Theresa Jansen1, Laura Hartog1, Melanie Krueger1, Dirk Oetting1
HörTech gGmbH, Oldenburg, Germany

Complaints about loudness settings of the hearing aid after the first fit occur frequently. They are attempted to be resolved by the audiologist during the fine tuning with the help of the client’s problem description. In order to increase satisfaction a normal loudness perception should be pursued already during the first fit for binaural broadband signals.
In this study a method for measuring and assessing individual aided loudness perception with natural signals was developed and evaluated. This procedure should detect deviations from a normal loudness perception and indicate in which frequency range (low, medium, high) and level ranges (50, 65, 80 dB) a correction of the amplification is necessary. The procedure is designed for the use during the initial fitting of hearing aids, before clients test the hearing aids in real-life situations.
For this purpose, 60 natural signals with different spectral characteristics were selected. In addition to signals with the main energy in low, medium and high frequencies, signals were also selected with spectra similar to speech.
These signals were presented via loudspeakers at different levels and rated by the subjects on a scale from “not heard” to “extremely loud”.
First, the measurement was carried out with 33 normal-hearing listeners in order to define the reference range of loudness ratings. The evaluation study with hearing-impaired subjects was conducted with two groups. The first group showed a particularly high loudness summation and the second group a particularly low loudness summation, with both groups showing similar audiometric hearing losses. Loudness assessments were performed unaided and fitted with hearing aids with NAL-NL2. The results show lower-than-normal loudness perception in listeners with low loudness summation and higher-than-normal loudness perception in listeners with high loudness summation when fitted with NAL-NL2.