Technology with attitude

Hand prosthesis with sense of touch shows lots of promise (video)

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As Neurogadget reported last week, ‘feeling’ hand prosthetic technology has taken a great leap forward in the past year. However, as successeful as Dr. Silvestro Micera’s technology is, it is not the only line of research currently being investigated. Dr. Dustin Tyler’s research group at Cleveland Veterans Affairs Medical Center and Case Western Reserve University also released a demonstration of their ‘feeling’ hand in December of 2013, and the results they obtained are truly incredible.

Igor Spetic,  a 48 year old man who lost his hand in a workplace accident, has been implanted with the sensors necessary to feel feedback from the prosthetic hand for over 18 months.

These sensors allow Mr. Septic to feel from 20 distinct locations along the hand. The sensors can be further tuned to transmit different types of feedback, which allow him to feel different textures. All in all, this feedback allows for an unparallelled level of control. For instance, in the video below, Mr. Septic can be seen using the hand to remove cherry stems.

The reason this hand can be so sensitive, is the nature of the sensor technology. Sensory nerves in the arm are arranged in bundles, which means that the majority of the nerves are not readily accessible for implantation.

What Dr. Dustin Tyler’s research group has done, is create a 7mm tube or “cuff” electrode that flattens out the nerve bundle. This increases the surface area of the nerve bundle, which makes more of the nerves easier to access. The significance of this is that stimulators can be planted more precisely to correspond to different parts of the hand. For instance, Mr. Septic can detect sensations on several fingers and on the back and side of his missing hand.

These sensations correspond to stimulation on the corresponding part of the prosthetic. Furthermore, the sensations are consistent over time. Everytime the prosthetic is connected to the sensors, the sensations are localized to the same parts of the hand.

bionic prosthetics
The tubes pictured in this photo wrap around nerve bundles and flatten them.

This technology is currently undergoing a pilot feasibility trial, and if that is successful, the technology could be on the market 5-10 years from now.

In the mean time, Mr. Septic is maintaining a positive attitude. “It’s real exciting to see what they are doing, and I hope it can help other people,” Spetic says. “I know that science takes a long time. If I don’t get something to take home, but the next person does, it’s all to the better.”

Source: technologyreview.com