thought-controlled leg. This device works by
implanting a metal electrode onto the remaining
bone near the amputation site. Test subject Zac
Vawter says that the robotic prosthetic allows him
to walk as he would have before his leg
amputation; he does not need to think about the
process and did not have to train his body to use
the device.
Thought-controlled prosthetic limbs are
especially exciting because the device has the
potential to function in a two-way system. Not
only does the brain send information to the
prosthetic limb but potentially — once a line of
communication is established between the brain
and the device — the device can send sensory
information back to the brain. In other words,
these prosthetics will likely have the ability to allow
the wearer to experience the sense of touch. In
the case of the leg prosthesis currently in testing,
this is a critical feature that allows the wearer to
walk normally without needing to guess where the
foot has landed with each step.
For hand prosthetics, implementing a sense of
touch will certainly also improve functionality but
contains an emotional component, as well.
Imagine how satisfying it will be for a soldier
injured in battle to reach out and pat his son on the
shoulder for the first time and be able to actually
“feel” the experience rather than just see it.
Robotics is also impacting the recovery of
patients who need physical therapy due to
strokes, accidents, and surgeries. The ZeroG
is essentially a harness to assist patients with
difficulty walking. The experience is similar to
walking on the moon; patients can use the
device to safely practice sitting, standing,
walking, and climbing stairs. The ZeroG also
safeguards the therapist against injury that
might be caused by attempting to support
the weight of a patient with limited mobility.
The ZeroG allows patients to improve
balance and gait while taking comfort in the
fact that the harness will catch them if they
begin to fall. The HEXORR is an exoskeleton
designed for use in therapeutic settings. It is
mainly designed for individuals who
experience weakness on one side of the
body due to a stroke. The robotic device can
improve range of motion and grip strength
in patients.
Dr. Allen Hoffman, professor at
Worcester Polytechnic University, developed
a brace to allow individuals with muscular
dystrophy to develop better movement in their
hands. The device is known as an arm orthosis
SERVO 12.2013 45
The i-Limb is one example of the astoundingly sensitive prosthetic
hands that are now available for private use.
Photo courtesy of Touch Bionics.
Zac Vawter is able to walk with ease with his
thought-controlled robotic leg prosthesis.
In this photo, Vawter has just finished climbing
103 stories to the top of the Willis Tower in Chicago,
making him the first to do so wearing a
robotic prosthetic limb.
Photo courtesy of ABC News.
