Recovery of motor disability and spasticity in post-stroke after repetitive transcranial magnetic stimulation (rTMS)

Forearm bisection task suggests an alteration in body schema in patients with functional movement disorders (motor conversion disorders)

OBJECTIVES

To explore potential alterations of the Body Schema, the implicit sensorimotor representation of one's own body, in patients with Functional Movement Disorders (FMD, Motor Conversion Disorders), characterized by neurological symptoms of altered voluntary motor function that cannot be explained by typical medical conditions. This investigation is prompted by the potential dissociation from their reportedly intact sense of ownership.

METHODS

10 FMD patients and 11 healthy controls (HC) underwent the Forearm Bisection Task, aimed at assessing perceived body metrics, which consists in asking the subject, blindfolded, to repeatedly point at the perceived middle point of their dominant forearm with the index finger of their contralateral hand, and a psychometric assessment for anxiety, depression, alexithymia, and tendency to dissociation.

RESULTS

FMD patients bisected their forearm more proximally (with an increased shift towards their elbow equal to 7.5%) with respect to HC; average bisection point was positively associated with anxiety levels in the whole sample, and with the tendency to dissociation in the FMD group.

CONCLUSIONS

FMD patients perceive their forearm as shorter than HC, suggesting an alteration of their Body Schema. The Body Schema can go through short- and long-term updates in the life course, mainly related to the use of each body segment; we speculate that, despite FMD being a disorder of functional nature, characterized by variability and fluctuations in symptomatology, the lack of sense of agency over a body part might be interpreted by the nervous system as disuse and hence influence the Body Schema, as deficits of organic etiology do.

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.

Research progress on the application of transcranial magnetic stimulation in spinal cord injury rehabilitation: a narrative review

Traumatic or non-traumatic spinal cord injury (SCI) can lead to severe disability and complications. The incidence of SCI is high, and the rehabilitation cycle is long, which increases the economic burden on patients and the health care system. However, there is no practical method of SCI treatment. Recently, transcranial magnetic stimulation (TMS), a non-invasive brain stimulation technique, has been shown to induce changes in plasticity in specific areas of the brain by regulating the activity of neurons in the stimulation site and its functionally connected networks. TMS is a new potential method for the rehabilitation of SCI and its complications. In addition, TMS can detect the activity of neural circuits in the central nervous system and supplement the physiological evaluation of SCI severity. This review describes the pathophysiology of SCI as well as the basic principles and classification of TMS. We mainly focused on the latest research progress of TMS in the physiological evaluation of SCI as well as the treatment of motor dysfunction, neuropathic pain, spasticity, neurogenic bladder, respiratory dysfunction, and other complications. This review provides new ideas and future directions for SCI assessment and treatment.

Poststroke rehabilitation using repetitive transcranial magnetic stimulation during pregnancy: A case report

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a form of magnetic stimulation therapy used to treat depression, migraine, and motor function impairment in patients with stroke. As there is little research on the effects of rTMS in pregnant women, it is not widely used in these patients. This case report aimed to demonstrate the safety of rTMS in pregnant patients.

CASE SUMMARY

After much consideration, we applied rTMS to treat recent stroke and hemiplegia in a 34-year-old pregnant woman. The patient received 45 sessions of low-frequency treatment over the course of 10 wk. We closely monitored the mother and fetus for potential side effects; the results showed significant improvement in the patient's motor function, with no harmful effects on the mother or fetus during pregnancy or after delivery. The patient’s fine motor and walking functions improved after treatment. This case is the first instance of a stroke patient treated with rTMS during pregnancy.

CONCLUSION

This case demonstrates that rTMS could be used to improve motor function recovery in stroke patients during pregnancy.

A bibliometric analysis of global publication trends on rTMS and aphasia

BACKGROUND

Aphasia is one of the most devastating cognitive disorders caused by brain injury and seriously hinders patients' rehabilitation and quality of life. Repetitive transcranial magnetic stimulation involves the repeated application of extracranial pulsed magnetic fields to the local central nervous system to alter the membrane potential of cortical nerve cells, generating induced currents that affect brain metabolism and electrical activity. As one of the most popular noninvasive brain stimulation techniques, it has been used to treat aphasia. However, only a few bibliometric studies have examined the research direction and main findings in the field.

METHODS

To obtain an in-depth understanding of the research status and trend in this area, a bibliometric analysis based on the Web of Science database was conducted. VOSviewer (Leiden University, Leiden, Netherlands) and Microsoft Excel (Microsoft, Redmond, USA) were used to extract bibliometric information. Analysis of global distribution was conducted using the webpage mapping implement GunnMap2 (http://lert.co.nz/map/).

RESULTS

Publications in this field were retrieved from the Web of Science Core Collection database, and 189 articles met the final inclusion criteria. The most influential authors, institutions, journals, and countries were Ralph MA from the University of Manchester, Harvard University, Neuropsychologia, and the USA, respectively.

CONCLUSION

This study revealed publication patterns and emerging trends in the literature, providing a detailed and objective overview of the current state of research on repetitive transcranial magnetic stimulation for the treatment of aphasia. This information will be of great benefit to anyone seeking information about this field and can serve as a reference guide for researchers aiming to conduct further research.

Predictive Factors and Interventional Modalities of Post-stroke Motor Recovery: An Overview

Stroke is the most common cause of motor impairment worldwide. Therefore, many factors are being investigated for their predictive and facilitatory effects on recovery of motor function after stroke. Motor recovery can be predicted through several factors, such as clinical assessment, clinical biomarkers, and gene-based variations. As for interventions, many methods are under experimental investigation that aim to improve motor recovery, including different types of pharmacological interventions, non-invasive stimulation, and rehabilitation training by inducing cortical reorganization, neuroplasticity, angiogenesis, changing the levels of neurotransmitters in the brain, and altering the inflammatory and apoptotic processes occurring after stroke. Studies have shown that clinical biomarkers combined with clinical assessment and gene-based variations are reliable factors for predicting motor recovery after stroke. Moreover, different types of interventions such as pharmacological agents (selective serotonin reuptake inhibitors {SSRI}, noradrenaline reuptake inhibitors {NARIs}, levodopa, and amphetamine), non-invasive stimulation, and rehabilitation training have shown significant results in improving functional and motor recovery.

Repetitive Transcranial Magnetic Stimulation and Rehabilitation Therapy for Upper Limb Hemiparesis in Stroke Patients: A Narrative Review

Recent technological advances in non-invasive brain stimulation (NIBS) have led to the development of therapies for post-stroke upper extremity paralysis. Repetitive transcranial magnetic stimulation (rTMS), a NIBS technique, controls regional activity by non-invasively stimulating selected areas of the cerebral cortex. The therapeutic principle by which rTMS is thought to work is the correction of interhemispheric inhibition imbalances. The guidelines for rTMS for post-stroke upper limb paralysis have graded it as a highly effective treatment, and, based on functional brain imaging and neurophysiological testing, it has been shown to result in progress toward normalization. Our research group has published many reports showing improvement in upper limb function after administration of the NovEl Intervention Using Repetitive TMS and intensive one-to-one therapy (NEURO), demonstrating its safety and efficacy. Based on the findings to date, rTMS should be considered as a treatment strategy based on a functional assessment of the severity of upper extremity paralysis (Fugl-Meyer Assessment), and NEURO should be combined with pharmacotherapy, botulinum treatment, and extracorporeal shockwave therapy to maximize therapeutic effects. In the future, it will be important to establish tailormade treatments in which stimulation frequency and sites are adjusted according to the pathological conditions of interhemispheric imbalance, as revealed by functional brain imaging.

