Short-Term Audiometric Profile in Army Recruits Following Rifle Firing: An Indian Perspective

Abstract

Aim: This study is aimed to assess the short-term audiometric profile in army recruits with green ears following rifle firing. Materials and Methods: A total of 100 fresh army recruits were selected by simple randomization. Recruits with a history of firearm exposure and ear surgery were excluded. Screened recruits underwent pure tone audiometry (PTA) by modified Hughson-Westlake method 1 day before firing. Recruits fired 100 rounds from 5.56 mm Indian Small Arm System rifle in a single session as per standard military protocol. After firing, recruits reported within 4 h for repeat evaluation. Ear complaints such as tinnitus and hearing loss were recorded and repeat PTA was performed. Recruits having standard threshold shift (STS) were not exposed to further firing and called for an evaluation of hearing after 2 weeks. Student's paired t-test and Chi-square test were used to analyze the results. Results: The mean age of subjects was 19.69 ± 0.61 years old. After rifle firing by the 100 recruits, 16 subjects (16.0%) had complaints of hearing loss and tinnitus. Only tinnitus was seen in further 11 subjects. Twelve subjects were found to have STS. In four subjects audiogram showed audiometric notch two being at 2 kHz, one at 4 kHz and one at 6 kHz. Double notch was observed in none of the audiograms. All subjects were asymptomatic at the end of 2 weeks after firing. P< 0.05 was considered significant. Conclusion: Short-term audiometric profile of army recruits shows there is a significant change in audiometric thresholds immediately after firing which recover back to normal within 2 weeks.