High-frequency air-conduction and electric bone-conduction audiometry. Comparison of two methods.

Threshold values for 147 subjects (9-43 years old) were measured with a high-frequency (HF) air-conduction (AC) (Interacoustics AS 10 HF) and an electric bone-conduction (EBC) (Audimax 500) audiometer. In addition, the reproducibility of these methods was studied in another group of 24 subjects. The results confirmed the previous findings of Okstad et al. (1988) that the electric current (i) used as a stimulus in the Audimax 500 audiometer can be converted into decibels with a correction factor of 40 log (i) re 1 mA as Tonndorf & Kurman (1984) have proposed. However, an additive frequency-dependent correction is needed to obtain similar loudness sensation increases with these audiometers. Reproducibility with the EBC audiometer was better than with the AC audiometer, especially in the HF range.