Enhancing mammalian hearing by a balancing between spontaneous otoacoustic emissions and spatial coupling

Nonlinear dynamics has provided significant insights into the origin of frequency discrimination and signal amplification underlying mammalian hearing. Existing signal amplification models, however, tend to ignore two basic known aspects of the hearing: spontaneous otoacoustic emissions (SOAEs) and intrinsic dynamical coupling in the cochlea. We construct and study a class of coupled-oscillator models to remedy this deficiency. Our analysis and computations reveal that the interplay and balance between the two aspects can naturally explain the phenomena of frequency discrimination and signal amplification and, more strikingly, the origin of hearing loss, all at a quantitative level. In the presence of SOAEs, there exists a critical coupling threshold below which hearing loss can occur, suggesting enhancement of coupling as a potentially effective therapeutic strategy to restore or even significantly enhance hearing.