Prosthetic Limbs

1. Prosthetic Limbs By Philip A. Blair

2. 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.

3. World War II • Created a large amount of amputees. • In response the US National Academy of Sciences created the Artificial Limb Program in 1945. • Military funding has since created vast improvements in Prosthetic limbs. • Unlike the rest of history, we had technology.

4. 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.

5. 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.

6. 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).

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

8. 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 1812. • http://www.youtube.com/watch?v=CaLVWlPshls

9. 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.

10. 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.

11. 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. • http://www.youtube.com/watch?v=ddInW6sm7JE

12. 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.

13. 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.

14. 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.

15. Fiber Optics

16. 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 exceedthe “Luke” hand. • Addition of artificial skin that can sense pressure and temperature. • “Never” have to replace. • http://www.youtube.com/watch?v=ppILwXwsMng&feature=related1:38-2:00

17. 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.

18. 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 2020. • Cause the iPhone will soon be boring. • http://www.youtube.com/watch?v=yff20TlHv34&feature=related4:19

19. 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.

20. Work Cited • http://science.howstuffworks.com/prosthetic-limb1.htm • http://blog.smu.edu/research/2010/09/8/smu-leads-5-6m-research-center-for-fiber-optic-interface-to-link-robotic-limbs-human-brain/ • http://www.popsci.com/scitech/article/2009-06/toyota-demonstrates-wheelchair-you-drive-your-brain • http://www.amputee-coalition.org/healthcare-providers/limb-loss-statistics/index.html