Device allows people to type with their mind

A team of researchers has developed a brain-computer interface that allows users to type at nearly normal rates.

A newly-developed brain-computer (BCI) interface allows people with severe limb weakness to type, using their minds, at speeds approaching normal. The participants each had an electrode array around the size of a baby aspirin implanted in their brains. The array recorded signals from the motor cortex, the region of the brain controlling muscle movement. Following the surgery, the participants were encouraged to visualise the arm, hand and finger movements involved in typing. The resulting neural signals were then translated by algorithms into point and click commands that were used to guide a cursor on an onscreen keyboard.

Similar techniques using headsets have already allowed users to control movies with their thoughts and to track stress levels. Participants in the study were able to outperform the results of any previous BCI, and without the use of any word prediction software. One participant was able to type 39 correct characters per minute, equivalent to about eight words per minute. Researcher Krishna Shenoy, professor of electrical engineering at Stanford, where the study took place, said, “This study reports the highest speed and accuracy, by a factor of three, over what’s been shown before … we’re approaching the speed at which you can type text on your cellphone.”

Previous studies used intracranial BCIs that were positioned at the brain’s surface beneath the skull. However, the BCI used in the Stanford study consisted of a tiny silicon chip, around one-sixth of an inch square, out of which protrude 100 electrodes that each penetrate around 1.7m mm into the brain, tapping into the electrical activity of individual nerve cells in the motor cortex. This allowed for greater precision. The team also noted that the point-and-click approach pioneered at Stanford could be applied to a variety of computing devices, including smartphones and tablets. This could substantially improve the ability to communicate and the quality of life for people with paralysis. Shenoy believes that they may be less than ten years away from a self-calibrating, fully implanted wireless BCI system, which can be used without caregiver assistance, to restore some function to those with severe neuromuscular impairment. Will the development of intracranial BCIs be able to restore communication, mobility and independence for people with neurologic disease or injury?