PhD: Impact on Presbycusis of Repeated Acoustic Trauma Institut Pasteur in France

This PhD project investigates the impact of repeated acoustic trauma on the progression of presbycusis, or age-related hearing loss, a prevalent chronic disability among older adults. The research centers on the molecular and cellular mechanisms underlying temporary threshold shifts (TTS) in hearing, which occur after exposure to loud or prolonged noise and are traditionally considered harmless. However, recent evidence suggests that repeated TTS may contribute to permanent hearing loss, tinnitus, hyperacusis, and accelerate presbycusis onset.

The project’s central hypothesis is that repeated TTS interferes with the repair of tip links—protein chains connecting hair cell actin filaments in the cochlea—thereby speeding up age-related hearing decline. Using the mouse as a model organism, the research will pursue three interconnected goals:

• Characterise tip link damage after single and repeated TTS: Mice will be exposed to brief, loud noise episodes to induce TTS. Functional hearing tests (auditory brain stem responses and otoacoustic emissions) will be conducted before and after exposure. Super-resolution imaging will visualize cochlear structures, revealing tip link breakage and regeneration dynamics.
• Identify conditions that enhance tip link regeneration: The study will compare post-trauma environments—total silence versus structured sound exposure—by sampling at multiple time points within two days after injury. This will determine which environment best supports rapid and complete tip link restoration.
• Determine the long-term impact of repeated TTS on age-related hearing loss: Young and adult mice will undergo repeated TTS sessions and be followed to 18 months of age. Comprehensive auditory assessments and histological analyses will evaluate synaptic connections and tip link integrity. A cohort will receive the optimal post-trauma acoustic protocol to test whether improved tip link repair slows presbycusis progression.

This research links everyday noise exposure to cellular damage and explores therapeutic interventions that do not rely on hair cell regeneration, which mammals lack. The findings will provide fundamental insights into how noise contributes to hearing decline and inform future clinical strategies, such as controlled sound environments after noise exposure, to preserve hearing health in aging populations.

The project is hosted at the Institut Pasteur, a leading center for biomedical research. Applicants should have a strong background in biological sciences, neuroscience, or medical science, with experience in animal models, auditory research, or cellular imaging considered advantageous. The application window is open; candidates should apply online via the provided portal.