Anti-spastic effect of contralesional dorsal premotor cortex stimulation in stroke patients with moderate-to-severe spastic paresis: a randomized, controlled pilot trial

OBJECTIVE

This study aimed at investigating the effect of a single-session repetitive transcranial magnetic stimulation (rTMS) of the contralesional dorsal premotor cortex on poststroke upper-limb spasticity.

MATERIAL AND METHODS

The study consisted of the following three independent parallel arms: inhibitory rTMS (n = 12), excitatory rTMS (n = 12), and sham stimulation (n = 13). The primary and secondary outcome measures were the Modified Ashworth Scale (MAS) and F/M amplitude ratio, respectively. A clinically meaningful difference was defined as a reduction in at least one MAS score.

RESULTS

There was a statistically significant change in MAS score within only the excitatory rTMS group over time [median (interquartile range) of - 1.0 (- 1.0 to - 0.5), p = 0.004]. However, groups were comparable in terms of median changes in MAS scores (p > 0.05). The proportions of patients achieving at least one MAS score reduction (9/12 in the excitatory rTMS group, 5/12 in the inhibitory rTMS group, and 5/13 in the control group) were also comparable (p = 0.135). For the F/M amplitude ratio, main time effect, main intervention effect, and time-intervention interaction effect were not statistically significant (p > 0.05).

CONCLUSIONS

Modulation of the contralesional dorsal premotor cortex with a single-session of excitatory or inhibitory rTMS does not appear to have an immediate anti-spastic effect beyond sham/placebo. The implication of this small study remains unclear and further studies into excitatory rTMS for the treatment of moderate-to-severe spastic paresis in poststroke patients should be undertaken.

CLINICAL TRIAL REGISTRATION NO

NCT04063995 (clinicaltrials.gov).

Effect of rTMS intervention on upper limb motor function after stroke: A study based on fNIRS

Background

Stroke is a disease with a high fatality rate worldwide and a major cause of long-term disability. In the rehabilitation of limb motor function after stroke, the rehabilitation of upper limb function takes a long time and the recovery progress is slow, which seriously affects the patients' self-care ability in daily life. Repeated transcranial magnetic stimulation (rTMS) has been increasingly used to improve limb dysfunction in patients with stroke. However, a standardized reference for selecting a magnetic stimulation regimen is not available. Whether to increase the inhibition of the contralateral hemispheric motor cortex remains controversial. This study has evaluated the effects of different rTMS stimulation programs on upper limb function and corresponding brain functional network characteristics of patients with stroke and sought a new objective standard based on changes in brain network parameters to guide accurate rTMS stimulation programs.

Method

Thirty-six patients with stroke were selected and divided into control group and treatment group by number table method, with 18 patients in each group, and 3 patients in the control group were turned out and lost due to changes in disease condition. The treatment group was divided into two groups. TMS1 group was given 1 Hz magnetic stimulation in the M1 region of the contralesional hemisphere +10 Hz magnetic stimulation in the M1 region of the affected hemisphere, and the TMS2 group was given 10 Hz magnetic stimulation in the M1 region of the affected hemisphere. The control group was given false stimulation. The treatment course was once a day for 5 days a week for 4 weeks. The Fugl-Meyer Assessment for upper extremity (FMA-UE) sand near-infrared brain function were collected before treatment, 2 weeks after treatment, and 4 weeks after treatment, and the brain function network was constructed. Changes in brain oxygenated hemoglobin concentration and brain network parameters were analyzed with the recovery of motor function (i.e., increased FMA score). Meanwhile, according to the average increment of brain network parameters, the rTMS stimulation group was divided into two groups with good efficacy and poor efficacy. Network parameters of the two groups before and after rTMS treatment were analyzed statistically.

Results

(1) Before treatment, there was no statistical difference in Fugl-Meyer score between the control group and the magnetic stimulation group (p = 0.178).Compared with before treatment, Fugl-Meyer scores of 2 and 4 weeks after treatment were significantly increased in both groups (p <0.001), and FMA scores of 4 weeks after treatment were significantly improved compared with 2 weeks after treatment (p < 0.001). FMA scores increased faster in the magnetic stimulation group at 2 and 4 weeks compared with the control group at the same time point (p <0.001).TMS1 and TMS2 were compared at the same time point, FMA score in TMS2 group increased more significantly after 4 weeks of treatment (p = 0.010). (2) Before treatment, HbO2 content in healthy sensory motor cortex (SMC) area of magnetic stimulation group and control group was higher than that in other region of interest (ROI) area, but there was no significant difference in ROI between the two groups. After 4 weeks of treatment, the HbO2 content in the healthy SMC area was significantly decreased (p < 0.001), while the HbO2 content in the affected SMC area was significantly increased, and the change was more significant in the magnetic stimulation group (p < 0.001). (3) In-depth study found that with the recovery of motor function (FMA upper limb score increase ≥4 points) after magnetic stimulation intervention, brain network parameters were significantly improved. The mean increment of network parameters in TMS1 group and TMS2 group was significantly different (χ ² = 5.844, p = 0.016). TMS2 group was more advantageous than TMS1 group in improving the mean increment of brain network parameters.

Conclusion

(1) The rTMS treatment is beneficial to the recovery of upper limb motor function in stroke patients, and can significantly improve the intensity of brain network connection and reduce the island area. The island area refers to an isolated activated brain area that cannot transmit excitation to other related brain areas. (2) When the node degree of M1_Healthy region less than 0.52, it is suggested to perform promotion therapy only in the affected hemisphere. While the node degree greater than 0.52, and much larger than that in the M1_affected region. it is suggested that both inhibition in the contralesional hemisphere and high-frequency excitatory magnetic stimulation in the affected hemisphere can be performed. (3) In different brain functional network connection states, corresponding adjustment should be made to the treatment plan of rTMS to achieve optimal therapeutic effect and precise rehabilitation treatment.

