Stimulating the cervical spinal cord - combining clinical, classical and basic motor perspectives on epidural stimulation.
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ABSTRACT:
SUBMITTER: Giszter SF
PROVIDER: S-EPMC9106106 | biostudies-literature | 2021 Jul
REPOSITORIES: biostudies-literature
Publications
Stimulating the cervical spinal cord - combining clinical, classical and basic motor perspectives on epidural stimulation.
The Journal of physiology 20210616 14
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Project description:Cervical spinal cord injury (SCI) leads to impaired trunk motor control, negatively impacting the performance of activities of daily living in the affected individuals. Improved trunk control with better sitting posture has been previously observed due to neuromuscular electrical stimulation and transcutaneous spinal stimulation, while improved postural stability has been observed with spinal cord epidural stimulation (scES). Hence, we studied how trunk-specific scES impacts sitting independence and posture. Fourteen individuals with chronic, severe cervical SCI with an implanted neurostimulator performed a 5-min tall-sit task without and with trunk-specific scES. Spine posture was assessed by placing markers on five spine levels and evaluating vertical spine inclination angles. Duration of trunk manual assistance was used to assess independence along with the number of independence changes and average independence score across those changes. With scES, the sacrum-L1 inclination and number of independence changes tended to decrease by 1.64 ± 3.16° (p = 0.07; Cohen's d = 0.53) and 9.86 ± 16.8 (p = 0.047; Cohen's d = 0.59), respectively. Additionally, for the participants who had poor sitting independence without scES, level of independence tended to increase by 12.91% [0%, 31.52%] (p = 0.38; Cohen's d = 0.96) when scES was present. Hence, trunk-specific scES promoted improvements in lower spine posture and lower levels of trunk assistance.
| S-EPMC10525621 | biostudies-literature
Project description:Background/Objectives: Preliminary observations support the view that spinal cord epidural stimulation (scES) combined with trunk-specific training can improve trunk stability during functional activities in individuals with thoracic spinal cord injury (SCI). We studied the acute effects of trunk-specific stimulation on sitting postural control. Methods: Twenty-three individuals with severe cervical SCI were implanted with an epidural stimulator. Postural control was assessed before any activity-based training, without and with trunk-specific scES. In particular, participants performed sitting with upright posture, forward/back lean, and lateral lean activities while sitting on a standard therapy mat. Full-body kinematics and trunk electromyography (EMG) were acquired. Anterior-posterior and lateral trunk displacement along with trunk velocity in all four directions were obtained and used to classify postural control responses. Results: Compared to no stimulation, application of trunk-specific scES led to trunk anterior-posterior displacement increases during forward/back lean (2.79 ± 0.97 cm; p-value = 0.01), and trunk lateral displacement increases during lateral lean (2.19 ± 0.79 cm; p-value = 0.01). After digital filtering of stimulation artifacts, EMG root mean square amplitudes for bilateral external oblique, rectus abdominus, and erector spinae muscles were higher with stimulation for all activities (all p-values < 0.03). Conclusions: The results indicate improvements in trunk lean distances and muscle activation when leaning activities are performed with trunk-specific epidural stimulation.
| S-EPMC11853460 | biostudies-literature
Project description:ObjectivesTo identify and synthesize the existing evidence on the effectiveness and safety of epidural spinal cord stimulation (SCS) for improving motor and voiding function and reducing spasticity following spinal cord injury (SCI).MethodsThis scoping review was performed according to the framework of Arksey and O'Malley. Comprehensive serial searches in multiple databases (MEDLINE, Embase, Cochrane Central, Cochrane Database of Systematic Reviews, LILACS, PubMed, Web of Science, and Scopus) were performed to identify relevant publications that focused on epidural SCS for improving motor function, including spasticity, and voiding deficits in individuals with SCI.ResultsData from 13 case series including 88 individuals with complete or incomplete SCI (American Spinal Injury Association Impairment Scale [AIS] grade A to D) were included. In 12 studies of individuals with SCI, the majority (83 out of 88) demonstrated a variable degree of improvement in volitional motor function with epidural SCS. Two studies, incorporating 27 participants, demonstrated a significant reduction in spasticity with SCS. Two small studies consisting of five and two participants, respectively, demonstrated improved supraspinal control of volitional micturition with SCS.ConclusionEpidural SCS can enhance central pattern generator activity and lower motor neuron excitability in individuals with SCI. The observed effects of epidural SCS following SCI suggest that the preservation of supraspinal transmission is sufficient for the recovery of volitional motor and voiding function, even in patients with complete SCI. Further research is warranted to evaluate and optimize the parameters for epidural SCS and their impact on individuals with differing degrees of severity of SCI.
