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Amputees Control Virtual Prosthetic Arm Using Nerve Signals (newscientist.com)

Posted by BeauHD on from the range-of-motion dept.

CanadianRealist writes: Current prosthetic arms are usually controlled by detecting signals from the user twitching muscles in the shoulder or arm. This allows only a limited number of possible movements, such as grasp and release. Researchers have developed a new technique that interprets signals from motor neurons in the spinal cord, allowing for a greater range of control of an arm. Signals from nerves associated with hand and arm movements were mapped to the corresponding movements. Test subjects were able to move a virtual prosthetic arm with greater freedom than has been achieved with muscle-controlled prosthetics. (Note: A virtual prosthetic arm was used rather than a real one as this work is still in the early stages.) The study has been published in the journal Nature Biomedical Engineering.

8 comments

  1. if i only had the nerve by turkeydance · · Score: 1

    https://www.youtube.com/watch?...

  2. You will be assimilated. Resistance is futile. by Anonymous Coward · · Score: 0

    - love, The Borg.

  3. MEC Troopers by spiritplumber · · Score: 1

    https://www.youtube.com/watch?...

    --
    Liberty - Security - Laziness - Pick any two.
  4. Axons by Anonymous Coward · · Score: 0

    This axon is 1.5 micrometers thick: https://commons.wikimedia.org/...

    And its also myelinated. While I certainly like to be optimistic, I do think it will take some time and some additional effort until it gets down to this scale.

  5. Done by Boston Arm 30 years ago by Anonymous Coward · · Score: 0

    Myo-electric sensors were used to control the "Boston Arm" more than 30 years ago. Electrical sensing of motor nervers *does not work well*. The electrical signals are so noisy, and so spread out spatially and temporally smeared, that only large aggregations can be sensed and take up to half-a-second to average out the noise.

    Generating a "love this limb" signal is flipping trivial. Generating a "move this limb when I want it to move" has always and will continue to have massive phase lag until and unless a better, more precise neural array is developed to sample the signals at the old nerve, and the existing processing of such signals was basically done by object oriented programmers who *refuse* to learn anything about how nerves actually work, and believe that if they can just "process it correctly" they can replace data that is already lost to physical signal overlap and massive, massive undersampling. Nerves work based in *state changes* on very small physical and temporal scales, on edge based transitions, not on signals that can be undersmpled and then reconstructed.

    Been there, done that, designed the electronics, could not patent my work due to policies for NIH funded projects.

    1. Re:Done by Boston Arm 30 years ago by tburkhol · · Score: 1

      This is a very different approach to interpreting the EMG than traditional myoelectric prostheses. They're using targeted muscle reinnervation with multi-electrode arrays to decompose the EMG into individual motor units, then using the more precise motor unit signals to control. ME control couples a preserved, non-involved muscle to control of a single prosthesis motor, where targeted reinnervation gives them access to neural signal intended for the missing muscles. Decomposing a complex EMG into its component motorneurons works well with fine wire electrodes, where the recording volume is fairly small, but surface EMG contains too much information/noise. Using the MEA to decipher that complex signal is pretty clever.

      It looks like it only worked well in 7/9 cases, and it's not clear whether they repeated over different days and different electrode placements. It's a proof-of-concept study showing that you can decompose surface EMG into a higher fidelity signal than just patterns of intensity

  6. It's about time! by Anonymous Coward · · Score: 0

    It's really hard to believe it took this long for this type of research to reach the medical field.

    For over 30 years people have been experimenting with avatars to find out what could be done and how they could be manipulated. They experienced a lot of bugs with their systems too, which in turn furthered experimentation. Eventually they started using all kinds of different humanoids, distorted avatars, different animals, fantasy beings etc..

    Eventually they discovered something extraordinary, that they could be a really weirdly shaped avatar, and still control your avatar body quite well. They were quickly adapting to new body shapes.

    One avatar in particular, way back in the early 80s, was a lobster. What they found was they could pull different bits of data from your body and combine them (like your wrist, ankle, and hip) to control the extra limbs of the lobster. Quite amazing actually when you think about it.

    But, it turns out it makes perfect sense.

    That's what's known as the homuncular flexibility phenomenon. The cortical homunculous is basically the mapping of your motor cortex onto your body, or more accurately a map of the proportionate association of the cortex with body members (you can google cortical homunculous for a visualization). It's well known, that everything in biology is pre-adaptive for evolutionary designs that don't exist yet. Our nervous system has evolved through all the different body shapes throughout time. The very same nervous system we have, had evolved to swim, crawl, walk etc..

    It really is about time they direct more attention into types of things like this in the medical field. In education as well.

  7. Good news by Anonymous Coward · · Score: 0

    See kids? these are real technologies we should be innovating.