High operating force
The Sierra prosthetic hand from 1945 performed better than the newer hands. The inner hand shown in the photo are covered by a cosmetic glove.
The study, which was carried out by researchers from TU Delft and the University of Groningen, measured the force required to operate a number of contemporary body-powered prosthetic hands. The researchers compared the results to earlier measurements from 1987 and came up with remarkable results: today’s prosthetic hands perform equally or less well than those from 1987. The grip strength of the hands is insufficient and a very high operating force is required. Another remarkable result: a prosthetic hand developed in 1945 performed better in the test than the newer prosthetic hands.
TU Delft researcher Gerwin Smit: “The study offers a possible explanation why over half of all people with a body-powered prosthetic hand do not use it or even wear it. Besides this, some prosthetic arm users tend to suffer overload problems over time. These problems may well be a result of the excessive operating force required.” This is currently being researched further in Groningen and Delft.
Worldwide over 30% of prosthesis users wear a body-powered prosthesis. A body-powered prosthesis is operated by pulling a cable (a little like the brake cable on your bike). This cable is attached to a harness worn on the opposite shoulder. Subtle movements between the arm wearing the prosthesis and the opposite shoulder pull the cable taut and open the prosthesis. Another popular prosthesis is the electric prosthesis. This is worn by about 40% of prosthesis users worldwide. Then there are also cosmetic prostheses.
The big question that the researchers raised as a result of this study was why there is hardly any investment in body-powered prostheses. Gerwin Smit: “With current technology it must be possible to easily improve prostheses, resulting in enormous progress for those who have to use them. In recent decades, millions have been invested in electric prostheses. The difference in price between the types of prosthesis may have influenced this, as the retail price of an electric prosthesis is around 10 to 100 time higher than a body-powered prosthesis. This makes it more attractive from a commercial point of view to invest in electric prostheses. Yet despite the investments, electric prostheses are slower and heavier than body-powered prostheses.”
In order to solve the problems of prosthesis users, TU Delft is working on making improvements to body-powered prosthetic hands. The ultimate aim is to develop a lightweight prosthetic hand with a lower operating force and a higher grip strength.
More informationGerwin Smit:
Ilona van den Brink | EurekAlert!
Scientists re-create brain neurons to study obesity and personalize treatment
20.04.2018 | Cedars-Sinai Medical Center
Research offers clues for improved influenza vaccine design
09.04.2018 | NIH/National Institute of Allergy and Infectious Diseases
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Health and Medicine
20.04.2018 | Materials Sciences
20.04.2018 | Earth Sciences