Researchers at the University of Maryland (UMD) continue to advance the development of their "brain cap" technology that allows users to turn their thoughts into motion. The team has already had success in using EEG brain signals captured from the cap's 64 electrodes attached to users' scalps to reconstruct 3D hand movements and to control a computer cursor with their thoughts, and now the team has successfully reconstructed the complex 3D-movements of the ankle, knee and hip joints during treadmill walking. The aim is to provide a non-invasive technology that can return motor function to victims of paralysis, injury or stroke.

For more than a year, the researchers have been matching specific brain activity recorded in real time with exact lower-limb movements by tracking the neural activity of people on a treadmill doing precise tasks, such as stepping over dotted lines. The data gathered could be used in a prosthetic device, called an "anklebot," that stores data from a normal human gait and assists partially paralyzed people. Larry Forrester, an associate professor of physical therapy and rehabilitation science at the University of Maryland School of Medicine, says that getting people, such as stroke survivors, up and moving could also help combat other health issues such as obesity, diabetes or cardiovascular problems.

The EEG data could also be used to "retrain" the healthy areas of stroke victims' brains in what is known ad neuroplasty.

"By decoding the motion of a normal gait, we can then try and teach stroke victims to think in certain ways and match their own EEG signals with the normal signals," says José 'Pepe' L. Contreras-Vidal, Associate Professor of Kinesiology at UMD.

One potential method of retraining envisioned by first-year bioengineering doctoral student, Steve Graff, is a virtual reality game that matches real EEG data with on-screen characters.

"It gives us a way to train someone to think the right thoughts to generate movement from digital avatars. If they can do that, then they can generate thoughts to move a device," says Graff, who has congenital muscular dystrophy and uses a motorized wheelchair. The advances he's working on could allow him to use both hands - to put on a jacket, dial his mobile phone or throw a football while operating his chair with his mind.

While there are a number of brain computer interface (BCI) technologies under development, Contreras-Vidal says these competing technologies either require electrodes to be implanted directly in the brain or, in the case of other non-invasive technologies, require much more training to use than the EEG-based, brain cap technology. The UMD researchers say their non-invasive interface is the only one to have demonstrated decoding results comparable to those achieved with implanted electrodes.

Multiple projects underway

The team is collaborating with researchers at a number of institutions to develop thought-controlled robotic prosthetics. Under a US$1.2 million grant from the National Science Foundation (NSF), the UMD team is collaborating with researchers at Rice University, the University of Michigan and Drexel University in a four-year project to design a prosthetic arm that amputees can control directly with their brains, and which will allow users to feel what their robotic arm touches.

In another National Institutes of Health (NIH)-supported project, the UMD team is pairing the brain cap's EEG-based technology with a DARPA-funded next-generation robotic arm designed by researchers at the Johns Hopkins Applied Physics Laboratory to function like a normal limb.

They also have partnerships with the University of Maryland School of Medicine in Baltimore and the Veterans Affairs Medical Center in Baltimore focusing on the use of the brain cap technology to help stroke victims whose brain injuries affect their motor-sensory control.

The UMD team is also developing a new collaboration with New Zealand start-up Rexbionics, the developer of the Rex robotic exoskelton that could be used to restore gait after spinal cord injury.

The latest of three papers the UMD team has published on their brain cap technology over the last 18 months appears in the Journal of Neurophysiology.