Spasticity Management: The Current State of Transcranial Neuromodulation

Noninvasive brain stimulation for spasticity rehabilitation in multiple sclerosis: A systematic review of randomized controlled trials

OBJECTIVE

To investigate the effects of noninvasive brain stimulation (NIBS) on spasticity in people with multiple sclerosis (PwMS).

LITERATURE SURVEY

We searched PubMed, SCOPUS, MEDLINE, REHABDATA, PEDro, CINAHL, AMED, and Web of Science until December 2022.

METHODOLOGY

Studies were selected if they included PwMS, used transcranial direct current stimulation (tDCS) or repetitive transcranial magnetic stimulation (rTMS) as a main intervention, and were randomized controlled trials (RCTs) including at least one outcome measure evaluating spasticity. Two researchers individually screened the selected studies. The study's quality was assessed using the Cochrane Collaborations tool. The researchers decided that the meta-analysis was not possible because the treatment interventions varied among the selected studies.

SYNTHESIS

In total, 147 studies were reviewed. Of them, nine studies met the eligibility criteria and included 193 PwMS (mean age = 43.2 years), 54.4% of whom were female. Eight studies were considered "high" quality and one was considered "moderate" quality. Seven studies that used rTMS demonstrated a significant decrease in spasticity in PwMS after the intervention. The remaining studies that provided tDCS did not show meaningful effects.

CONCLUSIONS

The evidence for the influences of rTMS on spasticity in PwMS is promising. The evidence for the impact of tDCS on spasticity in PwMS was limited. Further RCTs with long-term follow-ups are encouraged.

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.

Acupuncture alleviates spinal hyperreflexia and motor dysfunction in post-ischemic stroke rats with spastic hypertonia via KCC2-mediated spinal GABAA activation

The majority of patients simultaneously develop motor dysfunction and spastic hypertonia after ischemic strokes, which can be associated with an increasing trend in motor impairments, seriously impeding the rehabilitation process. Evidence suggests that some deficits in the KCC2 expression in the spinal cord along with maladaptive endogenous plasticity via GABA_A receptors are often involved in the pathology of spastic hypertonia after a stroke. In this respect, acupuncture has been commonly used in clinical settings for post-stroke patients' rehabilitation. Nevertheless, the mechanism of the modulating activity of this alternative medicine in the spinal pathways to relieve spasticity and improve functional recovery after a stroke has still remained unclear. Utilizing laser speckle imaging, functional assessments (viz. neurologic function scale, muscular tension scale, foot balance test, and gait analysis), H-reflex recording, TTC, Western blotting, RT-qPCR, ELISA, and immunofluorescence molecular assay, the study results illustrated that acupuncture could significantly alleviate the spinal hyperreflexia, decrease muscle tone, and enhance locomotor function by elevating the GABA, KCC2, and GABA_Aγ2 expressions in the lumbar spine of a rat model of post-ischemic stroke with spastic hypertonia. Furthermore, the KCC2 antagonist DIOA abolished the benefits induced by this practice. Overall, the data revealed that acupuncture is a promising therapeutic approach for spastic hypertonia after a stroke, and the positive outcomes in this sense could be achieved via activating the KCC2-mediated spinal GABA_A signaling pathway.

Cerebellar Intermittent Theta-Burst Stimulation Reduces Upper Limb Spasticity After Subacute Stroke: A Randomized Controlled Trial

Objective: This study aims to explore the efficacy of cerebellar intermittent theta-burst stimulation (iTBS) on upper limb spasticity in subacute stroke patients.

Methods: A total of 32 patients with upper limb spasticity were enrolled and randomly assigned to treatment with cerebellar iTBS or sham stimulation before conventional physical therapy daily for 2 weeks. The primary outcomes included the modified Ashworth scale (MAS), the modified Tardieu scale (MTS), and the shear wave velocity (SWV). The secondary outcomes were the H-maximum wave/M-maximum wave amplitude ratio (H_max/M_max ratio), motor-evoked potential (MEP) latency and amplitude, central motor conduction time (CMCT), and the Barthel Index (BI). All outcomes were evaluated at baseline and after 10 sessions of intervention.

