5.87, 95% CI [0.99, 10.76], p = 0.02, I2 = 86%, N of studies = 8, N of participants = 248). Subgroup analysis was performed on the stimulation frequency, treatment duration, and different stroke stages (stimulation frequency was low-frequency (LF)-rTMS (MD = 4.45, 95% CI [1.05, 7.85], p = 0.01, I2 = 0%, N of studies = 4, N of participants = 120); treatment time ≤ 15 d: (MD = 4.41, 95% CI [2.63, 6.18], p < 0.00001, I2 = 0%, N of studies = 4, N of participants = 124); post-stroke time ≤6 months: (MD = 4.37, 95% CI [2.42, 6.32], p < 0.0001, I2 = 0%, N of studies = 5, N of participants = 172).

CONCLUSION

LF-rTMS had a significant improvement effect on BI score, while high-frequency (HF)-rTMS and iTBS had no significant effect. And stroke time ≤6 months in patients with treatment duration ≤15 d had the best treatment effect.

Differential Effects of Continuous Theta Burst Stimulation over the Bilateral and Unilateral Cerebellum on Working Memory

Recent functional MRI studies have implicated the cerebellum in working memory (WM) alongside the prefrontal cortex. Some findings indicate that the right cerebellum is activated during verbal tasks, while the left is engaged during visuospatial tasks, suggesting cerebellar lateralization in WM function. The cerebellum could be a potential target for non-invasive brain stimulation (NIBS) to enhance WM function in cognitive disorders. However, the comprehensive influence of cerebellar lateralization on different types of WM and the effect of stimulation over the unilateral or bilateral cerebellum remain uncertain. This study was to investigate the cerebellum's functional lateralization and its specific impact on various aspects of WM in a causal manner using unilateral or bilateral cerebellar continuous theta burst stimulation (cTBS), a form of inhibitroy NIBS. Twenty-four healthy participants underwent four sessions of cTBS targeting the left, right, or bilateral Crus I of the cerebellum, or a sham condition, in a controlled cross-over design. WM performance was assessed pre- and post-stimulation using neuropsychological tests, including the 3-back task, spatial WM task, and digit span task. Results indicated that cTBS over the bilateral and right cerebellum both led to a greater improvement in 3-back task performance compared to sham stimulation. Additionally, active cTBS over the bilateral cerebellum yielded better performance in the spatial WM task than sham stimulation. However, no significant differences were observed between stimulation conditions for the auditory digit span task. This study may provide novel causal evidence highlighting the specific involvement of the right and bilateral cerebellum in various types of WM. Specifically, the right cerebellum appears crucial for updating and tracking 3-back WM content, while spatial WM processes require the coordinated engagement of both cerebellar hemispheres.

Effects of the intermittent theta burst stimulation on gait, balance and lower limbs motor function in stroke: study protocol for a double-blind randomised controlled trial with multimodal neuroimaging assessments

INTRODUCTION

Approximately, 50% of stroke survivors experience impaired walking ability 6 months after conventional rehabilitation and standard care. However, compared with upper limb motor function, research on lower limbs rehabilitation through non-invasive neuromodulation like repetitive transcranial magnetic stimulation (rTMS) has received less attention. Limited evidence exists regarding the effectiveness of intermittent theta-burst stimulation (iTBS), an optimised rTMS modality, on lower limbs rehabilitation after stroke. This study aims to evaluate the effects of iTBS on gait, balance and lower limbs motor function in stroke recovery while also exploring the underlying neural mechanisms using longitudinal analysis of multimodal neuroimaging data.

METHODS AND ANALYSIS

In this double-blinded randomised controlled trial, a total of 46 patients who had a stroke will be randomly assigned in a 1:1 ratio to receive either 15 sessions of leg motor area iTBS consisting of 600 pulses or sham stimulation over the course of 3 weeks. Additionally, conventional rehabilitation therapy will be administered following the (sham) iTBS intervention. The primary outcome measure will be the 10 m walking test. Secondary outcomes include the Fugl-Meyer assessment of the lower extremity, Timed Up and Go Test, Functional Ambulation Category Scale, Berg Balance Scale, modified Barthel Index, Mini-Mental State Examination, montreal cognitive assessment, tecnobody balance assessment encompassing both static and dynamic stability evaluations, surface electromyography recording muscle activation of the lower limbs, three-dimensional gait analysis focusing on temporal and spatial parameters as well as ground reaction force measurements, corticomotor excitability tests including resting motor threshold, motor evoked potential and recruitment curves and multimodal functional MRI scanning. Outcome measures will be collected prior to and after the intervention period with follow-up at 3 weeks.

ETHICS AND DISSEMINATION

The study has received approval from the Medical Research Ethics Committee of Wuxi Mental Health Center/Wuxi Central Rehabilitation Hospital (no. WXMHCCIRB2023LLky078). Results will be disseminated through peer-reviewed journals and scientific conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2300077431.

Efficacy of Cerebellar Transcranial Magnetic Stimulation for Post-stroke Balance and Limb Motor Function Impairments: Meta-analyses of Random Controlled Trials and Resting-State fMRI Studies

This study aimed to investigate the potential therapeutic effects of cerebellar transcranial magnetic stimulation (TMS) on balance and limb motor impairments in stroke patients. A meta-analysis of randomized controlled trials was conducted to assess the effects of cerebellar TMS on balance and motor impairments in stroke patients. Additionally, an activation likelihood estimation (ALE) meta-analysis was performed on resting-state functional magnetic resonance imaging (fMRI) studies to compare spontaneous neural activity differences between stroke patients and healthy controls using measures including the amplitude of low frequency fluctuation (ALFF), fractional ALFF (fALFF), and regional homogeneity (ReHo). The analysis included 10 cerebellar TMS studies and 18 fMRI studies. Cerebellar TMS treatment demonstrated significant improvements in the Berg Balance Scale score (p < 0.0001) and the Fugl-Meyer Assessment lower extremity score (p < 0.0001) compared to the control group in stroke patients. Additionally, spontaneous neural activity alterations were identified in motor-related regions after stroke, including the precentral gyrus, putamen, thalamus, and paracentral lobule. Cerebellar TMS shows promise as a therapeutic intervention to enhance balance and lower limb motor function in stroke patients. It is easy for clinical application and addresses the limitations of insufficient direct stimulation depth on the leg area of the cortex. However, further research combining neuroimaging outcomes with clinical measurements is necessary to validate these findings.

