Animal Model to Study the Effects of Noise on Humans.
Nielsen-DW; Elliott-DN; Hunter-Duvar-I
Final Report :31 pages
An appropriate animal model was sought to study the effects of long term noise exposure on the inner ear of humans. The growth of temporary threshold shift (TTS) for human volunteers and squirrel- monkeys was investigated, and the effects of synthetic and factory (stamping mill and stall wrench) noise on the hearing of each were studied. Attempts were also made to measure growth and frequency spread of TTS following exposure to five industrial noises that varied in spectral and temporal characteristics, enabling a comparison to be made of the effect of these noises on the hearing of humans and squirrel-monkeys. The effects of selected noises presented at high intensities on the inner ear of the squirrel- monkey were studied by means of light and electron microscopy. A marked difference was noted in the frequency spread of TTS for the humans and squirrel-monkeys between 500 hertz (Hz) and 1 kilohertz (kHz) and at 5.6kHz. The amount of TTS after 8 hours at other frequencies was within 2 or 3 decibels. The squirrel-monkey showed more TTS than humans between 500Hz and 1kHz and at 5.6kHz it showed less. The authors concluded that as an animal model, the squirrel- monkey may overestimate human TTS in the 500Hz to 1kHz range and underestimate it at 5.6kHz. At other frequencies, the amount of TTS and rate of TTS growth was similar to that of the human. The underlying causes of the TTS at frequencies other than 500Hz to 1kHz may be similar for the two species.
NIOSH-Publication; Hearing-loss; Noise-exposure; Noise-induced-hearing-loss; Inner-ear; Hearing-impairment; Laboratory-animals; Models;
Otolaryngology Henry Ford Hospital 2799 West Grand Boulevard Detroit, Mich 48202
NTIS Accession No.
Henry Ford Hospital, Detroit, Michigan