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Category: Health

Wie baue ich ein Fahrrad / Velo um für das Fahren mit einseitiger Armamputation? [Erfahrungsberichte / Vorschläge / Anleitung]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Wie baue ich ein Fahrrad / Velo um für das Fahren mit einseitiger Armamputation? [Erfahrungsberichte / Vorschläge / Anleitung]; published August 29, 2019, 16:36; URL: https://www.swisswuff.ch/tech/?p=10034.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Wie baue ich ein Fahrrad / Velo um für das Fahren mit einseitiger Armamputation? [Erfahrungsberichte / Vorschläge / Anleitung]}}, month = {August},year = {2019}, url = {https://www.swisswuff.ch/tech/?p=10034}}


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Für das Fahrradfahren mit Armamputation (bei mir: Unterarmamputation rechts) habe ich inzwischen einige praktische Erfahrungen gesammelt. Diese sind hier zusammengestellt.

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TRS Jaws [new product - first use report]

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Wolf Schweitzer: Technical Below Elbow Amputee Issues - TRS Jaws [new product - first use report]; published August 10, 2019, 10:51; URL: https://www.swisswuff.ch/tech/?p=9769.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - TRS Jaws [new product - first use report]}}, month = {August},year = {2019}, url = {https://www.swisswuff.ch/tech/?p=9769}}


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The TRS Jaws is a voluntary opening gripper where you can set the grip strength by a lever. The grip then varies between very light, maybe under 1 kg or so, to somewhere above 5 kg. This is a first real use report, after I used it permanently since roughly around May 21, 2019, give or take a few hours.

There are just a few points to address at this stage. If you wear a body powered arm for real work [link], you may now buy one.

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Angular constraints of prosthetic grippers and functional success correlation [technical evaluation]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Angular constraints of prosthetic grippers and functional success correlation [technical evaluation]; published February 11, 2019, 04:55; URL: https://www.swisswuff.ch/tech/?p=9322.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Angular constraints of prosthetic grippers and functional success correlation [technical evaluation]}}, month = {February},year = {2019}, url = {https://www.swisswuff.ch/tech/?p=9322}}


I had evaluated, subjectively, the grip performance of various prosthetic options that I have. These have been already analysed in the context of grip taxonomy, where so far, research has largely focused on grip geometry as such, using some idiosyncratic logic that I found not too relevant.

Using a more relevant logic, I approached the question of grip mechanic from a different angle, both verbally and proverbially speaking: from a user angle, both actually geometrically and subjectively speaking.

I realized that most of my frequently used grips and grip situations fall into a far more narrow range of angle distributions than I had ever assumed.  So I sat down to add "typical object angles" to my already present grip success statistics over a list of my most frequently or typically used grips. Then I did that in theory and THEN I figured, why not go and video some. Thereby, a prosthetic hook as gripper device appears to be a lot more advanced, design wise, geometrically, in reducing device materials, bulk and design to approximate a really good overall use performance than the iLimb (which I have here also for as much testing as I like) and with that, many current commercial (or other) multi articulated hands.

In fact, prosthetic hands appear to be by far the older (and thus possibly less reflected) geometric design idea of a prosthetic arm's terminal device than the definitely more modern split hook. I may also go history hunting, but the claim that a split hook is old or outdated, and that therefore by inference a prosthetic hand is automatically new or more modern, as an idea, is wrong, particularly technically speaking. But also historically, to replace a hand with a hand is a straightforward design idea, that does not take any imagination, thus it is reportedly old, very old.

The far more elegant reduction, also of angles and controls, to fit into the limited action and option constraints of an arm amputee, is certainly that of a body powered split hook. It boils down the prosthetic needs to a successful sleek elegant reduction of a functional minimum, making it the ideal choice for anyone that wants a maximum of performance from a minimum of failure, cost, decay, bulk, futile grip attempts and total overhead. The subtle distinction is that a "body powered split hook" is an entirely different beast than a passive hook, obviously, which probably no one ever noticed, particularly not the people that assumed that a body powered split hook is best portrayed by installing a "Captain Hook" metaphor.

