Robot Legs Obey Brain

A pair of mechanical leg braces that are controlled by their wearer’s brain signals could help paralyzed patients walk again.

Jef Akst
Jef Akst

Jef (an unusual nickname for Jennifer) got her master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses. After four years of diving off the Gulf...

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Sep 7, 2012

A new kind of robotic leg braces that are controlled by small voltage fluctuations of the brain, as read by an electroencephalogram (EEG) placed over the head, could pave the way for overcoming paralysis, according to a new study posted last month (August 24) on arXiv. As demonstrated by an able-bodied volunteer in the video below, the device, known as a “robotic gait orthosis” and developed by researchers at the Long Beach Veterans Affairs Medical Center and the University of California, Irvine, provides a completely noninvasive way of moving a patient’s legs in a walking pattern. All the patient has to do is imagine they are walking (or standing, to stop).

“It’s an important step toward helping people with lower limb paralysis,” biomedical engineer Matt Fifer of Johns Hopkins University, who was not involved in the study, told Wired Science. “But there are lots of challenges still,” he...

In preliminary tests, the device interpreted the participants’ brain signals with about 95 percent accuracy, with just a couple of false starts. To ensure that the participants, able-bodied as they were, did not aid the robotic legs, the researchers measured the activity of the leg muscles using an electromyogram (EMG), and found that, indeed, activity during robot-controlled movement was distinct from that during natural walking movement, suggesting that muscle control was not needed for the robot legs to work.

But the device has yet to be tested on paralyzed patients, and so far, the robot legs are limited to walking and standing. Speed and directional control will need to be added to the algorithm for the legs to be a more practical solution.