Effects of paired stimulation with specific waveforms on cortical and spinal plasticity in subjects with a chronic spinal cord injury

nTMS in spinal cord injury: Current evidence, challenges and a future direction

Spinal Cord Injury (SCI) has devastating consequences for patients and their families. Over the last few decades, a renewed interest in the utilization of non-invasive and cost-effective therapeutic technologies in the management of patients with SCI has emerged. This includes stimulation with navigated transcranial magnetic stimulation (nTMS) in order to improve the outcome for these patients alongside with existing clinical tools. nTMS has shown encouraging preliminary results in both clinical assessment and rehabilitation (motor and pain) of patients with SCI. However, different protocols - stimulation parameters, length of treatment and combination with other modalities - and patient selection criteria hampered definitive conclusions. So far, none of these have been adapted in regular clinical practice. In this article, we provide an overview on different assessment and therapeutic strategies using nTMS and review their effectiveness.

Non-invasive central nervous system stimulation to improve bladder and pelvic floor function in the aging population

PURPOSE OF REVIEW

The literature was reviewed for all noninvasive central nervous system (CNS) stimulation techniques, which includes transcranial brain or trans-spinal stimulation, in the aging population. Given the rising ubiquity of this technology, noninvasive nature, and low side-effect profile reported, this technology can have a big impact on the aging population. As patients afflicted with neurogenic disorders are living longer lives, a special emphasis is placed on the aging neurogenic population.

RECENT FINDINGS

Noninvasive CNS stimulation techniques have been applied to major bladder and pelvic floor disorders such as voiding dysfunction, chronic pelvic pain, urgency and urge incontinence, lower urinary tract dysfunction, and situational urge incontinence in both the idiopathic and neurogenic populations. Overall, these noninvasive technologies demonstrate effectiveness for the treatment of these conditions with some studies showing effectiveness with longer-term follow-up suggesting lasting CNS remodeling.

SUMMARY

Most manuscripts had a generally small number of patients and an even smaller number of geriatric patients represented. No studies were specifically designed to investigate geriatric outcomes. It is the hope of this systematic review to help model future studies according to existing literature, but with a focus on the geriatric population as they stand to gain the most from noninvasive technologies with limited adverse events.

Extracorporeal Shock Wave Therapy (eSWT) in Spinal Cord Injury-A Narrative Review

BACKGROUND

Injury of the spinal cord causes motor and sensory dysfunction as well as pathological reflexes, leading to paraplegia or tetraplegia. The sequelae of traumatic spinal cord injury (SCI) are a significant burden and impact on healthcare systems. Despite constant progress in medicine, traumatic SCI still remains irreversible. To date, no satisfying treatment that can enable neuronal regeneration and recovery of function at the damaged level has been found. Hundreds of experiments have been conducted on various possibilities of influencing spinal regeneration; some of them have yielded promising results, but unfortunately, the successes obtained in experimental animals have not translated into humans.

METHODS

This narrative review article presents the application of extracorporeal shock wave therapy (eSWT) in patients with SCI. The article has been divided into parts: 1) use of extracorporeal shock wave therapy for regeneration of the spinal cord after traumatic spinal cord injury; 2) application of extracorporeal shock wave therapy in spasticity after spinal cord injury. In both cases, the hypotheses of possible mechanisms of action will be described.

RESULTS AND CONCLUSIONS

A small number of clinical trials have demonstrated the potential of eSWT to influence the regeneration of the spine, as an innovative, safe, and cost-effective treatment option for patients with SCI. Some reports have shown that eSWT can improve spasticity, walking ability, urological function, quality of life, and independence in daily life.

Modulations in neural pathways excitability post transcutaneous spinal cord stimulation among individuals with spinal cord injury: a systematic review

Introduction

Transcutaneous spinal cord stimulation (TSCS), a non-invasive form of spinal cord stimulation, has been shown to improve motor function in individuals living with spinal cord injury (SCI). However, the effects of different types of TSCS currents including direct current (DC-TSCS), alternating current (AC-TSCS), and spinal paired stimulation on the excitability of neural pathways have not been systematically investigated. The objective of this systematic review was to determine the effects of TSCS on the excitability of neural pathways in adults with non-progressive SCI at any level.

Methods

The following databases were searched from their inception until June 2022: MEDLINE ALL, Embase, Web of Science, Cochrane Library, and clinical trials. A total of 4,431 abstracts were screened, and 23 articles were included.