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Myoelectric prosthetic arms do not "really" function - so whom to sell them to? [cynical economic considerations]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Myoelectric prosthetic arms do not "really" function - so whom to sell them to? [cynical economic considerations]; published February 2, 2019, 15:11; URL: https://www.swisswuff.ch/tech/?p=9304.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Myoelectric prosthetic arms do not "really" function - so whom to sell them to? [cynical economic considerations]}}, month = {February},year = {2019}, url = {https://www.swisswuff.ch/tech/?p=9304}}


Myoelectric prosthetic arms do not "really" work, we all know that, and it has been clear for decades.These factual aspects are difficult to make that problem go away like, poof. With that the more interesting question is: whom do we sell these to?

While selling to people that are gullible [link] seems to have a lot going for it, it is risky. A more sustained approach may base on taking actual risk factors for myoelectric failure into account:

  • Sweat
  • Weight
  • General error rate

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User perspective on the rubber hand illusion in a wider sense – prosthetic arm and ownership for real use [reflection and consideration]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - User perspective on the rubber hand illusion in a wider sense – prosthetic arm and ownership for real use [reflection and consideration]; published January 2, 2019, 22:16; URL: https://www.swisswuff.ch/tech/?p=8882.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - User perspective on the rubber hand illusion in a wider sense – prosthetic arm and ownership for real use [reflection and consideration]}}, month = {January},year = {2019}, url = {https://www.swisswuff.ch/tech/?p=8882}}


The year 2018 was interesting in relation to the rubber hand illusion subject.

I had participated in an extensive interview study regarding embodiment just a year before [link]. Then, I had been identified as a prosthesis "super user" [link] - these people wanted to investigate my type of "embodiment" through fMRI, but we quickly identified my prosthetic arm design (not my brain) as the key aspect regarding the question of why I have a prosthesis that I can actually use rather than just pose with as so many others. My own view here clearly is that if you are after embodiment, you have to go all Sherlock Holmes, you have to go all forensic, all CSI and all crime mystery: and as in "cherchez la femme" when looking for a motive in a crime, it is "cherchez le bras" when studying embodiment: for all issues that center around prosthetic use, go for the core physical aspects first. There are extremely bad things that may, can, and will happen if you do not make that your real first priority. The "rubber hand illusion" is an extreme variation of body ownership of a rubber hand that does not even touch a person and still that person thinks they are being touched if that rubber hand is touched. The illusion to make an amputee believe they embody or bodily own a prosthetic hand is quite different. But both pose risks, whereas the risk that an amputee faces when getting a prosthetic arm that is integrated into his body image has not been considered yet. My slightly experience based consideration proposes that the body image is tyrannically governed, for good and for bad, and if the prosthetic body part - already starting with bad cards, body image wise - craps out, and it always does so far too often, then it draws the hot red angry ire, the depressed disappointment, the falling apart of the cyborg body, of the amputee - and definitely not the cool "oh a neutral object just disintegrated" that one will wish for from a societal, insurance or repair view. The integration into a body image brings with it that the device becomes subject to totally tyranically governed bodies. When it is difficult enough to make any device ready for real world usage, making it ready to survive tyrannies of that nature will be even harder. I proposed an unforgiving approach to failure testing in a recent paper (link) but I cannot say that paper has been greeted with any enthusiasm by the industry that actually builds prosthetic arm components. Because they get to directly face the anger, hate, and rejection of all the users that they had not informed well of just how fragile their prosthetic arm parts really are (link), and they are in absolutely no position to technically improve these parts. So, manufacturers go into hiding. They do not want many users - they want users that buy and do not complain. The last thing they need is a hard bright unforgiving look into just how bad their engineering is. Every non-user, every rejector, should be cautiously left alone, not recruited to wear a prosthesis - because the risk is considerable (link). Researchers currently have the problem that amputees run away, everywhere (link), also because we are continously treated as mentally incompetent. So in essence, we are a group of people that increasingly realizes the extent to which we are being fooled, being had, told stories, and increasingly, we are getting critical. Potential rubber hand illusion switches, dragged to market to be soldered into prosthetic arms, if ever they are a medical treatment or a part thereof, will have negative effects as well: what are these? What do we know about deeply problematic aspects of bodily ownership? I had been invited to talk about that aspect for a group of people interested in robotic control and user interfaces, on December 7th 2018, in Mannheim (Germany). The presentation that I gave now is typed out here in more detail for further reference.