| S-EPMC10208259 | biostudies-literature
Project description:The number of elderly patients with spinal cord injury without radiographic abnormalities (SCIWORA) has been increasing in recent years and common of most cervical spinal cord injuries. Basic research has shown the effectiveness of early decompression after spinal cord injury on the spinal cord without stenosis; no studies have reported the efficacy of decompression in models with spinal cord compressive lesions. The purpose of this study was to evaluate the effects of decompression surgery after acute spinal cord injury in rats with chronic spinal cord compressive lesions, mimicking SCIWORA. A water-absorbent polymer sheet (Aquaprene DX, Sanyo Chemical Industries) was inserted dorsally into the 4-5th cervical sublaminar space in 8-week-old Sprague Dawley rats to create a rat model with a chronic spinal compressive lesion. At the age of 16 weeks, 30 mildly myelopathic or asymptomatic rats with a Basso, Beattie, and Bresnahan score (BBB score) of 19 or higher were subjected to spinal cord compression injuries. The rats were divided into three groups: an immediate decompression group (decompress immediately after injury), a sub-acute decompression group (decompress 1 week after injury), and a non-decompression group. Behavioral and histological evaluations were performed 4 weeks after the injury. At 20 weeks of age, the BBB score and FLS (Forelimb Locomotor Scale) of both the immediate and the sub-acute decompression groups were significantly higher than those of the non-decompression group. There was no significant difference between the immediate decompression group and the sub-acute decompression group. TUNEL (transferase-mediated dUTP nick end labeling) staining showed significantly fewer positive cells in both decompression groups compared to the non-decompression group. LFB (Luxol fast blue) staining showed significantly more demyelination, and GAP-43 (growth associated protein-43) staining tended to show fewer positive cells in the non-decompression group. Decompression surgery in the acute or sub-acute phase of injury is effective after mild spinal cord injury in rats with chronic compressive lesions. There was no significant difference between the immediate decompression and sub-acute decompression groups.
| S-EPMC9402533 | biostudies-literature
Project description: Not available
| S-EPMC6583212 | biostudies-literature
Project description:Previous studies have shown that epidural stimulation of the lumbosacral spinal cord (scES) can re-enable lower limb volitional motor control in individuals with chronic, clinically motor complete spinal cord injury (SCI). This observation entails that residual supraspinal connectivity to the lumbosacral spinal circuitry still persisted after SCI, although it was non-detectable when scES was not provided. In the present study, we aimed at exploring further the mechanisms underlying scES-promoted recovery of volitional lower limb motor control by investigating neuroimaging markers at the spinal cord lesion site via magnetic resonance imaging (MRI). Spinal cord MRI was collected prior to epidural stimulator implantation in 13 individuals with chronic, clinically motor complete SCI, and the spared tissue of specific regions of the spinal cord (anterior, posterior, right, left, and total cord) was assessed. After epidural stimulator implantation, and prior to any training, volitional motor control was evaluated during left and right lower limb flexion and ankle dorsiflexion attempts. The ability to generate force exertion and movement was not correlated to any neuroimaging marker. On the other hand, spared tissue of specific cord regions significantly and importantly correlated with some aspects of motor control that include activation amplitude of antagonist (negative correlation) muscles during left ankle dorsiflexion, and electromyographic coordination patterns during right lower limb flexion. The fact that amount and location of spared spinal cord tissue at the lesion site were not related to the ability to generate volitional lower limb movements may suggest that supraspinal inputs through spared spinal cord regions that differ across individuals can result in the generation of lower limb volitional motor output prior to any training when epidural stimulation is provided.
| S-EPMC7654217 | biostudies-literature
Project description:Cervical spinal cord injury (cSCI) severs bulbospinal projections to respiratory motor neurons, paralyzing respiratory muscles below the injury. C2 spinal hemisection (C2Hx) is a model of cSCI often used to study spontaneous and induced plasticity and breathing recovery post-injury. One key assumption is that C2Hx dennervates motor neurons below the injury, but does not affect their survival. However, a recent study reported substantial bilateral motor neuron death caudal to C2Hx. Since phrenic motor neuron (PMN) death following C2Hx would have profound implications for therapeutic strategies designed to target spared neural circuits, we tested the hypothesis that C2Hx minimally impacts PMN survival. Using improved retrograde tracing methods, we observed no loss of PMNs at 2- or 8-weeks post-C2Hx. We also observed no injury-related differences in ChAT or NeuN immunolabeling within labelled PMNs. Although we found no evidence of PMN loss following C2Hx, we cannot rule out neuronal loss in other motor pools. These findings address an essential prerequisite for studies that utilize C2Hx as a model to explore strategies for inducing plasticity and/or regeneration within the phrenic motor system, as they provide important insights into the viability of phrenic motor neurons as therapeutic targets after high cervical injury.
