TTS In Squirrel monkeys to 4 kHz octave band noise of long duration

The goal of this research is to investigate the suitability of the squirrel monkey as an animal model for the effects of long duration noise exposures on humans. In our previous report [J. Acoust. Soc. Am. 60 S87(A) (1976)] we demonstrated that TTS to an octave band noise centered at 500 Hz showed growth and recovery curves similar to those reported for humans. The present study exposed six squirrel monkeys to an 85 dB SPL octave band noise centered at 4 kHz for as long as 72 h and found that the resulting TTS was less than 10 dB. This compares to a TTS of about 18 dB in humans for exposures of 8–24 h, as reported by Melnick [Effects of Noise on Hearing, edited by Henderson, Hamernik, Dosanjh, and Mills (Raven, 1976)]. When the intensity of the 4 kHz CF OBN was increased to account for differences in absolute auditory sensitivity between squirrel monkeys and humans, the resulting development and recovery of TTS was similar to humans, resulting in a shift of about 16 dB for exposures of 8–24 h. [This research was supported by a Ford Foundation grant to Henry Ford Hospital. Ms. Fitton was supported by the Department of Audiology, Wayne State University School of Medicine.]