Results

Nineteen studies used TSCS at the thoracolumbar enlargement for lower limb rehabilitation (gait & balance) and four studies used cervical TSCS for upper limb rehabilitation. Sixteen studies measured spinal excitability by reporting different outcomes including Hoffmann reflex (H-reflex), flexion reflex excitability, spinal motor evoked potentials (SMEPs), cervicomedullay evoked potentials (CMEPs), and cutaneous-input-evoked muscle response. Seven studies measured corticospinal excitability using motor evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS), and one study measured somatosensory evoked potentials (SSEPs) following TSCS. Our findings indicated a decrease in the amplitude of H-reflex and long latency flexion reflex following AC-TSCS, alongside an increase in the amplitudes of SMEPs and CMEPs. Moreover, the application of the TSCS-TMS paired associative technique resulted in spinal reflex inhibition, manifested by reduced amplitudes in both the H-reflex and flexion reflex arc. In terms of corticospinal excitability, findings from 5 studies demonstrated an increase in the amplitude of MEPs linked to lower limb muscles following DC-TSCS, in addition to paired associative stimulation involving repetitive TMS on the brain and DC-TSCS on the spine. There was an observed improvement in the latency of SSEPs in a single study. Notably, the overall quality of evidence, assessed by the modified Downs and Black Quality assessment, was deemed poor.

Discussion

This review unveils the systematic evidence supporting the potential of TSCS in reshaping both spinal and supraspinal neuronal circuitries post-SCI. Yet, it underscores the critical necessity for more rigorous, high-quality investigations.

Modulatory effect of trans-spinal magnetic intermittent theta burst stimulation on diaphragmatic activity following cervical spinal cord contusion in the rat

BACKGROUND CONTEXT

Magnetic stimulation can noninvasively modulate the neuronal excitability through different stimulatory patterns.

PURPOSE

The present study hypothesized that trans-spinal magnetic stimulation with intermittent theta burst stimulatory pattern can modulate respiratory motor outputs in a pre-clinical rat model of cervical spinal cord injury.

STUDY DESIGN

In vivo animal study.

METHODS

The effect of trans-spinal magnetic intermittent theta burst stimulation on diaphragmatic activity was assessed in adult rats with unilateral cervical spinal cord contusion at 2 weeks postinjury.

RESULTS

The results demonstrated that unilateral cervical spinal cord contusion significantly attenuated the inspiratory activity and motor evoked potential of the diaphragm. Trans-spinal magnetic intermittent theta burst stimulation significantly increased the inspiratory activity of the diaphragm in cervical spinal cord contused rats. Inspiratory bursting was also recruited by trans-spinal magnetic intermittent theta burst stimulation in the rats without diaphragmatic activity after cervical spinal cord injury. In addition, trans-spinal magnetic intermittent theta burst stimulation is associated with increases in oxygen consumption and carbon dioxide production.

CONCLUSIONS

These results suggest that trans-spinal magnetic intermittent theta burst stimulation can induce respiratory neuroplasticity.

CLINICAL SIGNIFICANCE

We propose that trans-spinal theta burst magnetic stimulation may be considered a potential rehabilitative strategy for improving the respiratory activity after cervical spinal cord injury. This will require future clinical study.

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.

Motor Neuroplastic Effects of a Novel Paired Stimulation Technology in an Incomplete Spinal Cord Injury Animal Model

Paired stimulation of the brain and spinal cord can remodel the central nervous tissue circuitry in an animal model to induce motor neuroplasticity. The effects of simultaneous stimulation vary according to the extent and severity of spinal cord injury. Therefore, our study aimed to determine the significant effects on an incomplete SCI rat brain and spinal cord through 3 min and 20 min stimulations after 4 weeks of intervention. Thirty-three Sprague Dawley rats were classified into six groups: (1) normal, (2) sham, (3) iTBS/tsDCS, (4) iTBS/ts-iTBS, (5) rTMS/tsDCS, and (6) rTMS/ts-iTBS. Paired stimulation of the brain cortex and spinal cord thoracic (T10) level was applied simultaneously for 3−20 min. The motor evoked potential (MEP) and Basso, Beattie, and Bresnahan (BBB) scores were recorded after every week of intervention for four weeks along with wheel training for 20 min. Three-minute stimulation with the iTBS/tsDCS intervention induced a significant (p < 0.050 *) increase in MEP after week 2 and week 4 treatments, while 3 min iTBS/ts-iTBS significantly improved MEP (p < 0.050 *) only after the week 3 intervention. The 20 min rTMS/ts-iTBS intervention showed a significant change only in post_5 min after week 4. The BBB score also changed significantly in all groups except for the 20 min rTMS/tsDCS intervention. iTBS/tsDCS and rTMS/ts-iTBS interventions induce neuroplasticity in an incomplete SCI animal model by significantly changing electrophysiological (MEP) and locomotion (BBB) outcomes.

Novel Strategies for Spinal Cord Regeneration

A spinal cord injury (SCI) is one of the most devastating lesions, as it can damage the continuity and conductivity of the central nervous system, resulting in complex pathophysiology. Encouraged by the advances in nanotechnology, stem cell biology, and materials science, researchers have proposed various interdisciplinary approaches for spinal cord regeneration. In this respect, the present review aims to explore the most recent developments in SCI treatment and spinal cord repair. Specifically, it briefly describes the characteristics of SCIs, followed by an extensive discussion on newly developed nanocarriers (e.g., metal-based, polymer-based, liposomes) for spinal cord delivery, relevant biomolecules (e.g., growth factors, exosomes) for SCI treatment, innovative cell therapies, and novel natural and synthetic biomaterial scaffolds for spinal cord regeneration.