Different frequencies of repetitive transcranial magnetic stimulation combined with local injection of botulinum toxin type A for post-stroke lower limb spasticity: study protocol for a prospective, single-center, non-randomized, controlled clinical trial

No definite consensus has currently been reached regarding the safety and efficacy of low- or high-frequency repetitive transcranial magnetic stimulation in the treatment of post-stroke muscle spasticity. The latest research indicates that when combined with local injections of botulinum toxin type A, it is more effective on post-stroke muscle spasticity than local injections of botulinum toxin type A alone. We designed a prospective, single-center, non-randomized, controlled clinical trial to investigate the safety and efficacy of different frequencies of repetitive transcranial magnetic stimulation combined with local injections of botulinum toxin type A in treating post-stroke lower limb muscle spasticity to determine an optimal therapeutic regimen. This trial will enroll 150 patients with post-stroke muscle spasticity admitted to the Department of Rehabilitation Medicine at the First Affiliated Hospital of China Medical University. All enrolled patients will undergo routine rehabilitation training and will be divided into five groups (n = 30 per group) according to the particular area of cerebral infarction and treatment methods. Group A: Patients with massive cerebral infarction will be given local injections of botulinum toxin type A and low-frequency (1 Hz) repetitive transcranial magnetic stimulation on the contralateral side; Group B: Patients with non-massive cerebral infarction will be given local injections of botulinum toxin type A and high-frequency (10–20 Hz) repetitive transcranial magnetic stimulation on the affected side; Group C: Patients with massive/non-massive cerebral infarction will be given local injections of botulinum toxin type A; Group D: Patients with massive cerebral infarction will be given low-frequency (1 Hz) repetitive transcranial magnetic stimulation on the contralateral side; and Group E: Patients with non-massive cerebral infarction will be given high-frequency (10–20 Hz) repetitive transcranial magnetic stimulation on the affected side. The primary outcome measure of this trial is a modified Ashworth scale score from 1 day before treatment to 12 months after treatment. Secondary outcome measures include Fugl-Meyer Assessment of Lower Extremity, Visual Analogue Scale, modified Barthel index, and Berg Balance Scale scores for the same time as specified for primary outcome measures. The safety indicator is the incidence of adverse events at 3–12 months after treatment. We hope to draw a definite conclusion on whether there are differences in the safety and efficacy of low- or high-frequency repetitive transcranial magnetic stimulation combined with botulinum toxin type A injections in the treatment of patients with post-stroke lower limb spasticity under strict grouping and standardized operation, thereby screening out the optimal therapeutic regimen. The study protocol was approved by the Medical Ethics Committee of the First Affiliated Hospital of China Medical University (approval No. [2021] 2021-333-3) on August 19, 2021. The trial was registered with the Chinese Clinical Trial Registry (Registration No. ChiCTR2100052180) on October 21, 2021. The protocol version is 1.1.

Lesions causing post-stroke spasticity localize to a common brain network

Objective

The efficacy of clinical interventions for post-stroke spasticity (PSS) has been consistently unsatisfactory, probably because lesions causing PSS may occur at different locations in the brain, leaving the neuroanatomical substrates of spasticity unclear. Here, we investigated whether heterogeneous lesions causing PSS were localized to a common brain network and then identified the key nodes in this network.

Methods

We used 32 cases of PSS and the Human Connectome dataset (n = 1,000), using a lesion network mapping method to identify the brain regions that were associated with each lesion in patients with PSS. Functional connectivity maps of all lesions were overlaid to identify common connectivity. Furthermore, a split-half replication method was used to evaluate reproducibility. Then, the lesion network mapping results were compared with those of patients with post-stroke non-spastic motor dysfunction (n = 29) to assess the specificity. Next, both sensitive and specific regions associated with PSS were identified using conjunction analyses, and the correlation between these regions and PSS was further explored by correlation analysis.

Results

The lesions in all patients with PSS were located in different cortical and subcortical locations. However, at least 93% of these lesions (29/32) had functional connectivity with the bilateral putamen and globus pallidus. These connections were highly repeatable and specific, as compared to those in non-spastic patients. In addition, the functional connectivity between lesions and bilateral putamen and globus pallidus in patients with PSS was positively correlated with the degree of spasticity.

Conclusion

We identified that lesions causing PSS were localized to a common functional connectivity network defined by connectivity to the bilateral putamen and globus pallidus. This network may best cover the locations of lesions causing PSS. The putamen and globus pallidus may be potential key regions in PSS. Our findings complement previous neuroimaging studies on PSS, contributing to identifying patients with stroke at high risk for spasticity at an early stage, and may point to PSS-specific brain stimulation targets.

Effects of Non-Invasive Brain Stimulation on Post-Stroke Spasticity: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

In recent years, the potential of non-invasive brain stimulation (NIBS) for the therapeutic effect of post-stroke spasticity has been explored. There are various NIBS methods depending on the stimulation modality, site and parameters. The purpose of this study is to evaluate the efficacy of NIBS on spasticity in patients after stroke. This systematic review and meta-analysis was conducted according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. PUBMED (MEDLINE), Web of Science, Cochrane Library and Excerpta Medica Database (EMBASE) were searched for all randomized controlled trials (RCTs) published before December 2021. Two independent researchers screened relevant articles and extracted data. This meta-analysis included 14 articles, and all included articles included 18 RCT datasets. The results showed that repetitive transcranial magnetic stimulation (rTMS) (MD = −0.40, [95% CI]: −0.56 to −0.25, p < 0.01) had a significant effect on improving spasticity, in which low-frequency rTMS (LF-rTMS) (MD = −0.51, [95% CI]: −0.78 to −0.24, p < 0.01) and stimulation of the unaffected hemisphere (MD = −0.58, [95% CI]: −0.80 to −0.36, p < 0.01) were beneficial on Modified Ashworth Scale (MAS) in patients with post-stroke spasticity. Transcranial direct current stimulation (tDCS) (MD = −0.65, [95% CI]: −1.07 to −0.22, p < 0.01) also had a significant impact on post-stroke rehabilitation, with anodal stimulation (MD = −0.74, [95% CI]: −1.35 to −0.13, p < 0.05) being more effective in improving spasticity in patients. This meta-analysis revealed moderate evidence that NIBS reduces spasticity after stroke and may promote recovery in stroke survivors. Future studies investigating the mechanisms of NIBS in addressing spasticity are warranted to further support the clinical application of NIBS in post-stroke spasticity.

Electroencephalography Mu Rhythm Changes and Decreased Spasticity After Repetitive Peripheral Magnetic Stimulation in Patients Following Stroke

Background: Spasticity is common among patients with stroke. Repetitive peripheral magnetic stimulation (rPMS) is a painless and noninvasive therapy that is a promising approach to reducing spasticity. However, the central mechanism of this therapy remains unclear. Changes in cortical activity and decreased spasticity after rPMS intervention require further exploration. The aim of this study was to explore the electroencephalography (EEG) mu rhythm change and decrease in spasticity after rPMS intervention in patients with stroke. Materials and methods: A total of 32 patients with spasticity following stroke were recruited in this study and assigned to the rPMS group (n = 16) or sham group (n = 16). The modified Ashworth scale, modified Tardieu scale, and Fugl-Meyer assessment of the upper extremity were used to assess changes in upper limb spasticity and motor function. Before and after the rPMS intervention, EEG evaluation was performed to detect EEG mu rhythm changes in the brain. Results: After one session of rPMS intervention, spasticity was reduced in elbow flexors (p < 0.05) and wrist flexors (p < 0.05). Upper limb motor function measured according to the Fugl-Meyer assessment was improved (p < 0.05). In the rPMS group, the power of event-related desynchronization decreased in the mu rhythm band (8-12 Hz) in the contralesional hemisphere (p < 0.05). Conclusions: The results indicate that rPMS intervention reduced spasticity. Cortical activity changes may suggest this favorable change in terms of its neurological effects on the central nervous system.

