Novel Technology may Help Amputees Touch and Feel Again

Highlights:

• Scientists develop a novel robotic prosthetic arm or LUKE arm that helps amputees control hand movements by thought as well as touch and feel things once again
• The prosthetic arm and fingers are controlled by microelectrodes placed within the person’s muscles. These microwires send impulses to an external computer that interprets these impulses and tells the hand to move
• The robotic arm is also equipped with sensors that transmit signals to the microwires, replicating the feeling of touch when a person holds an object in their hand. Thus, a person can 'feel' the consistency of the object being held so that the right amount of pressure can be applied

LUKE arm is the novel robotic prosthetic arm developed that helps amputees control hand movements by thought, and to touch and feel things once again, something that is impossible with standard prosthetic arms. The study was led by Dept of Biomedical Engineering University of Utah and involved several other institutions including its Department of Neurosurgery, Department of Orthopedics, and Department of Physical Medicine and Rehabilitation, the Cleveland Clinic's Department of Biomedical Engineering, University of Chicago's Department of Organismal Biology and Anatomy, and Utah neuro-technology companies Blackrock Microsystems and Ripple Neuro LLC. Funding for the project was provided by the National Science Foundation and the Defense Advanced Research Projects Agency.

The findings of the study appear in the latest edition of the journal Science Robotics.

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LUKE Arm – Named After Star Wars Character Luke Skywalker

• The developing of the LUKE arm has been underway since 15 years. The arm mostly made of metal motors and components covered by a clear “silicon” hand. It works through an external battery and is attached to a computer. It was created by DEKA Research & Development Corp., a New Hampshire-based company founded by Dean Kamen, inventor of Segway
• During this time, the biomedical engineering department of the University of Utah developed the Utah Slanted Electrode Array which allows the wearer of the prosthetic arm to tap into the nerves of the wearer
• The Array consists of a bunch of 100 microwires placed within the nerves of the amputee’s forearm and attached to an external computer
• The array picks up electrical impulses from the still intact nerves and transmits them to the external computer which in turn converts them to digital signals and instructs the arm to move
• Additionally, the prosthetic arm is also equipped with sensors that transmit signals to the microwire Array, replicating the feeling of touch when a person holds an object in their hand. Thus, a person can 'feel' the consistency of the object being held so that the right amount of pressure can be applied for example without breaking an egg by squeezing too much. 
• The manner in which the sensors transmit the signals involves understanding how the brain deals with information when it initially touches an object. Upon initial contact with an external object, a burst of impulses travel rapidly to the brain and then tapers off. This phenomenon had to be recreated which was a major task and achievement

Professor Gregory Clark, University of Utah biomedical engineering associate, said: "Just providing sensation is a big deal, but the way you send that information is also critically important, and if you make it more biologically realistic, the brain will understand it better and the performance of this sensation will also be better."

Achieving this involved complex mathematical algorithms and calculations and recording impulses from the arms of primates to recreate a similar model of how touch and feel is interpreted by the human brain. This model was used in the LUKE arm

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Story of Keven Walgamott

Keven is one of seven study subjects, who lost part of this left arm and hand to an electrical accident in 2002. There are about 1.6 million amputees in the US, in whom anxiety and depression are common.

• After wearing the robotic arm, Walgamott was able to touch and feel objects, identify the size and consistency even while blindfolded and wearing headphones.
• He was able to feel up to 119 different sensations ranging from vibration to pressure.
• He could feel and identify objects accurately and much more quickly than with any other similar system
• He could peel a banana and even send text messages. He could pick up an egg without breaking it by applying too much pressure

After trying the LUKE arm, Mr. Walgamott said: “It almost put me to tears. It was really amazing. I never thought I would be able to feel in that hand again.”

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Scope of the Study and Future Plans

• The LUKE arm is a boon to amputees who can touch and feel things like normal persons
• Since the prostheses move by the person’s thoughts, it forms a part of a closed system loop and prevents “phantom” pain which amputees feel even though the limb is not there
• A completely portable version that does not need to be wired to an external computer is being developed. All parts will be wirelessly connected making it simpler for the wearer
• Currently, it has been developed to use on below-elbow amputations, but the system can be adapted to above the elbow amputees as well in the future

The team hopes that by next year three test subjects will be able to take the device home pending government approval.

In summary, the LUKE arm will be a godsend to amputees making them independent and productive and also improves their quality of life by reducing anxiety and depression.

Reference:

1. Reach out and touch someone - (https://unews.utah.edu/star-wars-inspired-arm/)

Source-Medindia