[Acoustic distortion products. Clinical values and limitations in the study of low frequencies]

Distortion products are otoemissions produced when the cochlea is stimulated by two pure, continuous sounds f1 and f2. The most ample distortion product in Man corresponds to a frequency of 2f1-f2. The aim of our work is to appreciate the possibilities to study the distortion products for the exploration of low frequencies in Man. Three populations of subjects have been studied: young subjects have been studied: young subjects with a normal hearing, subjects with pathological otoscopic findings in spite of a normal hearing, subjects with pathological otoscopic findings in spite of a normal audiometric study, and subjects with endocochlear perceptive deafness. The major result of this study was to demonstrate that the lowest frequency that can be explored with distortion products is 750 Hertz.