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I have one of the most advanced prosthetic arms in the world – and I hate it
- tdubhro1 6y agoHaving lived with a relative who used a prosthetic, I saw how it was a struggle every day to get the leg fitting just right, and how fatiguing it was to use for more than an hour. The popular perception seems to be way off here, most people think that modern prosthetics “solve the problem” when in fact, as this article explains, they are inconvenient and painful at best and worse than useless in many cases. I’ve got great respect for prosthetists and the “art” side of their work - the dozens of adjustments they make for each patient - but people should be aware of just how much time, effort, pain and inconvenience prosthetics cause their wearers, the technology is impressive but has a very long way to go.
- neolog 6y ago> It was only three pounds or so, but three pounds feels like a ton to a limb that typically carries no weight, and the heft of the prosthetic hand pulled hard on the socket and made me sweat. In order to open and close, myoelectric hands require that you flex your muscles where sensors inside of the socket can detect your movement. I wonder how much of the problem is because those muscles are underdeveloped.
- pineaux 6y agoJust walk around with a 3 pound weight strapped to your arm and tell me how it feels afterwards.
- neolog 6y agoThat's a bit heavier than a large water bottle. 1 liter water is 1 kg = 2.2 lbs. Definitely wouldn't make me sweat.
- cosmodisk 6y ago1 liter of water can be very, very heavy for your arm. Here's an experiment for you: take a bottle of water, lift it up so your arm would make 90° angle and hold it for 3 minutes without lowering your arm. When you carry a bottle, you keep passing it from one hand to another: inability to do so will make it very challenging in probably less than 20min.
- neolog 6y agoThat assumes all the weight is at the end of the arm, which it isn't in this case. I do have a weight on my shoulder: my arm. Holding your arm up for a long time is hard anyway. A human arm weights 8 pounds. > When you carry a bottle, you keep passing it from one hand to another That's a good point. > inability to do so will make it very challenging in probably less than 20min That seems a bit extreme. Anyway grip is the part that fails, not the shoulder strength.
- pineaux 6y agoPut your money where your mouth is. Get a 3 pound weight, strap it to your arm. See how comfy you are with it. Or don't, but don't assume you know better without an experiment.
- xg15 6y agoQuestion: What exactly makes it so hard to interface with the actual motor nerves directly? The tech to stimulate nerves seems to be regularly used in e.g. cochlear implants. We also can sense neuron activity e g. through EEG. So why are even the most advanced prosthetics still relying on kludges like the "flex to cycle through settings" routine described in the article?
- Engineering-MD 6y agoWe can read motor nerves invasively (ie after puncturing the skin) quite well, but noninvasive is much worse and often not useful for prosthetic control (although there are exceptions). The problem for invasive monitoring is you then have infection risks in the short-medium term. In the long term, biocompatibility is an issue and leads to tissue reaction to reject the device, impairing signal detection.