Epilepsy, a binding neurological disorder, is not a rare disease. It concerns about 1% of the world’s population and more than 500,000 patients in France, half of whom are under 20 years old. In the majority of cases, neuroleptics make it possible to attenuate or stop the seizures. But “about a third of patients are resistant to drugs and for several tens of thousands of them, epilepsy constitutes a real handicap in their daily life”, emphasizes Ludovic Gardy, CNRS engineer at the Brain and Cognition Research Center (CerCo) of Toulouse, whose thesis work is about to lead to the creation of a start-up which could improve the fate of these “drug-resistant” patients.
For the latter and if they meet certain conditions, there is a surgical solution as a last resort: the removal, directly in the brain, of the so-called “epileptogenic” zone, at the origin of the seizures. But this option, which concerns “nearly a thousand patients per year in France”, is laborious, very tedious. Because, often, to precisely locate the area to be operated on, it is first necessary to be hospitalized “ten to fifteen days” of days for the implantation of ten intracerebral electrodes – long rods of about ten centimeters in medium – lined with sensors to record neural activity. The specialist then finds himself with bundles of electroencephalogram (EEG) curves that he must decipher and compile to establish his diagnosis. A “colossal” and tedious investigation that can take several months. “It’s a bit like if the epileptologist had to swallow a 500-page novel every day, to make a summary and, in addition, to highlight each appearance of the word “house””, says Ludovic Gardy.
One hospitalization instead of two?
The specialist can use different biomarkers of epilepsy as a “compass”. According to “current literature”, the most effective are “fast ripples”, very rapid pathophysiological oscillations. But they are so microscopic that they are “strictly invisible to the naked eye” on the curves.
And this is where the algorithm developed by Ludovic Gardy and his two thesis supervisors Emmanuel Barbeau from CerCo and Christophe Hurter, researcher in artificial intelligence at the National School of Civil Aviation (Enac) comes into play. “Not only is the algorithm capable of ‘automatically detecting fast ripples, but we have wrapped it in software that allows classic data manipulation,’ says the engineer. This “tool” was tested a posteriori on the EEGs of around thirty “implanted” patients. He correctly localized the fast ripples in the areas determined by the specialists thanks to their classic biomarkers visible to the naked eye. But in a few days instead of a few months.
By the summer, the three researchers must create the start-up Avrio MedTech, a CNRS subsidiary, which will improve and then market the software. For “implanted” epileptics, the EEGs and the operation could be done in a single hospital stay, whereas the process can currently take a year.