Comparative Enhancement of Motor Function and BDNF Expression Following Different Brain Stimulation Approaches in an Animal Model of Ischemic Stroke

BACKGROUND

Combinatory intervention such as high-frequency (50-100 Hz) excitatory cortical stimulation (ECS) given concurrently with motor rehabilitative training (RT) improves forelimb function, except in severely impaired animals after stroke. Clinical studies suggest that low-frequency (≤1 Hz) inhibitory cortical stimulation (ICS) may provide an alternative approach to enhance recovery. Currently, the molecular mediators of CS-induced behavioral effects are unknown. Brain-derived neurotrophic factor (BDNF) has been associated with improved recovery and neural remodeling after stroke and thus may be involved in CS-induced behavioral recovery.

OBJECTIVE

To investigate whether inhibitory stimulation during RT improves functional recovery of severely impaired rats, following focal cortical ischemia and if this recovery alters BDNF expression (study 1) and depends on BDNF binding to TrkB receptors (study 2).

METHODS

Rats underwent ECS + RT, ICS + RT, or noCS + RT treatment daily for 3 weeks following a unilateral ischemic lesion to the motor cortex. Electrode placement for stimulation was either placed ipsilateral (ECS) or contralateral (ICS) to the lesion. After treatment, BDNF expression was measured in cortical tissue samples (study 1). In study 2, the TrkB inhibitor, ANA-12, was injected prior to treatment daily for 21 days.

RESULTS

ICS + RT treatment significantly improved impaired forelimb recovery compared with ECS + RT and noCS + RT treatment.

CONCLUSION

ICS given concurrently with rehabilitation improves motor recovery in severely impaired animals, and alters cortical BDNF expression; nevertheless, ICS-mediated improvements are not dependent on BDNF binding to TrkB. Conversely, inhibition of TrkB receptors does disrupt motor recovery in ECS + RT treated animals.

Quantitative Modeling of Spasticity for Clinical Assessment, Treatment and Rehabilitation

Spasticity, a common symptom in patients with upper motor neuron lesions, reduces the ability of a person to freely move their limbs by generating unwanted reflexes. Spasticity can interfere with rehabilitation programs and cause pain, muscle atrophy and musculoskeletal deformities. Despite its prevalence, it is not commonly understood. Widely used clinical scores are neither accurate nor reliable for spasticity assessment and follow up of treatments. Advancement of wearable sensors, signal processing and robotic platforms have enabled new developments and modeling approaches to better quantify spasticity. In this paper, we review quantitative modeling techniques that have been used for evaluating spasticity. These models generate objective measures to assess spasticity and use different approaches, such as purely mechanical modeling, musculoskeletal and neurological modeling, and threshold control-based modeling. We compare their advantages and limitations and discuss the recommendations for future studies. Finally, we discuss the focus on treatment and rehabilitation and the need for further investigation in those directions.

Multifocal transcranial stimulation in chronic ischemic stroke: A phase 1/2a randomized trial

BACKGROUND AND PURPOSE

Repetitive transcranial magnetic stimulation (rTMS) may promote recovery of motor function after stroke by inducing functional reorganization of cortical circuits. The objective of this study was to examine whether multifocal cortical stimulation using a new wearable transcranial rotating permanent magnet stimulator (TRPMS) can promote recovery of motor function after stroke by inducing functional reorganization of cortical circuits.

METHODS

Thirty³⁰ patients with chronic ischemic stroke and stable unilateral weakness were enrolled in a Phase 1/2a randomized double-blind sham-controlled clinical trial to evaluate safety and preliminary efficacy. Bilateral hemispheric stimulation was administered for 20 sessions 40 min each over 4 weeks. The primary efficacy endpoint was the change in functional MRI BOLD activation immediately after end of treatment. Secondary efficacy endpoints were clinical scales of motor function, including the Fugl-Meyer motor arm score, ARAT, grip strength, pinch strength, gait velocity, and NIHSS.

RESULTS

TRPMS treatment was well-tolerated with no device-related adverse effects. Active treatment produced a significantly greater increase in the number of active voxels on fMRI than sham treatment (median +48.5 vs -30, p = 0.038). The median active voxel number after active treatment was 8.8-fold greater than after sham (227.5 vs 26, p = 0.016). Although the statistical power was inadequate to establish clinical endpoint benefits, numerical improvements were demonstrated in 5 of 6 clinical scales of motor function. The treatment effects persisted over a 3-month duration of follow-up.

CONCLUSIONS

Multifocal bilateral TRPMS was safe and showed significant fMRI changes suggestive of functional reorganization of cortical circuits in patients with chronic ischemic stroke. A larger randomized clinical trial is warranted to verify recovery of motor function.

Quantifying Altered Neural Connectivity of the Stretch Reflex in Chronic Hemiparetic Stroke

Post-stroke flexion synergy limits arm/hand function and is also linked to hyperactive stretch reflexes or spasticity. It is implicated in the increased role of indirect motor pathways following damage to direct corticospinal projections. We hypothesized that this maladaptive neuroplasticity also affects stretch reflexes. Specifically, multi-synaptic interactions in indirect motor pathways may increase nonlinear neural connectivity and time lag between stretch and reflex muscle response. Continuous position perturbations were applied to the elbow joint when eleven participants with stroke generated two levels of shoulder abduction (SABD) torques with their paretic arm to induce synergy-related spasticity. Likewise, the perturbations were applied to eleven control subjects while performing SABD and elbow flexion levels matching the synergy torques in stroke. We quantified linear and non-linear connectivity and the corresponding time lags between perturbations and muscle activity. Enhanced nonlinear connectivity with a prolonged time lag was found in stroke as compared to controls. Non-linear connectivity and time lag also increased with the expression of the flexion synergy, as induced by greater SABD load levels, in stroke. This study provides new evidence of changes in neural connectivity and long-latency time lag in the stretch reflex response post-stroke. The results suggest the contribution of indirect motor pathways to synergy-related spasticity.

Combined effects of botulinum toxin type A and repetitive transcranial magnetic stimulation with intensive motor training immediately after injection in a patient with chronic stroke: A case report

STUDY DESIGN

Single case report.

INTRODUCTION

A previous study clarified that spasticity and motor function were improved by combined treatment with botulinum toxin type A (BTX) injection and 1-Hz repetitive transcranial magnetic stimulation (rTMS) with intensive motor training at 4 weeks after injection. However, it is not clear whether 1-Hz rTMS with intensive motor training immediately after BTX injection also improves spasticity and motor function in stroke patients.

PURPOSE OF THE CASE REPORT

The purpose of this case report is to test the short- and long-term effects of BTX injection and rTMS with intensive motor training on the spasticity, motor function, and usefulness of the paretic hand in a stroke patient.

METHODS

A 64-year-old male, who suffered from a right cerebral hemorrhage 53 months previously, participated in the present study. BTX was injected into the spastic muscles of the affected upper limb. He then received the new protocol for a total of 24 sessions. The Modified Ashworth Scale (MAS), Fugl-Meyer Assessment (FMA), and Motor Activity Log, consisting of the amount of use and quality of movement scales, were assessed before and immediately after BTX injection, at discharge, and monthly for up to 5 months after discharge.

RESULTS

For the short-term effects of the therapy, the MAS scores of the elbow and wrist, FMA score, and quality of movement score improved. For the long-term effects of the therapy, the MAS score of the fingers, FMA score, and amount of use score improved for up to 5 months after discharge.

