Interim dean gives hope to amputees

Jovany Betancourt

Contributing Writer

The arm that reaches for a pen, the legs that help a runner during a morning jog, and even the digestive tract are all controlled by the nervous system.

And Dr. Ranu Jun, who the University appointed as interim dean of the College of Engineering, continues to find ways to improve the lives of thousands of people who use prosthetics or have damaged nervous systems.

Jung, professor and chairwoman of the University’s Department of Biomedical Engineering, has worked on treatment for spinal cord injuries and designs for mordern neuro-prostheses, prosthetic systems that connect or interact with the host’s nervous system.

The nervous system is like a computer as they both use electrical impulses to transmit information which is later read in a binary code.

To make sense of the flood of signals it receives, the brain analyzes the signals’ frequency, or the number of impulses are sent back to muscle, glands, or organs to dictate the appropriate responses.

If someone suffers a spinal cord injury, say from a freak mountain climbing accident, the impulses cannot reach their targets and enact a response. This is why severe damage to the spinal cord can lead to paralysis or even organ failure.

The body’s natural response to a partially damaged spinal cord is to develop new pathways for the wandering signals using existing synapses. “Synaptic plasticity: refers to a synapse’s ability to take on new functions and to act as a new pathway for different signals.

Jung and her team have tested a method for promoting recovery after a partial spinal cord injury through electrical stimulation of the paralyzed muscle that exploits this plasticity and speeds up recovery time.

“We are sending back sensory information that would be lost otherwise,” Jung said.

She said her team’s data suggests that employing this stimulation therapy allows for the neurons to remain active and may preserve signaling pathways between the spared spinal cord circuits and the motor neurons.

If the damage to the spinal cord is too great or if the synapses fail to reform strong enough connections between the muscle and central nervous system, then the last resort of the patient is to use a prosthetic or orthotic device.

An orthosis is a device that assists the functionality of a body part while a prosthetic is a device that mimics the body part’s functionality. Essentially, a walking cane would be an orthotic device while a false hand would be a prosthetic device.

Recently, prosthetics that use neural-interfaces to communicate with the nervous system are picking up momentum as researchers from all over the world race to create prosthetics taht are as versatile as human body parts.

Susan M. Racher, chief financial officer and vice president of the Wallace H. Coulter Foundation, volunteered as a test subject in Jung’s lab. She said she had sensors all over her body to gather data while she walked in different patterns.

“I think it’s game changing,” said Racher.

Jung recently patented the idea for what she calls an “Orthoprosthesis.” This device, a poweredfalsefoot, can be fitted onto a broken or injured ankle to assist in walking, or it can be fitted onto a prosthetic foot so it works better.

“Her brilliance is only surpassed by her kindness,” said Racher.

Jung said these systems could become available to the public within the next few years because the National Institutes of Health and the Defense Advanced Research Projects Agency have just recently injected money into the field for further research.

The U.S. Army funded the orthoprosthetic to provide soldiers injured in battle a means of evacuation. It uses a battery to power an actuator controlling the foot and an electronic circuit with a biomimetic design for mimicking the action of walking.

Modern engineering, coupled with a new understanding of the nervous system, has brought the genesis of the long awaited biohybrid system: linking nerves and machines.

“The impact is going to be magical,” said Anil Thota, a member of Jung’s lab.

Current prosthetic for amputees only have simple mechanical or electrical functions, which Thota refers to as “tools.”

Future prosthetic biohybrid systems would allow not only for voluntary control of the prosthesis through existing nerves, but use those same nerves to convey back sensation such as touch and pressure.

“Amputees can finally say: this is my arm. I am controlling it. I am feeling it.” Thota said. “Not a piece of electronic, this is all me.”

Jovany Betancourt is a part of Science Qubed, a club seeking to be certified by the Council for Student Organizations, that reports scientific news.