Individual Differences and the Reliability of 2F1-F2 Distortion-Product Otoacoustic Emissions

Abstract

Distortion product otoacoustic emissions (DPOAEs) measured from the ear canal can be a sensitive tool to detect changes in cochlear function over time. However, if multiplemeasurement procedures are to be useful clinically, testing needs to be reliable and sources of variability within individuals should be known. Herein, the influence of time-of-day (TOD), stimulus frequency, stimulus sound pressure level (SPL), and gender were evaluated on 2f1-f2 DPOAE amplitude in 16 adult volunteers with normal hearing. The effects of oral temperature and resting-pulse rate were also assessed. This study demonstrated a TOD main effect, with a period approximating one cycle-per-day. The magnitude of this effect averaged less than one dB and was not dependent on stimulus (frequency or SPL) or participant variables (gender, oral temperature, or resting-pulse rate), nor was it synchronized to a particular point-in-time. Stimulus level and gender effects on DPOAEs across frequency were also observed. Using generalizability theory (GT), DP iso-level/frequency profiles (DPILFPs) were found to be reliable measures within-subjects over a contiguous 24-hour time period. Significant and reliable between-subject differences were also documented. This study demonstrates the influence of stimulus and participant variables, quantifies the within-subject reliability over a 24-hour time period, and confirms that significant and reliable between-subject differences exist on DPOAEs across frequency, SPL, and gender.

Otoacoustic emissions and extended high-frequency hearing sensitivity in young adults Emisiones otoacústicas y sensibilidad extendida a frecuencias altas en adultos jóvenes

“…The difference between the median values for the two gender groups was approximately 3.5 dB. This is in agreement with the data of Cacace et al (1996). Some other studies (e.g.…”

A normative study of otoacoustic emissions, ear asymmetry, and gender effect in healthy schoolchildren in Slovakia

“…There are studies in neonates and infants using DPOAE which also have not yielded any significant gender effect [42,43]. In contrast there are studies suggesting greater DPOAE in female versus male adults [17,23,24,44]. For example in a study DPOAE amplitudes in adults were greater for woman than for men especially at higher frequencies [25].…”

“…Many studies also indicate a gender effect, whereby stronger TEOAEs are observed in females across many age groups from infancy to childhood [5,15,[17][18][19][20][21][22]. Gender differences were also found in DPOAE [15,17,[23][24][25].…”

Test-retest variability of distortion-product otoacoustic emissions in human ears with normal hearing

“…However, the long-term component, as the main source of the test-retest variability of DPOAE measures, may be influenced by other factors, such as circadian effects. Cacace et al (1996) demonstrated a circadian effect on the DPOAE recording. The present study was not controlled for time of day effects.…”