Standard audiograms for the IEC 60118-15 measurement procedure

For the characterization of hearing aids, a new test method has been defined in the new International Electrotechnical Commission (IEC) standard 60118-15. For this characterization, the hearing aid will be set to actual user settings as programmed by standard fitting software from the hearing aid manufacturer. To limit the variation of programming outcomes, 10 standard audiograms, which cover the entire range of audiograms met in clinical practice, have been defined. This article describes how the set of standard audiograms has been developed. This set of standard audiogram has been derived by a vector quantization analysis method on a database of 28,244 audiograms. Using this analysis method, sets of typical audiograms have been obtained of sizes 12 and 60. It turned out that the smaller set could not be used for selecting audiograms as sloping audiograms were absent. Therefore, the larger set has been analyzed to provide seven standard audiograms for flat and moderately sloping hearing loss and three standard audiograms for steep hearing loss.