Upper-limb muscle responses to epidural, subdural and intraspinal stimulation of the cervical spinal cord

Sharpe, Abigail; Jackson, Andrew

doi:10.1088/1741-2560/11/1/016005

Cited by 62 publications

(64 citation statements)

References 33 publications

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“…Currently, data on the effects of epidural stimulation to neuromodulate the cervical cord chronically are non-existent. Previous work in the rats has shown that instraspinal stimulation of the cervical segments of the spinal cord in rats elicits motor responses in multiple forelimb muscles (Sunshine et al, 2013) and selected stimulation parameters can facilitate functional reaching and grasping movements in monkeys (Zimmermann et al, 2011; Sharpe and Jackson, 2014). Chronic intraspinal stimulation of the spinal cord has been reported to improve forelimb function in SCI rats (Kasten et al, 2013; Mondello et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of optimal electrode configurations for epidural spinal cord stimulation in cervical spinal cord injured rats

Alam

García-Alías

Shah

et al. 2015

Journal of Neuroscience Methods

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Background Epidural spinal cord stimulation is a promising technique for modulating the level of excitability and reactivation of dormant spinal neuronal circuits after spinal cord injury (SCI). We examined the ability of chronically implanted epidural stimulation electrodes within the cervical spinal cord to (1) directly elicit spinal motor evoked potentials (sMEPs) in forelimb muscles and (2) determine whether these sMEPs can serve as a biomarker of forelimb motor function after SCI. New method We implanted EMG electrodes in forelimb muscles and epidural stimulation electrodes at C6 and C8 in adult rats. After recovering from a dorsal funiculi crush (C4), rats were tested with different stimulation configurations and current intensities to elicit sMEPs and determined forelimb grip strength. Results: sMEPs were evoked in all muscles tested and their characteristics were dependent on electrode configurations and current intensities. C6(−) stimulation elicited more robust sMEPs than stimulation at C8(−). Stimulating C6 and C8 simultaneously produced better muscle recruitment and higher grip strengths than stimulation at one site. Comparison with existing method(s) Classical method to select the most optimal stimulation configuration is to empirically test each combination individually for every subject and relate to functional improvements. This approach is impractical, requiring extensively long experimental time to determine the more effective stimulation parameters. Our proposed method is fast and physiologically sound. Conclusions Results suggest that sMEPs from forelimb muscles can be useful biomarkers for identifying optimal parameters for epidural stimulation of the cervical spinal cord after SCI.

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Section: Introductionmentioning

confidence: 99%

Evaluation of optimal electrode configurations for epidural spinal cord stimulation in cervical spinal cord injured rats

Alam

García-Alías

Shah

et al. 2015

Journal of Neuroscience Methods

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show abstract

“…Epidural stimulation is thus an efficient tool to replace the missing source of excitation after the interruption of descending pathways in SCI and could lead to improved coordination and functional recovery in paralyzed patients. Other methods, such as intraspinal and subdural stimulations, are also commonly used for stimulating the spinal cord ( Sharpe and Jackson, 2014 ). Intraspinal stimulation preferentially recruits small motor units and produces prolonged weight-bearing standing and stepping in animal After SCI, the normal sensorimotor loop is disrupted.…”

Section: Neuroprostheses For Spinal Cord Stimulation and Rehabilitationmentioning

confidence: 99%

Spinal cord injury: overview of experimental approaches used to restore locomotor activity

Fakhoury

2015

Reviews in the Neurosciences

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AbstractSpinal cord injury affects more than 2.5 million people worldwide and can lead to paraplegia and quadriplegia. Anatomical discontinuity in the spinal cord results in disruption of the impulse conduction that causes temporary or permanent changes in the cord’s normal functions. Although axonal regeneration is limited, damage to the spinal cord is often accompanied by spontaneous plasticity and axon regeneration that help improve sensory and motor skills. The recovery process depends mainly on synaptic plasticity in the preexisting circuits and on the formation of new pathways through collateral sprouting into neighboring denervated territories. However, spontaneous recovery after spinal cord injury can go on for several years, and the degree of recovery is very limited. Therefore, the development of new approaches that could accelerate the gain of motor function is of high priority to patients with damaged spinal cord. Although there are no fully restorative treatments for spinal injury, various rehabilitative approaches have been tested in animal models and have reached clinical trials. In this paper, a closer look will be given at the potential therapies that could facilitate axonal regeneration and improve locomotor recovery after injury to the spinal cord. This article highlights the application of several interventions including locomotor training, molecular and cellular treatments, and spinal cord stimulation in the field of rehabilitation research. Studies investigating therapeutic approaches in both animal models and individuals with injured spinal cords will be presented.

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“…Previous work has shown that intraspinal stimulation at the cervical segments of the spinal cord elicits motor responses in multiple forelimb muscles in rats (Sunshine et al, 2013) and that selected stimulation parameters can facilitate functional reaching and grasping movements in non-injured monkeys (Zimmermann et al, 2011; Sharpe and Jackson, 2014). It also has been shown that chronic intraspinal stimulation at the cervical spinal cord can improve forelimb function in rats with a cervical SCI (Kasten et al, 2013; Mondello et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Electrical neuromodulation of the cervical spinal cord facilitates forelimb skilled function recovery in spinal cord injured rats

Alam

García-Alías

Jin

et al. 2017

Experimental Neurology

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Enabling motor control by epidural electrical stimulation of the spinal cord is a promising therapeutic technique for the recovery of motor function after a spinal cord injury (SCI). Although epidural electrical stimulation has resulted in improvement in hindlimb motor function, it is unknown whether it has any therapeutic benefit for improving forelimb fine motor function after a cervical SCI. We tested whether trains of pulses delivered at spinal cord segments C6 and C8 would facilitate the recovery of forelimb fine motor control after a cervical SCI in rats. Rats were trained to reach and grasp sugar pellets. Immediately after a dorsal funiculus crush at C4, the rats showed significant deficits in forelimb fine motor control. The rats were tested to reach and grasp with and without cervical epidural stimulation for 10 weeks post-injury. To determine the best stimulation parameters to activate the cervical spinal networks involved in forelimb motor function, monopolar and bipolar currents were delivered at varying frequencies (20, 40, and 60 Hz) concomitant with the reaching and grasping task. We found that cervical epidural stimulation increased reaching and grasping success rates compared to the no stimulation condition. Bipolar stimulation (C6− C8+ and C6+ C8−) produced the largest spinal motor-evoked potentials (sMEPs) and resulted in higher reaching and grasping success rates compared with monopolar stimulation (C6− Ref+ and C8− Ref+). Forelimb performance was similar when tested at stimulation frequencies of 20, 40, and 60 Hz. We also found that the EMG activity in most forelimb muscles as well as the co-activation between flexor and extensor muscles increased post-injury. With epidural stimulation, however, this trend was reversed indicating that cervical epidural spinal cord stimulation has therapeutic potential for rehabilitation after a cervical SCI.

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Upper-limb muscle responses to epidural, subdural and intraspinal stimulation of the cervical spinal cord

Cited by 62 publications

References 33 publications

Evaluation of optimal electrode configurations for epidural spinal cord stimulation in cervical spinal cord injured rats

Evaluation of optimal electrode configurations for epidural spinal cord stimulation in cervical spinal cord injured rats

Spinal cord injury: overview of experimental approaches used to restore locomotor activity

Electrical neuromodulation of the cervical spinal cord facilitates forelimb skilled function recovery in spinal cord injured rats

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