Brain-powered wheelchair shows real-world promise

People with motor disabilities have been able to operate a wheelchair just with their thoughts, as part of an international research project involving the University of Essex.

As one of the first studies of its kind, it is an important step forward for brain-machine interfaces — computer systems that turn mind activity into action.

The concept of a thought-powered wheelchair has been studied for years, but most projects have used non-disabled subjects or stimuli that leads the device to more or less control the person rather than the other way around.

The study, led by researchers at the University of Texas at Austin and published in the journal iScience, involved three people with tetraplegia, the inability to move their arms and legs due to spinal injuries.  They operated the wheelchair in a cluttered, natural environment to varying degrees of success. The interface recorded their brain activity, and a machine-learning algorithm translated it into commands that drove the wheelchair.

The researchers said this is a sign of future commercial viability for mind-powered wheelchairs that can assist people with limited motor function.

Dr Serafeim Perdikis, from Essex’s School of Computer Science and Electronic Engineering who was part of the project, said: "This study is important for showing that effective user training, on the one hand, and the combination of brain-computer interface (BCI) with smart, autonomous technologies, on the other hand, are the keys to unlocking the translational potential of BCI applications."

Professor José del R Millán, from the Cockrell School of Engineering’s Chandra Family Department of Electrical and Computer Engineering, who led the international research team, added: “We demonstrated that the people who will actually be the end users of these types of devices are able to navigate in a natural environment with the assistance of a brain-machine interface.”

The study is also significant because of the non-invasive equipment used to operate the wheelchair. The researchers did not implant any kind of device into the participants, nor did they use any kind of stimulation on them.

Participants wore a cap covered with electrodes that recorded brain electrical activity, known as an electroencephalogram (EEG). An amplifying device sent those electrical signals to a computer that interpreted each participant’s intentions and translated them into movement.

The was possible because the users were taught methods to visualize moving the chair as if they were imagining moving their hands and feet. As the researchers observed the study participants, they saw changes to their brain activity as they delivered commands.