Distortion Product Otoacoustic Emissions Evoked by Tone Complexes

Abstract

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.

Reverse Cochlear Propagation in the Intact Cochlea of the Gerbil: Evidence for Slow Traveling Waves

“…, f 1N ) turns both of these CDTs into tone complexes themselves ( Fig. 1A) (see also Meenderink and van der Heijden 2009). In addition to this spectral line splitting, a group of third-order DPs arises near the f 2 tone (Fig.…”

“…This allows the calculation of group delays from a single recording, thus avoiding interrecording variability that may occur when using two-tone frequency sweeps. Second, the multitone stimulus results in an additional group of emissions around the single tone primary (Meenderink and van der Heijden 2009). These OAEs can be evoked using a wide frequency separation (several octaves) between the lower and upper stimulus compo-nents.…”