Biomedical engineering specifications for epidural spinal cord stimulation to augment motor performance

Abstract

Stimulating electrodes were placed in the posterior portion of the epidural space in the upper thoracic spinal region in 28 patients with upper motor neuron disorders. Parameters of stimulation commonly used for chronic stimulation were a 200 microsecond pulse width, 22 Hz repetition rate, and 5 ma amplitude. Using a 16 gauge Touhy needle, platinum electrodes were passed between the posterior vertebral processes into and up the spinal epidural space to upper thoracic locations. Passive implanted receivers, powered and controlled by external RF transmitter/pulse-generator devices, were employed to provide the stimulus current to the electrodes. A description of available systems, problems and diagnosis of problems, and future directions is presented. This is based on studies in patients with stimulation systems implanted for more than six months.

Enhancing neural activity to drive respiratory plasticity following cervical spinal cord injury

“…Early attempts to treat pain by peripheral nerve stimulation encountered variability in outcome, and prompted a neurosurgeon in the late 60s – Clyde Norman Shealy – to speculate that direct stimulation of the spinal cord may be equally if not more effective (Shealy et al, 1967). Through assessing optimal electrode placement, and altering stimulation intensity and frequency, however, it became clear that patterned spinal motor activity could also be activated by epidural spinal stimulation (Dimitrijevic and Faganel, 1980; Sherwood et al, 1980). There is now rapidly growing appreciation for the fact that spinal stimulation (e.g.…”

Transcutaneous Electrical Spinal Stimulation Promotes Long-Term Recovery of Upper Extremity Function in Chronic Tetraplegia

“…Growing evidence indicates that tonic electrical spinal stimulation can leverage the intrinsic capacity of neural plasticity [3], [4], and can be utilized for restoration of function after SCI [5]. Epidural stimulation can enhance conscious motor control of locomotion in humans with incomplete SCI [6]- [8], and produce initiation of voluntary leg movements and gains in postural control even in cases of clinically-complete SCI [9]- [11]. In addition, direct current spinal cord stimulation via commercially available stimulators was used to activate the posterior spinal cord roots through the skin [12].…”

Supraspinal Control Predicts Locomotor Function and Forecasts Responsiveness to Training after Spinal Cord Injury

“…94,95 Other training approaches also targeted spinal circuits; for example, evidence that the flexor reflex response is closely tied to the locomotor central pattern generator 96 influenced the development of training approaches that incorporated stimulation to elicit stepping by activating reflex circuits. 97,98 Also beginning in the 1980s, there were published reports of spinal cord stimulation with implanted epidural electrodes to improve motor function in persons with neurological conditions, 99 to elicit step-like behavior in persons with SCI, 30 and facilitate walking in persons with motor-incomplete injuries. 100 More recently, there have been reports wherein epidural stimulation has been used to increase the excitability of spinal circuits to a level that allows some volitional movement in persons with injuries clinically classified as motor complete.…”