Signal-in-noise detection across the lifespan in a mouse model of presbycusis.

The auditory system is constantly tasked with detecting acoustic cues in complex auditory environments. Difficulty hearing speech in noise, largely a result of energetic masking, is a major communication complaint of the elderly, which impacts a third of the global population over 65. The neural mechanisms responsible for processing sound in background noise and subsequently achieving release from energetic masking remain obscure. Furthermore, the senescence of signal-in-noise detection is poorly understood, a phenomenon which could have a myriad of clinical implications. We tested over 300 CBA/CaJ mice aged 1-27 months on tone-in-noise detection ability utilizing prepulse inhibition of the acoustic startle response with a machine learning startle classifier. We found that mice developed profound tone-in-noise detection deficits throughout their lifespan as evidenced by Rd', a detection metric derived from signal detection theory. The most severe decline in Rd' corresponded to a 2.54-fold decrease in tone-in-noise detection across the lifespan. Our findings suggest that CBA/CaJ mice are an appropriate model to study the role of age-related hearing loss in the context of signal-in-noise masking.