Questions that came out of this webinar are, how to test, what to test, and how to go about getting clinic/lab and user on the same page.

Webinar#3 of ICORR Consortium 03.06.2024

Transcript via Youtube in footnote ¹, and structured summary of Youtube transcript by ChatGPT²

The approach from my view is as follows.

Amputees are different.

We are all different. We use technology differently. We think, act, are, different people. The body part affected for a prosthetic arm is an amputated arm. Now, service providers have a hard time understanding the implications of that. My body image is subject to my own tyrannic and willful decisions. Even if I do not want that, that is what happens. Our bodies are like that. They enforce us. I am the only one to rightfully determine everything there, that attributes meaning to pain, that sustains and bears, that holds out. While others probably take some part in that, have to, want to, will, usually that is not a given. With the amputation, on top of that being a tyrannic command chain, I will be disturbed, troubled, confused, bewildered and traumatized. There are a lot of things that are not as they were. Society acts, reacts, significantly differently. I react, am, different. There are no real deals to be made, no reliable foundation is there, not for many arm amputees. Only after a while, the dust may settle. It remains my tyrannic decision if I accept a totally nonfunctional piece of junk on my stump, and it remains for my body to work out the total pain from skin bruising and blisters in context of junk parts that cost as much as three cars without technical promise of improvement, no potential really – or whether I go on my own tangent and go/become all mechanic, top class functional, where things can still be optimized, as there is so much potential. But: we are different among each other and from non-disabled people, also in ways that exceed imaginations. That said, a surprising thing to do in that situation is have a competition that has arm amputees all try to open a jar that has been closed before by some other folks [etc]. But real dedicated rehabilitation and design discussions usually work differently.

What we can approximate from a testing side is this.

1. Test 1. How does the arm look. If there is anything that can undergo quality control, it is the look of the prosthesis. The bottom line is, if no one else sees that I wear a prosthetic arm, then test 1 has been passed. No prosthetic arm ever passes 1. You think I, anyone else in need of a prosthetic arm, ever forgets that? Take that, be empathic, let it sit. The degree to which this is earth shattering is not measurable.
2. Test 2. Is the prosthesis superbly comfortable, robust and functional. Individual focus and trained proper care does that, not 20 folks tested all trying to grab a clothespin. Test 2 is actually not passed by any service provider anywhere on the planet. The first prosthesis may be even made from scrap parts the prosthetist has lying around and that they couldn’t get anyone else to wear, like what I assumed was done in my case. The first prosthesis will cause outrageously uncomfortable skin itches and burns, rashes that take any fun out of anything there. Parts will fall apart left and right, they did on my arm for two years or so. After one realizes this, I suggest every arm amputee to follow this advice here. I built this website on that path, browse it. But it is an arduous path to, as amputee, achieve a pass for test 2, but rest assured, other people won’t do it for you. In an ideal case, other people support you, not necessarily service providers, but colleagues, friends, other professions. Can I do everything, over a day, week, month, year, for work and other life, so my body does not ache and so that I do not feel overly stressed out in the evening? Then the prosthesis solves medical problems of asymmetry caused orthopedic neck and shoulder problems. To achieve that, a medical approach needs to consider work/activity related hazards (link) and work with these. The highly frequent/repetitive, and, the seriously heavy tasks, these require design and build focus. Can I wear the prosthesis for weeks, 14 hours a day, without skin problems? A well set up prosthesis avoids also any skin problems. Read down, you’ll see. After you navigated to pass test 2, the world is basically your oyster.  Then you also managed to turn an insurance employee that didn’t want to replace a moldy gory sweaty liner; I once made it abundantly clear to one of these that they will smell my old liner, if they don’t approve a new one at once.
3. Test 4. Train lifting, pushing, grasping, handling all things that are dear to you, to oblivion, to the moon and back. Train until cows come home. Do complex and mixed training, do serial drills if necessary. But train, for the rest of your life. Read down, more ideas there.
4. Test 5. Ah, chill. No more “tests”. Now they can throw anything at you. It is literally a different world. Doing a Cybathlon would be unfair to others. But I once visited one of these Cybathlon demo setups at our Uni, with a friend, over lunch, it was right there in front of us. I showed him how to put a USB stick into that USB port. It was one sweeping motion with the prosthesis. Should have seen the face of the woman trying to use the prosthesis simulator to do same. The organizers there also never passed tests 2 or 3. You cannot hold it against them but they are probably trained differently, so, clueless [link]. With regard to testing, my prosthetist does not need me “tested”. I do things at work some of my colleagues with two hands cannot do.

