All the components needed to monitor electrical signals from the brain and skeletal muscle – electrodes, sensors, power supply and communications – are mounted on an ultrathin, skin-like membrane. Photo Credit: University of Illinois
The University of California, San Diego has demonstrated that a thin flexible, skin-like device, mounted with tiny electronic components, is capable of acquiring electrical signals from the brain and skeletal muscles and potentially transmitting the information wirelessly to an external computer. The development, published Aug. 12 in the journal Science, means that in the future, patients struggling with reduced motor or brain function, or research subjects, could be monitored in their natural environment outside the lab. For example, a person who struggles with epilepsy could wear the device to monitor for signs of oncoming seizures.
It also opens up a slew of previously unimaginable possibilities in the field of brain-machine interfaces well beyond biomedical applications, said Professor Todd Coleman, who joined the Department of Bioengineering at the UC San Diego Jacobs School of Engineering this summer. Until now, Coleman said, this brain-machine interface has been limited by the clunky, artificial coupling required by a vast array of electronic components and devices.
“The brain-machine interface paradigm is very exciting and I think it need not be limited to thinking about prosthetics or people with some type of motor deficit,” said Coleman. “I think taking the lens of the human and computer interacting, and if you could evolve a very nice coupling that is remarkably natural and almost ubiquitous, I think there are applications that we haven’t even imagined. That is what really fascinates me – really the coupling between the biological system and the computer system.”
In addition to Rogers, who was the main enabler of the technology with his expertise in stretchable electronics, the project was led by Northwestern University Mechanical Engineering Professor Yonggang Huang, who optimized the mechanical properties of the device, and Coleman, who helped define and demonstrate the utility of the device in biomedical applications. Coleman’s research group, with combined backgrounds in electrical engineering and neuroscience, helped in the circuit design for active electrodes to enable efficient coupling between the device and brain waves without the need for a conductive gel, and in the statistical signal processing required to reliably acquire the neural signals from the brain or muscles through Rogers’ device. For example, Coleman’s research group used the device to enable someone to control a computer game with muscles in his throat by speaking the commands. In principle, the same function could have been achieved by simply mouthing commands rather than speaking them out loud. This was done by applying a pattern-recognition algorithm implemented by Coleman’s group to data taken from a throat-based EMG. Now that the capability has been demonstrated, the next step is to integrate all the components onto a single device. Coleman believes the ramifications for health care are significant at a time when people are living longer but suffering more neurological problems like Parkinson’s disease and dementia.
At UC San Diego, Coleman is exploring what other capabilities could be achieved by the coupling of brain signals with computers, enabling two decision makers to cooperate to achieve a common goal. For example, by simultaneously acquiring the neural signals of many people collaborating with computers, this technology could enable the whole group to operate as a team with enhanced capabilities.