Tomorrow's Technology: Federal Funds Fuel Futuristic Technology

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By Judith Philipps Otto

The future of prosthetic research is looking considerably rosier, due to huge amounts of funding awarded in January 2006 by the Defense Advanced Research Project Agency (DARPA). The $70 million allocation, which comes from the Department of Defense (DoD), was specifically earmarked to drive the efforts of two approved projects: Prosthesis 2007 and Revolutionizing Prosthetics.

This is the first time such a significant amount has been offered by the federal government to develop prosthetic programs, according to 1st Lieutenant Joe Miller, CP, MS, Medical Service Corps, US Army Reserve, advisory scientist/ research prosthetist at the Armed Forces Amputee Patient Care Program at Walter Reed Army Medical Center (WRAMC).

"Because of the global war on terrorism and all the soldiers injured as a result, there was a need to develop more advanced upper-extremity prosthetics. The private sector typically would not invest in an area like this--certainly not to this extent--because the funds might not be available, and the return on the investment is not likely to be profitable. It's just not cost-effective for the O&P industry to tackle this research privately. So the military took on this role to enhance the technology for the injured troops."

DARPA's focus is futuristic, Miller explains, with an eventual high payoff anticipated for its high-dollar investment. DARPA previously has developed GPS systems, the Internet, and high-tech military defense systems; this is the first time, reports Miller, that the agency has designed a short-term project.

The cited proposals, submitted last year, were announced in January as award winners, and research is now under way, utilizing integrated teams that include neuroscience specialists in brain mapping and cognition, mechanical engineers, materials experts, and distribution strategists, among others. These widely diverse teams--one for each of the two projects--are working under the direction of Colonel Geoffrey Ling, MD, PhD, project manager for DARPA.

Projects Aim High

Prior to approval, the teams had to submit proposals that described their planned approach to achieving the project goal, including plans for neuro-sensing devices, control system, actuation, power storage, distribution, free-form manufacture, neuro-control, micro-fabrication, sensory feedback, flexure and transmission design, signal processing, information science, and more. The proposals needed to conclude with "the capability to generate this plan so that, at the end of four years, we have a brain/machine controlled or neuroprosthetic arm that is modular in design and that can be introduced for clinical trials and eventual private distribution within the marketplace--true technology transfer," Miller explains.

Two-Year Project

Prosthesis 2007 is a two-year project whose objective is to deliver a single prosthetic arm system that is suitable for use in transhumeral or shoulder disarticulation amputees. According to Miller, the technical goal of the program is to develop characteristics of an arm prosthesis that has initial properties that match the lost limb. That should include local control or "state sensing," task-based mode shifting between the devices, and simultaneous control of three to five different joints.

"They're going to look at things like fingertip force detection, hand grasping, elbow lift, grip strength up to 25 lb., wrist flexion up to ten lb.--all built into an intuitive control mechanism, and capable of 24-hour endurance without re-powering," Miller explains.

Alternate energy sources are being explored in order to achieve this goal, says Miller. "Instead of battery-powered, it may use some sort of fuel-powered system in order to get enough energy. Some people are looking at using the human body's ability to produce energy through movement."

According to the proposal, the team's goal is to develop a prosthesis with some different grasping patterns: e.g., fine pinch and lateral pinch power gripping. It should have two degrees of freedom at the wrist, humeral rotation, cosmetic matching to the amputee, a low-decibel noise level, and water and grit resistance. It should function as a modular automated system.

"These are huge goals to accomplish in just two years," Miller points out.

Four-Year Project

Revolutionizing Prosthetics is a four-year project. The proposal defines its goal as the creation of a neuro-controlled artificial limb that will restore full motor and sensory capability to upper-extremity amputee patients.

It will build upon the successes of the two-year program, Miller explains, but also has added such things as afferent (sensory) and efferent (motor control) systems.

"Whether the central nervous system or the peripheral nervous system will be utilized is what will be explored in the project. They will want to differentiate between two millimeters of movement and .1 Newton in force and sensation. These compare to human-like capabilities of sensory feedback."

Like the two-year program, this arm should offer simultaneous control of joints, but also should increase the degrees of freedom of the fingers; the elbow flexion strength should increase to 60 foot-pounds along with 24-hour endurance capabilities of the modular system.

"The four-year project builds upon the two-year one, but this one also goes into program phase testing, as well. The idea is to get it from the beginning of the bench research through delivery to the patient," says Miller, who is involved every step of the way as technical advisor to the project.

The DARPA programs will effectively leapfrog the industry forward 50 years, he believes, by pooling areas of existing science--robotics, brain/machine interfacing technologies, and thought control--and leveraging them all together to achieve a new, dramatically advanced prosthetic arm.