Rubber hand illusion is an idea that, by and large, was somehow transformed into multi-sensory rubber hand illusion, and they now want to put it into prosthetic arms to make users believe the prosthesis belongs to their bodies.

With that, rubber hand illusion goes to market1)As in: piggy goes to market..

This is not really that fascinating. While I am not interested in prosthetic arms because I find the field fascinating, I have been drawn into the field due to circumstances. And as much as you feel that I am locked into this constraint space of shared idiocies, dreams, hopes and failing hardware together with you, in some type of brotherhood by bad fate, you may also realize you are locked into this with me, as consequence of bad fate. Those then are also circumstances. As I deal with it, you may also have to find a way. If you think that is uncomfortable, send me a mail, so we may talk about uncomfortable a bit.

The ultimate consquence of this piece of reflection is not at all bad, however. We will see just how too much "ownership" has bad aspects as well. It risks to slip prosthetic hands into a domain where it is subject to the most vicious decision making that there is: tyrannic and wilful, impulsive and emotional decision making within one's own very personal domain of body or body image with owned body part dependent urgencies and requirements. To withstand these storms, a  prosthetic arm has to withstand not only the physical requirements of real life use (which it normally does not to a degree that will make your jaw drop), it also has to be acknowledged in that capacity by manufacturers and care-givers, emergency teams or repair units, where none of similarly urgencies are currently provided.

To even reach a level of "tool", to be useful enough to be accepted as technical solution (not as embodied "owned" limb), a typical prosthetic arm may have to undergo a most serious metamorphosis, from commercial parts (link)(link) to tuned and optimized parts (link). If you are in R&D and want to do something good in support of arm amputees, it may be relevant to address actual issues such as failing devices or phantom pain (link), before going all out on a limb and drag ill-defined concepts to a domain where they may wreck more than they really help.

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Footnotes   [ + ]

1. As in: piggy goes to market.

CE marking or norm in relation to components for prosthetic arms

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - CE marking or norm in relation to components for prosthetic arms; published December 25, 2018, 15:20; URL: https://www.swisswuff.ch/tech/?p=7749.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - CE marking or norm in relation to components for prosthetic arms}}, month = {December},year = {2018}, url = {https://www.swisswuff.ch/tech/?p=7749}}


CE-marking or norm

The CE-marking establishes that a particular item or product conform to European product law in relation to health, safety, and environmental protection standards [link].

As this text is not public or may be hard to get into the public eye, why not just go ahead and drag it out. I started to be interested by the backgrounds of what our prosthetic limbs and their technical documentation ideally could be already a few years ago [link].  So, a few blog posts here do have a long history, longer than others, and were assembled over quite a period of time.

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Coping with my own phantom pain {update: vascular congestion and cold skin: compression really helps}

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Coping with my own phantom pain {update: vascular congestion and cold skin: compression really helps}; published December 17, 2018, 22:07; URL: https://www.swisswuff.ch/tech/?p=9034.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Coping with my own phantom pain {update: vascular congestion and cold skin: compression really helps}}}, month = {December},year = {2018}, url = {https://www.swisswuff.ch/tech/?p=9034}}


I have gone after possible sources of my phantom pain, over the past years, to better cope with it.

There are aspects that I can influence directly, and others that I seem to be able to direct only indirectly.

