Acoustical Verification of Advanced Hearing Aids Claus Elberling Along with the increased hearing aid complexity it has become more and more important to develop measuring methods and techniques to evaluate the acoustical characteristics of the individual hearing aid with real signals from the environment (e.g. speech). The evaluation should preferably describe either the hearing aid function under real life conditions or relate to perceptual quantities (e.g. speech intelligibility, loudness or annoyance). In this way the measurements will be more closely related to the perceived benefits of the hearing aid. The use of real life signals like for instance speech, noise and speech-in-noise, clearly demonstrates that there are significant differences between technical measurements in the laboratory and those simulating real life conditions. Together with auditory models real life signals can be used to evaluate the characteristics of aided performance in specific perceptual domains e.g. loudness. Other techniques can be used to evaluate how individual speech elements (e.g. phonemes) are influenced both by the acoustics and the signal processing in the hearing aid. This could provide a better understanding of how speech intelligibility or other perceptual dimensions are affected by specific processing algorithms. Examples of the above types of measurements will be presented and finally, the use of these techniques to describe different signal processing techniques will be discussed. |