Two patients with amyotrophic lateral sclerosis (ALS) and one patient with a spinal cord injury were able to type with speed and accuracy as the result of receiving a brain-computer interface (BCI) transplant, according to Stanford University researchers.

Each patient received an intracortical brain-computer interface called the BrainGate Neural Interface System, which uses a tiny silicon chip from which 100 electrodes protrude to penetrate the brain to record signals from the brain’s motor cortex. These signals were transmitted to a computer via a cable and translated by algorithms into point-and-click commands guiding a cursor to characters on an onscreen keyboard.

After some training, each patient was able to outperform the results of any previous test of brain-computer interfaces for enhancing communication by people with similarly impaired movement. Notably, they all achieved these typing rates without the use of automatic word-completion assistance, according to a media release from Stanford University Medical Center.

Via the BCI, the SCI patient was able to type 39 correct characters per minute, which is equivalent to about 7.8 words per minute. The other two patients achieved 6.3 and 2.7 words per minute, respectively.

“Our study’s success marks a major milestone on the road to improving quality of life for people with paralysis,” says Jaimie Henderson, MD, professor of neurosurgery, who performed two of the three device-implantation procedures. The third took place at Massachusetts General Hospital.

Henderson and Krishna Shenoy, PhD, professor of electrical engineering, are co-senior authors of the study, which was published recently in the online journal eLife. The lead authors are former postdoctoral scholar Chethan Pandarinath, PhD, and postdoctoral scholar Paul Nuyujukian, MD, PhD, both of whom spent well over 2 years working full time on the project at Stanford, per the release.

“This study reports the highest speed and accuracy, by a factor of three, over what’s been shown before,” states Shenoy, a Howard Hughes Medical Institute investigator who has been pursuing BCI development for 15 years and has been working with Henderson since 2009. “We’re approaching the speed at which you can type text on your cellphone.”

“The performance is really exciting,” adds Pandarinath, who now has a joint appointment at Emory University and the Georgia Institute of Technology as an assistant professor of biomedical engineering, in the release. “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.”

“These high-performing BCI algorithms’ use in human clinical trials demonstrates the potential for this class of technology to restore communication to people with paralysis,” Nuyujukian says.

[Source(s): Stanford University Medical Center, Science Daily]