From left, Gerard Francisco, Contreras-Vidal, and O’Malley work with a UH graduate student testing MAHI-EXO II, a robotic rehabilitation device developed at Rice and being used at TIRR Memorial Hermann to help spinal-cord-injury patients recover. In a new project, a similar device will be matched with a noninvasive neural interface under development at UH to help rehabilitate stroke survivors. Photograph by Bruce French, courtesy of TIRR Memorial Herman.
The National Institutes of Health (NIH) and the President’s National Robotics Initiative (NRI) have awarded a $1.17 million grant to help further the development of and validate a noninvasive brain-machine interface (BMI) to a robotic orthotic device for upper-limb rehabilitation. The new neurotechnology will interpret brain waves that let a stroke patient willingly operate an exoskeleton that wraps around the arm from the fingertips to the elbow. The work is being conducted by a multidisciplinary team comprising researchers from Rice University, Houston, Texas; the University of Houston (UH); and TIRR Memorial Hermann, Houston.
Rice is developing the exoskeleton and UH the electroencephalograph-based (EEG) neural interface. The combined device will be validated by UT Health Science Center (UTHealth) physicians at TIRR Memorial Hermann with as many as 40 volunteer patients in the final two years of the four-year award. The new project will be one of the first to design a BMI system for stroke survivors and will be among the first to investigate the benefits of combined therapeutic interventions to help stroke survivors, according to a Rice press release.
Repetitive motion has proven effective at retraining motor nerve pathways damaged by a stroke, but patients must be motivated to do the work, said principal investigator Marcia O’Malley, PhD, an associate professor of mechanical engineering at Rice and director of Rice’s Mechatronics and Haptic Interfaces (MAHI) Lab. “With a lot of robotics, if you want to engage the patient, the robot has to know what the patient is doing,” O’Malley said. “If the patient tries to move, the robot has to anticipate that and help. But without sophisticated sensing, the patient has to physically move-or initiate some movement.”
“The capability to harness a user’s intent through the EEG neural interface to control robots makes it possible to fully engage the patient during rehabilitation…and is expected to accelerate motor learning and improve motor performance,” said José Luis Contreras-Vidal, PhD, director of UH’s Noninvasive Brain-Machine Interface Systems Laboratory and a UH professor of electrical and computer engineering. “The EEG technology will also provide valuable real-time assessments of plasticity in brain networks due to the robot intervention-critical information for reverse engineering of the brain.”
The team led by Contreras-Vidal was the first to successfully reconstruct three-dimensional hand and walking movements from brain signals recorded in a noninvasive way using an EEG brain cap. The technology allows thought control of robotic legs and neuroprosthetic limbs by individuals with transradial amputations.
Initially, EEG devices will translate brain waves from healthy subjects into control outputs to operate the MAHI-EXO II exoskeleton, and then from stroke survivors who have some ability to initiate movements, to prompt the robot into action. That will allow the team to refine the EEG-robot interface before moving to a clinical population of stroke patients with no residual upper-limb function.
When set into motion, the intelligent exoskeleton will use thoughts to trigger repetitive motions and retrain the brain’s motor networks. An earlier version of the MAHI-EXO II developed by O’Malley, already in validation trials to rehabilitate spinal-cord-injury patients at the UTHealth Motor Recovery Lab at TIRR Memorial Hermann, incorporates sophisticated feedback that allows the patient to work as hard as possible while gently assisting-and sometimes resisting-movement to build strength and accuracy. That work was published in the February 2012 issue of the Journal of Rehabilitation Medicine.
Editor’s note: This story was adapted from materials provided by Rice University.