CONCLUSIONS

The present case report showed the improvement of all assessments performed in the short and/or long term and suggest the possibility of shortening the intervention period of combined therapy of BTX and rTMS with intensive motor training.

Effect of different pulse numbers of transcranial magnetic stimulation on motor cortex excitability: Single-blind, randomized cross-over design

AIMS

We aimed to investigate the effect of different pulse numbers of high-frequency repetitive transcranial magnetic stimulation (rTMS) over the motor cortex on cortical excitability in healthy participants.

METHODS

Fifteen healthy participants received 600 and 1200 pulses of 5-Hz rTMS on separate days in a random order. Stimulation (duration, 2 seconds and interval, 1 seconds) was delivered over the left primary motor cortex for the hand, at 90% of resting motor threshold (rMT). The rMT and motor evoked potential (MEP) were measured before stimulation, and at 0 and 30 minutes after rTMS.

RESULTS

No significant differences were observed between the two conditions for MEP (P = .919) or rMT (P = .266). Compared with baseline, MEP was increased significantly at 0 (P < .001) and 30 minutes (P < .001) after stimulation. After stimulation, rMT was decreased at 0 minute for the 600 and 1200 pulse conditions (P < .001), but had recovered by 30 minutes (P = .073).

CONCLUSION

Subthreshold 5-Hz rTMS increased motor cortex excitability in healthy humans. However, the number of pulses may exhibit a ceiling effect in that beyond a certain point, that is, increasing the number of pulses may exhibit no further increase in cortical excitability.

Add-On Effects of Chinese Herbal Medicine for Post-Stroke Spasticity: A Systematic Review and Meta-Analysis

Background: Treatment for post-stroke spasticity (PSS) remains a major challenge in clinical practice. Chinese herbal medicine (CHM) is often administered to assist in routine care (RC) in the treatment of PSS, with increasing numbers of clinical research and preclinical studies suggesting that it has potential benefits. Therefore, we conducted a systematic review and meta-analysis to evaluate the add-on effects and safety of CHM for PSS. Methods: Five English and four Chinese databases were searched from their respective inception to 28 February 2018. We included randomized controlled trials that evaluated the add-on effects of CHM for PSS, based on changes in the scores of the (Modified) Ashworth Scale (AS or MAS), Fugl-Meyer Assessment of Sensorimotor Recovery (FMA), and Barthel Index (BI). Results: Thirty-five trials involving 2,457 patients were included. For upper-limb AS or MAS, the estimated add-on effects of CHM to RC were significantly better when using oral (SMD -1.79, 95% CI: -3.00 to -0.57) or topical CHM (SMD -1.06, 95% CI: -1.40 to -0.72). For lower-limb AS or MAS, significant add-on benefits to RC were also detected (SMD -1.01, 95% CI: -1.43 to -0.59 and SMD -1.16, 95% CI: -1.83 to -0.49) using oral and topical CHM, respectively. For FMA and BI, better results were detected when adding CHM to RC, except for the subgroup of oral CHM for upper-limb FMA. Ten of the 35 included studies reported safety information, with two of them mentioning two mild adverse events. Conclusions: Noting the quality concerns of the included trials, this review suggests that CHM appears to be a well-tolerated therapy for patients with PSS, and the potential add-on effects of CHM in reducing spasticity and improving the daily activities of patients with PSS require further rigorous assessment.

The Effect of Repetitive Transcranial Magnetic Stimulation on Spasticity in Patients with Multiple Sclerosis

Background and Purpose

This randomized controlled study examined the effect of repetitive transcranial magnetic stimulation (rTMS) on spasticity in patients with multiple sclerosis (MS).

Methods

This study included 16 patients with a history of MS and spasticity in the adductor hip muscles according to the Modified Ashworth Scale (MAS). The participants were randomized into the active group (n=10) and control group (n=6), in which active rTMS and sham rTMS were applied in 10 sessions, respectively. A physical therapy and rehabilitation program was applied along with rTMS sessions in both groups. The evaluation parameters were assessed at baseline and then 1 week and 1 month after applying rTMS.

Results

Statistical analyses with post-hoc correction revealed statistically significant improvements in the active group compared to the control group in the bilateral MAS score, Penn Spasm Frequency Scale score, patient satisfaction, amount of urine leakage, actual health status, perceived health status, energy and fatigue, role limitations due to physical problems, social function, overall quality of life, cognitive functioning, physical health composite score, mental health composite score, and total score on the Multiple Sclerosis Quality of Life-54 (MSQOL-54) (p<0.05). Statistically significant changes were detected in the MSQOL-54 social function and physical health composite scores of patients in the control group (p<0.05).

Conclusions

Active rTMS combined with a physical therapy program reduced spasticity in MS patients compared to the control group that received only physical therapy. Further comprehensive and more advanced studies are needed to confirm the present findings.

Neuromodulatory effect of repetitive transcranial magnetic stimulation pulses on functional motor performances of spastic cerebral palsy children

BACKGROUND

Neuromodulation is emerging as a new therapeutic field towards treatment of neurological disorders through advances in medical devices. Repetitive Transcranial Magnetic Stimulation (rTMS) is one such neuromodulatory device that has received increasing interest as a tool for modulating cortical excitability that influence motor activity in both normal and diseased population. However, the therapeutic effect of rTMS varies depending on stimulation frequency, intensity, pulse trains, duration, etc. Our previous studies had already demonstrated that higher frequency of 10 Hz was effective in improving the motor activity of spastic CP patients.

OBJECTIVE

This study was aimed to evaluate the effect of different rTMS pulses on gross motor performance of spastic CP patients.

METHOD

Thirty spastic CP patients were divided equally into three groups P1500, P2000 and P2500 with mean age (in years) 7.7 ± SD4.4, 6.8 ± SD5.3 and 7.2 ± SD5.1 respectively. Gross Motor Function Measure (GMFM) was employed as an outcome measure to assess the motor performance. Constant rTMS frequency of 10 Hz was delivered to each participant but the number of stimulation pulse varied according to the groups; which were 1500, 2000 and 2500 pulses for P1500, P2000 and P2500 group respectively. rTMS therapy of 15 minutes duration was followed by physical therapy of 30 minutes daily for 20 days.

RESULT

Statistical analysis of pre versus post GMFM scores of different groups revealed significant result (p < .001) and the improvement in functional motor activity was 2.33% in P1500, 3.58% in P2000 and 5.17% in P2500 group.

INTERPRETATION

The result demonstrated modulatory effect of rTMS pulse by improving motor function of spastic CP patients.

Effects of strengthening exercise integrated repetitive transcranial magnetic stimulation on motor function recovery in subacute stroke patients: A randomized controlled trial

OBJECTIVE

To investigate the effects of strengthening exercise integrated repetitive transcranial magnetic stimulation (rTMS) on motor function recovery in subacute stroke patients.

SUBJECTS AND METHODS

Thirty subacute stroke patients were randomly assigned to three groups: an ankle strengthening exercise group (group I), ankle strengthening exercise integrated rTMS group (group II), or an rTMS group (control group (CG)). Study subjects received therapy five days per week for eight weeks. Motor-evoked potential testing, peak torque at the ankle joint, and 10 m walk test were performed before and after the eight-week treatment period.

