An international research team has created a prosthetic leg that incorporates advanced neural stimulation, allowing it to recreate sensations of touch in the knee and foot that does not have conventional prosthetic designs, as published in the journal Science Translational Medicine.
The neuro-prosthesis, developed by scientists from a European consortium led by the Federal Polytechnic School of Zurich and the Federal Polytechnic School of Lausanne, together with the SensArs Neuroprosthetics spin-off, with clinical trials in collaboration with institutions in Belgrade (Serbia), improved the mobility and agility, prevented falls and allowed to perform complex tasks when tested on three people who had been amputated from the lower leg.
Current leg prostheses do not restore the sensation of touch in the lower leg amputees, so they are forced to rely on limited sensory feedback from where the device touches the remaining limb. As a result, they face serious problems, such as an increased risk of falls and poor mobility.
In addition, the lack of sensation means that the prosthesis is generally perceived as an external object rather than as part of the body. To overcome these obstacles, Francesco Petrini and his colleagues at SensArs Neuroprosthetics created a leg neuroprosthesis that mimics real-time sensory feedback by stimulating nerves in the remaining limb.
The device combines a commercially available lower leg prosthesis with knee and insole sensors that can provide feelings of pressure and balance. They tested the prosthesis in three patients with transfemoral amputations in the lower leg, who obtained better results in passive tasks such as tactile recognition when neurostimulation was active compared to when it was turned off.
The subjects also performed complex tasks, such as climbing stairs and performing an obstacle course more quickly and more easily. Finally, they showed a greater sense of ownership and were less mentally occupied with the prosthesis during field tests.