Effects of repetitive transcranial magnetic stimulation on lower extremity motor function and optimal parameters in stroke patients with different stages of stroke: a systematic evaluation and meta-analysis

Background

Repetitive transcranial magnetic stimulation (rTMS), as an emerging non-invasive neuromodulation technique, is now widely employed in rehabilitation therapy. The purpose of this paper is to comprehensively summarize existing evidence regarding rTMS intervention for lower limb motor function in patients at different stages of stroke.

Methods

A systematic search was conducted to identify randomized controlled trials (RCTs) assessing the efficacy of rTMS for treating lower limb motor dysfunction after stroke. Multiple databases, including China National Knowledge Infrastructure (CNKI), Wanfang Data Knowledge Service Platform, VIP Database, PubMed, Embase, Web of Science, and Cochrane Library, were searched. The search period extended from the inception of the libraries to June 2024. Literature information was extracted, and methodological quality was evaluated using the risk of bias assessment tool in the Cochrane Handbook. Meta-analysis was performed using Stata 17.0 software.

Results

Overall, 49 appropriate studies (including 3,558 stroke subjects) were found. Meta-analysis results demonstrated that rTMS effectively improved lower limb motor function across all stages of stroke. The intervention was particularly more effective in patients in the subacute stage than in the acute or chronic stages. Subgroup analysis revealed that, for acute-stage patients, low-frequency stimulation targeting the M1 or DLPFC brain regions on the unaffected side with 20-40 sessions significantly improved FMA-LE scores. In subacute-phase patients, low-frequency stimulation targeting the M1 brain regions on the unaffected side with 18 sessions significantly improved FMA-LE scores. The results demonstrated that HF-rTMS was more effective than LF-rTMS in improving walking speed, with the greatest efficacy observed at 20 sessions. While for enhancing gait balance in stroke patients, LF-rTMS with the best therapeutic effect was observed at a frequency of 20-40 treatments.

Conclusion

This study demonstrates the efficacy of rTMS in improving lower limb motor function, balance, and walking speed in stroke patients at various stages. The findings provide a valuable reference for the development of optimized rTMS treatment plans in clinical practice.Systematic review registration: PROSPERO: CRD42023466094.

No Additional Effects of Sequential Facilitatory Cerebral and Cerebellar rTMS in Subacute Stroke Patients

The aim of this study was to investigate the additional effects of cerebellar rTMS on the motor recovery of facilitatory rTMS over affected primary motor cortex (M1) in subacute stroke patients. Twenty-eight subacute stroke patients were recruited in this single-blind, randomized, controlled trial. The Cr-Cbll group received Cr-Cbll rTMS stimulation consisting of high-frequency rTMS over affected M1 (10 min), motor training (10 min), and high-frequency rTMS over contralesional Cbll (10 min). The Cr-sham group received sham rTMS instead of high-frequency rTMS over the cerebellum. Ten daily sessions were performed for 2 weeks. A Fugl-Meyer Assessment (FMA) was measured before (T0), immediately after (T1), and 2 months after the intervention (T2). A total of 20 participants (10 in the Cr-Cbll group and 10 in the Cr-sham group) completed the intervention. There was no significant difference in clinical characteristics between the two groups at T0. FMA was significantly improved after the intervention in both Cr-Cbll and Cr-sham groups (p < 0.05). However, there was no significant interaction in FMA between time and group. In conclusion, these results could not demonstrate that rTMS over the contralesional cerebellum has additional effects to facilitatory rTMS over the affected M1 for improving motor function in subacute stroke patients.

Effects of Cerebellar Non-Invasive Stimulation on Neurorehabilitation in Stroke Patients: An Updated Systematic Review

The cerebellum is emerging as a promising target for noninvasive brain stimulation (NIBS). A systematic review was conducted to evaluate the effects of cerebellar NIBS on both motor and other symptoms in stroke rehabilitation, its impact on functional ability, and potential side effects (PROSPERO number: CRD42022365697). A systematic electronic database search was performed by using PubMed Central (PMC), EMBASE, and Web of Science, with a cutoff date of November 2023. Data extracted included study details, NIBS methodology, outcome measures, and results. The risk of bias in eligible studies was also assessed. Twenty-two clinical studies involving 1016 participants were finally included, with a focus on outcomes related to post-stroke motor recovery (gait and balance, muscle spasticity, and upper limb dexterity) and other functions (dysphagia and aphasia). Positive effects were observed, especially on motor functions like gait and balance. Some efficiency was also observed in dysphagia rehabilitation. However, findings on language recovery were preliminary and inconsistent. A slight improvement in functional ability was noted, with no serious adverse effects reported. Further studies are needed to explore the effects of cerebellar NIBS on post-stroke non-motor deficits and to understand how cerebellar engagement can facilitate more precise treatment strategies for stroke rehabilitation.

Cerebellar transcranial magnetic stimulation for improving balance capacity and activity of daily living in stroke patients: a systematic review and meta-analysis

BACKGROUND

The application of cerebellar transcranial magnetic stimulation (TMS) in stroke patients has received increasing attention due to its neuromodulation mechanisms. However, studies on the effect and safety of cerebellar TMS to improve balance capacity and activity of daily living (ADL) for stroke patients are limited. This systematic review and meta-analysis aimed to investigate the effect and safety of cerebellar TMS on balance capacity and ADL in stroke patients.

METHOD

A systematic search of seven electronic databases (PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, Wanfang and Chinese Scientific Journal) were conducted from their inception to October 20, 2023. The randomized controlled trials (RCTs) of cerebellar TMS on balance capacity and/or ADL in stroke patients were enrolled. The quality of included studies were assessed by Physiotherapy Evidence Database (PEDro) scale.

RESULTS

A total of 13 studies involving 542 participants were eligible. The pooled results from 8 studies with 357 participants showed that cerebellar TMS could significantly improve the post-intervention Berg balance scale (BBS) score (MD = 4.24, 95%CI = 2.19 to 6.29, P < 0.00001; heterogeneity, I2 = 74%, P = 0.0003). The pooled results from 4 studies with 173 participants showed that cerebellar TMS could significantly improve the post-intervention Time Up and Go (TUG) (MD=-1.51, 95%CI=-2.8 to -0.22, P = 0.02; heterogeneity, I2 = 0%, P = 0.41). The pooled results from 6 studies with 280 participants showed that cerebellar TMS could significantly improve the post-intervention ADL (MD = 7.75, 95%CI = 4.33 to 11.17, P < 0.00001; heterogeneity, I2 = 56%, P = 0.04). The subgroup analysis showed that cerebellar TMS could improve BBS post-intervention and ADL post-intervention for both subacute and chronic stage stroke patients. Cerebellar high frequency TMS could improve BBS post-intervention and ADL post-intervention. Cerebellar TMS could still improve BBS post-intervention and ADL post-intervention despite of different cerebellar TMS sessions (less and more than 10 TMS sessions), different total cerebellar TMS pulse per week (less and more than 4500 pulse/week), and different cerebellar TMS modes (repetitive TMS and Theta Burst Stimulation). None of the studies reported severe adverse events except mild side effects in three studies.

