The reliability of auditory thresholds in the 8-to 20-kHz range using a prototype audiometer

This study was designed to evaluate both intra- and intertester reliability of auditory thresholds in the 8- to 20-kHz range using a recently developed high-frequency audiometer [Stevens et al., J. Acoust. Soc. Am. 81, 470-484 (1987)]. With this device, signals from a high-frequency transducer are introduced into the ear canal via a plastic tube. A calibration function is calculated for each ear and used to estimate the sound-pressure level (SPL) at the tympanic membrane. Twenty normal-hearing listeners were tested four times, twice by each of two examiners. In the higher frequencies, accurate calibration functions could not be obtained for many subjects; in these cases, values extrapolated from lower frequencies were used to estimate SPL. Findings reveal that the standard error of measurement for both intra- and intertester measures increases as a function of frequency. Intertester variability was only slightly higher than intratester variability. In most cases, variability of threshold estimates in dB SPL was higher than that observed for the uncorrected attenuator settings. Exclusion of extrapolated values improved reliability substantially.