A breakthrough in bionic prosthetics could make artificial limbs easier and more natural to control than ever before. Earlier this week, Icelandic orthopaedics company Ossur said they've created the world’s first truly “mind controlled” prosthetic leg—and while that might seem at odds with the premise of several prior stories, the claim isn’t actually overblown at all.
The crux of the issue is that, by collecting more and better control information from a patient's residual muscle tissue, Ossur said it has helped two patients control a bionic limb with the same muscle impulses that previously controlled the real appendage. This is at odds with many traditional modes of bionic control, which require the user’s focused attention to execute learned, brain-based commands.
It turns out that this form of direct, subconscious bionic control comes quickly and naturally
In a statement, lead researcher Dr. Thorvaldur Ingvarsson said that patients would “no longer need to think about their movements because their unconscious reflexes are automatically converted into myoelectric impulses that control their Bionic prosthesis.”
The breakthrough technology is Ossur’s implantable myoelectric sensor (IMES). An array of these sensors surgically implanted beneath the skin pick up muscular commands bound for the phantom limb. Those impulses are converted into digital messages which are then transmitted wirelessly to receivers in the artificial limb.
For over a year now, two test patients have been using networks of the 3mm by 5mm implants to control artificial legs with their minds. Even many years after their respective amputations, all that was required were small surgical incisions to insert the sensors in their leg muscles.
Even for a long-time user of traditional bionic technologies, it turns out that this form of direct, subconscious bionic control comes quickly and naturally; one test patient told Reuters that with an IMES-controlled limb he could walk normally within about 10 minutes. By allowing amputees to use their real motor cortex for motor control, IMES technology avoids forcing the patient to re-learn how to move.
On a qualitative level, this seems to be the distinction between restoring the function of a lost limb, and restoring the limb itself; the patient quoted above also told Popular Science that, “the first time, to be honest, I started to cry.”
Ossur is gearing up for wider clinical trials, with the goal of having a version of their technology approved for sale within 3 to 5 years.