Promotion of Poststroke Motor-Function Recovery with Repetitive Transcranial Magnetic Stimulation by Regulating the Interhemispheric Imbalance

Facilitating Corticomotor Excitability of the Contralesional Hemisphere Using Non-Invasive Brain Stimulation to Improve Upper Limb Motor Recovery from Stroke-A Scoping Review

Upper limb weakness following stroke poses a significant global psychosocial and economic burden. Non-invasive brain stimulation (NIBS) is a potential adjunctive treatment in rehabilitation. However, traditional approaches to rebalance interhemispheric inhibition may not be effective for all patients. The supportive role of the contralesional hemisphere in recovery of upper limb motor function has been supported by animal and clinical studies, particularly for those with severe strokes. This review aims to provide an overview of the facilitation role of the contralesional hemisphere for post-stroke motor recovery. While more studies are required to predict responses and inform the choice of NIBS approach, contralesional facilitation may offer new hope for patients in whom traditional rehabilitation and NIBS approaches have failed.

Neural correlates of fine motor grasping skills: Longitudinal insights into motor cortex activation using fNIRS

BACKGROUND

Motor learning is essential for performing specific tasks and progresses through distinct stages, including the rapid learning phase (initial skill acquisition), the consolidation phase (skill refinement), and the stable performance phase (skill mastery and maintenance). Understanding the cortical activation dynamics during these stages can guide targeted rehabilitation interventions.

METHODS

In this longitudinal randomized controlled trial, functional near-infrared spectroscopy was used to explore the temporal dynamics of cortical activation in hand-related motor learning. Thirty-one healthy right-handed individuals were randomly assigned to perform either easy or intricate motor tasks with their non-dominant hand over 10 days. We conducted 10 monitoring sessions to track cortical activation in the right hemisphere (according to lateralization principles, the primary hemisphere for motor control) and evaluated motor proficiency concurrently.

RESULTS

The study delineated three stages of nondominant hand motor learning: rapid learning (days 1 and 2), consolidation (days 3-7), and stable performance (days 8-10). There was a power-law enhancement of motor skills correlated with learning progression. Sustained activation was observed in the supplementary motor area (SMA) and parietal lobe (PL), whereas activation in the right primary motor cortex (M1R) and dorsolateral prefrontal cortex (PFCR) decreased. These cortical activation patterns exhibited a high correlation with the augmentation of motor proficiency.

CONCLUSIONS

The findings suggest that early rehabilitation interventions, such as transcranial magnetic stimulation and transcranial direct current stimulation (tDCS), could be optimally directed at M1 and PFC in the initial stages. In contrast, SMA and PL can be targeted throughout the motor learning process. This research illuminates the path for developing tailored motor rehabilitation interventions based on specific stages of motor learning.

NEW AND NOTEWORTHY

In an innovative approach, our study uniquely combines a longitudinal design with the robustness of generalized estimating equations (GEEs). With the synergy of functional near-infrared spectroscopy (fNIRS) and the Minnesota Manual Dexterity Test (MMDT) paradigm, we precisely trace the evolution of neural resources during complex, real-world fine-motor task learning. Centering on right-handed participants using their nondominant hand magnifies the intricacies of right hemisphere spatial motor processing. We unravel the brain's dynamic response throughout motor learning stages and its potent link to motor skill enhancement. Significantly, our data point toward the early-phase rehabilitation potential of TMS and transcranial direct current stimulation on the M1 and PFC regions. Concurrently, SMA and PL appear poised to benefit from ongoing interventions during the entire learning curve. Our findings carve a path for refined motor rehabilitation strategies, underscoring the importance of timely noninvasive brain stimulation treatments.

Acupuncture combined with repeated transcranial magnetic stimulation for upper limb motor function after stroke: A systematic review and meta-analysis

BACKGROUND

Upper limb motor dysfunction after stroke is an important factor affecting patients' motor function and daily life. Acupuncture and repetitive transcranial magnetic stimulation are effective methods for stroke rehabilitation. However, a systematic and comprehensive overview of the combined efficacy of the two is lacking.

OBJECTIVE

Through a systematic review and meta-analysis of randomized controlled trials, this study aimed to assess the effectiveness of acupuncture combined with repetitive transcranial magnetic stimulation on upper extremity motor function in post-stroke patients.

METHODS

The relevant randomized controlled trials on acupuncture combined with repetitive transcranial magnetic stimulation in the treatment of upper limb motor disorders after stroke were searched in PubMed, Embase, Cochrane Library, Web of Science CNKI, VIP, Wanfang, and CBM databases. After screening clinical trials that met the inclusion criteria, data extraction was conducted independently by two investigators. Meta-analysis was performed using RevMan 5.4 software.