CONCLUSIONS

Cerebellar TMS is an effective and safe technique for improving balance capacity and ADL in stroke patients. Further larger-sample, higher-quality, and longer follow-up RCTs are needed to explore the more reliable evidence of cerebellar TMS in the balance capacity and ADL, and clarify potential mechanisms.

Can cerebellar theta-burst stimulation improve balance function and gait in stroke patients? A randomized controlled trial

BACKGROUND

The cerebellum is a key structure involved in balance and motor control, and has become a new stimulation target in brain regulation technology. Interference theta-burst simulation (iTBS) is a novel simulation mode of repetitive transcranial magnetic simulation. However, the impact of cerebellar iTBS on balance function and gait in stroke patients is still unknown.

AIM

The aim of this study was to determine whether cerebellar iTBS can improve function, particularly balance and gait, in patients with post-stroke hemiplegia.

DESIGN

This study is a randomized, double-blind, sham controlled clinical trial.

SETTING

The study was carried out at the Department of Rehabilitation Medicine in a general hospital.

POPULATION

Patients with stroke with first unilateral lesions were enrolled in the study.

METHODS

Thirty-six patients were randomly assigned to the cerebellar iTBS group or sham stimulation group. The cerebellar iTBS or pseudo stimulation site is the ipsilateral cerebellum on the paralyzed side, which is completed just before daily physical therapy. The study was conducted five times a week for two consecutive weeks. All patients were assessed before the intervention (T0) and at the end of 2 weeks of treatment (T1), respectively. The primary outcome was the Berg Balance Scale (BBS), while secondary outcome measures included the Fugl Meyer Lower Limb Assessment Scale (FMA-LE), timed up and go (TUG), Barthel Index (BI), and gait analysis.

RESULTS

After 2 weeks of intervention, the BBS, FMA-LE, TUG, and BI score in both the iTBS group and the sham group were significantly improved compared to the baseline (all P<0.05). Also, there was a significant gait parameter improvement including the cadence, stride length, velocity, step length compared to the baseline (P<0.05) in the iTBS group, but only significant improvement in cadence was identified in the sham group (P<0.05). Intergroup comparison showed that the BBS (P<0.001), FMA-LE (P<0.001), and BI (P=0.002) in the iTBS group were significantly higher than those in the sham group, and the TUG in the iTBS was significantly lower than that in the sham group (P=0.002). In addition, there were significant differences in cadence (P=0.029), strip length (P=0.046), gain velocity (P=0.002), and step length of affected lower limb (P=0.024) between the iTBS group and the sham iTBS group.

CONCLUSIONS

Physical therapy is able to improve the functional recovery in hemiplegic patients after stroke, but the cerebellar iTBS can facilitate and accelerate the recovery, particularly the balance function and gait. Cerebellar iTBS could be an efficient and facilitative treatment for patients with stroke.

CLINICAL REHABILITATION IMPACT

Cerebellar iTBS provides a convenient and efficient treatment modality for functional recovery of patients with stroke, especially balance function and gait.

Theta-burst stimulation as a therapeutic tool in neurological pathology: a systematic review

TBS (theta-burst stimulation) is a novel therapeutic approach in a wide range of neurological diseases. The present systematic review aims to identify the various protocols used in the last years, to assess study quality and to offer a general overview of the current state of the literature. The systematic review was conducted according to the Preferred Reporting Item for Systematic Review and Meta-Analyses (PRISMA) guidelines. We applied the following inclusion criteria: (1) population over 18 years old with diagnosed neurological disorders, (2) patients treated with sessions of theta-burst stimulation, (3) randomized-controlled clinical trials, (4) articles in the English language, and (5) studies that report response and score reduction on a validated scale of the investigated disorder or remission rates. We included in the final analysis 56 randomized controlled trials focusing on different neurological pathologies (stroke, Parkinson`s disease, multiple sclerosis, tinnitus, dystonia, chronic pain, essential tremor and tic disorder), and we extracted data regarding study design, groups and comparators, sample sizes, type of coil, stimulation parameters (frequency, number of pulses, intensity, stimulation site etc.), number of sessions, follow-up, assessment through functional connectivity and neurological scales used. We observed a great interstudy heterogenicity that leads to a difficulty in drawing plain conclusions. TBS protocols have shown promising results in improving various symptoms in patients with neurological disorders, but larger and more coherent studies, using similar stimulation protocols and evaluation scales, are needed to establish guideline recommendations.

Comparative efficacy of different repetitive transcranial magnetic stimulation protocols for lower extremity motor function in stroke patients: a network meta-analysis

Background

Lower extremity motor dysfunction is one of the most severe consequences after stroke, restricting functional mobility and impairing daily activities. Growing evidence suggests that repetitive transcranial magnetic stimulation (rTMS) can improve stroke patients' lower extremity motor function. However, there is still controversy about the optimal rTMS protocol. Therefore, we compared and analyzed the effects of different rTMS protocols on lower extremity motor function in stroke patients using network meta-analysis (NMA).

Methods

We systematically searched CNKI, WanFang, VIP, CBM, PubMed, Embase, Web of Science, and Cochrane Library databases (from origin to 31 December 2023). Randomized controlled trials (RCTs) or crossover RCTs on rTMS improving lower extremity motor function in stroke patients were included. Two authors independently completed article screening, data extraction, and quality assessment. RevMan (version 5.4) and Stata (version 17.0) were used to analyze the data.

Results

A total of 38 studies with 2,022 patients were eligible for the NMA. The interventions included HFrTMS-M1, LFrTMS-M1, iTBS-Cerebellum, iTBS-M1, dTMS-M1, and Placebo. The results of NMA showed that LFrTMS-M1 ranked first in FMA-LE and speed, and HFrTMS-M1 ranked first in BBS, TUGT, and MEP amplitude. The subgroup analysis of FMA-LE showed that HFrTMS-M1 was the best stimulation protocol for post-stroke time > 1 month, and LFrTMS-M1 was the best stimulation protocol for post-stroke time ≤ 1 month.

Conclusion

Considering the impact of the stroke phase on the lower extremity motor function, the current research evidence shows that HFrTMS-M1 may be the preferred stimulation protocol to improve the lower extremity motor function of patients for post-stroke time > 1 month, and LFrTMS-M1 for post-stroke time ≤ 1 month. However, the above conclusion needs further analysis and validation by more high-quality RCTs.Systematic Review Registration:www.crd.york.ac.uk/prospero/, identifier (CRD42023474215).

