Smartphones and tablets have become an indispensable part of life, but for those with paralysis, they can be difficult, or even impossible, to use. A team of researchers from several hospitals and universities, including Stanford University, Harvard Medical School, Brown University, and Massachusetts General Hospital, are trying to change that.
The group, collectively known as BrainGate, are working on technology that would allow severely paralyzed individuals to communicate with ease–and recent research has allowed patients to operate an off-the-shelf tablet just by thinking about making cursor movements and clicks.
Brain-computer interface (BCI), sometimes called neural control interface, is a collaboration between a brain and a device that allows signals from the brain to direct some sort of activity, such as controlling a prosthetic limb. In that instance, a signal would be delivered directly from the brain to the mechanism directing the limb, rather than taking the normal route through the body’s neuromuscular system. BCIs work by reading signals from an array of neurons and using computer chips and programs to translate the signals into action.
The main goal in using brain-computer interface is to replace or restore hearing, sight, or movement for those living with severe neuromuscular disorders, but they may also prove useful in rehabilitation from stroke and other life-altering events.
Research began on BCIs at the University of California, Los Angeles in the 1970s, but it wasn’t until the mid-90s that the first neuroprosthetic devices were implanted in humans. Although the technology has come a long way since then, there are still several issues that prevent its widespread use. One of the biggest challenges with BCI is developing a process that is minimally invasive. Currently, the only option is to implant a mechanical device into the brain.
Aside from the standard issues which may arise during or after a surgical procedure, problems related to the system’s output have occurred. Once implanted, the device cannot be shifted to measure activity in another part of the brain. As a result, the implant only receives information from a very small area.
Other issues may include the body’s rejection of the object, the timescale of recorded information, the ability to maintain stable functionality of the device over a long period of time, and accuracy in decoding intent.
Current brain-interface devices require deliberate thought, meaning that if you have a prosthetic hand and want it to grasp a can, you have to consciously make that happen. Researchers are hoping that in the future it will be a more seamless process, and for instance, a prosthetic hand may move without thought, just as a real hand would.
The main goal in using BCIs is to replace or restore hearing, sight, or movement for those living with severe neuromuscular disorders, but they may also prove useful in rehabilitation from stroke and other life-altering events.
Researchers in the BrainGate project, which was published in the peer-reviewed journal PLOS ONE, feel that their latest findings mark an important breakthrough for individuals suffering from paralysis. The three patients used in the study all suffered from quadriplegia (the partial or total loss of all four limbs as the result of illness or injury. Two of the participants lost the use of their limbs due to amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig’s disease), while the other was paralyzed due to a spinal cord injury.
Thanks to new developments in BCI, they were able to use email, chat, video-streaming apps, and even shop online with ease. Researchers say subjects are able to make up to 22 point-and-click selections per minute and type up to 30 characters per minute using standard e-mail and text apps. One participant, a musician, even played a portion of Beethoven’s “Ode to Joy” on a digital piano interface.
The participants reported finding the interface intuitive and fun to use, the study noted. One said, “It felt more natural than the times I remember using a mouse.” Another reported having “more control over this than what I normally use.”
The work was completed by placing a chip the size of an aspirin in each subject’s motor cortex. A thin bundle of wires led to a plug fixed to the skull, and signals were from the brain decoded and sent to the tablets. Lead author Paul Nuyujukian said it usually takes about 5 to 10 minutes for the system to accurately translate a person’s brain waves into cursor movements.
“The participant is instructed to imagine moving the cursor to the right or the left or up or down while the cursor is actually making that movement automatically,” he said. “It turns out that simply imagining making that movement is very similar to the patterns of neural activity that occur when one actually makes this movement.”
This new approach to BCI has the potential to completely change the lives of people living with “locked-in” syndrome, meaning paralysis has robbed them of the ability to speak. Not only will it allow them to communicate more easily with family and friends but will also help them aid caregivers in making important medical decisions.
Krishna Shenoy, a senior author of the paper and electrical engineer and neuroscientist at Stanford University, says, “The assistive technologies that are available today, while they’re important and useful, are all inherently limited in terms of either the speed of use they enable, or the flexibility of the interface. That’s largely because of the limited input signals that are available. With the richness of the input from the BCI, we were able to just buy two tablets on Amazon, turn on Bluetooth and the participants could use them with our investigational BrainGate system right out of the box.”
For now, the technology is remaining in the research phase and it will be years before it becomes widely available. The final device, Nuyujukian says, “needs to be something that’s fully implantable, that needs to be miniaturized. It cannot be a giant stack of computers and a giant cart. That’s not a clinical device.”