By Donna Lu
Battelle Memorial Institute
A brain implant has restored movement and a sense of touch in the hand of a man with a severe spinal cord injury.
Patrick Ganzer at Battelle Memorial Institute in the US and his colleagues have developed a brain-computer interface (BCI) that has allowed 28-year-old Ian Burkhart to grasp and feel objects again.
Burkhart has a severe upper spinal cord injury and has complete paralysis in his hands and legs, but can move his elbows and shoulders. He had a brain implant inserted in 2014 as part of research aiming to restore movement in his right arm.
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The BCI uses the implant to record brain activity that is sent to a processor that decodes these signals into movements, which in turn feed in to bands around the forearm which electrically activate his hand muscles.
“We’ve made a lot of progress in the last six years: he can play [the video game] Guitar Hero, swipe a credit card and do about 20 different hand grips,” says Ganzer.
But because Burkhart had no sensation in his hands, he previously had no sense of touch or pressure when grasping objects, and if blindfolded, was not able to detect small objects such as a pencil.
The researchers discovered that although Burkhart’s hand cannot feel anything, the brain implant stills registers a faint sensory signal when he touches an object.
They boosted this signal by incorporating a band around the bicep which vibrates when Burkhart’s hand receives sensory information.
As a result, Burkhart is able to detect objects by touch alone. The BCI is also able to detect different levels of touch and adjust the strength of Burkhart’s hand movements depending on the object – a light grasp, for example, for a paper cup.
The researchers believe it is the first BCI that can simultaneously restore movement and touch.
When the brain implant was inserted, it was intended solely for controlling movement, but the added touch is possible because there is some overlap between the sensory and motor areas in Burkhart’s brain, says Ganzer.
Journal reference: Cell, DOI: 10.1016/j.cell.2020.03.054
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