In 2009, researchers at Duke University implanted intracortical penetrating electrodes in a monkey who was trained to walk on a treadmill and inferred the kinematics of the monkey’s lower limb movements from the spikes of neuronal activity in the brain. Inspired by this study, Jose L. Contreras-Vidal, PhD, Hugh Roy and Lillie Cullen University professor of electrical and computer engineering and director at the Laboratory for Noninvasive Brain-Machine Interface Systems at the University of Houston, and colleagues are testing scalp electroencephalography (EEG) on paralyzed patients to help them move again.
“In my lab we started looking at ways to identify patterns of brain activity that were associated with learning or with clinical intervention,” Contreras-Vidal told O&P Business News. “As we trained a patient with spinal cord injury to learn to walk again, we were interested in understanding how that can be seen in terms of brain activity.”
Through earlier studies with healthy, able-bodied individuals, Contreras-Vidal and colleagues found they could use scalp EEG to extract information about the user’s movement intent, eg, gait kinematic patterns and surface electromyography (EMG) patterns associated with walking.
“The results were surprising to us because it has been thought for a long time that you need to use intracortical electrodes inside the brain to gather this kind of information,” Contreras-Vidal said. “It was exciting because it meant we could use non-invasive signals from the EEG to perhaps drive robots, such as exoskeletons, to engage the user into his or her own therapy and to help the user be in control of the robot.”
Through these findings, Contreras-Vidal and Robert G. Grossman, MD, professor of neurosurgery at the Houston Methodist Hospital, created the NeuroRex, an exoskeleton modified with an EEG cap that reads electrical activity generated by the brain. Where current exoskeletons utilize crutches to help the patient move, the NeuroRex will allow patients to move by using their thoughts without the need for crutches or walkers.
University of Houston team and a SCI volunteer wearing NeuroRex (from left to right): Contreras-Vidal, PhD, Kevin Nathan (UH-TMHRI graduate fellow), Gene Alford, MD, (SCI paraplegic patient), Atilla Kilicarslan, PhD, and Anusha Venkatakrishnan, PT, PhD.
Image: Jake Brown, photographer/videographer for the UH Cullen College of Engineering
Learning from the exoskeleton
Along with his partners from the Methodist Hospital in Houston, and with help of RexBionics, a company from New Zealand that created Rex, a self-balancing power robot, Contreras-Vidal is conducting a phase 1 clinical trial to quantify the benefits and assess the safety of the NeuroRex. The team is also looking to understand the best way to introduce the patient to the exoskeleton, what kind of movements to use and not only how it affects brain activity, but cardiovascular health, bone density, skin conditions, bladder functions and bowel movements.
“As we learn more about the brain, about the co-adaptation of the body and the brain, I think we can say we are also reversing engineering how the brain and body work together,” Contreras-Vidal said. “We want to better understand how the brain works and what brain areas are responsible for what [areas of the body]. We are learning about the plasticity of the brain as users get to use this machine. We also are training the next generation of student practitioners who will work at clinics in prosthetics and orthotics because this [exoskeleton] is advancing technology, and even though we want to make it user-friendly we still need experts who will prescribe it and will follow up [with the patient].”
Although the team wants to make the NeuroRex accessible to everyone, regulatory, cost and reimbursement issues also must be worked out.
“If an individual becomes tetraplegic at 27 years of age it is going to cost about $3 million on average to take care of them for a lifetime,” Contreras-Vidal said. “Multiply that by millions of people worldwide and it is clearly one thing we need to do [to reduce the burden of health care].”
According to Contreras-Vidal, the first step is to make the NeuroRex available at hospitals and clinics so patients can visit a couple times a week for training and to start getting the benefits of the system. Eventually, Contreras-Vidal and his colleagues hope to make the NeuroRex available to everyone who needs one.
“There are many challenges and this is something no one can do alone. It needs to be a partnership,” Contreras-Vidal said. “It is important to get this information to the public and practitioners because we couldn’t do it without their support. We are interested in making an impact on these patients and we can’t do it without their help.”
Future of NeuroRex
The NeuroRex has been in development for 2 years, and Contreras-Vidal says it will be at least another 3 years before the research on safety and efficacy is complete.
“There are a handful of [exoskeleton] systems out there. About seven or eight in the world and in the United States probably three have FDA clearances as a class 1 device (including Rex), which basically means it can be used as an exerciser but nothing else,” Contreras-Vidal said. “To be able to use and prescribe it to patients in a clinical setting you need to prove the benefits and safety.”
Over the next few years, Contreras-Vidal hopes to develop the NeuroRex as an multifaceted system that serves for purposes of diagnostics, physical assistance and rehabilitation.
“We want to be able to understand the health status of a patient, the whole body and brain, at any given time. Once we know the status of a patient, we can prescribe a customized intervention and we believe the patient’s health will improve with the help of this technology,” Contreras-Vidal said. “I think this technology is one of the game changers. I think it is going to not only increase quality of life and well-being, but it is going to reduce the burden of health care [on paralyzed patients].” — by Casey Tingle
Disclosure: Contreras-Vidal received a grant from the National Institutes of Health. Contreras-Vidal and Grossman received philanthropic gifts from the Mission Connect-TIRR Foundation and the Cullen Foundation, both located in Houston.
