In 2023, it is the images of the Dutchman Gert-Jan controlling his legs by thought which are going around the world, a success signed by Swiss researchers. The common point? Wimagine, the brain implant designed by Clinatec, a biomedical research center created by the CEA with the CHU and Grenoble Alpes University. “We use physical modalities to treat serious brain pathologies without drug treatment.summarizes Jean-Philippe Bourgoin, the deputy director of technological research at the CEA. From the technology used to the preclinical evaluation and up to the clinical trial on humans, all stages take place in this building.
Detecting microvolts emitted by the brain
The second floor contains the rooms where medical devices are manufactured. Exoskeleton, robotic arm and wheelchair are visible in these spaces where mechanics and electronics dominate. A small clean room is used to manufacture electronic components, such as Wimagine implants. Others are equipped with medical machines for biological analyzes and preclinical studies. In one of them, the frozen brains of a mouse, a rat and a primate are visible. On the third floor, rodents, primates and mini-pigs make up a non-visitable pet room. Enough to test the biocompatibility of medical devices. This organization, quite unique when the building was built in 2012, has since been copied, notably in the United States with the Shirley Ryan AbilityLab, at the Chicago hospital.
By developing the Wimagine implant, which records brain electrical activity using 64 electrodes, CEA electronics engineers have accomplished a real feat. “Neural activity emits a few dozen microvolts, which the circuits integrated into the implant manage to detect”describes the head of the CEA brain-machine program, Guillaume Charvet. The data collected is transmitted to a computer to be translated into movement intentions using artificial intelligence algorithms also developed internally. All in real time.
Miniaturization as a challenge
A few steps from the movement analysis room, a sanitized hospital corridor, opening onto rooms that accommodate day patients, leads to an operating theater. For visitors, this 90 square meter surgical room (double that of traditional hospitals) can only be seen through the large window of the adjacent room. To the right of the operating table, one of the very first Rosa surgical robots, used to increase the precision of interventions on the brain. It is here that Thibault underwent a 5 centimeter diameter craniotomy in 2017, during which two pieces of bone were removed in order to “position the two Wimagine implants on the surface of the right and left motor cortex”remembers Guillaume Charvet.
If this first clinical trial aimed to demonstrate the functioning of the implants and their safety, the Clinatec teams are now working on everyday devices. First challenge: miniaturize the computer carrying out the AI calculations in a device that can be attached to the belt. They also think about “a neuromuscular stimulation system to be positioned on the arm so that the patient can grasp objects”lists the scientist. More complex movements to perform than walking since the arm moves in a 3D environment to reach targets. “The patient must control every muscle!”exclaims Guillaume Charvet. Medical performance for carrying out daily actions, for example grabbing a glass of water. Engineers are also looking to transform the bulky helmet that allows the implants to function into a cap equipped with flexible antennas. A first copy already exists.
Light treatments
Beyond brain-computer interfaces, Clinatec is investing in light. Neurosurgeon Stephan Chabardes started the NIR (Near InfraRed) project, the objective of which is to slow the progression of Parkinson’s through intracranial photobiomodulation. A disease that results in “degeneration of the substantia nigra with loss of dopamine neurons”he recalls. To slow it down, researchers send near-infrared light as close as possible to the modal cells. A probe, developed at Clinatec, is inserted and positioned as close as possible to the substantia nigra. It continuously emits light for eight minutes and turns off for four minutes. To test it, 14 people, diagnosed less than two years ago, will be followed for four years.
The same approach is envisaged to prevent Alzheimer’s disease in the Tiroc project. The effects of near-infrared light, applied using a helmet, are first studied on healthy patients. Then a clinical trial will include sick patients. Dozens of people with and without neurological disorders go through Clinatec to participate in trials. The patient area is “organized like a hospital service”describes Doctor Daniel Anglade. With a more intermittent effervescence.
Source: www.usinenouvelle.com
