Presbyacusis-hearing thresholds and the ISO 7029.

The purpose of this study was to analyse the changes in pure-tone hearing thresholds with age. We studied a random sample of 232 elderly subjects with a battery of audiological tests, including pure-tone audiometry in the conventional and extended high-frequency range, using the normative distributions from the International Organization for Standardization (ISO) standard 7029 for comparison. Sixty otologically normal (ON) subjects were selected for comparative analysis with the unscreened (US) sample, and for description of gender and age group differences. With the use of a mathematical transformation of threshold data, it was found that the ISO 7029 normative alpha coefficient in females may be set too low compared to our sample in the lower frequencies, leading to an underestimation of hearing thresholds in ON females. In our ON sample, hearing thresholds deteriorated with age in the extended high-frequency audiometric range. No gender threshold differences were found, although the prevalence of unmeasurable responses was higher in males at some of these frequencies. The ON screening criteria in ISO 7029 may be unreliable in subjects over 60 years of age, as threshold differences between ON and US subjects were not consistent at any frequency.