2010’s “bionic” prostheses and why they fail

Posted on February 8, 2010

We wonder why these very cool looking and beautifully designed “bionic” prostheses [BeBionic, iLimb, Michelangelo] remain cumbersome and why, as products, they just tank.

The mechanism why we must love them is neurological. Our brain is programmed to positively respond to certain triggers. We like shiney objects. We love 3D. And we sure love things that promise both. So it is clear why “boinic” hands are loved by engineers, tinkerers, media and the (non disabled or otherwise disabled) public alike: by virtue of the Mesmerized Bunny Effect.

They do not stand up to promise. And if previous clear indications keep getting ignored, I’ll repeat them here. After all, upper extremity prostheses are rejected by 33% to 38% of those users that do participate in surveys - and that is a lot. Not counting these that are disillusioned and stop participating. That failure rate is so high, in fact, that we see it is an industry failing its clients through small time tinkering and greed, not an industry facing a daunting job.

If these prostheses actually were ‘bionic’, they would not just look like a movie prop. Instead, by being truly bionic, they would:

1. Feel ‘bionic’ - that is, painless, seamlessly integrated, worrilessly angulated, stress free in grip control,
2. Move ‘bionic’ - prosthetic parts move in a fluid and effortless motion together with existing joints rather than just doing simple grasp/ungrasp motion,
3. Degrade and fail ‘bionically’ - that is, fail gracefully and gradually.

But in reality, ‘bionic’ used for such constructions is probably a straight plain lie. It is most likely founded in hyped up overadvertising and not at all in reality as particularly these myoelectric prosthetic arms:

1. do not feel seamlessly integrated, worrilessly angulated and stress free in their grip control but quite the contrary: grip control is typically unreliable, elbow motion is heavily and painfully restricted, there is no wrist motion at all at my level of amputation, so the term ‘bionic’ has no bearing here;
2. do not move in a fluid and effortless motion together with existing joints and residual extremities but in reality, they produce isolated uncoordinated motion that turn my elbow and shoulder muscles to painful hardwood;
3. do not at all fail gracefully and gradually, but are alive one moment, dead next moment, grip hard one moment and let go the next; I never dropped as much stuff as when wearing the myo arm. These are embarassingly unreliable. I much rather go out without prosthesis.

If we look at the materials, make, design, care of build and other details of many commercially available parts, it is mind-bogglingly easy to understand: prosthetic arms are built rather affordably and then sold for huge amounts of money, and getting that money back as a client, or revising any technical decision - as a client - is next to impossible. Once insurance buys that prosthesis, money is gone.

It takes a simple user as me just about a year to figure that out - but so-called specialists have been playing pogo-pogo with the subject for decades. Absent wrist and restricted elbow motion due to a painful and hard to use socket - and then act ’surprised’ that shoulders and back are overused and painful and hard when just touched gently? Obviously that type of outcome is common and in each and every instance it is very bad. Then what? More ‘bionic’ gadgets? Why insurances don’t investigate this is beyond me. Can’t they afford specialists?

Of course, amputees don’t melt or go away. Were you thinking that? Long lasting disappointment is one outcome, another one is to not even showing up for studies no more. Yet another outcome is shoulder overuse due to poor fitting of the prosthetic parts into one’s overall activity, and poor shoulder function is conversely associated with particularly poor prosthetic usage. A recent outcome is that amputees start to network and create their own activity to remedy the lack of cogent care by finding better representatives of support.

No, really we are dealing with an industry that is shooting itself into its own foot. In a major way. And it is necessary to address that in very clear terms.

When I tried my first myoelectric arm, I had a special socket made for testing purposes. It was very painful, I could not lift stuff, the hand was not reliable, the elbow could not be leaned upon. And all it all it was a particularly cumbersome experience so I read up in current medical literature. Also, I was surprised and asked other users.

• A user of > 20 years of experience: “And everything you describe is how it was for me. The elbow was pushed inward to fit tight over my elbow, to help hold the thing on…yeah right! The tiniest bit of sweat and it would slide down and pinch my elbow bones to the point of pain. And so, besides the cost of the thing, that’s why I don’t wear anything anymore.“
• A user of > 50 years of experience: “I have not yet seen any myo that can out perform a body powered unit unless there is no residual limb left to work with. Particularly if it’s bang for my own buck….there is no comparison. Just ask for a reference of a satisfied myo user with similar condition to yours. I’ll bet you don’t get one or if you do it will be disappointing. Also demand a gratis build if you find it too uncomfortable to use. I predict that there will be a lot of shuffling and maybees. 50 + years of experience here and nothing has changed but the costs.“
• Another user: “I have a myo electric arm and the not in control, I am finding out..(..) Just the slightest muscle movement its like the arm goes into a “fit”.”

So, here is why these “bionic” hands tank.

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RSL Steeper BeBionic

Posted on February 8, 2010

Competing with Touchbionics’ iLimb and Otto Bock’s Michelangelo hand, this now is RSL Steeper’s BeBionic. These “bionic” wonderworks all bank on the Mesmerized Bunny Effect while technologically missing just about all current points there are about to be missed.

Do we wonder: are these all, or at least some of these, built by the same Chinese OEM original equipment manufacturer for 180$ a piece before they are sold for 50′000$ to insurances or individuals? Yes, we wonder :) I should add that I have nothing against ‘made in China’ - I was there and got the chance to see this and that and from that it becomes apparent that a lot of very good stuff is built there. I only oppose the drastic price margin.

[UPDATE 1] Now, this product appears to be manufactured by RSL Steeper in the UK as one user that wants to support the company tells us, and its price allegedly may be a lot lower. That, of course, changes things as affordable products are a tee-totally other league in terms of trying them out, using them, wrecking them, repairing them and getting them tweaked.

[UPDATE 2] To me, this hand moves and looks so much like the iLimb that I wonder whether Touchbionics didn’t just diversify to have this model produced and sold in a lower price range and built from cheaper materials, maybe. It’s pure speculation, of course, but study the phalanges, their size proportions and their motion patterns as closely as you can. Just from looking at this, I feel there is more than a slight chance of technical overlap. Also, from a sales point of view - not only did Touchbionics almost fail to get a bank loan in January, but also it seems they hit bottom in terms of selling iLimb units. Plus, market tells us that brand new developments in this domain are so cost prohibitive that right from the outside this should be a copy rather than a new development. Friends of the company would like to suggest otherwise, but we’re here to freely speculate. At any rate, evaluate this one well.

Now, here’s some demos.
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