Three men are sitting in a lab. The man on the left is wearing a white shirt with a blue patterned tie. He has short black hair and glasses. The man in the middle is wearing a grey blazer over a striped shirt. He has short, curly dark brown hair with some grey. He is holding a small electronic device. The man on the right is wearing a black blazer over a dark navy shirt. He has short dark brown hair with some grey.

Brain-controlled exoskeleton offers hope for spinal cord injury patients

People living with spinal cord injury and paraplegia may one day be able to walk again using an exoskeleton controlled by their brain, a new study suggests.

Researchers in the US have developed a bidirectional brain-computer interface (BDBCI), which allows a person to control a robotic walking exoskeleton using brain signals and receive artificial leg sensations through direct electrical stimulation of the sensory cortex.

They say the system addresses the limitations of existing exoskeletons, which rely on manual control and provide no sensory feedback, resulting in reduced gait speed and an increased risk of falls.

“Millions of people worldwide suffer from paralysis from spinal cord injury, with loss of lower-extremity motor and sensory function leading to wheelchair dependence and increased risk of serious secondary conditions including heart disease, osteoporosis and pressure ulcers,” said Dr An Do, Associate Professor of Neurology at UC Irvine and co-author of the study.

“Recovering the ability to walk ranks among the highest rehabilitation priorities for paralysed individuals.”

In the study, a 50-year-old woman undergoing epilepsy evaluation operated the BDBCI-controlled exoskeleton after electrodes had been placed on the surface of her brain.

She completed 10 exercises and rapidly achieved a high level of performance, according to the researchers.

Artificial sensation was delivered through direct cortical electrical stimulation, a technique the researchers identify as the safest and most practical option for eliciting leg sensation in ambulatory settings.

To validate artificial sensory feedback, the participant completed a blind step-counting task, correctly identifying steps with an overall accuracy of almost 93%.

She also identified right leg, left leg and null (no stimulation) feelings with 96, 84 and 100 percent accuracy, respectively.

The participant confirmed in all 10 runs that exoskeleton steps triggered matching contralateral leg sensations and reported that the sensory feedback aided task performance.

No adverse events were noted throughout the study, the researchers said.

Looking ahead, the team planning to develop a fully implantable version of the BDBCI to eliminate transdermal components that pose infection risk.

They also hope to test the function of the system on people with complete leg paralysis.

“This work demonstrates that it’s feasible to restore both the motor and sensory dimensions of walking using a single, compact, embedded brain-computer interface system,” said Dr Do.

“We believe this lays a critical foundation for the development of fully implantable systems that could one day give paraplegic patients a meaningful and natural sense of movement.”