Or do the 8-Question test. There are eight simple questions to ask if you need to know whether a particular prosthetic arm will work for everyday use in real work situations  [link]. All that is not exactly rocket science or neurosurgery though [link].

Who is who.

User do this. Clinics do that. Manufacturers do something else. Prosthetists be prosthetists. Dermatologists, orthopedic doctor, neurologists, they have questions and problems. Everyone is headed somewhere else. And all that is normal. No one really discusses things with each other. What happens, people talk to each other in various single directions. There are several monologues without much counter traffic. There is no real ball game so to speak.

First of all, the personal and institutional goals of the stakeholders mostly seem at odds, asymmetric, if not conflicting. The user usually is overwhelmed and intimidated, and in no ice-cold-blooded expert modus mind to play a few years of test piloting super fragile toys. There user is not in a mind to spend gagazillions of hard and after the amputation impossibly hard earned money on insanely overpriced betaversions of technology that never really worked when it came out in the sixties such as the “Russian Arm” (link). The clinic or lab representative may have a critical and missionary attitude as they think they have the pinnacle of technology to administer to a possibly ungrateful or impatient patient, and they tend to focus on very selected aspects of prosthetic use, usually far or at least a bit away from the user’s real life. Does he flip the newspaper pages with the “bionic” hand as he said he would. They may want the user to pinch a coin when the user just has maybe like to move 1 household, keep a job but now with just 1 hand, and at the same time juggle all sorts of other responsibilities and tasks, go mow lawn for uncle and auntie, mount shelf for nephew and niece, then off to the roller coaster where s/he isn’t admitted because everyone failed to make the prosthesis look lifelike as they had promised they would – and the world collapses, did you count how many (tearful?) support groups posts there are about getting denied rides on fiveflags or their likes. The manufacturer wants to sell materials for money, and certainly not deal with angry or difficult users, and definitely not spend money on new stuff such as R&D, testing, or patents, or write extensive compliance or medical device registration documentation (here, here). But the user just once lifts something or even moves 20 or 30 boxes and realizes s/he needs an urgently better device, which when the sad realities of the manufacturer is revealed to the user. The manufacturer’s preferred mode may thus even be to produce cheaply elsewhere, anywhere on the planet, not overly do quality testing and let the prosthetist deal with all the fallout. The insurance seems to prefer a silent client, if necessary happy, but if not necessary, then unhappy and silent is probably fine for them, too. The academic researcher usually tests ill understood ideas that other academics also did not understand that well and that they therefore treat as pioneer idea. Such as whether a prosthetic arm needs to feel. The sensory feedback has a funny story though, but it was not meant to tell academics to put it into the devices. They still think that only the most sophisticated electronic devices can feel, and so it was a surprise to them that the Cybathlon 2020 with an extensive sensory feedback test wasn’t won by a myoelectric device user but by a man wearing a cheap 3D-printed body powered arm. There would be much to say was it a dialogue, but that in essence characterizes these people, always looking for new ideas none of which help me carry, sweat and control, work. Being academic to a large part may be understood to keep a visible distance from anything that remotely smells like dirty work, as it embodies a leisure class of its own [link]. The prosthetist typically just may want a modular kit to assemble, for whatever is being built, and not much difficult R&D or design thinking to do. As income / revenue is a real big issue for the prosthetist, devices that are expensive (as they may earn like 30% on hardware or such) and then not used too often (and that therefore do not break that often) are relative if not absolute gold. Myoelectric prostheses tend to fall in that niche. After all, no normal user in their right mind will even think of trying to attach a plough to a tractor with that, or think it is a good idea to rip the weeds out all afternoon with one of these, or shred 4 hours of (manual) salad harvesting, or go hammer some nails in (link). Sure, they may occasionally “use” or maybe “flash” the myoelectric, sure, but not for real work. A body powered arm that gets the user into a high wear and tear and repair use mode, in other words with a device where repairs don’t pay well for the prosthetist, are, for the prosthetist, of course not so interesting. With one of these, one may easily go about some 20-40 kg things over an afternoon and then find that the stock part body powered arm doesn’t hold up after all. Because once one starts with the real action there’s always a next weakest link. Like, I sawed a few wood pieces to fit under my curved cellar stair case for a shoe shelf, drilled a few holes with drills in the drill hammer, weakest link for me were the drill bits, because the concrete is really hard, so I got carbide drills. It is a different game after all but once you open the door for higher loads (weight, sweat, vibration, dirt) there is no end. So that is what prosthetists do not like, affordable mechanical prostheses that are truly robust at least to a degree and that make the user go use and wreck them, like, literally all the time. And that then want more. After all, life is life lived, not spent in prosthetist waiting room waiting for yet another repair. Which also risks to get forgotten, over all that toing and froing with endless frustration and resignation. But prosthetists want things their way.

