Abstract
The stimulated oto-acoustic emission (OAE) has peen investigated by stimulations of tone-bursts at frequencies between 1.0kHz and 2.0kHz because resonance frequencies of a mechano-acoustical characteristics of the recording system existed in this frequency area. In an effort to investigate the function of cochlear micromechanics in cochlear partitions in a wider range, we recorded OAE evoked by stimulations of tone-bursts at frequencies between 0.5kHz and 4.0kHz, and the emission cochleogram in this frequency area was investigated in 27 ears with normal hearing and type A tympanogram. The results obtained were as follows:
(1) No clear OAE was evoked by the stimulation of tone-burst at 0.5kHz in all ears. However, clear OAEs were evoked by stimulations of tone-bursts at frequencies between 1.0kHz and 4.0kHz in almost all ears and the emission cochleogram in this frequency area was obtained in each ear.
(2) The configuration of emission cochleogram in each ear showed the convex type, the high tone gradual loss type or the high tone abrupt loss type. The averaged emission cochleogram in 27 ears showed the configuration of the convex type with a peak at 2.0kHz.
(3) The analysis of emission cochleogram could be used to investigate the function of cochlear micromechanics in cochlear partitions in a wider range, and therefore it could increase the usefulness of OAE as the clinical tool to investigate the cochlear function.
