Human Nerve Stimulation Thresholds and Selectivity Using a Multi-contact Nerve Cuff Electrode

Abstract

Testing of the recruitment properties and selective activation capabilities of a multi-contact spiral nerve cuff electrode was performed intraoperatively in 21 human subjects. The study was conducted in two phases. An exploratory phase with ten subjects gave a preliminary overview of the data and data collection process and a systematic phase with eleven subjects provided detailed recruitment properties. The mean stimulation threshold of 25 +/- 17 nC was not significantly different than previous studies in animal models but much lower than muscle electrodes. The selectivity, defined as the percent of total activation of the first muscle recruited before another muscle reached threshold, ranged from 27% to 97% with a mean of 55%. In each case, the muscle that was selectively activated was the first muscle to branch distal to the cuff location. This study serves as a preliminary evaluation of nerve cuff electrodes in humans prior to chronic implant in subjects with high tetraplegia.

Fascicular Perineurium Thickness, Size, and Position Affect Model Predictions of Neural Excitation

“…Implantable nerve cuff electrodes can be used to selectively stimulate individual fascicles or fascicular groups, producing selective muscle activation [2]–[4]. Clinically, nerve cuff electrodes have been used to reduce seizures using vagus nerve stimulation [5], restore limited motor function in lower [6] and upper [7] extremities, and restore respiration in patients with spinal cord injury [8]. Despite these successes, there is room for improvement.…”

Neuroprosthetic technology for individuals with spinal cord injury

“…1D and E). 11,35 More complex systems will be required to restore natural movement of the upper limb including dexterous grasp function and fine motor control. To make full use of these additional stimulation capabilities, improvements in command signals will be required (see Neural Recording section for additional details).…”

“…Nerve-targeted FES systems often produce a more consistent, stronger contraction as they can recruit a larger volume of muscle tissue, can produce a more fatigue-resistant response, and allow for graded force production. 6,11,12 Nerve stimulation electrodes cannot be used to target muscles that have been denervated due to primary motor neuron damage, though these muscles are often weaker and have much higher thresholds for stimulation regardless of technique. Additional discussion of electrode design is included in the Neural Recording section.…”

An energy-efficient, dynamic voltage scaling neural stimulator for a proprioceptive prosthesis

“…Selective stimulation of efferent neurons (similar to the afferent Type Ia and Ib neurons we are targeting) in the human PNS has been demonstrated in [21], [22] to occur with charge packets of between 11±5 nC to 29±17 nC. Given these values our stimulator will be designed to deliver up to 50 nC in a 100 μs pulse (a common pulse duration).…”