A wheelchair controlled by the power of thought has been developed by scientists.
In experiments, monkeys were able to navigate their way around a lab just by thinking about moving toward a goal – in this case, a bowl of grapes.
A computer translates their brain activity into real time operation of the wheelchair, offering hope of restoring mobility for severely paralysed patients.
The wireless brain machine interface (BMI) works by picking up pulses of electricity emitted by electrodes implanted inside the cortex, a brain area responsible for movement and sensation.
The robotic chair could revolutionise life for those with severe disabilities who are unable to use a conventional joystick.
Neurobiologist Professor Miguel Nicolelis, of Duke University in the US, said: “In some severely disabled people, even blinking is not possible.
“For them, using a wheelchair or device controlled by non invasive measures like an EEG, a device that monitors brain waves through electrodes on the scalp, may not be sufficient.
“We show clearly that if you have intracranial implants, you get better control of a wheelchair than with non invasive devices.”
In the study his researchers implanted two rhesus monkeys with multi-electrode arrays that allowed wireless recordings to be made of their cortical neurons.
The animals were then seated in a robotic wheelchair and passively observed its movements as it navigated around a space, in order to train a computer decoder.
The monkeys then attempted to navigate in the wheelchair, using the wireless BMI system, from one of three starting positions to a target location, where the grapes had been placed as a reward.
The researchers found the BMI was capable of translating the monkeys’ brain activity into directional movements in the wheelchair in order to complete the task.
And, over time, the monkeys improved their ability to navigate in the wheelchair, which may have been mediated by changes in their brain structure in response to training.
Prof Nicolelis said the he interface, described in the journal Scientific Reports, shows the future potential for people with disabilities who have lost most muscle control and
The experiments began in 2012, with hundreds of hair-thin electrodes implanted in the pre-motor and somatosensory regions of the brains of two rhesus macaques. They trained the animals by passively navigating the chair toward the bowl of grapes.
During the training phase, the scientists recorded the primates’ large-scale electrical brain activity.
The researchers then programmed a computer system to translate brain signals into digital motor commands that controlled the movements of the wheelchair.
Prof Nicolelis said that as the monkeys learned to control the wheelchair just by thinking, they became more efficient at navigating toward the grapes and completed the trials faster.
The researchers also discovered that the monkeys’ brain signals showed signs they were contemplating their distance to the bowl of grapes.
Prof Nicolelis added: “This was not a signal that was present in the beginning of the training, but something that emerged as an effect of the monkeys becoming proficient in this task.
“This was a surprise. It demonstrates the brain’s enormous flexibility to assimilate a device, in this case a wheelchair, and that device’s spatial relationships to the surrounding world.”
The trials measured the activity of nearly 300 neurons in each of the two monkeys.
Prof Nicolelis said the team now hopes to expand the experiment by recording more neuronal signals to continue to increase the accuracy before seeking trials for an implanted device in humans.