RESULTS

Subjects in group II showed significantly higher amplitude of MEP, plantarflexor and dorsiflexor of peak torque, 10 m walk test than groups I and CG (p < 0.05). Subjects in groups I and II differed significantly in the pre- and post-test for all variables, (p < 0.05). In the CG group, the pre- and post-test scores for the amplitude of MEP, dorsiflexor, and 10-walk test differed significantly (p < 0.05).

CONCLUSIONS

Strengthening exercise integrated rTMS has positive effects on motor function recovery in subacute stroke patients.

Low-frequency rTMS of the unaffected hemisphere in stroke patients: A systematic review

The aim of this review was to summarize the evidence for the effectiveness of low-frequency (LF) repetitive transcranial magnetic stimulation (rTMS) over the unaffected hemisphere in promoting functional recovery after stroke. We performed a systematic search of the studies using LF-rTMS over the contralesional hemisphere in stroke patients and reviewed the 67 identified articles. The studies have been gathered together according to the time interval that had elapsed between the stroke onset and the beginning of the rTMS treatment. Inhibitory rTMS of the contralesional hemisphere can induce beneficial effects on stroke patients with motor impairment, spasticity, aphasia, hemispatial neglect and dysphagia, but the therapeutic clinical significance is unclear. We observed considerable heterogeneity across studies in the stimulation protocols. The use of different patient populations, regardless of lesion site and stroke aetiology, different stimulation parameters and outcome measures means that the studies are not readily comparable, and estimating real effectiveness or reproducibility is very difficult. It seems that careful experimental design is needed and it should consider patient selection aspects, rTMS parameters and clinical assessment tools. Consecutive sessions of rTMS, as well as the combination with conventional rehabilitation therapy, may increase the magnitude and duration of the beneficial effects. In an increasing number of studies, the patients have been enrolled early after stroke. The prolonged follow-up in these patients suggests that the effects of contralesional LF-rTMS can be long-lasting. However, physiological evidence indicating increased synaptic plasticity, and thus, a more favourable outcome, in the early enrolled patients, is still lacking. Carefully designed clinical trials designed are required to address this question. LF rTMS over unaffected hemisphere may have therapeutic utility, but the evidence is still preliminary and the findings need to be confirmed in further randomized controlled trials.

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.

A Systematic Review and Meta-Analysis on the Use of Repetitive Transcranial Magnetic Stimulation for Spasticity Poststroke

BACKGROUND

Spasticity is a common and potentially debilitating complication that develops after stroke, arising in approximately 30% of patients.

OBJECTIVE

To evaluate the effectiveness of repetitive transcranial magnetic stimulation (rTMS) in improving spasticity after stroke.

DESIGN

Meta-analysis and systematic review.

SETTING

Not applicable.

PATIENTS

A total of 273 poststroke (hemorrhagic = 123, ischemic = 150) participants were included with sample sizes ranging from 5 to 80. The majority of participants were male (66.0%) with a mean age ranging from 55.0 to 64.6 years. Mean stroke duration ranged from 6 months to 10 years.

METHODS

A literature search of multiple databases was conducted for articles published in English from January 1980 to April 2015 using select keywords. Studies were included if (1) the population included was >50% stroke patients; (2) the sample size included ≥4 subjects; (3) the intervention applied was rTMS; and (4) upper extremity spasticity was assessed pre- and postintervention. Randomized controlled trials (RCTs) were assessed for methodologic quality with the Physiotherapy Evidence Database tool. All research designs were given a level of evidence according to a modified Sackett Scale.

MAIN OUTCOME MEASUREMENTS

Modified Ashworth Scale (MAS).

RESULTS

Ten studies met the inclusion criteria: 2 RCTs (Physiotherapy Evidence Database scores 8-9) and 8 pre-post studies. Meta-analyses of primarily uncontrolled pre-post studies found significant improvements in MAS for elbow (P < .001), wrist (P < .001), and finger flexors (P < .001). However, a meta-analysis of the 2 available RCTs failed to find a significant rTMS treatment effect on MAS for the wrist (standardized difference = .34, P = .30).

CONCLUSIONS

There is limited available evidence to support the use of rTMS in improving spasticity poststroke. Despite the positive findings reported, better powered and appropriately controlled trials are necessary.

LEVEL OF EVIDENCE

II.

Effects of low-frequency repetitive transcranial magnetic stimulation on upper extremity motor recovery and functional outcomes in chronic stroke patients: A randomized controlled trial

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) was suggested as a preconditioning method that would increase brain plasticity and that it would be optimal to combine rTMS with intensive rehabilitation.

OBJECTIVE

To assess the efficacy of inhibitory rTMS on upper extremity motor recovery and functional outcomes in chronic ischemic stroke patients.

METHODS

In this randomized controlled trial, experimental group received low-frequency (LF) rTMS to the primary motor cortex of the unaffected side + physical therapy (PT), and control group received PT.

RESULTS

No statistically significant difference was found in baseline demographical and clinical characteristics of the subjects including stroke severity or severity of paralysis prior to intervention. There were statistically significant improvements in all clinical outcome measures except for the Brunnstrom Recovery Stages. Fugl-Meyer Assessment, Box and Block test, motor and total scores of Functional Independence Measurement (FIM), and Functional Ambulation Scale (FAS) scores were significantly increased in both groups, however, these changes were significantly greater in the rTMS group except for FAS score. FIM cognitive scores and standardized mini-mental test scores were significantly increased and distal and hand Modified Ashworth Scale scores were significantly decreased only in the rTMS group (p < .05).

CONCLUSIONS

LF-rTMS can safely facilitate upper extremity motor recovery in patients with chronic ischemic stroke. TMS seems to be a promising treatment for motor, functional, and cognitive deficits in chronic stroke. Further studies with a larger number of patients with longer follow-up periods are needed to establish its effectiveness in stroke rehabilitation.

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.

Physical treatment interventions for managing spasticity after stroke

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

Effects of repetitive transcranial magnetic stimulation on lower extremity spasticity and motor function in stroke patients

PURPOSE

To investigate the effect of low-frequency repetitive transcranial magnetic stimulation (rTMS) on lower extremity (LE) spasticity, motor function and motor neurone excitability in chronic stroke patients.

METHOD

This study was a randomised sham-controlled cross-over trial with 1-week follow-up. A total of 20 post-stroke patients were randomised to receive active (n = 10) or sham (n = 10) rTMS. Fourteen of them (7 in each group) crossed over to the sham or active rTMS after a washout period of 1 month. Interventions consist of five consecutive daily sessions of active or sham rTMS to the unaffected lower extremity motor area (1000 pulses; 1 Hz; 90% of the tibialis anterior motor threshold). Outcome measures were modified modified ashworth scale (MMAS), the H-reflex, lower extremity section of Fugl-Mayer assessment (LE-FMA) and timed UP and GO (TUG) test. All outcomes were measured at three levels in each intervention period: pre- and post-intervention and 1-week follow-up.

RESULTS

Friedman's test revealed significant improvement in MMAS score only after active rTMS. This improvement lasted for one week after the active rTMS. Repeated measure analysis of variance (ANOVA) showed significant time*intervention interaction for LE-FMA. There are no differences between groups for the MMAS and LE-FMA. No significant change in Hmax/Mmax ratio and TUG test was noted.

