When I was a child, the age-appropriate science magazines the school would distribute sometimes had stories about upcoming medical advances. That was where I first encountered the idea that scientists might one day construct a robotic exoskeleton that could help a man to walk. We’ve covered innovations in the field before at ET, including the development of remote-control limbs. Now, scientists have tested a new solution that proved capable of helping a quadriplegic man walk again, with control over all four mechanical limbs.
The work conducted at the Clinatec research center in Grenoble, France focused on two patients. One dropped out of the study due to a technical issue with the implants in question. The remaining individual had a C4-C5 spinal cord injury and suffered from quadriplegia/tetraplegia as a result. Two implants with 64 electrodes each were implanted in the upper limb sensory-motor areas of the brain.
Epidural electrocorticographic (ECoG) signals were processed by a decoding algorithm and relayed to the artificial muscles of the exoskeleton to allow them to respond to the man’s thoughts. The model used to decode the man’s neural impulses only had to be recalibrated every seven weeks. This is a significant achievement, though it might not sound like one at first glance. One of the challenges of developing a brain-computer interface is that calibrating the interface can take a significant amount of time — 20-30 minutes per session. Systems may also need to be recalibrated if significant amounts of time have passed since the previous calibration. Only needing to calibrate every seven weeks is an achievement in its own right.
According to the BBC, the patient in question, Thibault (no surname) spent two years in a trial using the Clinatec device. First, he used the implants to control an in-game avatar before moving on to the suit pictured below:
Controlling the arms was apparently significantly more difficult than the legs, and the 65kg robot obviously doesn’t completely restore function. Currently, the system only uses 32 electrodes on each 64-electrode chip, because they only have a 350-millisecond window to receive signals, decode those signals, and send the proper movement impulses back to the exoskeleton for moving. The system as it exists today doesn’t yet allow for fully autonomous movement — Thibault is attached to the frame in a ceiling-mounted rig for additional security and safety. But this only makes sense when dealing with a quadriplegic patient with no ability to brace or protect himself if the rig should fall.
The trials the team conducted weren’t completely successful, but Thibault can perform trials that require him to touch a specific target by moving his arm and rotating his wrist 71 percent of the time. The research team has plans to continue developing the interface, with a long-term goal of using the other 64 electrodes in the implant and using AI to predict muscle movements more quickly. The next step is to develop finger controls so that Thibault can lift and manipulate objects, and he’s also used the interface to control a wheelchair.
I do not often wax poetic about technology, but the ability of medical research like this to improve the lives of individuals is truly revolutionary. Obviously we are still some years away from exoskeletons or the sorts of brain-computer interfaces that allow a paraplegic or quadriplegic individual to control an exosuit the way James Rhodey does it in the later Marvel movies. But advances like this demonstrate that these science fiction applications are not as out of reach as they may have once seemed. Tony Stark’s rocket boots and wrist lasers are science fiction. The underlying concept behind his exosuits are increasingly part of our scientific reality.
Feature image by Clinatec
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