This "evaluation" was not directly intended at first, as we just wanted to know what worked better. The Cybathlon event had me first impose myself unto the organizers and convince them to also allow body powered arms and to furthermore test for practical daily use aspects, after which Bob Radocy won the competition with an Evolution Prehensor by TRS.
The attached Cybathlon symposium then was a great moment to share my own applied experiences that we had rather systematically collected already. For the written article, more clear explanations and clear justifications for statements were required than for the shorter and less forgivingly worded poster presentation. In short, myoelectric arms may have their role, but for real work for a unilateral below elbow amputee, they constitute a Dead Horse in my rather extensive experience.
However my main premise always was that academic researchers and even a number of commercial producers live on a totally different planet, which is why by the very design of our disjunct worlds, they will never be able to understand a single word I am saying, even if it is spread out and annotated, referenced and explained in ridiculous detail. The concepts and the language, the views and expectations, the smelly sweaty and rash covered realities, the financial and time wise aspects of crappy builds, and the repair, failure and decay issues, are all absolutely alien to most of them.
That also will be the reason why by far the best prosthetic arm for "real work" in 2019 certainly still will be the body powered split hook.
Prosthetic arm research predominantly focuses on “bionic” but not body-powered arms. However, any research orientation along user needs requires sufficiently precise workplace specifications and sufficiently hard testing. Forensic medicine is a demanding environment, also physically, also for non-disabled people, on several dimensions (e.g., distances, weights, size, temperature, time). As unilateral below elbow amputee user, the first author is in a unique position to provide direct comparison of a “bionic” myoelectric iLimb Revolution (Touch Bionics) and a customized body-powered arm which contains a number of new developments initiated or developed by the user: (1) quick lock steel wrist unit; (2) cable mount modification; (3) cast shape modeled shoulder anchor; (4) suspension with a soft double layer liner (Ohio Willowwood) and tube gauze (Molnlycke) combination. The iLimb is mounted on an epoxy socket; a lanyard fixed liner (Ohio Willowwood) contains magnetic electrodes (Liberating Technologies). An on the job usage of five years was supplemented with dedicated and focused intensive two-week use tests at work for both systems. The side-by-side comparison showed that the customized body-powered arm provides reliable, comfortable, effective, powerful as well as subtle service with minimal maintenance; most notably, grip reliability, grip force regulation, grip performance, center of balance, component wear down, sweat/temperature independence and skin state are good whereas the iLimb system exhibited a number of relevant serious constraints. Research and development of functional prostheses may want to focus on body-powered technology as it already performs on manually demanding and heavy jobs whereas eliminating myoelectric technology’s constraints seems out of reach. Relevant testing could be developed to help expediting this. This is relevant as Swiss disability insurance specifically supports prostheses that enable actual work integration. Myoelectric and cosmetic arm improvement may benefit from a less forgiving focus on perfecting anthropomorphic appearance.
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