Elicited upper limb motions through transcutaneous cervical spinal cord stimulation

Abstract

Objective. Transcutaneous cervical spinal cord stimulation (tsCSC) has been demonstrated to activate the dorsal root and activate targeted muscles. However, it is unclear whether tsCSC can elicit functionally relevant movements of the upper limb for assistive/rehabilitative purposes. Approach. The current study sought to elicit arm and hand movements by tsCSC by placing an electrode array near the cervical segments of the spinal cord. Anode stimulation current pulses were delivered to the dorsal side at 120 Hz and 30 Hz in separate trials. The elicited joint kinematics were captured using a motion tracking system. Main results. The results revealed that distal and proximal joint movements can be elicited either independently or synergistically. Specifically, different motions, including flexion and extension of the elbow, wrist, and five digits, can be selectively elicited by adjusting the stimulation parameters, such as stimulation location and stimulation intensity. Significance. The findings demonstrated the feasibility of the spinal cord stimulation technique in eliciting functional movements of the upper limb. The outcomes also revealed the potential of the tsCSC technique as a promising assistive or rehabilitative method for individuals with impaired function of the upper limb.

Neural Substrates of Transcutaneous Spinal Cord Stimulation: Neuromodulation across Multiple Segments of the Spinal Cord

“…However, when considering maximal tolerable stimulation with respect to the stimulation levels needed to evoke motor responses, tSCS with a carrier frequency was no different than unmodulated tSCS in reducing the perception of pain [56]. Interestingly, when using an array of electrodes and adjusting the parameters of stimulation-including intensity and location-different patterns of independent and coordinated upper limb motion at both distal and proximal joints have been elicited, showing the potential of tSCS without a carrier frequency to evoke functional movements [28]. Therefore, the chosen parameters of tSCS can have a meaningful effect on the recruited circuitry and the functional movements that are facilitated or inhibited.…”

“…This would also allow for the tSCS to build on the foundation of knowledge of the intrinsic circuitry recruited by eSCS. In case studies and small clinical trials, tSCS improved hand and arm function [2,[27][28][29], produced locomotor-like stepping [1,30], and improved walking function [22,31,32] in participants with neurological deficits including incomplete and complete SCI, stroke, and cerebral palsy. Evidence suggests that tSCS may also be used as a viable alternative to pharmacological anti-spasticity approaches, altering the excitability of spinal pathways and possibly augmenting pre-and post-synaptic inhibitory mechanisms [33,34].…”

Gait regulation of hindlimb based on central pattern generator in rats with a spinal cord injury

“…The autonomously generated signal can be combined with the control signal from the higher centre to generate gait movements. 12,13 In a previous study, 14 we found a specific CPG site on the right side of the rat spinal cord. In particular, rats can be induced to move the left hindlimb flexion and the right hindlimb extension by stimulating this site with positive pulses, while negative-pulse stimulation induces the opposite motion.…”

Trans-Spinal Electrical Stimulation Therapy for Functional Rehabilitation after Spinal Cord Injury: Review

“…Another study revealed an improvement of locomotion activity when applying tsPCS on rostral sites, while stimulating the caudal area aided restorative extensor movement of the trunk muscles [ 124 ]. Similarly, when the position of electrodes was changed to the innervation region of the biceps brachii (C5–C6) muscle, it led to the activation of joint movement, thereby improving the elbow’s range of motion [ 125 ]. The stimulus to the lateral side of T11 produced flexion, while at L1 it led to extension during walking [ 126 ], and the stimulation of upper limbs exhibited prolonged changes in neural linkages with continued recovery of hand and arm function in SCI [ 85 ].…”