Voluntary Modulation of Evoked Responses Generated by Epidural and Transcutaneous Spinal Stimulation in Humans with Spinal Cord Injury

Calvert, JS; Gill, ML; Linde, MB; Veith, DD; Thoreson, AR; Lopez, C; Lee, KH; Gerasimenko, YP; Edgerton, VR; Lavrov, IA; Zhao, KD; Grahn, PJ; Sayenko, DG

Voluntary Modulation of Evoked Responses Generated by Epidural and Transcutaneous Spinal Stimulation in Humans with Spinal Cord Injury

Calvert, JS Gill, ML Linde, MB Veith, DD Thoreson, AR Lopez, C Lee, KH Gerasimenko, YP Edgerton, VR Lavrov, IA Zhao, KD Grahn, PJ Sayenko, DG

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Publisher:: MDPI AG
Publication Type:: Journal Article
Citation:: Journal of Clinical Medicine, 2021, 10, (21), pp. 4898
Issue Date:: 2021-10-24

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Field	Value	Language
dc.contributor.author	Calvert, JS
dc.contributor.author	Gill, ML
dc.contributor.author	Linde, MB
dc.contributor.author	Veith, DD
dc.contributor.author	Thoreson, AR
dc.contributor.author	Lopez, C
dc.contributor.author	Lee, KH
dc.contributor.author	Gerasimenko, YP
dc.contributor.author	Edgerton, VR
dc.contributor.author	Lavrov, IA
dc.contributor.author	Zhao, KD
dc.contributor.author	Grahn, PJ
dc.contributor.author	Sayenko, DG
dc.date.accessioned	2022-02-03T04:49:30Z
dc.date.available	2022-02-03T04:49:30Z
dc.date.issued	2021-10-24
dc.identifier.citation	Journal of Clinical Medicine, 2021, 10, (21), pp. 4898
dc.identifier.issn	2077-0383
dc.identifier.issn	2077-0383
dc.identifier.uri	http://hdl.handle.net/10453/154169
dc.description.abstract	<jats:p>Transcutaneous (TSS) and epidural spinal stimulation (ESS) are electrophysiological techniques that have been used to investigate the interactions between exogenous electrical stimuli and spinal sensorimotor networks that integrate descending motor signals with afferent inputs from the periphery during motor tasks such as standing and stepping. Recently, pilot-phase clinical trials using ESS and TSS have demonstrated restoration of motor functions that were previously lost due to spinal cord injury (SCI). However, the spinal network interactions that occur in response to TSS or ESS pulses with spared descending connections across the site of SCI have yet to be characterized. Therefore, we examined the effects of delivering TSS or ESS pulses to the lumbosacral spinal cord in nine individuals with chronic SCI. During low-frequency stimulation, participants were instructed to relax or attempt maximum voluntary contraction to perform full leg flexion while supine. We observed similar lower-extremity neuromusculature activation during TSS and ESS when performed in the same participants while instructed to relax. Interestingly, when participants were instructed to attempt lower-extremity muscle contractions, both TSS- and ESS-evoked motor responses were significantly inhibited across all muscles. Participants with clinically complete SCI tested with ESS and participants with clinically incomplete SCI tested with TSS demonstrated greater ability to modulate evoked responses than participants with motor complete SCI tested with TSS, although this was not statistically significant due to a low number of subjects in each subgroup. These results suggest that descending commands combined with spinal stimulation may increase activity of inhibitory interneuronal circuitry within spinal sensorimotor networks in individuals with SCI, which may be relevant in the context of regaining functional motor outcomes.</jats:p>
dc.language	en
dc.publisher	MDPI AG
dc.relation.ispartof	Journal of Clinical Medicine
dc.relation.isbasedon	10.3390/jcm10214898
dc.rights	info:eu-repo/semantics/openAccess
dc.subject	1103 Clinical Sciences
dc.title	Voluntary Modulation of Evoked Responses Generated by Epidural and Transcutaneous Spinal Stimulation in Humans with Spinal Cord Injury
dc.type	Journal Article
utslib.citation.volume	10
utslib.for	1103 Clinical Sciences
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	open_access	*
dc.date.updated	2022-02-03T04:49:28Z
pubs.issue	21
pubs.publication-status	Published online
pubs.volume	10
utslib.citation.issue	21

Abstract:

Transcutaneous (TSS) and epidural spinal stimulation (ESS) are electrophysiological techniques that have been used to investigate the interactions between exogenous electrical stimuli and spinal sensorimotor networks that integrate descending motor signals with afferent inputs from the periphery during motor tasks such as standing and stepping. Recently, pilot-phase clinical trials using ESS and TSS have demonstrated restoration of motor functions that were previously lost due to spinal cord injury (SCI). However, the spinal network interactions that occur in response to TSS or ESS pulses with spared descending connections across the site of SCI have yet to be characterized. Therefore, we examined the effects of delivering TSS or ESS pulses to the lumbosacral spinal cord in nine individuals with chronic SCI. During low-frequency stimulation, participants were instructed to relax or attempt maximum voluntary contraction to perform full leg flexion while supine. We observed similar lower-extremity neuromusculature activation during TSS and ESS when performed in the same participants while instructed to relax. Interestingly, when participants were instructed to attempt lower-extremity muscle contractions, both TSS- and ESS-evoked motor responses were significantly inhibited across all muscles. Participants with clinically complete SCI tested with ESS and participants with clinically incomplete SCI tested with TSS demonstrated greater ability to modulate evoked responses than participants with motor complete SCI tested with TSS, although this was not statistically significant due to a low number of subjects in each subgroup. These results suggest that descending commands combined with spinal stimulation may increase activity of inhibitory interneuronal circuitry within spinal sensorimotor networks in individuals with SCI, which may be relevant in the context of regaining functional motor outcomes.

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