Age-related hearing difficulty in noise stems from reduced cochlear nonlinearity, not just thresholds

Evidence

As people age, this task becomes increasingly difficult, and elevated thresholds alone cannot account for this increased difficulty (e.g., Pichora-Fuller et al. 1995 ). One explanation for this discrepancy may be attributed to the decrease in the endocochlear potential that tends to occur with increasing age (e.g., Schuknecht et al. 1974 ). A decreased endocochlear potential negatively affects the function of inner and outer hair cells (OHCs) (e.g., Gates et al. 2002 ), and disruptions in OHC function could decrease cochlear nonlinearity (e.g., Schmiedt et al. 1980 ). A sensitive measure of cochlear nonlinearity is two-tone suppression, e.g., a nearly instantaneous reduction in the basilar membrane (BM) response to one tone in the presence of a second tone. — Dijk, Pim van, Physiology, Psychoacoustics and…, 922

Categorization

• DEFINE: Defines two-tone suppression as a near-instantaneous reduction in basilar membrane response to one tone caused by a second tone.