Posteroanterior cervical transcutaneous spinal stimulation targets ventral and dorsal nerve roots

Wu, Yu‐Kuang; Levine, Jonah M.; Wecht, Jaclyn R.; Maher, Matthew; LiMonta, James M.; Saeed, Sana; Santiago, Tiffany M.; Bailey, Eric; Kastuar, Shivani; Guber, Kenneth S.; Yung, Lok; Weir, Joseph P.; Carmel, Jason B.; Harel, Noam Y.

doi:10.1016/j.clinph.2019.11.056

Cited by 37 publications

(99 citation statements)

References 45 publications

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“…In our current study, the cathode electrode was placed on the spine between the C7 and T1 cervical spinal processes on the posterior side of the neck, and the anode electrode was placed along the midline of the anterior side of the neck (Figure 1) [21,23,27]. Previous studies investigating the neuromodulatory effects of cervical tSCS placed anode electrodes bilaterally over the iliac crests [15,16,19].…”

Section: Electrode Configuration Considerations For Cervical Tscsmentioning

confidence: 97%

Section: Transcutaneous Spinal Cord Stimulation (Tscs)mentioning

confidence: 99%

“…Single-(or double-) pulse tSCS can be used to consistently elicit spinal reflexes through the activation of monosynaptic connection between Ia sensory fibers and motoneurons at multiple spinal levels innervating upper-limb muscles [21,23,27]. To evaluate excitability of the spinal reflex circuits in multiple upper-limb muscles simultaneously, a constant current electrical stimulator (DS7A, Digitimer Ltd., Welwyn Garden City, UK) was used to apply a single monophasic square pulse with a 2-ms pulse width [23,27]. As during the conditioning intervention, the cathode electrode (50 × 50 mm) was placed on the spine between C6 and T1 cervical spine processes on the posterior side of the neck (Figure 1), and the anode electrode (75 × 100 mm) was placed along the midline of the anterior side of the neck [23].…”

Section: Transcutaneous Spinal Cord Stimulation (Tscs)mentioning

confidence: 99%

“…However, the effect of a single, short intervention (<10 min) and understanding of how neural activity is modulated by the intervention remain unclear. Shortening the intervention duration and using lowintensity stimulation may improve therapy adherence for patients in an effort to minimize discomforts in actual clinical therapy since it was reported that high-intensity cervical tSCS could induce discomfort [27].…”

Section: Introductionmentioning

confidence: 99%

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Low-Intensity and Short-Duration Continuous Cervical Transcutaneous Spinal Cord Stimulation Intervention Does Not Prime the Corticospinal and Spinal Reflex Pathways in Able-Bodied Subjects

Sasaki

Freitas

Sayenko

et al. 2021

JCM

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Cervical transcutaneous spinal cord stimulation (tSCS) has been utilized in applications for improving upper-limb sensory and motor function in patients with spinal cord injury. Although therapeutic effects of continuous cervical tSCS interventions have been reported, neurophysiological mechanisms remain largely unexplored. Specifically, it is not clear whether sub-threshold intensity and 10-min duration continuous cervical tSCS intervention can affect the central nervous system excitability. Therefore, the purpose of this study was to investigate effects of sub-motor-threshold 10-min continuous cervical tSCS applied at rest on the corticospinal and spinal reflex circuit in ten able-bodied individuals. Neurophysiological assessments were conducted to investigate (1) corticospinal excitability via transcranial magnetic stimulation applied on the primary motor cortex to evoke motor-evoked potentials (MEPs) and (2) spinal reflex excitability via single-pulse tSCS applied at the cervical level to evoke posterior root muscle (PRM) reflexes. Measurements were recorded from multiple upper-limb muscles before, during, and after the intervention. Our results showed that low-intensity and short-duration continuous cervical tSCS intervention applied at rest did not significantly affect corticospinal and spinal reflex excitability. The stimulation duration and/or intensity, as well as other stimulating parameters selection, may therefore be critical for inducing neuromodulatory effects during cervical tSCS.

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Section: Electrode Configuration Considerations For Cervical Tscsmentioning

confidence: 97%

Section: Transcutaneous Spinal Cord Stimulation (Tscs)mentioning

confidence: 99%

Section: Transcutaneous Spinal Cord Stimulation (Tscs)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Low-Intensity and Short-Duration Continuous Cervical Transcutaneous Spinal Cord Stimulation Intervention Does Not Prime the Corticospinal and Spinal Reflex Pathways in Able-Bodied Subjects

Sasaki

Freitas

Sayenko

et al. 2021

JCM

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“…This experiment was an exploratory post-hoc analysis of a larger study in which we tested a novel configuration for non-invasive cervical transcutaneous spinal stimulation in individuals with and without cervical SCI (clinicaltrials.gov NCT02469675) 19 . SCI participants were eligible if they had traumatic or non-traumatic SCI between segments C2-C8 with any evidence for partially retained movement of finger extension, finger flexion, or finger abduction of either hand.…”

Section: Methodsmentioning

confidence: 99%

Duration and reliability of the silent period in individuals with spinal cord injury

Sfreddo

Wecht

Alsalman

et al. 2020

Preprint

Self Cite

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Objective: We aim to better understand the silent period (SP), an inhibitory counterpart to the well-known motor evoked potential (MEP) elicited by transcranial magnetic stimulation (TMS), in individuals with spinal cord injury (SCI). Methods: Electromyographic responses were measured in the target abductor pollicis brevis at rest (TMS at 120% of resting motor threshold (RMT)) and during maximal effort (TMS at 110% of RMT). Participants with chronic cervical SCI (n=9) and able-bodied volunteers (n=12) underwent between 3-7 sessions of stimulation on separate days. The primary outcomes were the magnitude and reliability of SP duration, resting and active MEP amplitudes, and RMT. Results: SCI participants showed significantly increased RMT, decreased MEP amplitudes, and non-significantly longer SP duration compared to AB participants. In contrast to high inter-participant variability, SP duration demonstrated reduced intra-participant variability within and across sessions compared with resting and active MEP amplitudes. SCI participants also demonstrated a higher prevalence of SP "interruptions" compared to AB participants. Conclusions: SP reflects a balance between corticospinal excitatory and inhibitory processes. SP duration is more reliable within and across multiple sessions than MEP amplitude. Significance: The higher reliability of SP duration may make it a useful outcome measure for future trials of SCI interventions.

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Distinguishing reflex from non-reflex responses elicited by transcutaneous spinal stimulation targeting the lumbosacral cord in healthy individuals

Gordineer,

Stokic,

Krenn

2024

Exp Brain Res

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Transcutaneous spinal stimulation (TSS) studies rely on the depolarization of afferent fibers to provide input to the spinal cord; however, this has not been routinely ascertained. Thus, we aimed to characterize the types of responses evoked by TSS and establish paired-pulse ratio cutoffs that distinguish posterior root reflexes, evoked by stimulation of afferent nerve fibers, from motor responses, evoked by stimulation of efferent nerve fibers. Twelve neurologically intact participants (six women) underwent unipolar TSS (cathode over T11-12 spinal processes, anode paraumbilically) while resting supine. In six participants, unipolar TSS was repeated 2–3 months later and also compared to a bipolar TSS configuration (cathode 2.5 cm below T11-12, anode 5 cm above cathode). EMG signals were recorded from 16 leg muscles. A paired-pulse paradigm was applied at interstimulus intervals (ISIs) of 25, 50, 100, 200, and 400 ms. Responses were categorized by three assessors into reflexes, motor responses, or their combination (mixed responses) based on the visual presence/absence of paired-pulse suppression across ISIs. The paired-pulse ratio that best discriminated between response types was derived for each ISI. These cutoffs were validated by repeating unipolar TSS 2–3 months later and with bipolar TSS. Unipolar TSS evoked only reflexes (90%) and mixed responses (10%), which were mainly recorded in the quadriceps muscles (25–42%). Paired-pulse ratios of 0.51 (25-ms ISI) and 0.47 (50-ms ISI) best distinguished reflexes from mixed responses (100% sensitivity, > 99.2% specificity). These cutoffs performed well in the repeated unipolar TSS session (100% sensitivity, > 89% specificity). Bipolar TSS exclusively elicited reflexes which were all correctly classified. These results can be utilized in future studies to ensure that the input to the spinal cord originates from the depolarization of large afferents. This knowledge can be applied to improve the design of future neurophysiological studies and increase the fidelity of neuromodulation interventions.

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Posteroanterior cervical transcutaneous spinal stimulation targets ventral and dorsal nerve roots

Cited by 37 publications

References 45 publications

Low-Intensity and Short-Duration Continuous Cervical Transcutaneous Spinal Cord Stimulation Intervention Does Not Prime the Corticospinal and Spinal Reflex Pathways in Able-Bodied Subjects

Low-Intensity and Short-Duration Continuous Cervical Transcutaneous Spinal Cord Stimulation Intervention Does Not Prime the Corticospinal and Spinal Reflex Pathways in Able-Bodied Subjects

Duration and reliability of the silent period in individuals with spinal cord injury

Distinguishing reflex from non-reflex responses elicited by transcutaneous spinal stimulation targeting the lumbosacral cord in healthy individuals

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