Distortion-product otoacoustic emission reflection-component delays and cochlear tuning: Estimates from across the human lifespan

Abstract

A consistent relationship between reflection-emission delay and cochlear tuning has been demonstrated in a variety of mammalian species, as predicted by filter theory and models of otoacoustic emission (OAE) generation. As a step toward the goal of studying cochlear tuning throughout the human lifespan, this paper exploits the relationship and explores two strategies for estimating delay trends-energy weighting and peak picking-both of which emphasize data at the peaks of the magnitude fine structure. Distortion product otoacoustic emissions (DPOAEs) at 2f 1 Àf 2 were recorded, and their reflection components were extracted in 184 subjects ranging in age from prematurely born neonates to elderly adults. DPOAEs were measured from 0.5-4 kHz in all age groups and extended to 8 kHz in young adults. Delay trends were effectively estimated using either energy weighting or peak picking, with the former method yielding slightly shorter delays and the latter somewhat smaller confidence intervals. Delay and tuning estimates from young adults roughly match those obtained from SFOAEs. Although the match is imperfect, reflection-component delays showed the expected bend (apical-basal transition) near 1 kHz, consistent with a break in cochlear scaling. Consistent with other measures of tuning, the term newborn group showed the longest delays and sharpest tuning over much of the frequency range.

Optimizing swept-tone protocols for recording distortion-product otoacoustic emissions in adults and newborns

“…9. (Color online) The inset displays data from two previous studies showing reflection-component delays (Abdala et al, 2014) and stimulusfrequency OAE delays (Shera et al, 2010) expressed in periods. Both confirm longer delays with increasing frequency.…”

“…The conventional discrete-tone methods slow down OAE recording, making it less likely to obtain sufficient SNR for reliable measurement, in particular when challenging populations are being tested such as newborns. Swept-tone OAE protocols are particularly useful for the neonatal population Dhar, 2010, 2012;Abdala et al, 2013;Abdala et al, 2014), which sometimes offers limited moments of quiet recording time and produces elevated and erratic noise.…”

Estimating Cochlear Frequency Selectivity with Stimulus-frequency Otoacoustic Emissions in Chinchillas

“…Although these approaches could be applied to other types of emission (e.g. Zurek 1981;Zwicker and Wesel 1990;Harris et al 1992;Abdala et al 2014), SFOAEs seem most suitable for two reasons. First, SFOAEs are evoked with a single tone which minimizes the intricacies of interaction between responses to complex stimuli (e.g.…”

Electrophysiological Evidence of the Basilar-Membrane Travelling Wave and Frequency Place Coding of Sound in Cochlear Implant Recipients

“…This delay has been measured in humans by deriving frequency-specific responses from auditory brainstem responses (ABR) or extracochlear electrocochleography [Eggermont, 1979], usually by masking with high-pass-filtered noise [Parker and Thornton, 1978]. Basilar-membrane travelling-wave characteristics have also been studied in humans using transient evoked otoacoustic emissions (OAE) [Harte et al, 2009;Moleti and Sisto, 2008] and distortion product OAE [Schoonhoven et al, 2001;Ruggero, 2004;Abdala et al, 2014]. For OAE techniques, the time taken for sounds of different frequencies to travel from the stimulating/recording probe to the intracochlear site of OAE generation and back again has been elucidated from either direct measurement or from phase gradient analyses.…”