RESULTS

After the screening, 18 articles were included, with a total of 1083 subjects. The results of meta-analysis showed that combination therapy could effectively improve the patients' upper limb motor function (MD = 7.77, 95%CI [6.32, 9.22], P < 0.05), ability of daily living (MD = 8.53, 95%CI [6.28, 10.79], P < 0.05), and hemiplegic shoulder pain (MD = - 1.72, 95%CI [- 2.26, - 1.18], P < 0.05). Meanwhile, for neurophysiological indexes, combined treatment could significantly shorten the latency of motor evoked potential and central motor conduction time (MD = - 1.42, 95%CI [- 2.14, - 0.71], P < 0.05); (MD = - 0.47, 95%CI [- 0.66, - 0.29], P < 0.05), and also could increase the amplitude of motor evoked potential (SMD = 0.71, 95%CI [0.28, 1.14], P < 0.05).

CONCLUSION

According to the results of the meta-analysis, we can conclude that acupuncture combined with repeated transcranial magnetic stimulation can significantly improve the upper limb motor function and daily living ability of stroke patients.

Excitatory Repetitive Transcranial Magnetic Stimulation Over the Ipsilesional Hemisphere for Upper Limb Motor Function After Stroke: A Systematic Review and Meta-Analysis

Background

Repetitive transcranial magnetic stimulation (rTMS) is a promising therapy to promote recovery of the upper limb after stroke. According to the regulation of cortical excitability, rTMS can be divided into excitatory rTMS and inhibitory rTMS, and excitatory rTMS includes high-frequency rTMS (HF-rTMS) or intermittent theta-burst stimulation (iTBS). We aimed to evaluate the effects of excitatory rTMS over the ipsilesional hemisphere on upper limb motor recovery after stroke.

Methods

Databases of PubMed, Embase, ISI Web of Science, and the Cochrane Library were searched for randomized controlled trials published before 31 December 2021. RCTs on the effects of HF-rTMS or iTBS on upper limb function in patients diagnosed with stroke were included. Two researchers independently screened the literature, extracted the data, and assessed quality. The meta-analysis was performed by using Review Manager Version 5.4 software.

Results

Fifteen studies with 449 participants were included in this meta-analysis. This meta-analysis found that excitatory rTMS had significant efficacy on upper limb motor function (MD = 5.88, 95% CI, 3.32–8.43, P < 0.001), hand strength (SMD = 0.53, 95% CI, 0.04–1.01, P = 0.03), and hand dexterity (SMD = 0.76, 95% CI, 0.39–1.14, P < 0.001). Subgroup analyses based on different types of rTMS showed that both iTBS and HF-rTMS significantly promoted upper limb motor function (iTBS, P < 0.001; HF-rTMS, P < 0.001) and hand dexterity (iTBS, P = 0.01; HF-rTMS, P < 0.001) but not hand strength (iTBS, P = 0.07; HF-rTMS, P = 0.12). Further subgroup analysis based on the duration of illness demonstrated that applying excitatory rTMS during the first 3 months (<1 month, P = 0.01; 1–3 months, P = 0.001) after stroke brought significant improvement in upper limb motor function but not in the patients with a duration longer than 3 months (P = 0.06). We found that HF-rTMS significantly enhanced the motor evoked potential (MEP) amplitude of affected hemisphere (SMD = 0.82, 95% CI, 0.32–1.33, P = 0.001).

Conclusion

Our study demonstrated that excitatory rTMS over the ipsilesional hemisphere could significantly improve upper limb motor function, hand strength, and hand dexterity in patients diagnosed with stroke. Both iTBS and HF-rTMS which could significantly promote upper limb motor function and hand dexterity, and excitatory rTMS were beneficial to upper limb motor function recovery only when applied in the first 3 months after stroke. HF-rTMS could significantly enhance the MEP amplitude of the affected hemisphere. High-quality and large-scale randomized controlled trials in the future are required to confirm our conclusions.

Clinical Trial Registration

www.crd.york.ac.uk/prospero/, identifier: CRD42022312288.

Current Status of Neuromodulation-Induced Cortical Prehabilitation and Considerations for Treatment Pathways in Lower-Grade Glioma Surgery

The infiltrative character of supratentorial lower grade glioma makes it possible for eloquent neural pathways to remain within tumoural tissue, which renders complete surgical resection challenging. Neuromodulation-Induced Cortical Prehabilitation (NICP) is intended to reduce the likelihood of premeditated neurologic sequelae that otherwise would have resulted in extensive rehabilitation or permanent injury following surgery. This review aims to conceptualise current approaches involving Repetitive Transcranial Magnetic Stimulation (rTMS-NICP) and extraoperative Direct Cortical Stimulation (eDCS-NICP) for the purposes of inducing cortical reorganisation prior to surgery, with considerations derived from psychiatric, rehabilitative and electrophysiologic findings related to previous reports of prehabilitation. Despite the promise of reduced risk and incidence of neurologic injury in glioma surgery, the current data indicates a broad but compelling possibility of effective cortical prehabilitation relating to perisylvian cortex, though it remains an under-explored investigational tool. Preliminary findings may prove sufficient for the continued investigation of prehabilitation in small-volume lower-grade tumour or epilepsy patients. However, considering the very low number of peer-reviewed case reports, optimal stimulation parameters and duration of therapy necessary to catalyse functional reorganisation remain equivocal. The non-invasive nature and low risk profile of rTMS-NICP may permit larger sample sizes and control groups until such time that eDCS-NICP protocols can be further elucidated.

