Dr. Alix Trouillet

Bionic hearing in mammalian species using a soft Auditory Implant

Guest Speaker:

Dr. Alix Trouillet, Research scientist, department of Otorhinolaryngology, Lausanne University Hospital, Lausanne, Switzerland.

Abstract:

By 2050, nearly 700 million people will require hearing rehabilitation (world health organization). With more than 1 million people implanted worldwide, cochlear implants (CI) are the first line of treatment for severe deafness when traditional non-invasive hearing aids fail to restore acceptable hearing levels and huge a success in the field of auditory neuroprosthesis. Modern CI restores meaningful sound perception and speech comprehension to both children and adults with severe hearing loss and greatly improving their quality of life. However, allowing speech recognition but the variability of the outcomes among the treated population, leaves some room for rehabilitation strategy improvement.

However, significant limitations remain, underscoring the urgent need for innovation: 1) CIs cannot convey real-world hearing experiences such as complex acoustic contents like music or speech in noisy environments 2) Outcomes are highly variable across implanted patients, with some achieving only limited improvements. 3) CIs are ineffective for individuals with cochlear and auditory nerve abnormalities and central disorders leaving a large patient population without efficient solutions. Several strategies can be envisioned to pave the way of the next generation neuroprosthesis for auditory disorders: – technological improvement in order to increase device resolution and versatility while reducing footprint – change target tissue and stimulate other structure along the auditory pathway such as the cortex -improve the way stimulation is processed and encoded.

To address these challenges, we leveraged soft bioelectronics technology and developed a novel soft auditory brainstem implant (ABI) and a soft auditory cortical implant (ACI). We have developed well-hearing animal models enabling systematic assessment of neuroprosthetic stimulation of the auditory system from electrophysiology and behavioral readouts. Through cortical recordings and frequency discrimination task paradigm, we applied the framework to different mammalian species, rodents, minipigs and non-human primates. We were able to quantify the quality of prosthetic hearing such as spatial resolution, selectivity, perception and biocompatibility. We obtained a direct comparison between natural and prosthetic evoked activity and our results indicate the potential of the soft auditory implants in creating relevant and high-resolution hearing percepts.