Accession Number : ADA130673

Title :   Auditory and Non-Auditory Effects of Exposure to Low-Frequency Noise.

Descriptive Note : Final rept. Sep 79-Sep 81,


Personal Author(s) : Mills,John H ; Osguthorpe,J David

PDF Url : ADA130673

Report Date : 15 Sep 1981

Pagination or Media Count : 27

Abstract : Groups of human subjects were exposed for 8 or 24 h to an octave-band noise centered at 63, 125, or 250 Hz. For a 24 h exposure at 84 dBA, temporary threshold shifts (TTS) increased for 8-12 h and then either decreased or remained constant. TTS was maximal in the frequency region between 350-700 Hz regardless of the center frequency of the exposure. Although TTS was less than 20 dB, complete recovery for many of the subjects required as long as 48 h. Accordingly, the higher level exposure which was planned at 94 dBA for 24 h was reduced to 90 dBA for 8 h. For this condition TTS increased throughout the 8 h exposure. TTS from the 90-dBA exposure for 8 h exceeded the TTS produced by the 24 h exposure at the 84 dBA. Whereas recovery from the 24 h exposure which produced TTS's of 15 dB required as long as 48 h, recovery from the 8 h exposure which produced TTS's of 20 dB required 12-24 h. Thus, the time required for recovery from TTS is determined in part by the duration of exposure. Nonauditory effects included small increases in serum cortisol only during the first hour of exposure. Heart rate, blood pressure, and catecholamines showed small changes which were not statistically significant. (Author)

Descriptors :   *Exposure(Physiology), *Noise, Hearing, Threshold effects, Low frequency, Time, Recovery, Deafness, Cortisol, Heart rate, Blood pressure, Catecholamines, Physiological effects, Stress(Physiology), Audiometry, Humans, Males

Subject Categories : Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE