Individuals who have lost sensation or movement in their limbs may soon find hope for recovery — thanks to a new assistive technology that uses robotics, virtual reality and a brain-machine interface (BMI).
Eight paraplegic patients, all of whom have suffered spinal cord injuries, were reported to have regained both sensation and motor abilities after undergoing a 12-month neurorehabilitation program using robotics and VR.
The results are documented in a groundbreaking study published in Scientific Reports, supplementing much-needed information on whether this type of rehabilitation — with the help of machines — leads to clinical recovery in patients.
For years, the researchers note, robotic assistance, electrostimulation and body weight support systems have offered ways to assist paraplegic patients in their movement.
"Yet, none of these approaches have generated any consistent clinical improvement in neurological functions," the study points out.
Today, experiments involving rats and monkeys, and also clinical studies participated in by human subjects, have given credence to BMI as an alternative therapy for restoring sensory and motor abilities.
The year-long machine-based training helped the study subjects, aged 3 to 13 years, recover somatic sensation and voluntary muscle control, and all this points to actual neurological improvements. These include the ability to sense fine or crude touch or feel pain in localized areas. Apart from regaining sensation, patients have also shown improvements in their walking ability after BMI rehabilitated key muscles affected by their spinal cord injury.
"If you touched them with a pin, or a brush … they would feel something that they didn't experience before," Professor Miguel Nicolelis of Duke University's Center for Neuroengineering, tells the BBC. Nicolelis led the study.
How Neurorehabilitation Works
The team's Walk Again Neurorehabilitation program combined the immersive technology of VR, the assistive technology of a robotic body weight support gait system, and a brain-controlled, sensorized robotic exoskeleton.
The training included having the patients sit or stand throughout a VR session (where their brain activity was monitored), walk on a treadmill, or stay fixed on an overground track, among other physically and neurologically stimulating activities.
During the VR sessions, for instance, patients were able to control a human body avatar while they received visuo-tactile feedback.
"Throughout the application of our protocol," the researchers note, "the complexity of activities was increased over time to ensure cardiovascular system stability and better patient postural control."
After a comprehensive neurological examination, all eight patients unexpectedly showed marked clinical improvements.
Tactile feedback and robotic gait training have helped enrich neurorehabilitation. This suggests that the protocols used in the study may result in cortical and subcortical plasticity, which can in turn stimulate partial neurological recovery in people with brain or spinal injury.