Extended high-frequency audiometry: hearing thresholds in adults

PURPOSE: This study aimed to determine hearing thresholds in an otologically normal population without occupational noise exposure aged 18 to 64 years using extended high-frequency audiometry (EHFA). METHODS: Individuals from the general population who have never had hearing problems and whose job was not associated with noise exposure were included in the study and classified by age into 5 categories: 18–24 and, further, by 10 years of age. Each of these groups was further divided according to gender. All subjects underwent tympanometry, conventional pure-tone audiometry within the 0.125–8 kHz range, and extended high-frequency audiometry within the 9–16 kHz range, performed according to the standards. The significance level for statistical testing was set at 5%. RESULTS: Here, we established hearing thresholds in an otologically healthy population within the extended high-frequency (EHF) range (9–16 kHz). We found the EHFA to be a highly sensitive method for early detection of hearing loss, with hearing thresholds decreasing as soon as 35 years of age. In males, the hearing thresholds grew with age more rapidly than in women. The ability to respond at EHF gradually decreased with age and increasing frequency. CONCLUSION: Our results can help improve the knowledge of EHF hearing thresholds for individual sexes and age groups. So far, the standard 7029:2017 is not binding and, moreover, it only reaches up to the frequency of 12.5 kHz. EHFA is a highly sensitive method for the evaluation of hearing loss depending on age and sex.