Implications of a critical level in the ear for assessment of noise hazard at high intensities

Abstract

A critical level (CL) exists for the ear at high intensities where the loss mechanism undergoes a fundamental change. CL probably represents the intensity at which a given level of mechanical stress is reached in the organ of Corti. Electrophysiology, histology, and threshold shifts support a CL. CL varies as a function of the spectrum of the sound. The freefield SPL [sound pressure level] reaching CL in the human ear and the distribution of CL is estimated. The implications for human exposure and damage-risk are discussed.