University of Pittsburgh Medical Center
One of the most impressive examples of the promise of a brain implant comes in On the video Where a paralyzed person controls a robotic arm, nothing but the mind. Technology alone is impressive, but the joy on the face of the respondents when you first had a drink in over a decade really shows how important this technology really is.
While we are still decades away from widespread use of the implants, there are steady signs of progress in making implants more effective. Last week we saw an implant that could do just that Convert fictional script into real text. This week, the research community followed up with an implant-driven robotic arm that sends tactile feedback to the user with a second implant.
Add the senses
When we retrieve an object, we find that object mainly through sight. From there other senses take over. People have a feeling called proprioception, which helps us to know where parts of the body are, even when they are not visible. Our sense of touch tells us when we have called an object, and the sense of pressure gives us an indication of how well we understand it. The visual system quickly becomes subordinate to the process.
But for early robotic arms, the visual system was all we had to go through. Users had to visually track the arm during the maneuver and estimate when they were holding an object properly by looking at it. While it’s an improvement over paralysis, it’s not particularly intuitive. It also requires extensive training and requires the arm user’s full attention. Adding some other senses will lead to obvious benefits.
While proprioception is very difficult to reconstruct, the senses of touch and pressure are much simpler. The first attempts to give feedback on pressure and pressure involved giving a feeling of a skin blemish. The system required extensive training to translate everything the user felt into information about the pressure exerted by the robot fingers.
But since then, we’ve developed a solid understanding of the areas of the brain that process the information sent to them from the sensory neurons in your hand. For the new study, a team implanted two sets of electrodes in an area of the brain that deals specifically with information coming from the skin. Activating these 32 electrodes gave the feeling that something was interacting with the palm and fingers.
New (old) experiences
The study participant, who was paralyzed from the neck down, controlled a robotic arm for about two years using brain implants in the motor region of the brain. He can use his arm successfully even without any feeling. However, for the new experiments, the research team changed tests where the arm received additional haptic feedback and tests where the system did not work. In most tests, things had to be picked up in different ways, moved somewhere, and then put down.
Several individual tests showed a similar pattern: sense of touch significantly improved performance. The mean time it took to complete the selection / movement / projection sequence decreased in all cases, and the difference was statistically significant in about half of them. In other words, in the time it took a participant to complete nine tasks with the touch system turned off, he could complete more than a dozen with the system activated.
While all aspects of completing the mission were optimized, the main promise in the process came from grabbing items. The time elapsed after contacting the participant’s body with the arm and lifting the object from the table was reduced by two-thirds when haptic responses were triggered. After the system was turned off, the participant spent more time grooming the hand to ensure a stable grip before continuing.
As with the brain implant type system last week, this study only had one participant, so we need to confirm that the system generally works before we get too excited. But there is no reason to be surprised by the results, although we may not always be aware of them: Touch and pressure play an important role in everything we do with our hands. By targeting the right brain area, the implant uses the systems the brain already has to deal with this kind of sensory information.
All in all, the work highlights the promise of these implants and the work that remains to be done. Even this kind of basic regime has the potential to improve the lives of many paralyzed people. Implantation technology will grow over time and we will continue to improve our understanding of how the relevant brain regions function. At some point, the technology may enter larger studies and potentially widespread medical use.
ScienceDOI: 2021. 10.1126 / science. abd0380 (Om DOI).
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