Prosthetic Limbs By Philip A. Blair

Overview Prosthetics combines three main subjects: – Biology How the body connects to the synthetic limb. – Technology How the synthetic limb receives and sends information from and to the body. Also, how the limb moves and it’s design. – Psychology How the user can use and sense the limb.

World War II Created a large amount of amputees. In response the US National Academy of Sciences created the Artificial Limb Program in – Military funding has since created vast improvements in Prosthetic limbs. – Unlike the rest of history, we had technology.

Current Main Researchers Almost every major country. In the United States: – A large amount of research is carried out through the Defense Advance Research Projects Agency, aka DARPA. Division of the military. Investment is far above 100 million. – NASA provides designs used on their missions that could be repurposed for prosthetics. – Universities are often given grants.

Why does it matter? About 1.9 million people in the U.S. are amputees. – About 1 out of every 160 – 54% - Vascular Disease (blood vessel issues). Ex) Diabetes – If one leg it lost to diabetes, there is a 55% chance to lose the other leg within 2 years. Over 90% lose their legs. – 45% - Trauma Ex) The armed forces.

Job Description From DARPA DARPA told the researchers two main things: – It must be less than 9 pounds. – They must be able to pick up a raisin or a grape without squishing it and be able to tell the difference without seeing it. At first, the researchers laughed and said it was impossible, but they accepted the challenge (and money).

Modern Controllable Prosthetic Types: – Physical: 1.Using other body parts to act as signals. – Ex) Attaching straps to the other shoulder. – Mental: 1.Targeted Muscle Reinnervation (TMR) – Using nerves to the missing limb and reconnecting it to muscles near the affected area. 2.Directly through the missing limb’s nerve. 3.Directed by brain waves.

Control via other limbs A prosthetic can be controlled by other limbs or muscles that still work. – Controlled by the other shoulder, sensor on the feet, or muscle for the limb that is still functional. – Can be mechanical or electrical. – The most common type has a “hook” attachment, but others exist that are far more complex. – Can cost as low as $3,000. First use of this was in

Phantom Limb A phantom limb is when a person still perceives a limb exist when it does not. – There have been reports of people stating that their arm is cold or their finger hurts, when they no longer have that limb. The nerves that relate to that limb still exist. – The user can use their “Phantom Limb” to be able to use the nerve controlled Prosthetics.

Targeted Muscle Reinnervation Nerve signals extremely complex to decode. – This is a brilliant work around. Researchers could not decode the brain’s nerve signals, so they rewired them to surrounding muscles. – They then could detect when a muscle was being used and passed that information to the Prosthetic.

TMR Example It was the first time that a synthetic limb could be controlled by trying to move the missing limb. In other words, it was a thought to motion robot. m/watch?v=ddInW6sm 7JE m/watch?v=ddInW6sm 7JE

Two way communication? An unexpected development is that the user developed the ability to feel temperature and pressure on their missing limb at the retargeted location. – How to relay that information? – Current pressure transmitters either too large or too heavy.

Direct Nerve Control Success made, but still under research. User does not have to train or use other muscles, only think to move their “phantom limb”. The Prosthetic can return information to the nerves and thus to the brain. – This could include pressure and temperature.

Materials to use They started with a Electronic Neural Interface. – Not completely biocompatible. Must be replace every 2 years. – Painful and expensive. – Not MRI compatible. Researching fiber optics. – Highly biocompatible. Last up to 70 years. – Vastly faster Enables two way communication on more areas.

Fiber Optics

Fiber Optics Implications Fiber optics can be used to patch spinal cord injuries. Advanced control and sense of artificial limbs. – Goal is to reach and exceed the “Luke” hand. – Addition of artificial skin that can sense pressure and temperature. “Never” have to replace. Mng&feature=related 1:38-2:00 Mng&feature=related

Downside It cost at least $90,000. Still 3 years away from passing FDA regulations. – Even though it is on the “fast-track”. Still under research. – But it has worked.

Brain Waves Toyota developed a wheelchair that can move forward, rotate, and stop by monitoring the brain waves of the user. – It has a reaction time of 125 milliseconds. Side note – Intel plans to have brain implants ready for customers by Cause the iPhone will soon be boring. &feature=related 4:19 &feature=related

Questions 1. What is a Phantom Limb? – When a person does not have a limb, but can still sense it. 2. What is the first or second cause of amputation? – Trauma or blood vessel issues. 3. Do companies plan to someday plant chips in your head? – Yes.

Work Cited research-center-for-fiber-optic-interface-to-link-robotic-limbs- human-brain/ research-center-for-fiber-optic-interface-to-link-robotic-limbs- human-brain/ demonstrates-wheelchair-you-drive-your-brain demonstrates-wheelchair-you-drive-your-brain coalition.org/healthcare-providers/limb-loss- statistics/index.html coalition.org/healthcare-providers/limb-loss- statistics/index.html