The future of hand prostheses depends on the development of myoelectric control. Today, myoelectric control is the best form of neuromuscular control we have. However in the future, EMG pattern recognition will be possible, and it is crucial that such technology be utilized for multifunction control of prosthesis. If that area of research is developed, the future will allow individual finger movements and coordinated movements of the hand, wrist, and elbow. Neuroelectric control is a more advanced form to monitor impulses between the motor nervous system and the brain. When these direct impulses are recognized, better human-like finger movements can be performed. Limited movements of fingers and hands will be overcome by designing a non-linear control system as well as the micro sensory system equipped with force sensors and joint position sensors integrated into the mechanical structure of the finger. Besides the major electro-mechanical control system, many peripheral components of hand prosthesis are expected to improve. They consist of smaller and more efficient batteries and biomaterials that mimic the texture of actual skin. Such material is very important in the cosmetic aspect of artificial hand. Aside from the inner mechanism of hand prosthesis, the ability to perform remote diagnosis, adjustments, and other remote consulting services offers tremendous promise for the patients and families, as well as the other members of the rehabilitation team. Of course, the Internet as a whole-with all its potential to educate in a variety of formats and to promote greater communication-will only become a more refined instrument over the next several years. Here are several research groups paving the way for future technologies: Rutgers University Kathryn Laurentis and Constantinos Mavroidis are working on a Shape Memory Alloy actuated prosthetic hand that has 20 degrees of freedom and is light and compact. AShape Memory Alloys consist of a group of metallic materials that demonstrate the ability to return to some previously defined shape or size when subjected to the appropriate thermal procedure. This phenomenon is known as the Shape Memory Effect (SME). The SME occurs due to a temperature and stress dependent shift in the material’s crystalline structure between two different phases called Martensite and Austenite. Martensite, the low temperature phase, is relatively soft whereas Austenite, the high temperature phase, is relatively hard. (1) This property allows the mechanical actuation of the hand using very light and durable components.

Another project lead by Bill Craelius and Sam Phillips is working on an artificial hand designed to give amputees individual control over at least three fingers by using their original nerve pathways. The prototype allows so much control that one amputee has been able to play a keyboard with it. (2,4) The prosthetic uses electrical impulses in the arm from "phantom limb" movement, called residual kinetic imaging (3). The user's original motor pathways are used to control robotic replacement parts without relearning how to move their hands. Oxford Orthopaedic Engineering Centre Dr Peter Kyberd has been working on a new prosthetic hand that is controlled by a small computer contained within it. The hand uses low-level signals generated by the user flexing muscles in the forearm, and translates them into action. The user of the hand can give three basic instructions: open, close, and grip. What makes the device unique is that sensors inside it allow it to decide what grip shape to adopt and how hard to squeeze. If it feels an object slipping, it will automatically grip harder without the user's intervention. (5,6)

Autonomous Systems Engineering Labs Wenwei Yu and Ryu Katoh are developing a prosthetic hand that uses electromyogram (EMG) for presuming the amputee's intention. EMG is electric potential measured on a skin surface when a muscle contracts. It can be generated from amputee's partially lost muscle. (7)

References: (1) http://cronos.rutgers.edu/~mavro/papers/THC.pdf (2) http://www.cnn.com/HEALTH/9806/10/artificial.hand/ (3) W Craelius, The Bionic Man: Restoring Mobility. Science 295 (8 Feb 2002) 1018-1021 (4) http://www.voicesofinnovation.org/archives/Sept_02/P3_9_4_02.asp (5) http://www.ox.ac.uk/gazette/1996-7/weekly/010597/news/story_3.htm (6) http://www.dinf.ne.jp/doc/english/Us_Eu/conf/tide98/131/tide3.htm (7) http://junji.complex.eng.hokudai.ac.jp/projects/ProstheticHand/cgi/sender.cgi?index (8) http://www.oandp.com/edge/issues/articles/2003-03_05.asp (9) www.surrey.ac.uk/eng/InfoPoint/online/mechatronics_case_studies/Prosthetic%20hand%20report.doc