And that brings us to the users. We? We just want our life back, have a prosthesis that is comfortable and good looking and that always works. Yeah, we know, … – that? That doesn’t “just” exist out of the box. And as clearly no one else cares about the parts that I really need on my prosthesis, then I’m a fixing to look for my own parts (summary here), because these other monologues aren’t all that interesting.

The prosthetist. If they want, they make great sockets. Otherwise, they use commercial components and these are mostly only so so, if at all. Then also the way they deal with users. My prosthetist lied to me. Several times. In my face. I tried three different prosthetists with that question: when I leave you and your services because I am unhappy, and switch to a different prosthetic service provider, will you talk bad about me behind my back? All affirmed, two even laughed. So they have clearly different goals with regard to some things. So we, the arm amputees, usually tell the prosthetist the non-offensive story, the things they want to hear. They may tend to not deal with any other conflicting information. So, all that sensory feedback drama we get these days? Yes, that is a great prosthetist amputee client relationship story, we can learn from that. Prosthetist (with stern look), you do wear the myoelectric prosthesis, do you. Amputee (shivering already), um yes. Prosthetist (keen eye for detail), but the prosthesis really lacks wear and tear. Can’t believe that. Admit it, you don’t really wear it? Amputee (trying to find an excuse that doesn’t blame the prosthetist) well it isn’t comfortable really, is it? Prosthetist (getting upset) That cannot be, we already had three appointments, so what are you saying, that I am a bad prosthetist? Amputee (a bit in trouble now) Um the arm isn’t just that functional, it has a mind on its own and it fails often. Prosthetist (more upset), but we bought the lastest parts, and they cost a fortune! How can you be so ungrateful, saying these things! Amputee (at wit’s end), well most importantly, I cannot feel that well with the prosthesis. When I just have my stump out, I feel everything (adding truthful smile of happiness). Prosthetist, oh well, we cannot fix that though (takes note to pass on to researcher) (researcher later makes questionnaire) (detaches verbal content from actual meaning). — As you have to realize, adding more contraptions to a contraption won’t make it less of a contraption. But sensory feedback wasn’t what we ever really wanted to say there.

As manufacturers usually only sell what they sell, their component offering is of limited use. I want perfect body powered control. It is possible to achieve that. So we built a perfect shoulder anchor from carbon fiber and other plastic (read our paper, or, here). My reach space is near perfect, with rather little compensatory motion, I can work also over the head (videos here), I have only 4 cm of arm stretch from fully closed to open so hardly any compensatory motion — totally unlike the attempts that prosthetists usually give to users under the umbrella term of body powered arms (link). Look if you can’t properly build stuff that is not my problem. I patented my own cable mount, it lasts over 6-9 months and also works about twice the grip power of commercial cable mounts with around the same cable force (here). Commercial cable mounts were not that swell, I these tore up after 4-10 days over the first two years (here). And I invited to cooperate with Brad Veatch for the V2P (here). There are things one does, but only once one knows one is on one’s own. I now have a body powered prosthesis that levels my asymmetry almost perfectly, no neck/back pain even after weeks of real work. My arm needs 1 repair every 8-10 months that I perform at home, with a few USD cost, as modular industry parts design can also be done if one fixes oneself to do that.

Academic researchers, in their own world, need to write scientific papers that have high impact (like, here or here or here). If they can research isolated problems, then they are in heaven. No need to deal with amputees trying to get their life back. Smelly stumps with friction rashes, eww. Hard testing? Nope (here and here and here). I once had a researcher in his lab tell me his accelerometer based control was perfect. I should try it at home. So I grabbed and hovered the paper cup with water in it, wearing his prosthetic device, over his laptop and asked him, sure about that? He went pale and said no, but, he said that in a split second he learned more about real prosthetic arm use than in years of academia before. So also, they now use “healthy” study subjects, because amputees are increasingly hard to come by (here).

