Ask Slashdot: What Would You Look For In a Prosthetic Hand?

Arglebarf writes "A family member is recovering from a serious illness and, unfortunately, the medication that saved her life will probably cost her hands and feet. She is an artist by trade, so this is a pretty big deal. Replacement prostheses might restore a degree of independence, as well as enabling her to continue with her creative passions. Do any Slashdotters have experience with replacement hands? What features do you look for? Do any models allow you tweak the software for fine tuning? Beyond the day-to-day uses, she will want something that can hold small objects precisely (e.g. a paintbrush)."

I'd look for a transplant

[Brandano]

If at all possible. It isn't too far fetched, hand and forearm transplants have been made, and have even achieved sensorial feedback.

I think I speak for everyone when I say

[Intrepid imaginaut]

Lasers.

Re:Dean Kamen - Luke

[TubeSteak]

If you want something you can actually buy:
http://www.touchbionics.com/products/active-prostheses/i-limb-ultra/ [touchbionics.com]

It runs ~$100,000 and is more or less top of the line.

Re:What kind of artist?

[spopepro]

Indeed, it is a challenge to get used to at first, but after going to school with a major burn survivor who had the krukenberg procedure on both arms and was able to win the audition to be the drummer in the top jazz band at a prestigious music school for multiple years, it seems like the procedure allows amputees to do more than any prosthesis.

Re:What kind of artist?

[Miamicanes]

After reading about them, I can't help but wonder whether an interesting prosthetic compromise might be to somehow attach muscle fibers to implanted force-feedback strain gauges, then use the strain-gauge readings to control the hand itself (possibly in conjunction with all-electrical sensors used with other nerves to provide additional control. In other words, instead of pulling on bones, the muscles would pull on artificial ligaments cemented onto strain gauges attached to some kind of stretchy/springy plastic that itself is attached to a worm gear that moves the far point closer or farther from the muscle to alter the resistance.

For finer control (like individual fingers), it would take an idea from the way HTC's hybrid mechanical-capacitive switches used on their last few Windows Mobile and early Android phones worked. Basically, they used capacitive means to determine WHERE (approxiamtely) you were touching the phone, but used an actual switch triggered by a press anywhere in the region to determine when you actually intended to fire a switch event.

In a similar manner, the hand's controller could attempt to discern things like individual finger control by sensing the nerve bundle directly to come up with blunt motions, but sanity-check it in realtime against the muscle-triggered strain gauge, and use fuzzy logic to correlate patterns of nerve activity with specific variants of strain-gauge muscle tension to produce an intended action (so the actual finger, for instance, curled in direct response to the real-world forearm muscle pulling on the implanted strain gauge).

The problem with non-mechanical nerve interfaces is that they basically have the same kind of problems that capacitive touchscreens do... terrible signal to noise ratio and processing latency compared to real-world direct actuation. Nerves aren't like switch-triggered wires in a harness... they're more like a bundle of coax carrying multiplexed spread-spectrum QPSK signals with unbelievable amounts of background noise. By directly interfacing a few muscles with strain gauges, we can bypass the hundred (give or take) years of R&D it's going to take to get signal processing up to the point where it really needs to be, and just take advantage of the signal processing that the forearm muscles ALREADY HAVE to pick out the right signals and translate them into commands for the prosthetic hand.

Re:I'd look for a transplant.. another alternative

[Anonymous Coward]

http://en.wikipedia.org/wiki/Krukenberg_procedure [wikipedia.org]

Re:Mouth will probably work better than prosthetic

[complete loony]

My dad lost both hands and most of his forearms as a child. He has always preferred to use his own stumps as-is, rather than mucking about with prosthetics. But then he learnt to use his arms at an early age, and he was determined to do everything he could.

He can do practically everything you or I could do, except for things he simply can't reach or that require juggling to many things too rapidly. He has the neatest "handwriting" of anyone I know, he types by holding a pen, he can drive a car, develop software, and he's built a house extension. As an adult he's always been a productive member of society.

While you may develop the dexterity to use a prothethic. Don't discount the potential usefulness of your remaining limbs just as they are.