Impulse noise induced hearing loss from simulated work-week exposures.
Henderson D; Hamernik RP; Hynson K
Department of Otolaryngology and Communication Sciences, State University of New York, Upstate Medical Center, Syracuse, New York, 1981 Jan; :1-25
After preexposure thresholds had been determined, six adult monaural chinchillas were exposed to a repetitive, reverberant impulse for 8 hours per day, for 5 days. The noise impulses were produced by two automated, cam driven, brass hammers hitting a steel plate. Thresholds were measured at 0.25, 0.5, 1, 2, 4, and 8 kilohertz (kHz) 0.5 hour before and 0.5 hour after each of the five 8 hour exposures. After the last exposure the recovery of threshold was monitored for 5 successive days. Final hearing thresholds were obtained starting at 30 days postexposure and were either the average of 3 days of averaged evoked response (AER) testing or 10 days of behavioral testing. The AER thresholds were systematically higher than the behavioral thresholds by 5 to 18 decibels. All frequencies were shifted by approximately the same amount by the end of the 5 day exposure as they were at the end of the first day's exposure, and there was no cumulative effect. There was still some residual threshold shift with 2 days' recovery. The actual degree of oscillation of threshold presumably would be a function of the actual noise exposure as well as the acoustic environment during recovery.
NIOSH-Grant; Noise-induced-hearing-loss; Laboratory-animals; Sensory-thresholds; Hearing-threshold
Otolaryngology Upstate Medical Center Departm 750 E Adams Street Syracuse, N Y 13210
Final Grant Report
NTIS Accession No.
Department of Otolaryngology and Communication Sciences, State University of New York, Upstate Medical Center, Syracuse, New York
Upstate Medical Center, Syracuse, New York