Mind-controlled legs give paralyzed people hope of walking again

Wheelchair-bound paralyzed patients have been given a ray of hope – they can be returned to physical activity via a robotic leg prosthesis controlled by the brain, which has been successfully tested by a team of US researchers.

­The medical team from the University of California campus in Irvine, together with the Long Beach Veterans Affairs Medical Center in California, has succeeded in connecting a mind-computer interface to a robotic leg, which will give a chance of walking again to patients with spinal cord injuries.

The team built and successfully tested a prosthetic lower limb that can be controlled in real time by electroencephalogram (EEG) signals fed into a computer.

"This finding represents the first successful demonstration of a Brain-Computer Interface (BCI)- controlled lower extremity prosthesis for independent ambulation," the science, research and technology news website Phys.org quotes the researchers as stating.

In previous work, they developed a way of using EEG signals to control the walking motion of an avatar in a virtual reality environment.

The patient then was able to alternate between 30-second bouts of sitting and walking via the power of robotic legs alone, for a total of 10 minutes.

The data was used to generate an EEG prediction model for online BCI operation. A commercial robotic gait orthosis system was interfaced with the BCI computer to allow for computerized control.

The legs were solely controlled by the patient’s mind, without slow physical walk-arounds built into current robotic prostheses, and allowing the device to be used by even the fully paralyzed.

Fearing that the legs would be hard to master by a patient unused to working with brain-computer interfaces, the medical team asked the patient to practice mind-controlling a computerized "walking avatar" for five hours before donning the legs.

This gave the subject time to familiarize him or herself with the device and within three trials he or she was ready to “go”.  The video shows a stroke patient using BCI-controlled electrical stimulation to mitigate foot drop.

The device, currently called the "BCI RoGO (robotic gait orthosis), System", is still in the early stages of testing and is not without shortcomings, according to the Huffington Post.

For example, it takes five seconds to start walking and seven seconds to stop, which may be inconvenient for a walker on a busy street. The device has been taught how to recognize when the owner wants to start and stop walking, but it doesn't yet recognize other things, like turning, sitting or standing. There were also some “false starts" – when the system began walking without the owner’s mental command.

The team is currently getting ready for their next step – to "test their system in individuals with paraplegia."