Written by Josh Doyle

Advancements in prosthetic limbs bring hope for future amputees

Pull: According to the research and reports from the RIC, you move the limb simply by thinking about it, just like a real one. This process is enabled by the little known fact that your brain doesn’t forget that it once had an arm or leg, even if you have been without one for a long period of time.

“Imagine not being able to bring a coffee cup to your lips, or brush your own teeth?”
It’s difficult to do, and as Dr. Lori A. Vallis proposed this idea, it was even more difficult knowing that people with amputations don’t need to imagine this in order to know what it’s like.
But hope does exist, and steps are being taken that may one day make these problems a thing of the past.
Recent research by large scientific organizations, such as the Rehabilitation Institute of Chicago (RIC), have brought us closer than ever to prosthetic limbs that are as functional to the human body as nature’s own. Prosthetic limbs aren’t new and have existed, at least in theory, since the first treatment of an amputation.
The first recorded prosthetic limb, known as the Roman Capua Leg, was constructed around 300 BC. Major breakthroughs occurred after WWII, when the National Academy of Sciences started the Artificial Limb Program.
Within the past 10 years, prosthetics have improved considerably in both appearance and practicality. Lightweight materials have made them lighter to carry, and motors have been implemented to allow up to three movements in a single limb. This is impressive work that we as humans should be proud of, but even this is nothing compared to the steps being taken now.
Researchers from Johns Hopkins University and the RIC have been collaborating for years and are closing in on creating lifelike limbs, which would offer nearly all of the movements of a regular arm.
The advancements came from a focus on the human nervous system, which seems only natural since this is where movement is controlled in an ordinary limb. Limbs of this nature are still experimental, and are known as ‘neural prostheses,’ or as many like to call them, ‘bionic limbs.’ By attaching electrical devices to nerve endings on the remaining part of a limb, the neural prosthetic receives messages from your brain and moves the limb as if it was your own.
“For an arm amputee, they use different muscles in the pectoral area, and through mechanical means, you can use a person’s brain impulses to control a robot,” explained Dr. Vallis, a professor in the department of Human Health and Nutritional Sciences, and a leading scholar in biomechanics.
According to the research and reports from the RIC, you move the limb simply by thinking about it, just like a real one. This process is enabled by the little known fact that your brain doesn’t forget that it once had an arm or leg, even if you have been without one for a long period of time. There exists a sensation, known as having a ‘phantom limb,’ which is basically the sensation of having the limb in your subconscious.
Some amputees even complain of feeling an itch in a limb that no longer exists, and the feeling only disappears when a prosthetic is introduced. This is evidence for how pervasive your mind is, and it is this power that scientists are honing in on in order to make prosthetics more effective.
“This research is so innovative and creative – it really pushes the scope of the science to become very applied,” said Dr. Vallis, who was excited by the advancements that have come of late.
One advancement is the improved precision of using hands and fingers. The absence of feeling can lead to over-squeezing, which in the case of a delicate object like another person’s hand, is something to be concerned about. Fortunately, the development of neural prostheses don’t stop at the development of joints and movements, but includes work on artificial skin as well.
Researchers are working on pressure-sensing pads, designed for fingertips and on the insides of hands, so that a person can feel what they are touching. The sensors create feeling in the remaining part of the limb depending on the texture and temperature of a surface. Scientists hypothesize that bionic limbs could have functioning skin within the next 20 years.
A large portion of the innovation has been made with prosthetic arms, which Dr. Vallis attributes to a higher degree of complexity than in developing legs. Still more challenging are postural components, because of balance issues.
But work is being done on legs as well, most notably by the United States military to help bring mobility back to injured troops.
On the same level of advancement in prosthetic limbs is the development of artificial eyesight.
The same theories exist in artificial eyesight where mechanical hardware is used in a cooperative effort with your existing nerve endings in order to transmit images to the brain. The levels it works at now allow one to see just outlines – blurry and vague – but it’s a start.
The idea at work here is medical advancement, positive in every aspect. Achievements like this are a reminder of our potential for bettering society, which is a refreshing focus when so much evidence rather supports our shortcomings.