| S-EPMC9065093 | biostudies-literature
Project description:Cerebral strokes can disrupt descending commands from motor cortical areas to the spinal cord, which can result in permanent motor deficits of the arm and hand. However, below the lesion, the spinal circuits that control movement remain intact and could be targeted by neurotechnologies to restore movement. Here we report results from two participants in a first-in-human study using electrical stimulation of cervical spinal circuits to facilitate arm and hand motor control in chronic post-stroke hemiparesis ( NCT04512690 ). Participants were implanted for 29 d with two linear leads in the dorsolateral epidural space targeting spinal roots C3 to T1 to increase excitation of arm and hand motoneurons. We found that continuous stimulation through selected contacts improved strength (for example, grip force +40% SCS01; +108% SCS02), kinematics (for example, +30% to +40% speed) and functional movements, thereby enabling participants to perform movements that they could not perform without spinal cord stimulation. Both participants retained some of these improvements even without stimulation and no serious adverse events were reported. While we cannot conclusively evaluate safety and efficacy from two participants, our data provide promising, albeit preliminary, evidence that spinal cord stimulation could be an assistive as well as a restorative approach for upper-limb recovery after stroke.
| S-EPMC10291889 | biostudies-literature
Project description:Epidural spinal cord stimulation has a long history of application for improving motor control in spinal cord injury. This review focuses on its resurgence following the progress made in understanding the underlying neurophysiological mechanisms and on recent reports of its augmentative effects upon otherwise subfunctional volitional motor control. Early work revealed that the spinal circuitry involved in lower-limb motor control can be accessed by stimulating through electrodes placed epidurally over the posterior aspect of the lumbar spinal cord below a paralyzing injury. Current understanding is that such stimulation activates large-to-medium-diameter sensory fibers within the posterior roots. Those fibers then trans-synaptically activate various spinal reflex circuits and plurisegmentally organized interneuronal networks that control more complex contraction and relaxation patterns involving multiple muscles. The induced change in responsiveness of this spinal motor circuitry to any residual supraspinal input via clinically silent translesional neural connections that have survived the injury may be a likely explanation for rudimentary volitional control enabled by epidural stimulation in otherwise paralyzed muscles. Technological developments that allow dynamic control of stimulation parameters and the potential for activity-dependent beneficial plasticity may further unveil the remarkable capacity of spinal motor processing that remains even after severe spinal cord injuries.
| S-EPMC4824029 | biostudies-literature
Project description:Background. Epidural stimulation of the spinal cord can reorganize and change the excitability of the neural circuitry to facilitate stepping in rats with a complete spinal cord injury. Parkinson's disease results in abnormal supraspinal signals from the brain to the spinal cord that affect the functional capacity of the spinal networks. Objective. The objective was to determine whether epidural stimulation (electrical enabling motor control, eEmc) of the lumbosacral spinal cord can reorganize the spinal networks to facilitate hindlimb stepping of rats with parkinsonism. Methods. A unilateral 6-OHDA (6-hydroxydopamine) lesion of the nigrostriatal pathway was used to induce parkinsonism. Sham rats (N = 4) were injected in the same region with 0.1% of ascorbic acid. Stimulation electrodes were implanted epidurally at the L2 and S1 (N = 5) or L2 (N = 5) spinal levels. Results. The 6-OHDA rats showed severe parkinsonism in cylinder and adjusting step tests and were unable to initiate stepping when placed in a running wheel and dragged their toes on the affected side during treadmill stepping. During eEmc, the 6-OHDA rats initiated stepping in the running wheel and demonstrated improved stepping quality. Conclusion. Stepping was facilitated in rats with parkinsonism with spinal cord stimulation. The underlying assumption is that the normal functional capacity of spinal networks is affected by supraspinal pathology associated with Parkinson's disease, which either generates insufficient or abnormal descending input to spinal networks and that eEmc can appropriately modulate spinal and supraspinal networks to improve the motor deficits.
| S-EPMC6920580 | biostudies-literature