One of the most impressive examples is the promise of a brain implant On the video Where a paralyzed person controls a robotic arm, nothing but the mind. Technology alone is impressive, but the joy that appears on respondents’ faces when they first had a drink more than a decade ago really shows just how important this technology really is.
While we’re still decades away from widespread use of implants, there are steady signs of progress in making implants more effective. Last week we saw a transplant that can do that Convert fictitious text to real text. This week, the research community followed up with an implant-powered robotic arm sending tactile feedback to the user with a second implant.
Add the senses
When we recall something, we find that thing mainly through sight. From there other senses take over. People have a feeling called proprioception, which helps us know where parts of the body are, even when they are not visible. The sense of touch tells us when we’re calling something, and the sense of pressure gives us an indication of how well we understand it. The visual system quickly becomes operational.
But for early robotic arms, the optical system was all we had to go through. Users had to visually follow the arm while maneuvering and estimate the time they were properly grasping an object by looking at it. While it is an improvement over paralysis, it is not particularly intuitive. It also requires extensive training and requires the full attention of the arm user. Adding some other senses will lead to clear benefits.
While proprioception is very difficult to reconstruct, the senses of touch and pressure are much simpler. The first attempts to provide feedback on stress involved giving a feeling of imperfections in the skin. The system required extensive training to translate whatever the user was feeling into information about the pressure exerted by the robot’s fingers.
But since then, we have developed a solid understanding of the regions of the brain that process the information sent to them from the sensory neurons in your hand. In the new study, a team implanted two sets of electrodes into an area of the brain that specifically deals 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
Paralyzed from the neck down, the study participant controlled a robotic arm for about two years using brain implants in the motor region of the brain. He can successfully use his arm even without feeling. However, for the new experiments, the research team changed the tests as the arm received additional haptic feedback and tests where the system did not work. In most of the tests, things had to be picked up in various ways, transported somewhere, and then extinguished.
Several individual tests showed a similar pattern: The sense of touch significantly improved performance. The mean time taken 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 a participant took 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 improved, the main promise in the operation came from capturing items. The time elapsed after touching the participant’s body with the arm and raising the object from the table was reduced by two-thirds when the haptic responses were triggered. After turning off the system, the participant spent more time cleaning the hand to ensure a stable grip before proceeding.
As with the type of brain implant 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’s 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 region, the implant uses the systems the brain already has to handle this type of sensory information.
Overall, the work highlights the promise of these implants and the work that remains to be done. Even this type of platform has the potential to improve the lives of many paralyzed people. The 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 into larger studies and possibly widespread medical use.