High-frequency air-conduction and electric bone-conduction audiometry. Age and sex variations

208 subjects representing both sexes and five age groups (15-70 years) were examined to obtain age-related threshold values for high-frequency (HF) electric bone-conduction (EBC) audiometry. The measurements also included conventional pure-tone audiometry and air-conduction (AC) HF (8-18 kHz) audiometry. The measured EBC thresholds were comparable to the values obtained with AC audiometers, and were equal to ISO standards at the frequencies of 0.5-6 kHz. The 15- and 20-year-old groups' EBC thresholds at 8 kHz were equivalent to thresholds of 15-year-old people from a cross-sectional material in Northern Finland. Thresholds deteriorated as a function of age, particularly in the HF range. The males had poorer thresholds than the females, especially in the age groups of 40 and 60 years. This could be attributed mainly to their greater noise exposure. The EBC method is quite practical and reliable for routine clinical measurements, but the dynamic range of the audiometer limits its use to relatively young subjects.