CONCLUSION

Low-frequency rTMS over the LE motor area can improve clinical measures of muscle spasticity and motor function. More studies are needed to clarify the changes underlying this improvement in spasticity. Implications for Rehabilitation Spasticity is a common disorder and one of the causes of long-term disability after stroke. Physical therapy modalities, oral medications, focal intervention and surgical procedures have been used for spasticity reduction. Beneficial effect of the repetitive transcranial magnetic stimulation (rTMS) for post-stroke upper extremity spasticity reduction and motor function improvement was demonstrated in previous studies. This study shows amelioration of lower extremity spasticity and motor function improvement after five daily sessions of inhibitory rTMS to the unaffected brain hemisphere which lasted for at least 1 week following the intervention.

Brain stimulation: Neuromodulation as a potential treatment for motor recovery following traumatic brain injury

There is growing evidence that electrical and magnetic brain stimulation can improve motor function and motor learning following brain damage. Rodent and primate studies have strongly demonstrated that combining cortical stimulation (CS) with skilled motor rehabilitative training enhances functional motor recovery following stroke. Brain stimulation following traumatic brain injury (TBI) is less well studied, but early pre-clinical and human pilot studies suggest that it is a promising treatment for TBI-induced motor impairments as well. This review will first discuss the evidence supporting brain stimulation efficacy derived from the stroke research field as proof of principle and then will review the few studies exploring neuromodulation in experimental TBI studies. This article is part of a Special Issue entitled SI:Brain injury and recovery.

A pilot study on the effects of low frequency repetitive transcranial magnetic stimulation on lower extremity spasticity and motor neuron excitability in patients after stroke

PURPOSE

To evaluate the effect of low frequency, repetitive transcranial magnetic stimulation (rTMS) on the lower extremity spasticity and motor neuron excitability in patients after stroke.

METHODS

Seven patients after stroke aged 42-78 years were included in this pretest-posttest clinical trial. The rTMS at 1 Hz and duration of 20 min was applied to the intact leg motor cortex for five consecutive sessions. Primary outcome measures were the Modified Modified Ashwoth Scale (MMAS) and the H(max)/M(max) ratio. Measurements were taken at baseline (T0), after the last treatment (5th) session (T1), and at 1 week follow up (T2).

RESULTS

Clinically assessed ankle plantar flexor spasticity (p = 0.05) improved significantly after treatment at T1. Knee extensor spasticity scored 0 after treatment at T1 and T2. The H(max)/M(max) ratio showed no statistically significant improvement after treatment.

CONCLUSION

The pilot data indicate that the inhibitory rTMS of the intact leg motor cortex in patients after stroke may improve the lower extremity spasticity.

Motor System Reorganization After Stroke: Stimulating and Training Toward Perfection

Stroke instigates regenerative responses that reorganize connectivity patterns among surviving neurons. The new connectivity patterns can be suboptimal for behavioral function. This review summarizes current knowledge on post-stroke motor system reorganization and emerging strategies for shaping it with manipulations of behavior and cortical activity to improve functional outcome.

Effects of repetitive transcranial magnetic stimulation on arm function and decreasing unilateral spatial neglect in subacute stroke: a randomized controlled trial

Objective:

The objective of this study is to investigate the effect of repetitive transcranial magnetic stimulation (rTMS) on the functional recovery of stroke patients with unilateral neglect.

Design:

Randomized controlled experimental study.

Setting:

Outpatient rehabilitation hospital.

Subjects:

Thirty patients with stroke were randomly assigned to two groups: an rTMS group (experimental) and a control group.

Interventions:

Stroke patients in the experimental group underwent comprehensive rehabilitation therapy and rTMS. Stroke patients in the control group underwent sham therapy and comprehensive rehabilitation therapy. Participants in both groups received therapy 5 days per week for 4 weeks.

Main measures:

Line bisection, Albert, Box and block and Grip strength tests were assessed before and after the four-week therapy period.

Results:

A significant difference in the post-training gains in Line bisection (16.53 SD 9.78 vs. 3.60 SD 5.02), Albert (14.13 SD 4.92 vs. 3.26 SD 2.01), Box and block (15.06 SD 9.68 vs. 6.93 SD 7.52), and Grip strength tests (3.60 SD 2.66 vs 0.80 SD 1.26) was observed between the experimental group and the control group ( P<0.05). In addition, the effect size for gains in the experimental and control groups was very strong in AT, BBT (effect size=2.15, 0.77 respectively).

Conclusion:

We conclude that rTMS might be effective in improvement in reduction of the unilateral neglect and motor function.

Non-invasive brain stimulation: an interventional tool for enhancing behavioral training after stroke

Stroke is the leading cause of disability among adults. Motor deficit is the most common impairment after stroke. Especially, deficits in fine motor skills impair numerous activities of daily life. Re-acquisition of motor skills resulting in improved or more accurate motor performance is paramount to regain function, and is the basis of behavioral motor therapy after stroke. Within the past years, there has been a rapid technological and methodological development in neuroimaging leading to a significant progress in the understanding of the neural substrates that underlie motor skill acquisition and functional recovery in stroke patients. Based on this and the development of novel non-invasive brain stimulation (NIBS) techniques, new adjuvant interventional approaches that augment the response to behavioral training have been proposed. Transcranial direct current, transcranial magnetic, and paired associative (PAS) stimulation are NIBS techniques that can modulate cortical excitability, neuronal plasticity and interact with learning and memory in both healthy individuals and stroke patients. These techniques can enhance the effect of practice and facilitate the retention of tasks that mimic daily life activities. The purpose of the present review is to provide a comprehensive overview of neuroplastic phenomena in the motor system during learning of a motor skill, recovery after brain injury, and of interventional strategies to enhance the beneficial effects of customarily used neurorehabilitation after stroke.

Pulsed Transcranial Ultrasound Stimulation Immediately After The Ischemic Brain Injury is Neuroprotective

GOAL

We applied a low-intensity pulsed transcranial ultrasound stimulation (pTUS) to the ischemic cortex after a distal middle cerebral artery occlusion (dMCAO) to study whether pTUS is capable of protecting brain from ischemic injury.

METHODS

Rats were randomly assigned to Sham (n = 6), Control (n = 16), and pTUS (n = 16) groups. The pTUS-treated rats were subjected to 60-min ultrasonic stimulation immediately after the ischemia. After 48 h, the sensorimotor-related behavioral outcomes were assessed by a neurological severity score (NSS), and the permanent brain injury was assessed by the histologic analysis of TTC staining of brain slices.

RESULTS

pTUS group showed significantly lower NSS (n = 10, 5.5 ± 2.5) than the Control group ( n = 10, 10.5 ±1.4) (p < 0.01). Concordantly, the ischemic lesion was significantly reduced after receiving pTUS immediately after dMCAO. The cortical infarct volume in the control group was more than threefold of the pTUS group (43.39% ± 2.33%, n = 16 versus 13.78% ± 8.18%, n = 16, p < 0.01). Immunohistochemical staining indicated reduction of neutrophils in the affected area, and laser speckle imaging showed significant increase of a cerebral blood flow after pTUS, which consistently supported the neuroprotection of pTUS in ischemic brain injury.

