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!
When wheels and heads are spinning - DFG research project on motion sickness in automated driving
22.05.2019 | Technische Universität Berlin
A new approach to targeting cancer cells
20.05.2019 | University of California - Riverside
Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.
The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...
Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...
With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.
Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...
'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.
However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...
Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future
When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
23.05.2019 | Materials Sciences
23.05.2019 | Materials Sciences
23.05.2019 | Physics and Astronomy