Results: After the intervention, both groups showed significant improvements in the MAS, MTS, SWV, and BI. In addition, patients treated with cerebellar iTBS had a significant increase in MEP amplitude, and patients treated with sham stimulation had a significant decrease in H_max/M_max ratio. Compared with the sham stimulation group, the MAS, MTS, and SWV decreased more in the cerebellar iTBS group.

Conclusion: Cerebellar iTBS is a promising adjuvant tool to reinforce the therapeutic effect of conventional physical therapy in upper limb spasticity management after subacute stroke (Chinese Clinical Trial Registry: ChiCTR1900026516).

Bilateral Motor Cortex tDCS Effects on Post-Stroke Pain and Spasticity: A Three Cases Study

Stroke patients frequently suffer from chronic limb pain, but well-suited treatment approaches have been not established so far. Transcranial direct current stimulation (tDCS) is a safe and non-invasive brain stimulation technique that alters cortical excitability, and it has been shown that motor cortex tDCS can reduce pain. Some data also suggest that spasticity may be improved by tDCS in post-stroke patients. Moreover, multiple sessions of tDCS have shown to induce neuroplastic changes with lasting beneficial effects in different neurological conditions. The aim of this pilot study was to explore the effect of multiple anodal tDCS (atDCS) sessions on upper limb pain and spasticity of stroke patients, using a within-subject, crossover, sham-controlled design. Brain damage was of similar extent in the three patients evaluated, although located in different hemispheres. The results showed a significant effect of 5 consecutive sessions of atDCS, compared to sham stimulation, on pain evaluated by the Adaptive Visual Analog Scales -AVAS-, and spasticity evaluated by the Fugl-Meyer scale. In two of the patients, pain was completely relieved and markedly reduced, respectively, only after verum tDCS. The pain improvement effect of atDCS in the third patient was considerably lower compared to the other two patients. Spasticity was significantly improved in one of the patients. The treatment was well-tolerated, and no serious adverse effects were reported. These findings suggest that multiple sessions of atDCS are a safe intervention for improving upper limb pain and spasticity in stroke patients, although the inter-individual variability is a limitation of the results. Further studies including longer follow-up periods, more representative patient samples and individualized stimulation protocols are required to demonstrate the efficacy and safety of tDCS for improving limb symptoms in these patients.

The Effect of Sham Controlled Continuous Theta Burst Stimulation and Low Frequency Repetitive Transcranial Magnetic Stimulation on Upper Extremity Spasticity and Functional Recovery in Chronic Ischemic Stroke Patients

OBJECTIVE

This randomized controlled study examined the effect of continuous theta burst stimulation (cTBS) and low frequency repetitive transcranial magnetic stimulation (rTMS) on upper extremity spasticity and functional recovery in chronic ischemic stroke patients.

MATERIALS AND METHODS

Twenty chronic ischemic stroke patients were randomized into three groups as real rTMS group (n = 7), real cTBS group (n = 7) and sham cTBS group (n = 6), in which real rTMS with physical therapy (PT), real cTBS with PT and sham cTBS with PT were applied in 10 sessions, respectively. The evaluation parameters were assessed at pre-treatment, post-treatment and follow up at 4 weeks.

RESULTS

Ten sessions of real rTMS or real cTBS combined with PT were found beneficial in motor functional recovery and daily living activities both at post-treatment and follow up at 4 weeks (p ˂ 0.05). In the sham cTBS group, functional improvement was not significant (p > 0.05). In addition, in the real rTMS group, elbow flexor, pronator, wrist flexor and finger flexor spasticity were significantly decreased; in the real cTBS group, significant decrease was observed in the elbow flexor and wrist flexor spasticity (p ˂ 0.05). In comparison with sham cTBS group, only in the real cTBS group, significant improvement was observed in the level of wrist flexor spasticity at follow up at 4 weeks (p ˂ 0.017).

CONCLUSIONS

In this study, it was observed that real cTBS or real rTMS combined with PT provided improvement on upper extremity motor functions and daily living activities in chronic ischemic stroke patients, but improvement in spasticity was limited.

