Periodic Reporting for period 2 - HearLight (Towards optogenetic cortical implants for hearing impaired)
Période du rapport: 2022-04-01 au 2023-09-30
Cochlear implants are the first and currently most successful sensory rehabilitation strategy, and equip thousands of hearing impaired patients. However, they suffer from strong information throughput limitations, making music perception and speech intelligibility in noise impossible, extremely detrimental to implanted patients. In this project, we propose to establish a clear proof of concept for a radically new auditory rehabilitation strategy by direct stimulation of the main sound processing center in the brain, the auditory cortex. The auditory cortex not only offers one order of magnitude more interfacing surface, to boost information throughput, but it is also a plastic structure, adaptable to complex auditory codes, which could benefit from acoustic information preprocessing by modern artificial intelligence algorithms. To demonstrate that cortical implants are feasible and outperform cochlear implants, artificial sound perceptions will be optogenetically generated via an LED display placed over the full extent of auditory cortex in behaving mice. Perceptual precision for a wide range of acoustic features will be precisely benchmarked against cochlear implant thanks to a range of psychophysical assays available in this animal model. The benefits of sound preprocessing by machine learning algorithms (deep learning networks) will be tested, and we will develop a new generation of ultrathin, flexible, biocompatible LED displays, that could be placed on the convoluted surface of human auditory cortex to activate precise and rich perceptions. Together, these brain-interfacing and bioelectronics innovations will enable a new implant strategy in that promises to be a major changer for hearing restoration quality in deaf patients, and pave the way for improvement of other sensory restoration strategies.
During the second reporting period, we have achieved important steps towards the validation of the cortical implant concept. We have fully established brain stimulator prototype both for high reolution electrical and optogenetic stimulation, and demonstrated their robustness for flawless performance of preclinical tests. We have performed preclinical trials to evaluate the quality of the auditory perception achieved with the implant prototypes and compared it to cochlear implants in the same tasks. We have developped an encoding model based on a deep learning network model. Our results show that the cortical implant generate a good quality perception that could be beyond the quality of cochlear implant. We have also achieved the insertion of LEDs in flexible bioelectronic. Intellectual property protection and publications of these results are in preparation.
The demonstration that auditory cortical implants produce robust and precise perception in preclinical trial is a major step beyond the state of the art. Cortical implants can therefore become a new solution for patients suffering from deafness and who are unable to receive cochlear implants. Our results also suggest that they could provide an improvement or complement of cochlear implants boosting auditory restoration and life quality of the patient.