I could go on. But there is no multidisciplinary team. This all. This is pure dystopia. No need to watch Bladerunner reruns (link). People wearing toy technology for nuclear power plant prices denigrate and vilify hooks (link). Blessed anyone of these stakeholders who does not rely on any of these other stakeholders to paint their room of dreams and goals. As discussed elsewhere (link): this very clearly is a world of survival of the fittest. We cannot even properly blame anyone, as everyone has their own little motives and constraints. But that is about where it’s at.

So the question that was really asked was how to bring amputee everyday life and reality together with the reality in the clinic or laboratory.

You may do that as Facebook or Google does it. You sell to the user the prospect of a bright future while asking for their privacy. You monitor the hell out of the user. What you may achieve is that privacy is further split, into a prosthetist’s privacy part and the real private aspects of real life. But accept that the real reason for excessive monitoring is probably a lack of understanding and trust.

What you really may want to do instead is the hardest: build good prostheses that are so good the true smile on the face doesn’t require tracking. In order to do that, you need technical delimiters (grip angles, max weights, max torque, etc.) of tasks, and your device just has to be able to deliver/withstand a bit more than these. In doubt overengineer a little.

Use aspects.

My prosthesis is a balancing tool first and a gripping tool second. First of all it has to alleviate or reduce my shoulder-neck-back pains from asymmetry. For that it has to provide weigh wise balance and be very comfortable first, and reduce “compensatory” motion second, but not for all tasks and with perfection – noo. Only for these things where I do dozens or hundreds a day, or for the heavy ones. So I need perfectly symmetric equipment box lifting. I need symmetric arm load for the hedge cutter, 2 hours in over 30 deg C summer sunshine (whaaat). I need symmetry for industrial amounts of keyboard typing (here). Whereas I do not care a bit whether I have compensatory motion taking the trash out (once every 5-6 days), make coffee (3-4 times a day), or, open a curtain. Heavy or repetitive: there, in that subject area, all analysis for builds and compensatory motion needs to go. Not a few clothespins a week. At the end of the day, I feel the cumulative strain without any extensive monitoring or device tracking (link EODF and link pain) — and it is lowest or even absent when I wear my body powered arm, that one with the shoulder anchor, tuned cable mount, own wrist, and so on, and with a good gripper. Strain will be far more when I do not wear the prosthesis, or when I wear a nonfunctional device such as a myoelectric arm that does not even approximate my activity/use levels with robust and reliable support.

In order to then grip with confidence and help with all overuse, training has to be absolutely dominating. For that, zero downtime is key. Zero downtime concept starts by having the prosthesis not cause any skin issues, like, at all. For that, I wear a body powered arm, Ohio Willowwood Alpha gel liner and cotton tubular gauze as liner liner. It has to work under any amount of sweat, and that setup does it. Control needs the feel of an extremely tight road bike, not like the steering of a 50’s US station wagon, so that was what we built, shoulder anch0r and my cable mount, absolutely unlike what is sold elsewhere. Robustness must be there, not the slightest wiggle is tolerated, so my wrist connector does that. We built that, too. So once I have such a device, it goes everywhere all the time. I wear it so much that using it has become second nature. I relied on it even more after shoulder surgery [due to accident, not overuse related] (link). No one else has that? No one else actually understand body powered technology? Well, you want to pay me, I can explain all that to you … again.

The elements.

So, grip. I want a grip angles of the always pre-configured hook, hand, gripper, whatever, that is compliant with everyday objects and their statistically most frequent angle occurrences. Drive car, make coffee, type, all that should be effortless, access angle wise. Hosmer hook, V2P, these work. iLimb, not so much, got to contort a bit much. Read here [link]. Grip surfaces got to be soft and compliant [link]. We are all constrained, in our world access angles, through a range of anatomical and not so anatomical aspects, and a prosthetic arm is a big factor here.

