Narrowband stimulation and synchronization of otoacoustic emissions.
Tone-burst-evoked otoacoustic emissions were obtained for several normal listeners with and without spontaneous otoacoustic emission using an optimized tone burst. The dependence of the response amplitude on stimulation level shows a linear increase below a certain value close to the threshold in quiet and levels off at higher levels exhibiting only small differences between non-linear and linear averaging modus. In addition, the latency of the response tends to decrease and the sharpness of the resonance decreases with increasing stimulation level. Synchronization tuning-curves were obtained using a fixed tone burst to elicit an evoked otoacoustic emission and a probe tone at different frequencies for synchronizing the SOAE. These synchronization tuning curves exhibit relatively sharp resonance characteristics (Q3 varying between 3 and 8) for subjects with spontaneous otoacoustic emissions and less sharp tuning (Q3 varying between 1 and 3) for subjects without spontaneous otoacoustic emissions. These experimental results could be reproduced very well with a model of a single non-linear Van-der-Pol-oscillator with the appropriate parameters. The results indicate that spontaneous otoacoustic emissions and narrow-band-evoked otoacoustic emissions are generated by the same mechanism which can be modelled as a self-sustained oscillator.
Uppenkamp
S
S
Drittes Physikalisches Institut, Universität Göttingen, Germany.
Kollmeier
B
B
D000161:Acoustic Stimulation; D000328:Adult; D001299:Audiometry; D001309:Auditory Threshold / Q000502:physiology*; D003198:Computer Simulation; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008838:Microcomputers; D008954:Models, Biological; D009991:Oscillometry; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*