Theta burst stimulation: what role does it play in stroke rehabilitation? A systematic review of the existing evidence

Various post-stroke dysfunctions often result in poor long-term outcomes for stroke survivors, but the effect of conventional treatments is limited. In recent years, lots of studies have confirmed the effect of repetitive transcranial magnetic stimulation (rTMS) in stroke rehabilitation. As a new pattern of rTMS, theta burst stimulation (TBS) was proved recently to yield more pronounced and long-lasting after-effects than the conventional pattern at a shorter stimulation duration. To explore the role of TBS in stroke rehabilitation, this review summarizes the existing evidence from all the randomized controlled trials (RCTs) so far on the efficacy of TBS applied to different post-stroke dysfunctions, including cognitive impairment, visuospatial neglect, aphasia, dysphagia, spasticity, and motor dysfunction. Overall, TBS promotes the progress of stroke rehabilitation and may serve as a preferable alternative to traditional rTMS. However, it's hard to recommend a specific paradigm of TBS due to the limited number of current studies and their heterogeneity. Further high-quality clinical RCTs are needed to determine the optimal technical settings and intervention time in stroke survivors.

EEG microstates analysis after TMS in patients with subacute stroke during the resting state

To investigate whether intermittent theta burst stimulation over the cerebellum induces changes in resting-state electroencephalography microstates in patients with subacute stroke and its correlation with cognitive and emotional function. Twenty-four stroke patients and 17 healthy controls were included in this study. Patients and healthy controls were assessed at baseline, including resting-state electroencephalography and neuropsychological scales. Fifteen patients received lateral cerebellar intermittent theta burst stimulation as well as routine rehabilitation training (intermittent theta burst stimulation-RRT group), whereas 9 patients received only conventional rehabilitation training (routine rehabilitation training group). After 2 wk, baseline data were recorded again in both groups. Stroke patients exhibited reduced parameters in microstate D and increased parameters in microstate C compared with healthy controls. However, after the administration of intermittent theta burst stimulation over the lateral cerebellum, significant alterations were observed in the majority of metrics for both microstates D and C. Lateral cerebellar intermittent theta burst stimulation combined with conventional rehabilitation has a stronger tendency to improve emotional and cognitive function in patients with subacute stroke than conventional rehabilitation. The improvement of mood and cognitive function was significantly associated with microstates C and D. We identified electroencephalography microstate spatiotemporal dynamics associated with clinical improvement following a course of intermittent theta burst stimulation therapy.

Noninvasive cerebellar stimulation and behavioral interventions: A crucial synergy for post-stroke motor rehabilitation

BACKGROUND

Improvement of functional movements after supratentorial stroke occurs through spontaneous biological recovery and training-induced reorganization of remnant neural networks. The cerebellum, through its connectivity with the cortex, brainstem and spinal cord, is actively engaged in both recovery and reorganization processes within the cognitive and sensorimotor systems. Noninvasive cerebellar stimulation (NiCBS) offers a safe, clinically feasible and potentially effective way to modulate the excitability of spared neural networks and promote movement recovery after supratentorial stroke. NiCBS modulates cerebellar connectivity to the cerebral cortex and brainstem, as well as influences the sensorimotor and frontoparietal networks.

OBJECTIVE

Our objective was twofold: (a) to conduct a scoping review of studies that employed NiCBS to influence motor recovery and learning in individuals with stroke, and (b) to present a theory-driven framework to inform the use of NiCBS to target distinct stroke-related deficits.

METHODS

A scoping review of current research up to August 2023 was conducted to determine the effect size of NiCBS effect on movement recovery of upper extremity function, balance, walking and motor learning in humans with stroke.

RESULTS

Calculated effect sizes were moderate to high, offering promise for improving upper extremity, balance and walking outcomes after stroke. We present a conceptual framework that capitalizes on cognitive-motor specialization of the cerebellum to formulate a synergy between NiCBS and behavioral interventions to target specific movement deficits.

CONCLUSION

NiCBS enhances recovery of upper extremity impairments, balance and walking after stroke. Physiologically-informed synergies between NiCBS and behavioral interventions have the potential to enhance recovery. Finally, we propose future directions in neurophysiological, behavioral, and clinical research to move NiCBS through the translational pipeline and augment motor recovery after stroke.

Disability and persistent motor deficits are linked to structural crossed cerebellar diaschisis in chronic stroke

Brain imaging has significantly contributed to our understanding of the cerebellum being involved in recovery after non-cerebellar stroke. Due to its connections with supratentorial brain networks, acute stroke can alter the function and structure of the contralesional cerebellum, known as crossed cerebellar diaschisis (CCD). Data on the spatially precise distribution of structural CCD and their implications for persistent deficits after stroke are notably limited. In this cross-sectional study, structural MRI and clinical data were analyzed from 32 chronic stroke patients, at least 6 months after the event. We quantified lobule-specific contralesional atrophy, as a surrogate of structural CCD, in patients and healthy controls. Volumetric data were integrated with clinical scores of disability and motor deficits. Diaschisis-outcome models were adjusted for the covariables age, lesion volume, and damage to the corticospinal tract. We found that structural CCD was evident for the whole cerebellum, and particularly for lobules V and VI. Lobule VI diaschisis was significantly correlated with clinical scores, that is, volume reductions in contralesional lobule VI were associated with higher levels of disability and motor deficits. Lobule V and the whole cerebellum did not show similar diaschisis-outcome relationships across the spectrum of the clinical scores. These results provide novel insights into stroke-related cerebellar plasticity and might thereby promote lobule VI as a key area prone to structural CCD and potentially involved in recovery and residual motor functioning.

The effectiveness of intermittent theta burst stimulation for upper limb motor recovery after stroke: a systematic review and meta-analysis of randomized controlled trials

Background

Intermittent theta burst stimulation (iTBS) is a promising noninvasive therapy to restore the excitability of the cortex, and subsequently improve the function of the upper extremities. Several studies have demonstrated the effectiveness of iTBS in restoring upper limb function and modulating cortical excitability. We aimed to evaluate the effects of iTBS on upper limb motor recovery after stroke.

Objective

The purpose of this article is to evaluate the influence of intermittent theta-burst stimulation on upper limb motor recovery and improve the quality of life.