Introduction to spasticity and related mouse models

Although spasticity is one of the most common causes of motor disability worldwide, its precise definition and pathophysiology remain elusive, which to date renders its experimental targeting tricky. At least in part, this difficulty is caused by heterogeneous phenotypes of spasticity-causing neurological disorders, all causing spasticity by involving upper motor neurons. The most common clinical symptoms are a series of rapid muscle contractions (clonus), an increased muscle tone (hypertonia), and augmented tendon reflex activity (hyperreflexia). This muscle overactivity is due to disturbed inhibition of spinal reflexes following upper motor neuron dysfunction. Despite a range of physical and pharmacological therapies ameliorating the symptoms, their targeted application remains difficult. Therefore, to date, spasticity impacts rehabilitative therapy, and no therapy exists that reverses the pathology completely. In contrast to the incidence and importance of spasticity, only very little pre-clinical work in animal models exists, and this research is focused on the cat or the rat spastic tail model to decipher altered reflexes and excitability of the motor neurons in the spinal cord. Meanwhile, the characterization of spasticity in clinically more relevant mouse models of neurological disorders, such as stroke, remains understudied. Here, we provide a brief introduction into the clinical knowledge and therapy of spasticity and an in-depth review of pre-clinical studies of spasticity in mice including the current experimental challenges for clinical translation.

Nonsurgical Treatment Options for Upper Limb Spasticity

There are many nonsurgical treatment options for patients with upper limb spasticity. This article presents an algorithmic approach to management, encompassing evidence-based rehabilitation therapies, medications, and promising new orthotic and robotic innovations.

Motor and Perceptual Recovery in Adult Patients with Mild Intellectual Disability

Introduction

The relationship between intellectual disability (ID) and hand motor coordination and speed-accuracy, as well as the effect of aging on fine motor performance in patients with ID, has been previously investigated. However, only a few data are available on the impact of the nonpharmacological interventions in adult patients with long-term hand motor deficit.

Methods

Fifty adults with mild ID were enrolled. A group of thirty patients underwent a two-month intensive ergotherapic treatment that included hand motor rehabilitation and visual-perceptual treatment (group A); twenty patients performing conventional motor rehabilitation alone (group B) served as a control group. Data on attention, perceptual abilities, hand dexterity, and functional independence were collected by a blind operator, both at entry and at the end of the study.

Results

After the interventions, group A showed significantly better performance than group B in all measures related to hand movement from both sides and to independence in activities of daily living.

Discussion

Multimodal integrated interventions targeting visual-perceptual abilities and motor skills are an effective neurorehabilitative approach in adult patients with mild ID. Motor learning and memory-mediated mechanisms of neural plasticity might underlie the observed recovery, suggesting the presence of plastic adaptive changes even in the adult brain with ID.

Motor and Perceptual Recovery in Adult Patients with Mild Intellectual Disability

INTRODUCTION

The relationship between intellectual disability (ID) and hand motor coordination and speed-accuracy, as well as the effect of aging on fine motor performance in patients with ID, has been previously investigated. However, only a few data are available on the impact of the nonpharmacological interventions in adult patients with long-term hand motor deficit.

METHODS

Fifty adults with mild ID were enrolled. A group of thirty patients underwent a two-month intensive ergotherapic treatment that included hand motor rehabilitation and visual-perceptual treatment (group A); twenty patients performing conventional motor rehabilitation alone (group B) served as a control group. Data on attention, perceptual abilities, hand dexterity, and functional independence were collected by a blind operator, both at entry and at the end of the study.

RESULTS

After the interventions, group A showed significantly better performance than group B in all measures related to hand movement from both sides and to independence in activities of daily living.

DISCUSSION

Multimodal integrated interventions targeting visual-perceptual abilities and motor skills are an effective neurorehabilitative approach in adult patients with mild ID. Motor learning and memory-mediated mechanisms of neural plasticity might underlie the observed recovery, suggesting the presence of plastic adaptive changes even in the adult brain with ID.