How paralysed patients powered machines with their minds to move again

Advances in computing and robotics technology are allowing scientists to restore movement and sensation to people who have suffered devastating spinal injuries.

The World Health Organisation estimates that between 250,000 and 500,000 people suffer a spinal cord injury every year. In the worst cases these injuries leave a person unable to move, or without feeling below the neck.

Dr. Miguel Nicolelis leads a team of scientists at Duke University Center for Neuroengineering in Sao Paolo. His team is doing pioneering work to reverse the damage caused by spinal injury.

Eight paraplegics received 12 months of “brain training”, using a combination of virtual reality, a robotic walker and a brain-machine interface.

In sessions using virtual reality, participants in the study were able to imagine regaining full control of their limbs. Then, patients used a walking device, typically used in physical therapy, which allowed them to combine the movement of walking with their virtual reality imagination. In the final part of the training programme, the participants were connected via computer to a custom-designed exoskeleton.

 Neurorehabilitation training

Image: Nature

The brain communicates messages using electrical impulses. Patients wore a cap fitted with electrodes that picked up these messages and sent them to a computer. The computer then told the exoskeleton how to move. This happens in the same amount of time it would take a non-paralysed person’s brain to perform the same message function. The exoskeleton essentially becomes an extended part of the patient.

The result of the “brain training” was that the participants were able to move the exoskeleton using their own brains. But the results also went further than the Brazilian team had anticipated. They saw a partial neural recovery.

In other words, the scientists believe that some fibres within the spinal cord were “woken up” by the training, allowing patients to regain some voluntary movement and sense of touch. As a result, half the participants were downgraded from fully, to partially paralysed.

All eight patients regained some control of their lower limbs. This was true even for those who had been injured a decade or more earlier.

The Brazilian team’s research showed that work is advancing on enabling computers attached to our brains to read our thoughts. This has significant implications, including allowing amputees to control their prosthetic limbs and allowing spinal cord injury patients to move again.

Dr. Miguel Nicolelis believes this technique could ultimately make the wheelchair a thing of the past.

“Once you get the brain outside the physical limits of the body,” he said, “The limit is the imagination.”

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