Method

A literature search was conducted using PubMed, EMBASE, MEDLINE, The Cochrane Library, Web of Science, and CBM, including only English studies, to identify studies that investigated the effects of iTBS on upper limb recovery, compared with sham iTBS used in control groups. Effect size was reported as standardized mean difference (SMD) or weighted mean difference (WMD).

Results

Ten studies were included in the meta-analysis. The results of the meta-analysis indicated that when compared to the control group, the iTBS group had a significant difference in the Fugl-Meyer Assessment (FMA) and Action Research Arm Test (ARAT) (WMD: 3.20, 95% CI: 1.42 to 4.97; WMD: 3.72, 95% CI: 2.13 to 5.30, respectively). In addition, there was also a significant improvement in the modified Ashworth scale (MAS) compared to the sham group (WMD: -0.56; 95% CI: -0.85 to -0.28). More evidence is still needed to confirm the effect of Barthel Index (BI) scores after interventions. However, no significant effect was found for the assessment of Motor Evoked Potential (MEP) amplitude and MEP latency (SMD: 0.35; 95% CI: -0.21 to 0.90; SMD: 0.35, 95% CI: -0.18 to 0.87; SMD: 0.03, 95% CI: -0.49 to 0.55; respectively).

Conclusion

Our results showed that iTBS significantly improved motor impairment, functional activities, and reduced muscle tone of upper limbs, thereby increasing the ability to perform Activities of Daily Living (ADL) in stroke patients, while there were no significant differences in MEPs. In conclusion, iTBS is a promising non-invasive brain stimulation as an adjunct to therapy and enhances the therapeutic effect of conventional physical therapy. In the future, more randomized controlled trials with large sample sizes, high quality, and follow-up are necessary to explore the neurophysiological effects.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023392739.

The Effect of Cerebellar rTMS on Modulating Motor Dysfunction in Neurological Disorders: a Systematic Review

The effectiveness of cerebellar repetitive transcranial magnetic stimulation (rTMS) on motor dysfunction in patients with neurological disorders has received increasing attention because of its potential for neuromodulation. However, studies on the neuromodulatory effects, parameters, and safety of rTMS implementation in the cerebellum to alleviate motor dysfunction are limited. This systematic review aimed to evaluate the effectiveness and safety of cerebellar rTMS treatment for motor dysfunction caused by neurological disorders and to review popular stimulation parameters. Five electronic databases-Medline, Web of Science, Scopus, Cochrane Library, and Embase-were searched for relevant research published from inception to July 2022. All randomized controlled trials (RCTs) that reported the effects of cerebellar rTMS combined with behavioral rating scales on motor dysfunction were eligible for enrollment. Additionally, reference lists of the enrolled studies were manually checked. Among 1156 articles screened, 21 RCTs with 666 subjects were included. rTMS conducted on the cerebellum showed an improvement in stroke (spasticity, balance, and gait), cervical dystonia, Parkinson's disease (tremor), cerebellar ataxia, and essential tremor but not in multiple sclerosis. The 8-shaped coil with a diameter of 70 mm was determined as the most common therapeutic choice. None of the studies reported severe adverse events except mild side effects in three. Therefore, rTMS appears to be a promising and safe technique for the treatment of motor dysfunction, targeting the cerebellum to induce motor behavioral improvement. Further rigorous RCTs, including more samples and longer follow-up periods, are required to precisely explore the effective stimulation parameters and possible mechanisms.

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.

Long-term iTBS Improves Neural Functional Recovery by Reducing the Inflammatory Response and Inhibiting Neuronal Apoptosis Via miR-34c-5p/p53/Bax Signaling Pathway in Cerebral Ischemic Rats

To investigate intermittent theta-burst stimulation (iTBS) effect on ischemic stroke and the underlying mechanism of neurorehabilitation, we developed an ischemia/reperfusion (I/R) injury model in Sprague-Dawley (SD) rats using the middle cerebral artery occlusion/reperfusion (MCAO/r) method. Next, using different behavioral studies, we compared the improvement of the whole organism with and without iTBS administration for 28 days. We further explored the morphological and molecular biological alterations associated with neuronal apoptosis and neuroinflammation by TTC staining, HE staining, Nissl staining, immunofluorescence staining, ELISA, small RNA sequencing, RT-PCR, and western blot assays. The results showed that iTBS significantly protected against neurological deficits and neurological damage induced by cerebral I/R injury. iTBS also significantly decreased brain infarct volume and increased the number of surviving neurons after 28 days. Additionally, it was observed that iTBS decreased synaptic loss, suppressed activation of astrocytes and M1-polarized microglia, and simultaneously promoted M2-polarized microglial activation. Furthermore, iTBS intervention inhibited neuronal apoptosis and exerted a positive impact on the neuronal microenvironment by reducing neuroinflammation in cerebral I/R injured rats. To further investigate the iTBS mechanism, this study was conducted using small RNA transcriptome sequencing of various groups of peri-infarcted tissues. Bioinformatics analysis and RT-PCR discovered the possible involvement of miR-34c-5p in the mechanism of action. The target genes prediction and detection of dual-luciferase reporter genes confirmed that miR-34c-5p could inhibit neuronal apoptosis in cerebral I/R injured rats by regulating the p53/Bax signaling pathway. We also confirmed by RT-PCR and western blotting that miR-34c-5p inhibited Bax expression. In conclusion, our study supports that iTBS is vital in inhibiting neuronal apoptosis in cerebral I/R injured rats by mediating the miR-34c-5p involvement in regulating the p53/Bax signaling pathway.

Cerebral Theta-Burst Stimulation Combined with Physiotherapy in Patients with Incomplete Spinal Cord Injury: A Pilot Randomized Controlled Trial

OBJECTIVE

To measure the effects of cerebral intermittent theta-burst stimulation with physiotherapy on lower extremity motor recovery in patients with incomplete spinal cord injury.

DESIGN

Randomized, double-blinded, sham-controlled trial.

SUBJECTS

Adults with incomplete spinal cord injury.

METHODS

A total of 38 patients with incomplete spinal cord injury were randomized into either an intermittent theta-burst stimulation or a sham group. Both groups participated in physiotherapy 5 times per week for 9 weeks, and cerebral intermittent theta-burst stimulation or sham intermittent theta-burst stimulation was performed daily, immediately before physiotherapy. The primary outcomes were lower extremity motor score (LEMS), root-mean square (RMS), RMS of the quadriceps femoris muscle, walking speed (WS), and stride length (SL). Secondary outcomes comprised Holden Walking Ability Scale (HWAS) and modified Barthel Index (MBI). The outcomes were assessed before the intervention and 9 weeks after the start of the intervention.

