Brain Implant that Made a Paralyzed Monkey Walk is Soon to be tested on Humans

Image Courtesy: EPFL
Image Courtesy: EPFL

A recent experiment conducted on paralyzed monkeys shows much promise in making persons with disabilities walk again. The research involved minuscule brain and spine implants which instantaneously restored leg motion when they were activated.

The monkeys experimented on have a severed spinal cord, cutting a pathway in the brain-spine connection that enables leg movement.  Using data gathered from analyzing healthy monkeys on a treadmill, the team managed to map out the parts of the brain that send the electric signals responsible for walking. They also studied how the lower spine receives these signals before they’re transmitted to the leg muscles.

By implanting microelectrode arrays in the paralyzed monkey’s brain, they were able to receive the brain signals responsible for leg movement. A wireless transmitter placed on the skull sends these brain signals to a computer program which decodes them. The computer then, sends these signals to the electrodes attached to the spinal cord, just below the disconnected part, triggering electric pulses to start leg motion. Using this computer program, they were able to simulate the brain-spine interface (BSI) that has been cut off due to an injury.

When the monkey tried moving the paralyzed leg while the BSI program is off, nothing happened. But when the program was turned on, the leg moved to its desired purpose. The program’s results were immediate without needing any kind training or physiotherapy beforehand. The rhythmic motion is still imperfect but coordinated and strong enough to support the monkey’s weight.

The study is considered as the fruit of decades of work and is a significant milestone in bioelectronic medical treatment. Similar tests have been conducted in rats for years, but this is the first time they were able to get the same results testing it on a primate.

Use of bioelectronic treatments is nothing new. The technology for reading brain signals is currently used to move robotic arms in paralyzed people. Arm and hand movements require complex readings than leg motion, but it’s an all or nothing scenario for the lower limbs. The legs should be able to support the weight while maintaining movement balance of the user simultaneously.

Translating the same technology for human use poses a massive challenge, but this doesn’t stop scientists from finding ways to further improve it. Two patients in a hospital in Switzerland already volunteered for clinical trials. Electric-pulse generators have been embedded in their lower spines but nothing has been installed in their brains yet to enable them to control their legs.

It will still take several years to optimize it for human treatments but can be considered a great step towards improving the lives of people who have disabilities and those who are suffering from debilitating accidents.

Reference: EPFL