Researchers at the Battelle Memorial Institute, a private and non-profit company of applied science and technology and Ohio State University Wexner Medical Center recently reported in the journal Cell that they had successfully restored the sense of touch of a patient with severe spinal cord injury via a brain-computer interface (BCI) system.
A BCI to enhance subperceptual signals
The patient – 28-year-old Ian Burkhart injured his spinal cord in a diving accident happened ten years ago. In 2014, Burkhart began participating in NeuroLife, an initiative by Battelle to empower paralyzed individuals by restoring their conscious control of hands and fingers. Researchers believe even if a patient is suffering from a “clinically complete” paralysis, they bound to have some tiny bits of nerve fiber that are spared from the injuries.
In the case of Burkhart, the sensation in his hand was nearly vanished. However, when his skin was triggered, a minute neural signal was still being sent to the brain, even though his brain was not able to perceive it. So, what the researchers did was to enhance these subperceptual signals to a level that the brain will respond naturally.
With an aim to regain his right arm’s functions, a tiny computer chip was implanted in Burkhart’s motor cortex and a system of electrodes was placed on his skin. Wires within this setup would bring the subperceptual movement signals from the brain to the muscles; bypassing the injured areas in the spinal cord before reaching Burkhart using haptic feedback or an experience of touch similar to mobile phone vibrations or rumbles from game controllers. All these enable Burkhart to raise his arm and hand to hold onto a coffee mug, swipe a credit card and play video games.
Changes brought about by BCI
Researchers involved in the project thought the BCI system had brought about three significant changes. First, Burkhart used to have trouble controlling his hand unless he is watching his movements closely but now he is able to accurately identify an object using only his sense of touch. This means he will be able to find and pick up an object without having to look at it in the near future.
Next, the BCI system renders Burkhart a better sense of control and allows him to perform tasks more efficiently because he had recovered both his touch and movement. Last but not least, improvements made by Burkhart allows the BCI system to detect the amount of pressure required to handle or pick up an object. This will permit Burkhart to have a softer grip for lighter objects and a firmer hold for heavier items.
In the long run, researchers hope that the BCI will be able to work just as well in a non-laboratory setting. To do so, they are working on a portable version of BCI which will come with a next generation sleeve that embeds all the required electrodes and sensors for the system to work. They also hope to control the system using a tablet or mobile phone rather than a computer.