Determination of the Hearing Thresholds of Naval Recruits in Terms of British and American Standards

Abstract

A group of 111 naval recruits was examined in order to establish reference hearing level against which to assess the effects of noise exposure in serving men. The pure-tone thresholds were taken in a quiet ordinary room with a commercial audiometer. After exclusion of some subjects for reasons given, the thresholds of the main group of 74 men were analyzed. Precautions taken to insure constancy of performance of the audiometer are described and its calibration was obtained relative to both the appropriate British and American standards. The results of the survey showed good agreement with the British standard as regards the main group and additionally for a group of 15 men selected for minimal exposure to gunfire (less than seven rounds of small-arms fire). A comparison was made with the hearing level of a small group of more experienced listeners when an improvement of about 2.5 db was found. The relation of the work to other hearing surveys and laboratory measurements is discussed.