An amputation of part of the arm results in an
immense functional loss, which limits the patient in performing activities of
daily life. This is due to the divergent functions of a hand, including complex
motor functions but also non-verbal communication and sensing of the direct
environment. Worldwide, the major cause that results in the amputation of a
limb is trauma (severe tissue damage) like industrial, farming and motor
vehicle accidents or war related injuries. Further causes are infection,
malignant tumours, burns, frostbite and congenital anomalies.
After amputation of a limb an
attempt for recovery can be made by replacing the original body part by a
prosthesis. There are three commonly used prosthetic options to consider for
the upper-extremity amputee: a pure cosmetic prosthesis, a body-powered
prosthesis or a myoelectric prosthesis. Pure mechanical (or body-powered)
prostheses are the most durable prostheses and have a form of sensory feedback.
They, however, are cosmetically less pleasing than a myoelectric unit, require
gross limb movement, and their functionality is very limited. In myoelectric
prostheses, electromyographic activity of the remaining muscles is measured by
means of electrodes on the skin and then converted into a control signal.
Currently, the usage of the myoelectric prosthesis
type is low, mainly due to lack in functionality, limited selectivity in
control, lack of natural control, shortage in sensory feedback and loss of
functional muscle contraction possibilities (since residual muscle training is
only possible after prosthetic fitting). Due to these shortcomings of currently
available myoelectric prostheses, about 70% of the patients do not use their
powered prostheses.
To enable practical and long-term use, the
amputee needs a prosthesis with a natural, intuitive, fast and non-fatiguing
command interface. The combination with a virtual reality environment, in which
the patient can start selective muscle training immediately, is an entirely new
concept and forms the basis of a functional prosthetic system that could
restore part of the lost arm and hand function. Therefore, the goals of this
project are to:
- improve the control of a myoelectric
arm-prosthesis by increasing the number of degrees of freedom using
multichannel surface electromyography
- develop a natural and intuitive feedback
mechanism
- develop a virtual reality training program to
enable aimed early-phase rehabilitation
The project is divided into 7 work packages.
