The man learned to walk again, using his own brain power.
Credit: Dr. Zoran Nenadic
It is the first time that an individual who is unable to walk due to spinal cord injury (SCI) has purposefully operated a noninvasive brain computer interface (BCI) system for overground walking in real time, giving hope for the feasibility of developing BCI brain implants to help people to walk.
Surveys indicate that for people who have paraplegia due to SCI, being able to walk again is a high priority on the way to improving their quality of life. Sixty-percent of them say they would be willing to use a BCI implant if it would help them to walk.
Until now, most people who become paralyzed due to SCI achieve mobility by using a wheelchair, but the sedentary lifestyle that ensues often leads to further problems, notably osteoporosis, heart disease, respiratory illnesses and pressure ulcers. Not only do these cause further suffering to the individual, but they also contribute to medical costs.
The current study, led by Dr. Zoran Nenadic of the University of California, shows that it is possible for someone to use their own brain power to be able to walk again.
The participant underwent training and tests for 19 weeks to prepare for the walk. In each session, he gained more control and completed more tests.
Initially, mental training was needed to reactivate the brain's walking ability. From a seated position, and wearing an electroencephalogram (EEG) cap that read his brainwaves, the participant learned to control an avatar in a virtual reality environment.
He also underwent physical training to recondition and strengthen his leg muscles.
Next, he practiced walking while suspended 5 cm above the ground, in order to be able to move his legs freely without having to support himself.
On his 20th visit, he used these skills and an EEG-based system to walk along a 3.66-meter course on the ground.
He wore a body-weight support system for aid and to stop him from falling. The author of the report adds that he was also able to carry on a light conversation during the walk, without interfering with the system, suggesting good real-time control.
Moving toward brain implants to enable mobility
Robotic exoskeletons and functional electrical stimulation (FES) have been used to achieve mobility, but they have disadvantages. First, they cannot exploit the neuroplasticity of the pathways between the brain and the spinal motors pools. Second, they lack the supra spinal control that an able body intuitively has. They also have the inconvenience of tending to rely on manually controlled switches.
The researchers believe that if a system can be developed without these drawbacks, it would drastically improve the quality of life of individuals who are unable to walk due to SCI.
Spinal cord stimulation using BCIs offers hope of regaining voluntary lower extremity movements to those with SCI. It would enable intuitive and direct brain control of walking via an external device.
If the feasibility of such a device can be established through successfully testing it among enough people, a fully implantable BCI could be developed, that might restore the ability to walk in a way that resembles nature.
In the words of Dr. Nenadic:
"Once we've confirmed the usability of this noninvasive system, we can look into invasive means, such as brain implants. We hope that an implant could achieve an even greater level of prosthesis control because brain waves are recorded with higher quality. In addition, such an implant could deliver sensation back to the brain, enabling the user to feel their legs."
Earlier this month, Medical News Today reported that a man had been able to walk again after 4 years using a robotic exoskeleton.