TEMPORARY HEARING LOSSES FOR PROTECTED AND UNPROTECTED EARS AS A FUNCTION OF EXPOSURE TIME TO CONTINUOUS AND IMPULSE NOISE
Abstract
Temporary hearing losses for frequencies 250 to 8000 cps were noted for bare and protected ears (CVC helmet) after 6-, 12-, and 18-minute exposures to impulse noise (recorded 30-cal. machine gun fire) and continuous wideband noise of comparable energy. Threshold losses for both types of noise were generally confined to frequencies above 1000 cps and tended to become greater with increasing exposure time. Continuous noise caused greater hearing losses than the impulse noise under bare ear conditions for the three exposure times. A comparison of these losses against those noted when using the helmet indicated that the helmet gave significant protection against continuous noise but little protection against impulse noise. A second experiment studied the recovery of 4000 cps threshold losses for a 20-min period after exposure to the noise conditions cited above. Especially for the longer exposure times (12 and 18 min), threshold recovery from bare ear exposures to continuous noise was slower than that noted for impulse noise. As compared with the bare ears, wearing the helmet provided faster rates of recovery from losses due to continuous noise exposures but did not facilitate recovery from losses due to impulse noise.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1961
- Accession Number
- AD0262722
Entities
People
- Alexander Cohen