Inherent envelope fluctuations in forward masking: Effects of age and hearing loss

Forward masking is generally greater for Gaussian noise (GN) than for low-fluctuation noise maskers, i.e., GN disruption. Because the minimal hearing loss that is associated with older age may affect GN disruption differently than more significant hearing loss, the current study explored the contribution of minimal hearing loss associated with older age to GN disruption. GN disruption was measured using three masker-signal delays (25, 75, and 150 ms) for three adult groups: younger participants with normal hearing, older participants with minimal hearing loss, and older participants with sensorineural hearing loss. The role of underlying mechanisms was tested using a computational model for midbrain neurons. The primary result suggests that older listeners with mild threshold elevations that typically occur with age may be more susceptible to the deleterious effects of masker-envelope fluctuations than younger listeners with normal hearing. Results from the computational model indicate that there may be a larger influence of efferent feedback and saturation of inner hair cells on forward masking and GN disruption than previously thought. ### Competing Interest Statement The authors have declared no competing interest. * Auditory Nerve : (AN) Auditory Nerve Fiber : (ANF) characteristic frequency : (CF) equivalent-rectangular bandwidth : (ERBN) Gaussian noise : (GN) inferior colliculus : (IC) inner hair cell : (IHC) low-fluctuation noise : (LFN) low/high-spontaneous rate : (L/HSR) Mean : (M) Medial Olivocochlear : (MOC) normal hearing : (NH) outer hair cell : (OHC) older participants with minimal hearing loss : (OMHL) older participants with Sensorineural hearing loss : (OSNHL) same-frequency inhibition-excitation : (SFIE) sensorineural hearing loss : (SNHL) younger participants with normal hearing : (YNH).