For the first time, scientists at Caltech have induced natural sensations in the arm of a paralyzed man by stimulating a certain region of the brain with a tiny array of electrodes. The patient has a high-level spinal cord lesion and, besides not being able to move his limbs, also cannot feel them. The work could one day allow paralyzed people using prosthetic limbs to feel physical feedback from sensors placed on these devices.
The research was done in the laboratory of Richard Andersen, James G. Boswell Professor of Neuroscience, T&C Chen Brain-Machine Interface Center Leadership Chair, and director of the T&C Chen Brain-Machine Interface Center. A paper describing the work appears in the April 10 issue of the journal eLife.
The somatosensory cortex is a strip of brain that governs bodily sensations, both proprioceptive sensations (sensations of movement or the body’s position in space) and cutaneous sensations (those of pressure, vibration, touch, and the like). Previous to the new work, neural implants targeting similar brain areas predominantly produced sensations such as tingling or buzzing in the hand. The Andersen lab’s implant is able to produce much more natural sensation via intracortical stimulation, akin to sensations experienced by the patient prior to his injury.
Mayo Clinic researchers used electrical stimulation on the spinal cord and intense physical therapy to help a man intentionally move his paralyzed legs, stand and make steplike motions for the first time in three years.
The case, the result of collaboration with UCLA researchers, appears today in Mayo Clinic Proceedings. Researchers say these results offer further evidence that a combination of this technology and rehabilitation may help patients with spinal cord injuries regain control over previously paralyzed movements, such as steplike actions, balance control and standing.
“We’re really excited, because our results went beyond our expectations,” says neurosurgeon Kendall Lee, M.D., Ph.D., principal investigator and director of Mayo Clinic’s Neural Engineering Laboratory. “These are initial findings, but the patient is continuing to make progress.”
A new approach that combines functional electrical stimulation (FES) technology with a brain-computer interface (BCI) has allowed a paralyzed man to walk without the use of an exoskeleton or manual controls. According to researchers at the University of California-Irvine who worked on the project, their breakthrough is the first-ever demonstration that “restoring brain-controlled overground walking after paraplegia due to [spinal cord injury] is feasible,”
The subject of the project was Adam Fritz, a 26-year-old man who had suffered a spinal cord injury (SCI) in 2008 that left him with no motor function in the lower extremities and, other than minimum sensation for bladder fullness, no feeling below the T6 site of the SCI. Researchers selected Fritz not only because of the nature of his injury, but because he was physically active both before and after his injury, and thus more likely to respond well to the physical training needed to prepare for the new system. Results of the project were published in the Journal of NeuroEngineering and Rehabilitation.
Researchers began by connecting Fritz to a virtual reality environment (VRE) by way of an EEG cap that allowed him to engage in “motor imagery practice.” The VRE helped him activate the areas of his brain needed to walk and stand as he advanced and paused in a virtual setting, which in turn counteracted the suppression of the supraspinal areas related to gait that can occur after chronic SCI.