Stents are used by cardiologists to prop open blood vessels, and this implant is designed around one; it slides through an incision made in the jugular vein up to a blood vessel near the motor cortex in the brain. At the end of the stent, a metallic mesh with electrodes picks up brain activity and relays this information to a recording device in the wearer’s chest, which wirelessly transmits it to an external computer that will control the exoskeleton. The researchers have called their device a “stentrode.”
When a wearer thinks about a certain direction — for example, left — the brain fires in a particular way. By uncovering and detecting the way the brain fires, brain-computer interfaces are able to effectively “read” thoughts and translate them into actions.
The stentrode has advantages over other devices that detect brain signals. Electrodes are non-invasive but not always reliable when attached to the outside of the head, where they have to pick up signals through the skull. Direct implantation requires brain surgery, and since the brain sees the electrodes as foreign objects, it covers them in scar tissue, inhibiting their function.
The stentrode on the other hand is minimally invasive, requiring no open brain surgery, and can pick up brain signals with high fidelity. The device was trialled with live sheep last year.
“The brain doesn’t even know it’s there,” David Grayden, a University of Melbourne engineer who oversaw the devices development, told New Scientist. “The recordings are not quite as detailed as those from directly implanted electrodes,” he added, “but they’re close.”
Next year as many as five quadriplegic patients will test the device. The causes of their paralysis vary, including from a stroke, spinal cord injury, and muscular dystrophy.
“The end goal is that the person will be able to think about moving and an exoskeleton will obey,” Grayden said.
The new tech is timely — modern exoskeletons are quickly surpassing science fiction’s dreams.
