Paralysed man feeds himself for the first time in 8 years
A man paralysed from the neck down has been able to drink a coffee and feed himself for the first time in 8 years thanks to a pioneering system of implants.
Prior to the intervention, apart from some minor movements of one shoulder, the 53 year old man had been incapable of voluntary movement following a traumatic spinal injury that left him permanently paralysed.
In 2014 he underwent surgery to implant two microelectrode arrays into his nervous system. These were positioned within the area of the brain called the motor cortex. Nerve cells in this region pre-programme movements and send instructions down the spinal cord to tell motor nerves to move muscles. The implants were able to eavesdrop on the neurological chatter produced by the underlying brain tissue and transmit this to a nearby computer.
Initially this was hitched up to a "virtual reality arm", the movements of which were controlled by the computer's interpration of the signals recorded from the patient's brain. And because different movements are programmed by different and distinct patterns of brain activity, after training the patient was able to control accurately the positioning of the virtual arm in three dimensional space.
At the same time the patient also underwent further surgery to implant stimulating electrodes into the muscles of his shoulder, upper arm and wrist on the opposite side of his body to the brain implant. This is because the nervous system is cross-wired, so one half of the brain controls the opposite side of the body. Activating these electrodes triggered the underlying muscles to contract.
These electrodes were linked to the output from the computer, so rather than controlling a virtual arm, the patient could now, just by thinking, send signals to the muscles of his paralysed arm and move his hand to any position in three dimensional space in front of him. To make things easier and to prevent muscle fatigue, the arm was supported by a motorised sling, but this responded only passively to the patient's intended movements.
Using the device, more than 80% of the time the man was able to make an accurate movement towards an intended target. He was even able to reach out to retrieve a cup of coffee and bring it to his mouth to drink, and he could feed himself, something he'd been entirely reliant upon others to do for him for nearly a decade.
This is the first time that such a device, which couples a brain-computer interface with a muscle stimulating system, has been tested successfully in a human. The results, presented this week in The Lancet medical journal are a landmark step forward in helping to restore movements and improved quality of live to tetraplegic patients.
According to Cleveland-based Robert Kirsch, who's team at Case Western Reserve University, carried out the work, "Future systems inspired by this work might provide full-time and more accurate control of the arm and hand to enable restoration of a wider range of functional activities..."