Then, control reliability. I need the arm to work so well that I can trust it with critical items. Only my body powered arm that is – as stated above – most severely tweaked, tuned and modified, does that. If you are happy with 85% or 95% control reliability, not my problem. Sweat is an issue. To give a number, 1% grip error costs 3000 USD for using that per year in one estimate that I made, if one consistently uses the arm. Yeah, I can neoliberal this, too. Read this here, [link, link, link]. Yeah, I know you didn’t really want to read that. Crappy control arms cost the users a lot of money, and if one does not want to spend that, one will not use the crappy control arm. Wear it, maybe, use it, no. Don’t track that though. Build better controls.

Skin needs to stay clear. My skin usually starts to flash itchy motion/sweat/friction rash after maybe 1-2 hours of prosthetic use. Myoelectric was a bit of a real nightmare [link]. So I use body powered and there, we fixed that for good [link]. I occasionally get fan letters from other users for that blog post.

Mechanical reliability. Wrist, screws [link, link]. Don’t get one if you won’t use it anyway.

Wasn’t that hard, now, was it.

The drop outs.

Yeah, I tried the myoelectric, I have an iLimb even. Jeez. Here. And of course, Britt H. Young. Here.

What are user evaluations.

There are a few archetypical or standard users.

We are, however, mentally impenetrable with regard to the predicament. You won’t get to the bottom anywhere. Never mind.

1. OMG I have a new myoelectric 3D printed arm! 4 photos on Instagram. After that, no more use evidence. Life is fun!
2. I feel not authentic with a prosthetic arm. But I have the most serious overuse and asymmetry problems. I have cervical disc hernia, rotator cuff damage, and wrist arthritis along with carpal tunnel syndrome. Life is hard.
3. I feel authentic only with my myoelectric arm. Despite that, I have the most serious overuse and asymmetry problems. I have cervical disc hernia, rotator cuff damage, and wrist arthritis along with carpal tunnel syndrome. Life is hard. [The device does not really work. No myoelectric REALLY helps there, I tried, I do overuse type stuff].
4. I have a prosthesis but it does not help me. I wear it because then people talk about it. In a restaurant I get the waiter to cut the food for me. Just because I can. Life is fun.
5. I have a body powered arm but it breaks all the time. My prosthetist does not seem to help. Life is hard.
6. I have a myoelectric arm, but it breaks all the time. My prosthetist does not seem to help. Life is hard.
7. I have a myoelectric arm but d0 not use it. It failed me once when I was distressed and probably sweated. I do n0t feel safe using it any more. Life is better without it on.
8. I look at the device and it looks like shit. They all look like shit.
9. Britt H. Young. Here.

Failure? Hard testing!

Usually there are non-negotiable fail situations. Once these occur, the user may not go back to really using the device, or have (possibly unconscious) “penalty use rules” in place.

If your user has such tasks, go for these if you are a provider.

• Garden and house work. Pick the harder ones and start with exhaustive drill exercises. I taught myself laundry work and kitchen stuff by declaring these as “hook zones” from day 1. Got to have a bit of discipline. I managed to pick up stuff from the ground when standing in a single sweep motion, using my prosthesis, after maybe 2 weeks of continuous use, and if I can do such, anyone can.
• Freestyle hard and difficult manual work. Repairing my bicycles forced me to go with the flow, to use my brain on autopilot. Changing watch band or battery, puh. Do that to anyone, expose them, let them figure it out. Only dead fish swim with the stream.
• Move a household or furniture. Go for sports events that are absolutely exhausting. Use a real power tool for a real amount of time. When we rode the bicycles up to Stelvio pass from Prado. But, reach for some stars. Go past comfort zone. Then look back and analyze. After that, you learned something.
• Once you master hard and difficult things, the other stuff follows. Like, once I bolted up a shelf, making coffee felt like, nothing really.
• It is the big things that matter. Not (just) the small things. These are OK. But the big things, they are the ones that put a grin on your face for years or decades even. With a potentially devastating and depressing disability, you want to go for the big grins that last for years or decades even. Unless, of course, you are not very empathetic and heartless and do not care. Well, read above again, with that in mind now. Isn’t it a different read now? So much for circular hermeneutics.

Ice cold.

The number of absolutely ice cold blooded test pilots that go invent their own prototypes are an absolute minority. That are far from impulsive.

For the rest of the users, you need 1000% empathy for a life situation that no one else can mentally penetrate. Try to get them to cool TF down. Also, try to build a prosthesis for them that makes them smile in a very sustained way when they wear it.

But then, seeing as if the actual goals are so different anyway (see above), who cares.