Time course of organ of Corti degeneration after noise exposure.

From our permanent collection of plastic-embedded flat preparations of chinchilla cochleae, 22 controls and 199 ears from noise-exposed animals were used to determine when, postexposure, hair cell (HC) and supporting cell (SC) degeneration were completed. The exposed ears were divided into four groups based on exposure parameters: 0.5- or 4-kHz octave band of noise at moderate (M) or high (H) intensities.

Calibrated finger rub auditory screening test (CALFRAST).

Background: Determination of auditory function is a fundamental part of a complete neurologic examination. Disability from permanent hearing loss is common in the general population. Current bedside auditory tests are unreliable and cumbersome.

Relation of focal hair-cell lesions to noise-exposure parameters from a 4- or a 0.5-kHz octave band of noise.

In a previous study, we examined the relation between total energy in a noise exposure and the percentage losses of outer (OHC) and inner (IHC) hair cells in the basal and apical halves of 607 chinchilla cochleae [Harding, G.W., Bohne, B.

Effect of infrasound on cochlear damage from exposure to a 4 kHz octave band of noise.

Infrasound (i.e., <20 Hz for humans; <100 Hz for chinchillas) is not audible, but exposure to high-levels of infrasound will produce large movements of cochlear fluids.

Distribution of focal lesions in the chinchilla organ of Corti following exposure to a 4-kHz or a 0.5-kHz octave band of noise.

An octave band of noise (OBN) delivers fairly uniform acoustic energy over a specific range of frequencies. Above and below this range, energy is at least 30 dB SPL less than that within the OBN. When the ear is exposed to an OBN, hair-cell loss often occurs outside the octave band.