CONCLUSION

Both behavior and histological results suggested that pTUS on ischemic core immediately after ischemic stroke could be neuroprotective.

SIGNIFICANCE

The noninvasiveness and high spatiotemporal resolution of pTUS makes it a unique neuromodulation technique in comparison with the current TMS and tDCS.

Use of functional near-infrared spectroscopy to evaluate the effects of anodal transcranial direct current stimulation on brain connectivity in motor-related cortex

Transcranial direct current stimulation (tDCS) is a noninvasive, safe and convenient neuro-modulatory technique in neurological rehabilitation, treatment, and other aspects of brain disorders. However, evaluating the effects of tDCS is still difficult. We aimed to evaluate the effects of tDCS using hemodynamic changes using functional near-infrared spectroscopy (fNIRS). Five healthy participants were employed and anodal tDCS was applied to the left motor-related cortex, with cathodes positioned on the right dorsolateral supraorbital area. fNIRS data were collected from the right motor-related area at the same time. Functional connectivity (FC)between intracortical regions was calculated between fNIRS channels using a minimum variance distortion-less response magnitude squared coherence (MVDR-MSC) method. The levels of Oxy-HbO change and the FC between channels during the prestimulation, stimulation, and poststimulation stages were compared. Results showed no significant level difference, but the FC measured by MVDR-MSC significantly decreased during tDCS compared with pre-tDCS and post-tDCS, although the FC difference between pre-tDCS and post-tDCS was not significant. We conclude that coherence calculated from resting state fNIRS may be a useful tool for evaluating the effects of anodal tDCS and optimizing parameters for tDCS application.

Outcomes in spasticity after repetitive transcranial magnetic and transcranial direct current stimulations

Non-invasive brain stimulations mainly consist of repetitive transcranial magnetic stimulation and transcranial direct current stimulation. Repetitive transcranial magnetic stimulation exhibits satisfactory outcomes in improving multiple sclerosis, stroke, spinal cord injury and cerebral palsy-induced spasticity. By contrast, transcranial direct current stimulation has only been studied in post-stroke spasticity. To better validate the efficacy of non-invasive brain stimulations in improving the spasticity post-stroke, more prospective cohort studies involving large sample sizes are needed.

Benefits of repetitive transcranial magnetic stimulation (rTMS) for spastic subjects: clinical, functional, and biomechanical parameters for lower limb and walking in five hemiparetic patients

Introduction. Spasticity is a disabling symptom resulting from reorganization of spinal reflexes no longer inhibited by supraspinal control. Several studies have demonstrated interest in repetitive transcranial magnetic stimulation in spastic patients. We conducted a prospective, randomized, double-blind crossover study on five spastic hemiparetic patients to determine whether this type of stimulation of the premotor cortex can provide a clinical benefit. Material and Methods. Two stimulation frequencies (1 Hz and 10 Hz) were tested versus placebo. Patients were assessed clinically, by quantitative analysis of walking and measurement of neuromechanical parameters (H and T reflexes, musculoarticular stiffness of the ankle). Results. No change was observed after placebo and 10 Hz protocols. Clinical parameters were not significantly modified after 1 Hz stimulation, apart from a tendency towards improved recruitment of antagonist muscles on the Fügl-Meyer scale. Only cadence and recurvatum were significantly modified on quantitative analysis of walking. Neuromechanical parameters were modified with significant decreases in H max⁡ /M max⁡ and T/M max⁡ ratios and stiffness indices 9 days or 31 days after initiation of TMS. Conclusion. This preliminary study supports the efficacy of low-frequency TMS to reduce reflex excitability and stiffness of ankle plantar flexors, while clinical signs of spasticity were not significantly modified.

Effects of repetitive transcranial magnetic stimulation and intensive occupational therapy on motor neuron excitability in poststroke hemiparetic patients: a neurophysiological investigation using F-wave parameters

BACKGROUND

The combination protocol of repetitive transcranial magnetic stimulation (RTMS) and intensive occupational therapy (OT) improves motor function of the paretic upper limb in poststroke patients. However, the effect of RTMS/OT on motor neuron excitability remains to be investigated. The purpose of this study was to determine the effect of 15-day application of RTMS/OT on motor neuron excitability in such patients using neurophysiological studies including F-wave parameter measurements.

SUBJECTS AND METHODS

Ten poststroke patients with spastic upper limb hemiparesis were studied (mean age: 57.4 ± 8.1 years, ± SD). Patients were hospitalized for 15 days to receive RTMS/OT. One session of 40-min low-frequency RTMS and two sessions of 120-min intensive OT were provided daily. Neurophysiological studies including F-wave parameters measurements were performed on the days of admission/discharge. Motor function and spasticity of the affected upper limb were evaluated on the same time points.

RESULTS

RTMS/OT significantly improved motor function of the affected upper limb. RTMS/OT decreased the modified Ashworth scale (MAS) in the affected upper limb (p < 0.05), but did not change F-wave frequency in either upper limb. However, both F-mean/M ratio and F-max/M ratio significantly decreased in the affected upper limb (all p < 0.05).

CONCLUSIONS

The 15-day protocol of LF-RTMS/OT produced significant reduction of motor neuron excitability. RTMS/OT can potentially produce significant reduction in upper limb spasticity in the affected upper limb, although this finding should be confirmed in a larger number of patients.

Differential effect of conditioning sequences in coupling inhibitory/facilitatory repetitive transcranial magnetic stimulation for poststroke motor recovery

INTRODUCTION

While neuromodulation through unihemispheric repetitive transcranial magnetic stimulation (rTMS) has shown promise for the motor recovery of stroke patients, the effectiveness of the coupling of different rTMS protocols remains unclear.

AIMS

We aimed to test the long-term efficacy of this strategy with different applying sequences and to identify the electrophysiological correlates of motor improvements to the paretic hand.

RESULTS

In our sham-controlled, double-blinded parallel study, 48 stroke patients (2-6 months poststroke) were randomly allocated to three groups. Group A underwent 20-session rTMS conditioning initiated with 10-session 1 Hz rTMS over the contralesional primary motor cortex (M1), followed by 10-session intermittent theta burst stimulation (iTBS) consequently over the ipsilesional M1; Group B underwent the same two paradigms but in reverse; and Group C received sham stimulation that was identical to Group A. We tested cortical excitability and motor assessments at the baseline, postpriming rTMS, postconsequent rTMS, and at 3-months follow-up. Group A manifested greater improvement than Group B in Fugl-Meyer Assessment (FMA), Wolf Motor Function testing (WMFT) score, and muscle strength (P = 0.001-0.02) post the priming rTMS. After the consequent rTMS, Group A continued to present a superior outcome than Group B in FMA (P = 0.015) and WMFT score (P = 0.008) with significant behavior-electrophysiological correlation.

CONCLUSIONS

Conditioning the contralesional M1 prior to ipsilesional iTBS was found to be optimal for enhancing hand function, and this effect persisted for at least 3 months. Early modulation within 6 months poststroke rebalances interhemispheric competition and appears to be a feasible time window for rTMS intervention.