RESULTS

Nine weeks of cerebral intermittent theta-burst stimulation with physiotherapy intervention resulted in improved recovery of lower extremity motor recovery in patients with incomplete spinal cord injury. Compared with baseline, the changes in LEMS, WS, SL, RMS, HWAS, and MBI were significant in both groups after intervention. The LEMS, WS, SL, RMS, HWAS, and MBI scores were improved more in the intermittent theta-burst stimulation group than in the sham group.

CONCLUSION

Cerebral intermittent theta-burst stimulation with physiotherapy promotes lower extremity motor recovery in patients with incomplete spinal cord injury. However, this study included a small sample size and lacked a comparison of the treatment effects of multiple stimulation modes, the further research will be required in the future.

Effectiveness of cerebellar vermis intermittent theta-burst stimulation in improving trunk control and balance function for patients with subacute stroke: a randomised controlled trial protocol

INTRODUCTION

Balance impairments frequently occur after stroke. Achieving effective core trunk stability is the key to improving balance ability. However, there is still a lack of advanced well-defined rehabilitation protocols for balance improvement in patients with stroke. Intermittent theta-burst stimulation (iTBS) is a non-invasive brain activity modulation strategy that can produce long-term potentiation. The cerebellar vermis is a fundamental structure involved in balance and motor control. However, no study has demonstrated the therapeutic effect and potential mechanism of cerebellar vermis iTBS on balance after stroke.

METHODS AND ANALYSIS

This study will be a prospective single-centre double-blind randomised controlled clinical trial with a 3-week intervention and 3-week follow-up. Eligible participants will be randomly allocated to the experimental group or the control group in a 1:1 ratio. After routine conventional physical therapy, patients in the experimental group will receive cerebellar vermis iTBS, whereas patients in the control group will receive sham stimulation. The overall intervention period will be 5 days a week for 3 consecutive weeks. The outcomes will be measured at baseline (T0), 3 weeks postintervention (T1) and at the 3-week follow-up (T2). The primary outcomes are Berg Balance Scale and Trunk Impairment Scale scores. The secondary outcomes are balance test scores via the Balance Master system, muscle activation of the trunk and lower limbs via the surface electromyography recordings, cerebral cortex oxygen concentrations measured via the resting-state functional near-infrared spectroscopy, Fugl-Meyer Assessment of Lower Extremity and Barthel index scores.

ETHICS AND DISSEMINATION

This study was approved by the West China Hospital Clinical Trials and Biomedical Ethics Committee of Sichuan University. All participants will sign the informed consent form voluntarily. The results of this study will be published in peer-reviewed journals and disseminated at academic conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2200065369.

Cerebellum-Cerebrum paired target magnetic stimulation on balance function and brain network of patients with stroke: A functional near-infrared spectroscopy pilot study

Transcranial magnetic stimulation (TMS) modulation over the cerebellum, primary motor cortex, and supplementary motor cortex individually can improve the balance function of patients with stroke. However, whether their combination could have a better balance modulation effect is uncertain. Therefore, we hypothesized that performing TMS over a combination of these targets can regulate the balance function of patients with stroke. We compared the effects of one-session TMS on eye-open and eye-closed balance conditions in patients with stroke, using different target pairs of unilateral cerebellar (CB-single), cerebellar-primary motor cortex (CB-M1), and cerebellar-supplementary motor area (CB-SMA) targets. A total of 31 patients with stroke were enrolled and randomly divided into three groups to receive single sessions of intermittent theta burst stimulation each. Functional near-infrared spectrum data on resting and standing task states (eye-open and eye-closed) and center of pressure parameters (eye-open and eye-closed) were collected before and after the intervention. Compared with the results in the CB-single group, five intergroup differences in the changes in the center of pressure parameters in the CB-M1 group and two significant differences in the CB-SMA group were observed after one session of intermittent theta burst stimulation. In the CB-SMA group, 12 out of the 14 parameters improved significantly in the EC condition after the intervention. Meanwhile, the functional near-infrared spectrum results showed that the CB-SMA group exhibited a significant inhibitory pattern in the resting-state functional connectivity, which was not observed in the other two groups. In conclusion, we believe that paired targeting of the CB-SMA can reshape the brain network and improve the balance function of patients with stroke.

Targeting Cerebellum with Non-Invasive Transcranial Magnetic or Current Stimulation after Cerebral Hemispheric Stroke-Insights for Corticocerebellar Network Reorganization: A Comprehensive Review

Non-invasive brain stimulation (NIBS) has emerged as one of the methods implemented in stroke rehabilitation. Cerebellar stimulation has gained research interest as an alternative strategy to cortical stimulation, based on the role of the cerebellum and corticocerebellar tracts in different motor and cognitive functions. This review investigates the role of the cerebellum in motor and cognitive rehabilitation following cerebral stroke using NIBS techniques combined with other therapies (e.g., speech or physical therapy). Fifteen randomized clinical trials were included. The majority of the literature findings point towards the cerebellum as a promising neurostimulation target following stroke of the cerebral cortex. Findings concern mostly rehabilitation of gait and balance, where cathodal transcranial direct current stimulation (tDCS) and intermittent theta-burst stimulation (iTBS) of the contralesional cerebellar hemisphere produce, in the presented clinical sample, improved performance and plasticity changes in the corticocerebellar network, combined with other rehabilitation methods. Data regarding aphasia rehabilitation are scarce, with right cerebellar tDCS exercising some impact in individual linguistic functions combined with language therapy. Based on recent data concerning cerebellar functions and corticocerebellar networks, along with the development of clinical protocols regarding non-invasive cerebellar (NICS) application, the cerebellum can prove a crucial intervention target in rehabilitation following stroke.

Does noninvasive cerebellar stimulation improve the balance and walking function of patients with stroke: A meta-analysis of randomized controlled trials

OBJECTIVES

Investigating the efficacy and safety of noninvasive cerebellar stimulation in improving the balance and walking function of patients with stroke.

METHODS

We searched 7 databases for randomized controlled trials (RCTs) related to noninvasive cerebellar stimulation in the treatment of stroke. The Berg Balance Scale (BBS), 6-minute walk test (6MWT), and Barthel Index (BI) were used as the outcome indexes to evaluate balance, walking and activities of daily living (ADL). The quality of the research was evaluated using the Cochrane Risk of Bias Tool. A meta-analysis was performed to evaluate the difference between the noninvasive cerebellar stimulation and control groups. Heterogeneity tests were performed to assess differences in treatment effects across noninvasive cerebellar stimulation modalities. A sensitivity analysis was performed to evaluate the robustness of the results.

