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Tomorrow's Technology: Federal Funds Fuel Futuristic Technology
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. 
Table Of Contents - March 2006
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