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BLUE LIGHT SPECIAL: Pitch black cynicism in the Cybathlon 2020: "the role of a disabled person" [not funny]

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Wolf Schweitzer: Technical Below Elbow Amputee Issues - BLUE LIGHT SPECIAL: Pitch black cynicism in the Cybathlon 2020: "the role of a disabled person" [not funny]; published October 25, 2018, 23:02; URL: https://www.swisswuff.ch/tech/?p=8680.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - BLUE LIGHT SPECIAL: Pitch black cynicism in the Cybathlon 2020: "the role of a disabled person" [not funny]}}, month = {October},year = {2018}, url = {https://www.swisswuff.ch/tech/?p=8680}}


"With that, visitors of the Cybathlon Experience (TM) can test the role of a disabled person" (können in die Rolle einer behinderten Person schlüpfen) (Oral presentation: "CYBATHLON – bewegt Mensch und Technik", 5.15pm–6.00pm, Dr. Roland Sigrist, Cybathlon, ETH Zurich, Raum E 1.2) -- I was there, one among the 8 people that made the audience of this "sold out" Cybathlon talk; amputees are there for "entertainment" (clearly one of the requirements written on a slide in the presentation) (ist es das, was wir als behinderte Personen spielen? eine Rolle, ja?).

After defining a remarkably strange prosthetic arm race, the makers of the Cybathlon 2020 now start to openly bathe us in their pitch-black cynicism.

Why? Pressing question.

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Embodiment of a prosthetic arm [reflections, thoughts, considerations]

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Wolf Schweitzer: Technical Below Elbow Amputee Issues - Embodiment of a prosthetic arm [reflections, thoughts, considerations]; published September 16, 2018, 15:42; URL: https://www.swisswuff.ch/tech/?p=8513.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Embodiment of a prosthetic arm [reflections, thoughts, considerations]}}, month = {September},year = {2018}, url = {https://www.swisswuff.ch/tech/?p=8513}}


So, apparently I had been "identified" as a "super prosthesis user" by a group of researchers. And I was invited to talk about embodiment in context of the "rubber hand illusion" at a user interface or robotic control workshop [link].

So is that what I am: a "user"?

Tsk.

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Modifying Shimano Ultegra road bike setup on a Colnago C40 for left handed use - second approach [technical right below elbow amputee core focus work / bike adaptation]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Modifying Shimano Ultegra road bike setup on a Colnago C40 for left handed use - second approach [technical right below elbow amputee core focus work / bike adaptation]; published January 27, 2018, 15:30; URL: https://www.swisswuff.ch/tech/?p=8196.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Modifying Shimano Ultegra road bike setup on a Colnago C40 for left handed use - second approach [technical right below elbow amputee core focus work / bike adaptation]}}, month = {January},year = {2018}, url = {https://www.swisswuff.ch/tech/?p=8196}}


After a first approach, where also the history and idea where it came from is detailed [link], I now set up and tested a second approach to modifying my Colnago C40 carbon bike with a triple chainring Shimano Ultegra chainset.

The extensive testing of my first approach that I had performed there lead to a range of concise detailed issues and problems. There were now addressed, all, and thus a second (and significantly better) approach resulted.

As stated before, no disability sports advocate specializing in road bikes and no bicycle mechanic specializing in individualization and custom solutions over the years ever thought this was possible in this way. They all said it could not be done. And I had asked a few of them, since it had bugged me a lot. And as I had sold my Cannondale road bike after the amputation, thinking there was no way, I now got myself a road bike back and decided to go down my own path to really use it the way it is meant to be used.

Generally and as part of riding a road bike, I wanted fast and comfortable gear switching, fast and accessible and comfortable braking, and I wanted to be able to enjoy various and if possible equally comfortable sitting positions or body positions. A great road bike trip may be a lot longer than a fast mountain bike trip into the forest. Last but not the least, as amputee my stump usually would suffer from vibration induced pain after 20 minutes  particularly with hard connectors such as the Mert or Freelock adapters, so padding definitely was an issue.

