Accession Number : AD0283276

Title :   FREE FIELD THRESHOLD SHIFT AND TEMPORARY THRESHOLD SHIFT REDUCTION AS MEASURES OF EFFICIENCY OF EAR PROTECTIVE DEVICES

Corporate Author : ARMY MEDICAL RESEARCH LAB FORT KNOX KY

Personal Author(s) : FLETCHER, JOHN L. ; LOEB, MICHAEL

Report Date : 28 MAY 1962

Pagination or Media Count : 12

Abstract : The protective (attenuation) characteristics of two insert and one helmet ear protective device using the free field threshold shift (FFTS) and temporary threshold shift reduction (TTSR) techniques were evaluated with both impulse and continuous noise exposure. All devices tested were shown significantly to reduce TTS from impulseAND CONTINUOUS NOISE EXPOSURE. The insert devices were more effective at low frequencies, approximately equal to the helmet at high frequencies. It is believed the TTSR technique adds important information regarding the operational efficiency of the ear protectors tested. Because of special problems associated with helmets, it seems particularly desirable to include the TTSR technique in their evaluation. The data suggest that susceptibility to TTS from continuous exposure is not significantly correlated with that from impulse exposure. (Author)

Descriptors :   *EAR PROTECTORS, EFFECTIVENESS, MEASUREMENT, TEST METHODS, TESTS.

Distribution Statement : APPROVED FOR PUBLIC RELEASE