Crude prosthetics have been with us from the very first experience of losing a part of ourselves whether it’s a fictional Captain Hook or the immortalized Long John Silver’s peg leg. My first experiences with semi-modern prosthetics occurred in my med school days at the height of the Thalidomide crisis. This was the era of new synthetic rubbers and plastics but there were always the two drawbacks of rigid immobility and no sensation. The Vietnam war fast forwarded changes including the addition of flexing joints. Robotics took another great leap when industry began programming repetitious behaviors in mass production lines and of course the CANADARM in space was a great kudo for our scientific community. Back here on the home planet, the same base limitation continued. No sensation. Progressive improvements in motor skills and flex joint function combined with new advances in durable materials were all great strides even though they only addressed the motor and aesthetics of artificial limb functionality.
In November of this year, a University of Utah team revealed its breakthrough construct at the annual Society for Neurosciences meeting in Washington. For the first time…a limb that provides the wearer both a sensationof touch and an awareness of position. Funding and drive wheel behind all this advance is the HAPTIX program of the U.S. military specifically charged with fast tracking more advanced robotics for military amputees.
It works by a computer program that simulates the touching of a VIRTUAL object in a manner similar to the principles behind the workings to existing home computer virtual reality games. As the wearer moves the arm across the object a virtual hand on the computer screen moves as well recording the ridges and grooves on the object then storing the “sensations” for future reference. Almost every object can be scanned in this fashion creating a permanent computer memory. These memories are then transferred via a series of micro electrodes placed in the nerves in the patient’s arm.
How effective is the transfer? Dexterity Testing has been done on small food objects such as grapes with impressive feedback from the amputee patient
Three unexpected benefits observed by the researchers included an initial reduction in the frequency and severity of “phantom limb” pain syndromes but by far the greatest positive bonus was the noticeable improvements in motor skills when compared with the motor functions of other robotic devices in common usage.Lastly, it’s an intangible for the rest of us but for the amputee it’s a dream to “feel” again.
To date, this science in its infancy has only evolved upper limb constructs but I will state categorically similar progress with lower limb amputees will soon follow
Dr. David Carll