Using an Artificial Neural Bypass to Restore Cortical Control of Rhythmic Movements in a Human with Quadriplegia.

Gaurav Sharma,Nicholas Annetta,Connor Majstorovic,Bradley Glenn,Stephanie Domas,Marcie Bockbrader,Chad Bouton,David A Friedenberg,W Jerry Mysiw,Ali Rezai

doi:10.1038/srep33807

Abstract

Neuroprosthetic technology has been used to restore cortical control of discrete (non-rhythmic) hand movements in a paralyzed person. However, cortical control of rhythmic movements which originate in the brain but are coordinated by Central Pattern Generator (CPG) neural networks in the spinal cord has not been demonstrated previously. Here we show a demonstration of an artificial neural bypass technology that decodes cortical activity and emulates spinal cord CPG function allowing volitional rhythmic hand movement. The technology uses a combination of signals recorded from the brain, machine-learning algorithms to decode the signals, a numerical model of CPG network, and a neuromuscular electrical stimulation system to evoke rhythmic movements. Using the neural bypass, a quadriplegic participant was able to initiate, sustain, and switch between rhythmic and discrete finger movements, using his thoughts alone. These results have implications in advancing neuroprosthetic technology to restore complex movements in people living with paralysis.

Highlights

Neuroprosthetics aim to restore or substitute for a lost function such as motion, hearing, vision, cognition, or memory in patients suffering from neurological disorders
The wavelet transformed data were input into a Support Vector Machine (SVM)-based neural decoder that could discriminate between brain activity associated with the participant’s desire to perform rhythmic versus discrete movements
We identified and decoded signals recorded from the primary motor cortex of a quadriplegic human to control a virtual Central Pattern Generator (CPG) oscillator which was linked to a neuromuscular electrical stimulation (NMES) system to allow volitional control of both rhythmic and discrete movements in the thumb and wrist

Summary

Introduction

Neuroprosthetics aim to restore or substitute for a lost function such as motion, hearing, vision, cognition, or memory in patients suffering from neurological disorders. A neuroprosthetic bridge that bypassed the injury of the spinal cord was developed to link intracortical signals to a neuromuscular electrical stimulation (NMES) system and enable cortical control of discrete hand movements to a paralyzed person[12]. Decoded cortical signals were used to drive the virtual CPG oscillator which in turn controlled the NMES to stimulate the paralyzed muscles and generate movements thereby bypassing the injured spinal cord. Using this technology, we have demonstrated for the first time an artificial neural bypass can be used to allow a paralyzed person to perform both discrete and complex rhythmic movements years after injury

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Conclusion