Waking up in the morning, then getting up and dressing is the most common thing to do to almost everyone living in the United States. But each year 150,000 Americans undergo a lower-extremity amputation and need to take an extra step between waking up and getting up, this step is putting their protesis on. The leading causes of amputation are diabetes mellitus, peripheral vascular disease, neuropathy, and trauma. Many of these people are able to walk almost normally again thanks to an artifact called Myoelectric Knee.
Myoelectric refers to the electrical impulses (signals) generated by muscles of the body and captured by electrodes. Myoelectric signals are studied and analyzed using electromyography. Electromyography reads the electric signals produced by the muscles, similar to the ones produced by the heart, and analyzes the amplitude or energy transmitted through the muscle to move a certain part of the body.
Usually, myoelectric signals are received with a lot of noise and require significant signal processing to obtain a clear signal. Myoelectric signal processing typically includes one or more stages of amplification, high-and low-pass filtering, rectification, integration and sampling
A myoelectric prosthesis uses the myoelectric as information, once the signal is processed, it can be transformed into a movement by myoelectric controls. Such movements can be flexion/extension in the case of the knee, opening/closing of the fingers or wrist supination/pronation (rotation). A myoelectric knee uses the residual neuromuscular system of the human body for control of the electric-powered prosthetic knee, hand, elbow, foot or wrist.
Myoelectric knee benefits
One benefit is that myoelectric knee is easy and fast to learn and use. At a study done by the School of Kinesiology at the University of Michigan, it was found that people with lower limb amputations, using myoelectric prosthetics were able to match the accuracy of the non amputated control group after short-term practice. Results from Gordon and Ferris suggest that practice plays a larger role in control than the location of the muscle where the myoelectric prosthetic is attached. For this reason, it is expected that individuals with different levels of amputation demonstrate similar results.
The oldest prosthetic known is a 3,000-year-old wood toe found in a mummy in Egypt. The best limb prosthesis would be the biological one, to grow your own new limb and attached it to your own body. The second-best limb prosthesis would be like the one that Luke Skywalker gets after losing his hand at a battle with Dart Vader, or even better to have super strength like the Six Million Dollar Man and The Bionic Woman. Until Science and technology get us to these realities, the technology that gives amputee people the most natural movements and looking are the Myoelectric prosthesis, giving natural movements controlled by the brain through the energy emitted by the muscles and tendons that use to retrieve and release the body parts that are now missing. Science and technology have advanced a lot in the last 3,000 years, hopefully, the best limb prosthesis will be available in the next 10 to 25 years.