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 Ossur implanted tiny sensors in the residual muscle tissue of two
amputees that they say trigger movement in the prosthesis via a
receiver. Ossur President & CEO Jon Sigurdsson was due to announce
in Copenhagen on Wednesday (May 20) that the two amputees are the
first world-wide to be able to control their lower-limb prostheses
subconsciously.
One of the patients trialing the new implants, Gummi Olafsson, lost
his right foot and lower leg years after a childhood traffic
accident. He said the implants allowed him to control his bionic leg
and foot almost instantly.
"As soon as I put my foot on, it took me about 10 minutes to get
control of it. I could stand up and just walk away. Come back, sit
down, use my muscles to move my foot in the position I wanted to use
it. It was, like you couldn't believe the feeling when you were
moving your ankle. It was really strange. I couldn't explain it. It
was like, I was moving it with my muscles, there was nobody else
doing it, the foot was not doing it, I was doing it, so it was
really strange and overwhelming," Olafsson remembered.
The signals sent from the brain to nerve-endings in muscles that
prompt movement continued even when Olafsson used a different
prosthesis that did not have the receiver. He said it was
frustrating to be unable to control the foot once more.
The Implanted Myoelectric Sensors (IMES) measure 5 millimeters (mm)
long and 3mm wide and were provided by the United States-based
Alfred Mann Foundation, which develops medical technology for use in
patients.
Olafsson said his body continues to adapt to his prosthetic limb
more each day, allowing him increased control of it.
"Your muscles are always getting bigger, so you get more control
over it. So everyday if you are using it, you're always getting more
and more control over what you're doing with your foot, so in a way,
everyday you're learning more about how to walk properly with the
foot, how to use it to go downhill, uphill, downstairs, upstairs,
even sitting down and standing up from a chair," he said.
He has been living with the IMES and an Ossur bionic limb for over a
year. Ossur plans to continue assessing the technology with clinical
trials.
Orthopedic surgeon, and Ossur's director of research and
development, Thorvaldur Ingvarsson implanted the sensors in the two
patients involved in the trial himself while they were under local
anesthetic in what he said was a straightforward procedure.
Ingvarsson said the new technology allows the patient's brain to
control both subconscious and intentional movements.
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"So, the brain power, when it takes over, it actually gives impulses
through the brain into the muscles, then the muscles contract. We
put sensors into the muscles, and the muscles would pick up the
signals, and the signals move their way into the prosthetics, and
then the prosthetics react as your brain wants," he explained.
The mobility technology company has designed the system to be
compatible with its current bionic devices, which already
automatically adapt to their user's gait, speed and the ground
terrain, but still require intentional thought.
Ossur says it will be more of a technology "upgrade" for its current
patients and anticipates that the system will be on the market
within three to five years.
Ingvarsson said Ossur was on the way to creating prosthetics that
are more integrated with their user.
"Our ultimate goal is to replace the function of the lost limb, and
we've been doing so step-by-step and doing very well. However, as
our technology move on - you have sensors for muscles, you're able
to replace function by the new mind-controlled prosthetics - the
next step might be to get sensing from the environment so you have a
feedback loop," he said.
The company says the device is the first to use an implanted sensor
inside the patient's body, whereas other mind-controlled prosthetic
technologies involve transplanting muscle tissue from another part
of the body and repurposing it, requiring neuroplasticity (brain
retraining) to operate.
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