Scientists are developing brain-to-computer interfaces to allow those with spinal cord injuries to control prosthetic limbs or track a computer cursor using nothing but their thoughts.
It builds on earlier work in epilepsy patients and also in monkeys trained to use a robot arm to feed themselves marshmallows and turn a doorknob.
“We are now ready to begin testing BCI [brain-to-computer] technology in the patients who might benefit from it the most, namely those who have lost the ability to move their upper limbs due to a spinal cord injury,” Dr Michael Boninger, director of the University of Pittsburgh Rehabilitation Institute, told a session at the American Association for the Advancement of Science annual meeting.
One approach involves using a special cap to record the brain’s electrical activity. The spinal cord injury subject wears this for a month and learns how to use the neural activity in the brain to control computer cursors, virtual hands, computer games and assistive devices such as a motorised wheelchair. The research is funded by the US National Institutes of Health.
Other research, funded by the US Defense Advanced Research Projects Agency, uses minute four-millimetre square microchips that carry tiny electrodes. They are implanted on the surface of the brain - for example in areas associated with limb control.
The electrodes are sensitive enough to respond to individual nerve cells, and after training the person can learn to activate the nerve cells by thought in order to control an artificial limb. This has already been done using monkeys who can manipulate a highly complex arm and hand.
“Our animal studies have shown that we can interpret the messages the brain sends to make a simple robotic arm reach for an object and turn a mechanical wrist,” said Dr Andrew Schwartz, professor of neurobiology at Pittsburgh School of Medicine. “The next step is to see not only if we can make these techniques work for people, but also if we can make the movements more complex.”