RESULTS

Seven studies were included, and 5 articles (71.43%) were rated as having a low risk of bias. Among the primary outcome indicators, 4 of the 7 articles were combined into the fixed effect model (I2 = 38%, P = .18). Compared with the control group, noninvasive cerebellar stimulation improved the BBS score, and the difference was statistically significant (mean difference [MD]: 3.00, 95% confidence interval [CI]: 1.10-5.40, P = .03); the sensitivity analysis showed that the statistical model was still stable after sequentially eliminating each article. Compared with the control group, noninvasive cerebellar stimulation improved the 6MWT results of patients with stroke (MD: 25.29, 95% CI: 4.86-45.73, P = .02). However, noninvasive cerebellar stimulation did not improve the BI (MD: 15.61, 95% CI: -7.91 to 39.13, P = .19). No safety problems or adverse reactions to noninvasive cerebellar stimulation were observed.

CONCLUSIONS

Noninvasive cerebellar stimulation improves balance and walking function of patients with stroke, but its effect on ADL is uncertain. Due to the methodological weaknesses in the included trials, more RCTs are needed to confirm our conclusions.

Therapeutic mechanism of transcranial iTBS on nerve regeneration and functional recovery in rats with complete spinal cord transection.. [DOI: 10.21203/rs.3.rs-2026215/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background: After spinal cord transection injury, the inflammatory microenvironment formed in the injury site and the cascade of secondary injury results in limited regeneration of injured axons and the apoptosis of neurons in the sensorimotor cortex (SMC). It is crucial to reverse these adverse processes for the recovery of voluntary movement. In this study, transcranial intermittent theta-burst stimulation (iTBS) was used for the treatment of complete spinal cord transection in rats. The mechanism of transcranial iTBS as a new non-invasive neural regulation paradigm in promoting axonal regeneration and motor function repair was explored. Methods: Rats from the iTBS group were treated with transcranial iTBS 72h after spinal cord injury (SCI). Each rat was received behavioral testing. Inflammation, neuronal apoptosis, neuroprotective effect, regeneration and synaptic plasticity were measured by immunofluorescence staining, western blotting and mRNA sequencing 2 or 4w after SCI. Each rat was received anterograde tracings in the SMC or the long descending propriospinal neurons and tested for motor evoked potentials. Regeneration of corticospinal tract (CST) and 5-hydroxytryptamine (5-HT) nerve fibers were detected eight weeks after SCI. Results: Compared with the control group and the sham iTBS group, rats of the iTBS group showed reduced inflammatory responses and neuronal apoptosis in the SMC two weeks after treatment. After four weeks, the neuroimmune microenvironment at the injury site was improved, and neuroprotective effects were seen to promote axonal regeneration and synaptic plasticity. Significantly, eight weeks after treatment, transcranial iTBS also increased the regeneration of CST, 5-HT nerve fibers, and the long descending propriospinal tract (LDPT). Moreover, motor evoked potentials and hindlimb motor function were significantly improved at eight weeks. Conclusions: Collectively, our results verified that iTBS has the potential to provide neuroprotective effects at early injury stages and pro-regeneration effects related to the 1) CST–5-HT; 2) CST–LDPT; and 3) CST–5-HT–LDPT descending motor pathways and revealed the relationships among neural pathway activation, neuroimmune regulation, neuroprotection, and axonal regeneration, as well as the interaction network of key genes. The proposed non-invasive transcranial iTBS treatment is expected to provide a serviceable practical and theoretical support for spinal cord injury.

Intermittent theta-burst stimulation with physical exercise improves poststroke motor function: A systemic review and meta-analysis

Background

Intermittent theta-burst stimulation (iTBS) is an optimized rTMS modality that could modulate the excitability of neural structures. Several studies have been conducted to investigate the efficacy of iTBS in improving the motor function of stroke patients. However, the specific role of iTBS in motor function recovery after stroke is unclear. Hence, in our study, we performed a meta-analysis to investigate the efficacy of iTBS for the motor function improvement of stroke patients.

Methods

MEDLINE, Embase, and Cochrane Library were searched until May 2022 for randomized controlled trials (RCTs).

Results

Thirteen RCTs with 334 patients were finally included in our study. The primary endpoints were the Fugl-Meyer assessment scale (FMA) and Motor Assessment Scale (MAS) change from baseline. We found that iTBS led to a significant reduction in FMA score (P = 0.002) but not in MAS score (P = 0.24) compared with the sham group. Moreover, standard 600-pulse stimulation showed a better effect on motor function improvement than the sham group (P = 0.004), however, 1200-pulse iTBS showed no effect on motor function improvement after stroke (P = 0.23). The effect of iTBS for improving motor function only exists in chronic stroke patients (P = 0.02) but not in subacute patients (P = 0.27).

Conclusion

This study supports that iTBS has good efficacy for improving motor function in stroke patients. Therefore, standard 600-pulse stimulation iTBS therapy is proper management and treatment for chronic stroke.

Structural cerebellar reserve positively influences outcome after severe stroke

The concept of brain reserve capacity positively influencing the process of recovery after stroke has been continuously developed in recent years. Global measures of brain health have been linked with a favourable outcome. Numerous studies have evidenced that the cerebellum is involved in recovery after stroke. However, it remains an open question whether characteristics of cerebellar anatomy, quantified directly after stroke, might have an impact on subsequent outcome after stroke. Thirty-nine first-ever ischaemic non-cerebellar stroke patients underwent MRI brain imaging early after stroke and longitudinal clinical follow-up. Structural images were used for volumetric analyses of distinct cerebellar regions. Ordinal logistic regression analyses were conducted to associate cerebellar volumes with functional outcome 3-6 months after stroke, operationalized by the modified Rankin Scale. Larger volumes of cerebellar lobules IV, VI, and VIIIB were positively correlated with favourable outcome, independent of the severity of initial impairment, age, and lesion volume (P < 0.01). The total cerebellar volume did not exhibit a significant structure-outcome association. The present study reveals that pre-stroke anatomy of distinct cerebellar lobules involved in motor and cognitive functioning might be linked to outcome after acute non-cerebellar stroke, thereby promoting the emerging concepts of structural brain reserve for recovery processes after stroke.

Effects of the Intermittent Theta Burst Stimulation of the Cerebellar Vermis on Balance Recovery After Stroke: A Study Protocol for a Randomized Controlled Trial

Background

The recovery of balance function is a critical segment in the rehabilitation treatment of stroke. The cerebellum is considered as the key structure involved in balance and motor control. The cerebellar vermis plays an important role in integrating vision, proprioception, and sensory skin input and may be a candidate stimulation target for regulating the motor network related with balance. However, evidence that the intermittent theta burst stimulation (iTBS) of cerebellar vermis can promote the recovery of balance function after stroke remains insufficient. Therefore, this study aims to explore the efficacy of the cerebellar vermis iTBS for the treatment of balance function in patients with stroke.

