Distortion Product Otoacoustic Emissions Evoked by Tone Complexes
Distortion product otoacoustic emissions (DPOAEs) are traditionally evoked by two-tone stimuli. In this study, emission data
from Mongolian gerbils are reported that were obtained with stimuli consisting of six to 10 tones. The stimuli were constructed
by replacing one of the tones of a tone pair by a narrowband multitone complex. This produced rich spectra of the ear canal
sound pressure in which many of the third-order DPOAEs originated from the interaction of triplets of stimulus components.
A careful choice of the stimulus frequencies ensured that none of these DPOAE components coincided. Three groups of DPOAEs
are reported, two of which are closely related to DPOAEs evoked by tone pairs. The third group has no two-tone equivalent
and only arises when using a multitone stimulus. We analyzed the relation between multitone-evoked DPOAEs and DPOAEs evoked
by tone pairs, and explored the new degrees of freedom offered by the multitone paradigm.