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Neura Engineers Seek Solutions vl^^** From Battlefielc to Homefront

Two projects are putting HMRI Neu­ral Engineering researchers on the front line in care for war fighters on

the battlefield and during rehabilitation upon their return home.

Both projects require the unique expertise for which HMRI's neural engineers are internation­ally known and respected. The two projects are funded by the U.S. Army'sTelemedicine and Advanced Technology Research Center (TATRC) and the Defense Advanced Research Projects Agency (DARPA).

New deep eye scanner for fast battleground diagnosis

The TATRC project is concerned with eye trauma in the battlefield and is done in collaboration with Dr. Shuliang Jiao and other investigators at the Department of Ophthalmology, Keck School of Medicine at use. One part of the TATRC project, led by HMRI's Dr. Victor Pikov, aims to develop a device for eye trauma screen­ing in the battlefield, while the other part, led by HMRI's Drs. Douglas McCreery and Martin Han, will develop an implant­able device to restore useful vision by stimulating visual centers of the brain. This visual prosthesis could be used to rehabilitate war fighters whose eyes have sustained very severe injury.

"In the current conflicts, blunt cranial trauma is the most common injury from

roadside lEDs (improvised explosive devices)," said Dr. McCreery, Neural Engineering director. "They get frontal cranial damage, along with dam­age to the eyes from blast impact."

There's a "golden hour in which to provide treatment for best results," he continued "For example, the golden hour for a gunshot wound is one hour to get the patient into surgery."

For eye injuries, that "golden hour" can stretch into several hours to seek treat­ment. "For eye trauma, one of the things that happens is a detached retina and that must be remedied within hours and 'tacked' down; otherwise the lack of blood supply will cause the retina to die," Dr. McCreery explained.

"They inject a silicone oil into the vitre­ous (the space between the lens and the retina of the eyeball) to press down the retina to reattach it," explained Dr. Pikov. "Ironically, just as we have to change the oil in a car, a patient has to have an

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From Battlefield to Homefront from cover ophthalmologist change the silicone oil in his eye every six months or so.

"War fighters cannot open their eyes many times due to eye lid trauma or eye bleeding, so the medics cannot do a regular ophthal­mologic screening," Dr. Pikov said.

"What we are propos­ing is a novel retinal testing device that uses a penetrating electro­magnetic wave that can go through the eyelid, cornea and the general eye structure to stimulate the retina noninvasively to see if some parts of the retina are still functional."

Dr. Martin l-lan, Dr. Douglas McCreery, Director of Neural Engineering Program, and Dr. Victor Pikov.

"By having this diagnostic tool on the battlefield, tests can be done immediately and, if needed, reattachment of the retina can be performed by oil injection into the eye, and then keeping the eyes closed to prevent more injury," he said.

Meeting the need for better artificial limbs

The Department of Defense has been faced with a growing challenge to develop better prosthetics for wounded war fight­ers. Today's best artificial limbs have low functionality, and DARPA needs to upgrade to models with greater dexterity.

brain communication capability and longevity.

That's where Dr. Han, the principal investigator on the DARPA project, along with Dr. McCreery and Dr. Pikov, come in. They will develop a bet­ter interface between the brain and prosthetic limbs for wounded warriors.

While some existing prosthetic arms use signals from the nerves or muscles, implanting microelectrodes into the brain to transmit signals directly from its neurons offers users greater control and more natural movement. The micro-electrodes must be as thin as a single strand of hairand made of metal

or metal-like silicon. Moreover, Dr. Han has recently created even thinner and more flexible polymer electrodes.

The team will determine why current brain interfaces intended to control prosthetic limbs fail after a relatively short time, usu­ally within a few months. Once that has been determined, the researchers will develop implantable electrodes to enable con­trol of complex arm prosthetics by the brain to boost capability from 2 degrees of movement to 22 degrees, increasing elbow and wrist rotation and finger movements for greater facility in grasping and handling objects.

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From Battlefield to Homefront from page 2 In a clinical trial, "intracortical electrodes that recorded motor signals directly from brain cells could eventually be used to con­trol the complex robotic arms. However, these electrodes have shown to be unreliable," said Dr. Han. "That interface between neurons and prosthetic device is created when a microelectrode is implanted into the brain to record and decode its instruc­tions to the robotic arm. When you lose that interface, you lose robotic control."

Researchers have been trying to answer the question "Why do these devices fail?" "However, different researchers have used different surgical techniques, and different devices implanted into different brain regions," Dr. Han said.

By incorporating four widely used electrode designs into a hybrid array, HMRI investigators will determine why the mi­croelectrodes fail to record signals from brain cells ("neuronal action potentials") for long periods of time.

Instead of stimulating neurons to fire, the microelectrodes use spontaneous neuronal activity to drive a prosthetic arm in a cer­tain way, for example, for direction and velocity of movement.

Findings from this study could go beyond prosthetics to ap­plications for other neurological disorders, including Parkinson's disease and epilepsy. Dr. Han added. "This could be used for detecting epileptic seizures," he said. "Before an onset of an epileptic seizure, there's known to be some subtle change in brain activity that's hard to detect with current technologies, but with these electrodes in the brain, they can predict the pending onset of a seizure before it happens." •

Part of this worl< is sponsored by the Defense Advanced Research Projects Agency (DARPA) Microsystems Technology Office (MTO), under the direction ofDr Jack W. Judy as part of the Reliable Neural Technology Program, through the Space and Naval Warfare Systems Command (SPAWAR) Systems Center (SSC) Pacific grant No. N66001-11-1-4010.

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