A new variant of brain implant has brought patients hope by sensing the intention of the user in order to move a robotic arm which offers promise to those who have lost limbs or suffer from paralysis.
Scientists at CalTech announced their achievement on May 21: the development of an implantable chip which allowed a tetraplegic man, Erik G. Sorto, to drink beer with a robot arm.
Mind-controlled prosthetic limbs are nothing new, but their movements tend to be rather jerky, which severely limits what their human wearer’s are able to do with them. This is because most tap into the brain’s motor cortex – the part of the noggin used to direct physical actions.
The CalTech professors took a different approach, relying not just on the motor cortex, but also two implants consisting of 96 electrodes apiece. These implants are attached to the brain’s posterior parietal cortex (PPC), which plans physical movement rather than perform it.
Richard Andersen, the James G. Boswell Professor of Neuroscience at CalTech, was quoted by the The Register in a report as having said that the “PPC is earlier in the pathway, so signals there are more related to movement planning — what you actually intend to do — rather than the details of the movement execution.”
The PPC is earlier in the pathway, so signals there are more related to movement planning — what you actually intend to do — rather than the details of the movement execution. We hoped that the signals from the PPC would be easier for the patients to use, ultimately making the movement process more intuitive
For the patient who tried on the gear, the idea worked. Mr. Sorto was able to direct the robotic arm with more precision than other brain-controlled prosthetics offered. He was able to pick up a plastic cup of beer and drink it without any spillage, shake hands with another person in a relatively smooth fashion, and play rock-paper-scissors while exhibiting fluid precision movements.
Sorto, who has been paralyzed from the neck down for the past ten years, was quoted in the aforementioned report on The Register as having said that “this study has been very meaningful” to him and that the project needed him just as much as he needed the project.
This study has been very meaningful to me. As much as the project needed me, I needed the project (…) I joke around with the guys that I want to be able to drink my own beer – to be able to take a drink at my own pace, when I want to take a sip out of my beer and to not have to ask somebody to give it to me. I really miss that independence. I think that if it was safe enough, I would really enjoy grooming myself – shaving, brushing my own teeth. That would be fantastic.
Mind-controlled prosthetic limbs are not the sole research development to exhibit promise in relatively recent times, as a group in Lausanne, Switzerland announced back in January that it had managed to help mice with near-severed spines once again walk with a ribbon of stretchable silicon surgically implanted under their nerve tissue. The researchers then used the gadget to second electrical signals through the mice in order to induce the delivery of chemicals for nerve impulse transmission. In six weeks, the mice could not only walk, but they could once again run and climb, according to a report by The Scientific American, which likened the technique to fixing a cuts in a telephone cable.
Last year in Ohio, doctors operated on a 22-year-old man and managed to insert a chip into his brain, which connected to a port leading to a cable plugged into a computer programmed to decode messages from the brain. The electrodes were designed to pulse in such a fashion as to stimulate muscle fibers, causing the the muscles to pull the tendons in the man’s hand. The man, Ian Burkhart, recovered use of his hand as well as his fingers.
