[Evaluation of frequency selectivity from psychoacoustic tuning curves]

Psychoacoustic tuning curves (PTC) can be regarded as filter curves, whereas their forms represent hair cell activity. Different influences--for example, noise, toxins, pharmacological causes and age--can change the PTC as a consequence of changed frequency selectivity without indication of deterioration in the audiogram. The objective of this investigation was to determine the visually perceivable change in the PTC as a quantifiable result. In so doing, the PTC was transformed into a hyperbola characterized by a parameter Q5. An example demonstrates the temporal change of Q5 under the influence of pharmacological drugs.