Methods and Analysis

Forty patients with stroke will be recruited in this prospective, randomized, sham-controlled trial. Participants will be randomized in a 1:1 ratio to receive either 15 sessions of cerebellar vermis iTBS (600 pulses) or sham stimulation. Additionally, a routine rehabilitation therapy follows the intervention. The primary outcome is the Berg Balance Scale, and the secondary outcomes are the Fugl–Meyer assessment of the lower extremity and modified Barthel index. The above outcomes will be assessed before intervention and at the end of each week. Pre- and post-iTBS resting-state functional magnetic resonance imaging (rs-fMRI) will be acquired, and the regional homogeneity, fractional amplitude of low-frequency fluctuation and functional connectivity will be calculated and analyzed.

Discussion

This protocol holds promise as a potential method to improve balance function in patients with stroke. If the outcomes of patients improve after the intervention, the study will provide new insights into improving balance function.

Ethics and Dissemination

This study has been approved by the Medical Research Ethics Committee of Wuxi Mental Health Center (Wuxi Tongren Rehabilitation Hospital). Results will be disseminated through (open-access) peer-reviewed publications, networks of scientists, professionals, and the public and presented at conferences.

Clinical Trial Registration Number

www.chictr.org.cn, identifier ChiCTR2100052590.

The Immediate Effects of Intermittent Theta Burst Stimulation of the Cerebellar Vermis on Cerebral Cortical Excitability During a Balance Task in Healthy Individuals: A Pilot Study

Objective: This pilot study aimed to investigate the immediate effects of single-session intermittent theta-burst stimulation (iTBS) on the cerebellar vermis during a balance task, which could unveil the changes of cerebral cortical excitability in healthy individuals.

Subjects: A total of seven right-handed healthy subjects (26.86 ± 5.30 years) were included in this study.

Interventions: Each subject received single-session iTBS on cerebellar vermis in a sitting position.

Main Measures: Before and after the intervention, all subjects were asked to repeat the balance task of standing on the left leg three times. Each task consisted of 15 s of standing and 20 s of resting. Real-time changes in cerebral cortex oxygen concentrations were monitored with functional near-infrared spectroscopy (fNIRS). During the task, changes in blood oxygen concentration were recorded and converted into the mean HbO₂ for statistical analysis.

Results: After stimulation, the mean HbO₂ in the left SMA (P = 0.029) and right SMA (P = 0.043) significantly increased compared with baseline. However, no significant changes of mean HbO₂ were found in the bilateral dorsolateral prefrontal lobe (P > 0.05).

Conclusion: Single-session iTBS on the cerebellar vermis in healthy adults can increase the excitability of the cerebral cortex in the bilateral supplementary motor areas during balance tasks.

Clinical Trial Registration: [www.ClinicalTrials.gov], identifier [ChiCTR2100048915].

Cerebellar Theta Burst Stimulation on Walking Function in Stroke Patients: A Randomized Clinical Trial

Objectives: The objective of this study was to explore the efficacy of cerebellar intermittent theta burst stimulation (iTBS) on the walking function of stroke patients.

Methods: Stroke patients with walking dysfunction aged 25–80 years who had suffered their first unilateral stroke were included. A total of 36 patients [mean (SD) age, 53 (7.93) years; 10 women (28%)] were enrolled in the study. All participants received the same conventional physical therapy, including transfer, balance, and ambulation training, during admission for 50 min per day during 2 weeks (10 sessions). Every session was preceded by 3 min procedure of cerebellar iTBS applyed over the contralesional cerebellum in the intervention group or by a similar sham iTBS in control group. The groups were formed randomly and the baseline characteristics showed no significant difference. The primary outcome measure was Fugl–Meyer Assessment–Lower Extremity scores. Secondary outcomes included walking performance and corticospinal excitability. Measures were performed before the intervention beginning (T0), after the first (T1) and the second (T2) weeks.

Results: The Fugl–Meyer Assessment for lower extremity scores slightly improved with time in both groups with no significant difference between the groups and over the time. The walking performance significantly improved with time and between group. Two-way mixed measures ANOVA showed that there was significant interaction between time and group in comfortable walking time (F_2,68 = 6.5242, P = 0.0080, η²_partial = 0.276, ε = 0.641), between-group comparisons revealed significant differences at T1 (P = 0.0072) and T2 (P = 0.0133). The statistical analysis of maximum walking time showed that there was significant interaction between time and groups (F_2,68 = 5.4354, P = 0.0115, η²_partial = 0.198, ε = 0.734). Compared with T0, the differences of maximum walking time between the two groups at T1 (P = 0.0227) and T2 (P = 0.0127) were statistically significant. However, both the Timed up and go test and functional ambulation category scale did not yield significant differences between groups (P > 0.05).

Conclusion: Our results revealed that applying iTBS over the contralesional cerebellum paired with physical therapy could improve walking performance in patients after stroke, implying that cerebellar iTBS intervention may be a noninvasive strategy to promote walking function in these patients. This study was registered at ChiCTR, number ChiCTR1900026450.

A narrative review on non-invasive stimulation of the cerebellum in neurological diseases

IMPORTANCE

The cerebellum plays an important role in motor, cognitive, and affective functions owing to its dense interconnections with basal ganglia and cerebral cortex. This review aimed at summarizing the non-invasive cerebellar stimulation (NICS) approaches used to modulate cerebellar output and treat cerebellar dysfunction in the motor domain.

OBSERVATION

The utility of NICS in the treatment of cerebellar and non-cerebellar neurological diseases (including Parkinson's disease, dementia, cerebellar ataxia, and stroke) is discussed. NICS induces meaningful clinical effects from repeated sessions alone in both cerebellar and non-cerebellar diseases. However, there are no conclusive data on this issue and several concerns need to be still addressed before NICS could be considered a valuable, standard therapeutic tool.

CONCLUSIONS AND RELEVANCE

Even though some challenges must be overcome to adopt NICS in a wider clinical setting, this tool might become a useful strategy to help patients with lesions in the cerebellum and cerebral areas that are connected with the cerebellum whether one could enhance cerebellar activity with the intention of facilitating the cerebellum and the entire, related network, rather than attempting to facilitate a partially damaged cortical region or inhibiting the homologs' contralateral area. The different outcome of each approach would depend on the residual functional reserve of the cerebellum, which is confirmed as a critical element to be probed preliminary in order to define the best patient-tailored NICS.