Typing With Thought

Researchers from Stanford University have built a new brain-computer interface (BCI) that allows paralyzed people to type with their brains at a rate faster than was previously possible.

For their study, they worked with three participants with severe limb weakness, two due to Lou Gehrig’s disease and one with limited movement due to a spinal cord injury. All three participants had electrode arrays embedded in their brains to record signals from the motor cortex, which controls muscle movement. A cable then transmitted the brain signals to a computer, and they were then translated by algorithms into point-and-click commands that prompted a cursor to move over letters. Basically, participants were able to move the cursor by imagining their own hand movements.

While it took some training, the subjects were able to achieve BCI results that outperformed any available platform today. One patient was able to type 39 correct characters per minute, which is around eight words per minute, proving that BCIs have the potential to enhance communication among people with impaired movement. It should be noted that these typing-rates were achieved without the use of automatic word-completion.

“The performance is really exciting. We’re achieving communication rates that many people with arm and hand paralysis would find useful. That’s a critical step for making devices that could be suitable for real-world use,” says Chethan Pandarinath, one of the authors of the paper, told Stanford.

BCIs on the Rise

The Stanford team’s contribution toward advancing people’s ability to control machines with just their thoughts reflects the progress being made in this field. In addition to this breakthrough, a team from the Wyss Center for Bio and Neuroengineering in Geneva, Switzerland, built a BCI that can decipher thoughts of people with complete locked-in syndrome, giving them the ability to answer yes or no questions. Meanwhile, researchers at Harvard are using BCI tech to restore sight in the blind.

In the U.S. alone, millions of people suffer from paralysis, some from degenerative conditions like ALS and others from unfortunate accidents that cause severe spinal cord injury. This point-and-click approach developed at Stanford could be the key to making a more efficient BCI geared toward improving the quality of life for those people. It could restore their ability to communicate while teams like that at the Center for Sensorimotor Neural Engineering (CSNE) work on ways to use BCIs to help the paralyzed walk again.

With some modifications, the team believes its system could be applied to other devices, including smartphones or tablets. “We’re approaching half of what, for example, I could probably type on a cell phone,” neurosurgeon and co-senior author Jaimie Henderson of Stanford University told Scientific American. “This study reports the highest speed and accuracy, by a factor of three, over what’s been shown before.” In the future, the team hopes to refine the technology so that it becomes wireless, fully implanted, and self-calibrating, thus being able to provide around-the-clock support.