Distortion product otoacoustic emissions upon ear canal pressurization

Neonatal Hearing Screening Using Wideband Absorbance and Otoacoustic Emissions Measured Under Ambient and Pressurized Conditions

BACKGROUND

The objective was to analyze wideband acoustic absorbance and transiently evoked otoacoustic emissions (TEOAEs) from newborns without risk indicators of hearing loss and test the effectiveness of measuring TEOAEs under pressurized ear canal conditions.

METHODS

Evaluation of 102 newborns from a maternity hospital, who stayed in the well-baby nursery and did not have risk indicators for hearing loss. The procedures involved wideband tympanometry and TEOAEs performed at ambient pressure (AP) and at a pressure corresponding to maximum compliance (PP). Newborns were then divided into three groups according to their AP and PP results: G1 (PASS/PASS), G2 (FAIL/PASS), and G3 (FAIL/FAIL).

RESULTS

Comparing the three groups, pressurization improved the pass rate for G2 only. For wideband absorbance, differences were statistically significant for frequencies of 2, 3, and 6 kHz, with lower values under the AP condition. For TEOAEs, the differences were statistically significant in all bands, with lower values under the AP condition.

CONCLUSIONS

Pressurization was effective in detecting more TEOAEs in G2, thus reducing the number of failures in neonatal hearing screening and reducing the need to return for retesting.

Contrasting Effects of Pressure Compensation on TEOAE and DPOAE in Children With Negative Middle Ear Pressure

In children with normal cochlear acuity, middle ear fluid often abolishes otoacoustic emissions (OAEs), and negative middle ear pressure (NMEP) reduces them. No convincing evidence of beneficial pressure compensation on distortion product OAE (DPOAE) has yet been presented. Two studies aimed to document effects of NMEP on transient OAE (TEOAE) and DPOAE. In Study 1, TEOAE and DPOAE pass/fail responses were analyzed before and after pressure compensation in 50 consecutive qualifying referrals having NMEP from -100 to -299 daPa. Study 2 concentrated on DPOAE, recording both amplitude (distortion product amplitude) and signal-to-noise ratio (SNR) before and after pressure compensation. Of the 20 participants, 5 had both ears qualifying. An effect of compensation on meeting a pass criterion was present in TEOAE for both left and right ear data in Study 1 but not demonstrable in DPOAE. In Study 2, the distortion product amplitude compensation effect was marginal overall, and depended on recording frequency band. SNR values improved moderately after pressure compensation in the two (overlapping) sets of single-ear data. In the five cases with both ears qualifying, a stronger compensation effect size, over 3 dB, was seen. The absolute dependence of SNR on frequency was also strongly replicated, but in no analysis, the frequency × compensation interaction was significant. Independent of particular frequency range, the data support a limited SNR improvement in 2 to 3 dB for compensation in DPOAE, with slightly larger effects in ears giving SNRs between 0 dB and +6 dB, where pass/fail cutoffs would generally be located.

Conventional audiometry, extended high-frequency audiometry, and DPOAEs in youth recreational firearm users

To determine if conventional audiometry, EHFA, and pDPOAEs are useful as early indicators of cochlear damage from recreational firearm impulse noise exposure in youth firearm users. Quantitative cross-sectional descriptive pilot study. Descriptive statistics and MANOVA with post hoc Tukey Honestly Significant Difference test were used to compare pDPOAEs (1-10 kHz), conventional audiometry (0.25-8 kHz), and EHFA (10-16 kHz) in YFUs. 25 YFUs (n = 11 7-12 years; n = 14 13-17 years) with self-reported poor compliance with hearing protector device wear. Conventional audiometric thresholds at 2-, 3- and 4 kHz were significantly poorer than normal but did not distinguish between older and younger YFUs or between the GBE and the contralateral ear. EHFA thresholds at 14- and 16 kHz were significantly poorer than for other frequencies, and differentiate between older and younger youths, but do not distinguish the GBE from the contralateral ear. Finally, pDPOAE levels were significantly reduced at 8- and 10 kHz but did not show any differences for the younger versus older YFUs or for the GBE from the contralateral ear. Conclusion: Both EHFA and pDPOAEs provide early evidence of NIHL in YFUs, and may be useful for the early detection of NIHL in YFUs.