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Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment [article out]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment [article out]; published January 4, 2018, 14:29; URL: https://www.swisswuff.ch/tech/?p=8066.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment [article out]}}, month = {January},year = {2018}, url = {https://www.swisswuff.ch/tech/?p=8066}}


 


This is a blog post of one of the rare focused and well based scientific journal articles that really explains how real work, body powered and myoelectric arms relate and go together for a unilateral right below elbow amputee in a physically demanding work environment.

The prior presentation of this paper [poster at Cybathlon symposium 2016], which had been more pragmatically worded (with me thinking people would know anyway), this was now written up as article and published. During that process, the reviewers clearly made great points of all kinds of aspects I never knew were not sky clear to everyone.

So maybe, writing a ~ 30 page case study with > 210 references does clarify stuff, at least potentially and for those that actually read it. But possibly, it still requires attention to even just read it.

Knowledge does not come easy, Highlander! (Nakano, in: Highlander III The Final Dimension)

 

If you are more interested in visionary posts, read about the gadget features of the prosthetic arm in Kingsmen: The Golden Circle [link]. And technically, myoelectric control did have it coming. That technology remained uncool for four decades [link].

Publication [link]

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Modifying Shimano Ultegra road bike setup on a Colnago C40 for left handed use - first approach [technical right below elbow amputee core focus work / bike adaptation]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Modifying Shimano Ultegra road bike setup on a Colnago C40 for left handed use - first approach [technical right below elbow amputee core focus work / bike adaptation]; published December 3, 2017, 15:11; URL: https://www.swisswuff.ch/tech/?p=7816.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Modifying Shimano Ultegra road bike setup on a Colnago C40 for left handed use - first approach [technical right below elbow amputee core focus work / bike adaptation]}}, month = {December},year = {2017}, url = {https://www.swisswuff.ch/tech/?p=7816}}


I got myself a Colgnago C40 carbon road bike / race bike / Rennrad for leisure amateur purposes. That is, for the colloquial ride. With that, I am not a professional or competitive racer. Modifying my Shimano Ultegra road bike setup for left handed use therefore aims towards leisure purposes.

How to go about riding a road bike as arm amputee. This is the first approach and test. If you are after the improved set-up, head over to the page with the second approach [link] because that really worked a lot better.

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iLimb / myoelectric arm: chronic skin rash due to local myoelectric skin electrode placement during bicycle ride [complication report] [bad hand days/weeks/month] (towards the AUA/WIFUCD dichotomy)

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - iLimb / myoelectric arm: chronic skin rash due to local myoelectric skin electrode placement during bicycle ride [complication report] [bad hand days/weeks/month] (towards the AUA/WIFUCD dichotomy); published January 29, 2017, 17:10; URL: https://www.swisswuff.ch/tech/?p=7130.

BibTeX: @MISC{schweitzer_wolf_1568601217, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - iLimb / myoelectric arm: chronic skin rash due to local myoelectric skin electrode placement during bicycle ride [complication report] [bad hand days/weeks/month] (towards the AUA/WIFUCD dichotomy)}}, month = {January},year = {2017}, url = {https://www.swisswuff.ch/tech/?p=7130}}


Testing myoelectric arm components in general: uncharted territories

Prosthetic arms in general do not usually appear to be tested a lot before getting thrown at the user, which is a statement that I find many examples for (glove may disintegrate all by itself; glove dies after just a few minutes of car washing; bolts never checked for size; etc.).

This is not to say that this is intrinsically bad - no. This is to say that the burden of testing and suffering the associated negative consequences of that also then reside with the user. If - at all - a company finds it unacceptable that users perform the testing and resulting discussions bad in any way, then (and only then) may they wish to consider a different type of product marketing and testing approach.

The question of whether manufacturers of prosthetic components test anything at all, also for skin safety, that question: it now also officially extends to skin electrodes.

As suggested by their ample advertising, a range of "bionic" myoelectric arms are demonstrated and shown around, as being able to sustain bicycle riding. So we have to assume that everyone seems to be of the opinion that it is cool to ride bikes, with, say, wearing an iLimb.

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