Driving Oscillatory Dynamics: Neuromodulation for Recovery After Stroke

Stroke is a leading cause of death and disability worldwide, with limited treatments being available. However, advances in optic methods in neuroscience are providing new insights into the damaged brain and potential avenues for recovery. Direct brain stimulation has revealed close associations between mental states and neuroprotective processes in health and disease, and activity-dependent calcium indicators are being used to decode brain dynamics to understand the mechanisms underlying these associations. Evoked neural oscillations have recently shown the ability to restore and maintain intrinsic homeostatic processes in the brain and could be rapidly deployed during emergency care or shortly after admission into the clinic, making them a promising, non-invasive therapeutic option. We present an overview of the most relevant descriptions of brain injury after stroke, with a focus on disruptions to neural oscillations. We discuss the optical technologies that are currently used and lay out a roadmap for future studies needed to inform the next generation of strategies to promote functional recovery after stroke.

Repetitive transcranial magnetic stimulation increases neurological function and endogenous neural stem cell migration via the SDF-1α/CXCR4 axis after cerebral infarction in rats

Neural stem cell (NSC) migration is closely associated with brain development and is reportedly involved during recovery from ischaemic stroke. Chemokine signalling mediated by stromal cell-derived factor 1α (SDF-1α) and its receptor CXC chemokine receptor 4 (CXCR4) has been previously documented to guide the migration of NSCs. Although repetitive transcranial magnetic stimulation (rTMS) can increase neurological function in a rat stroke model, its effects on the migration of NSCs and associated underlying mechanism remain unclear. Therefore, the present study investigated the effects of rTMS on ischaemic stroke following middle cerebral artery occlusion (MCAO). All rats underwent rTMS treatment 24 h after MCAO. Neurological function, using modified Neurological Severity Scores and grip strength test and NSC migration, which were measured using immunofluorescence staining, were analysed at 7 and 14 days after MCAO, before the protein expression levels of the SDF-1α/CXCR4 axis was evaluated using western blot analysis. AMD3100, a CXCR4 inhibitor, was used to assess the effects of SDF-1α/CXCR4 signalling. In addition, neuronal survival was investigated using Nissl staining at 14 days after MCAO. It was revealed that rTMS increased the neurological recovery of rats with MCAO, facilitated the migration of NSC, augmented the expression levels of the SDF-1α/CXCR4 axis and decreased neuronal loss. Furthermore, the rTMS-induced positive responses were significantly abolished by AMD3100. Overall, these results indicated that rTMS conferred therapeutic neuroprotective properties, which can restore neurological function after ischaemic stroke, in a manner that may be associated with the activation of the SDF-1α/CXCR4 axis.

Does a combination treatment of repetitive transcranial magnetic stimulation and occupational therapy improve upper limb muscle paralysis equally in patients with chronic stroke caused by cerebral hemorrhage and infarction?: A retrospective cohort study

The clinical presentation of stroke is usually more severe in patients with intracerebral hemorrhage (ICH) than in those with cerebral infarction (CI); recovery of stroke-related muscle paralysis is influenced and limited by the type of stroke. To date, many patients have been treated by neurorehabilitation; however, the changes in the recovery of motor paralysis depending on the type of stroke, ICH or CI, have not been established. This study aimed to determine this difference in improvement of upper extremity paralysis using 2-week in-hospital NovEl intervention Using Repetitive transcranial magnetic stimulation combined with Occupational therapy (NEURO).We scrutinized the medical records of all patients with poststroke (ICH or CI) upper extremity muscle paralysis using Fugl-Meyer assessments (FMAs) who had been admitted to 6 hospitals between March 2010 and December 2018 for rehabilitation treatment. This was a multiinstitutional, open-label, retrospective cohort study without control patients. We evaluated the effects of NEURO on patients with CI and ICH by dividing them into 2 groups according to the type of stroke, after adjustment for age, sex, dominant hand, affected hand side, time since stroke, and prediction of recovery capacity in the upper extremity.The study included 1716 (CI [n = 876] and ICH [n = 840]) patients who had undergone at least 2 FMAs and had experienced stroke at least 6 months before. The type of stroke had no effect on the outcomes (changes in the FMA-upper extremity score, F[4,14.0] = 2.05, P = .09, partial η2 = 0.01). Patients from all 5 groups equally benefited from the treatment (improvement in FMA scores) according to the sensitivity analysis-stratified analysis (F = 0.08 to 1.94, P > .16, partial η2 < 0.001).We conclude that NEURO can be recommended for chronic stroke patients irrespective of the type of stroke.