Effects of Reverberant Blast Trauma (Impulse Noise) on Hearing: ParametricStudies

摘要

The effects of exposure to high levels of reverberant blast waves (impulse noise) on the auditory system using an animal (chinchilla) model are reported. Blast waves were generated by two different shock tubes which produced wave signatures having different spectral distributions of energy. Tntensities for each blast wave source were 150, 155, and 160 dB peak SPL with exposure to 1, 10, or 100 impulses. Repetition rates were fixed at one impulse/sec. There were 15 subjects per group. Brainstem evoked potentials were used to estimate temporary and permanent threshold shifts and conventional surface preparations of the cochlea were used to guantitatively assess sensory cell loss. In addition, pre- and postexposure cubic distortion product otoacoustic emissions (3DPE) were collected on a subset of these animals for correlation with audiometric and histological indices of trauma. Trauma systematically increased with sound exposure level (SSL) and was dependent on the energy spectrum of the impulse. An application of the A- and P-weighting functions to the spectra improved the correlations between indices of trauma and SEL. The 3DPE data were consistent with PTS and, overall, both measures were correlated with sensory cell loss. (AN).