A True Brain-Controlled Bionic Leg, Now In Use By Research Participants
December 26, 2024 8:24 AM   Subscribe

 
(slow-motion whooshing noises)
posted by Lemkin at 8:27 AM on December 26 [3 favorites]


Haven't read anything yet, but I'm not convinced the man in the picture at the top of the article isn't Billy Joel.
posted by donuy at 10:01 AM on December 26


Speaking of the picture at the top of the article, the article is about a brain-controlled bionic leg. Pretty sure Billy Joel lookalike has a bionic arm not leg.
posted by JohnnyGunn at 10:18 AM on December 26


I read that article and somehow still have no idea how the brain control part works?
posted by latkes at 10:32 AM on December 26


This was interesting, thank you for posting! Something about which I now worry when I hear about incredible stories and advances like this is that they will be produced in the future by a company that will stop supporting them; I've heard a bunch of heartbreaking stories about this happening with assistive technology and this is so cool and exciting I hope these devices are as functional and easy to access as possible for people who want them.
posted by an octopus IRL at 11:08 AM on December 26 [4 favorites]


"reëngineering" - ah, the New Yorker.
posted by doctornemo at 11:20 AM on December 26 [3 favorites]


https://www.nature.com/articles/s41591-024-02994-9 is the relevant paper explaining more about how it works.

Briefly:

In this work, we sought to augment residual muscle afferents through a modified amputation, the agonist–antagonist myoneural interface (AMI) The AMI procedure surgically links residual agonist and antagonist muscles to recreate agonist–antagonist muscle dynamics within the amputated residuum. By restoring natural muscle dynamics, the AMI aims to leverage native sensory organs within the residual muscles and tendons to generate biological afferents corresponding to free-space movements of the amputated joints. Our previous reports demonstrated that the below-knee AMI amputation improves volitional free-space control in a benchtop setting. Preliminary results suggested improved neural control of swing-phase kinematics compared with those without the neuroprosthetic interface. However, in this preliminary investigation the entire stance phase of gait remained under intrinsic control without external neural inputs. Consequently, the bionic gait was not fully driven by the human nervous system.
posted by StrikeTheViol at 12:00 PM on December 26 [3 favorites]


I read that article and somehow still have no idea how the brain control part works?

The prosthetic has electrodes implanted into muscles that listen to the neural signals in the muscles, which are really motor control directions from the brain. The chip then learns each subject's patterns of intended motion individually. They integrate those signals to drive the motion of the prosthetic.

They also leverage the fact that almost all voluntary muscle motion involves opposing push and pull sets of muscles (agonist and antagonist), which helps the prosthetic mimic natural motion.
posted by Dashy at 1:55 PM on December 26 [1 favorite]


latkes, it's driven by the brain the same way our own limbs are driven by the brain: without conscious thought, we control the muscles that operate our limbs. These bionic legs respond to signals detected in what remains of those muscles.

I guess you could 'wire' things in different ways, including confusing ones, but they seem to have found something that feels pretty natural and so people are able to work with it really well.

(I recall a recent article about a third thumb that was controlled using the big toes of either foot, so perhaps the controls don't even need to make sense… can't find the article now, sadly.)
posted by demi-octopus at 1:57 PM on December 26




Thank you, StrikeTheViol.
posted by doctornemo at 2:59 PM on December 26


Thanks all! The part I missed was the implanted electrodes and that those electrodes respond to neuronal signals.
posted by latkes at 4:09 PM on December 26


latkes, it's driven by the brain the same way our own limbs are driven by the brain: without conscious thought, we control the muscles that operate our limbs. These bionic legs respond to signals detected in what remains of those muscles.

It's now twenty five+ years out of date but the last time I read about the developmental psychology of walking the new thinking was that 'gait intelligence' (my own just invented phrase for what I can't recall) was distributed throughout the entire system because the process is simply computationally impossible for a brain (any possible brain even) to properly control when accounting for all the parameters that can vary on each stride. There is almost nothing that remains constant in a person's gait. Your height, weight, footwear, etc all vary. It's pretty wild how complicated a very simple but pretty uniquely human behavior actually is.
posted by srboisvert at 5:30 PM on December 26


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