Helping Amputees ‘Feel’ Through Their Artificial Arms

Recent estimates suggest that nearly 800,000 upper limb amputees live in the United States. They have lost hands/arms from civilian or military wounds or accidents, but they are young and active and could benefit substantially from more usable artificial (prosthetic) arms. Many advances have been made in movement control and usefulness of prosthetic limbs, yet a fundamental problem remains: amputees must cope with the fact that they cannot feel with their artificial hands/arms in a world where feedback to the brain about touch, limb movement, and hand/arm position all play a vital role in activities of daily living. Since amputees do not receive sensory feedback from their lost limb, they must use vision to make up for this missing sense. It is very difficult for an amputee to “multi-task” while using a prosthetic limb because they must closely watch their own movement and the placement of that limb at all times.

A primary interest of the Marasco laboratory is integrating the feedback loop of the brain in relation to the patient’s nerves and muscles and a prosthetic arm/hand. Working closely with amputees, we investigate a variety of ways to decrease amputees’ need to rely on sight and to “close-the loop” by providing touch and movement feedback for artificial limbs. To do this, we examine the sensory nervous system by specifically focusing on how the brain is organized and how much it can change and thus compensate for what it has lost. We use different model systems and many approaches that combine results from the lab and actual experiences and suggestions of the patients themselves, including mapping areas of the brain and conducting physical, intellectual, and psychological studies to help us figure out how sensory feedback can be returned from artificial limbs to amputees through appropriate nerve channels. Our work focuses on establishing a better understanding of how these channels organize and work together to establish in the patient a sense of self and of the body, as well as awareness of limb movement, all of which can be translated to clinical applications.

Summary: Dr. Marasco and his team work to understand the sensory nervous system and develop approaches that can provide natural touch and movement feedback for amputees with artificial upper limbs.

See also: Marasco Lab