The effect external and middle ears have in otoacoustic emissions

Spectral features related to the auditory perception of twang-like voices

BACKGROUND

To the best of our knowledge, studies on the relationship between spectral energy distribution and the degree of perceived twang-like voices are still sparse. Through an auditory-perceptual test we aimed to explore the spectral features that may relate with the auditory-perception of twang-like voices.

METHODS

Ten judges who were blind to the test's tasks and stimuli rated the amount of twang perceived on seventy-six audio samples. The stimuli consisted of twenty voices recorded from eight CCM singers who sustained the vowel [a:] in different pitches, with and without a twang-like voice. Also, forty filtered and sixteen synthesized-manipulated stimuli were included.

RESULTS AND CONCLUSIONS

Based on the intra-rater reliability scores, four judges were identified as suitable to be included in the analyses. Results showed that the frequency of F1 and F2 correlated strongly with the auditory-perception of twang-like voices (0.90 and 0.74, respectively), whereas F3 showed a moderate negative correlation (-0.52). The frequency difference between F1 and F3 showed a strong negative correlation (-0.82). The mean energy between 1-2 kHz and 2-3 kHz correlated moderately (0.51 and 0.42, respectively). The frequency of F4 and F5, and the energy above 3 kHz showed weak correlations. Since the spectral changes under 2 kHz have been associated with the jaw, lips, and tongue adjustments (i.e. vowel articulation) and a higher vertical laryngeal position might affect the frequency of all formants (including F1 and F2), our results suggest that vowel articulation and the laryngeal height may be relevant when performing twang-like voices.

Finite-Element Modelling of the Acoustic Input Admittance of the Newborn Ear Canal and Middle Ear

Admittance measurement is a promising tool for evaluating the status of the middle ear in newborns. However, the newborn ear is anatomically very different from the adult one, and the acoustic input admittance is different than in adults. To aid in understanding the differences, a finite-element model of the newborn ear canal and middle ear was developed and its behaviour was studied for frequencies up to 2000 Hz. Material properties were taken from previous measurements and estimates. The simulation results were within the range of clinical admittance measurements made in newborns. Sensitivity analyses of the material properties show that in the canal model, the maximum admittance and the frequency at which that maximum admittance occurs are affected mainly by the stiffness parameter; in the middle-ear model, the damping is as important as the stiffness in influencing the maximum admittance magnitude but its effect on the corresponding frequency is negligible. Scaling up the geometries increases the admittance magnitude and shifts the resonances to lower frequencies. The results suggest that admittance measurements can provide more information about the condition of the middle ear when made at multiple frequencies around its resonance.

The profile of otoacoustic emissions and multifrequency tympanometry in otosclerotic patients undergoing two types of stapes surgery: small fenestra and microtraumatic stapedotomy

BACKGROUND

Otoacoustic emissions (OAEs) are influenced in otosclerosis. The aim of the current study was to investigate the profile of transient evoked (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) in association with multifrequency tympanometry measures in otosclerotic patients undergoing 2 types of stapes surgery: small fenestra and microtraumatic stapedotomy.

MATERIAL AND METHODS

A retrospective analysis of prospectively collected data was conducted evaluating 51 otosclerotic patients and 50 normal hearing subjects. Small fenestra and microtraumatic stapedotomy were performed in 27 and 24 patients, respectively. Pure tone audiometry (PTA) was always measured. Detection of TEOAEs and DPOAEs at 5 frequency steps (1, 1.4, 2, 2.8, and 4 kHz) preoperatively and at 2 and 5 months postoperatively, stratified by the type of surgery, represented the main goal of the study. Resonant frequency derived by multifrequency tympanometry was also evaluated.

RESULTS

All patients demonstrated improvement in hearing level postoperatively, with significant closure of air-bone gap on PTA. Resonant frequency values returned to normal after microtraumatic stapedotomy but were exceedingly decreased following the small fenestra technique. The detection of both TEOAEs and DPOAEs was improved, but when the detection was stratified by the tested frequencies, significant increase in the number of patients with detectable OAEs was observed, mainly during testing at 1 and 1.4 kHz.

CONCLUSIONS

Otosclerotic patients exhibited improvement in the detection of OAEs, particularly at low frequencies, after both procedures. Resonant frequency was normalized following the microtraumatic stapedotomy, whereas it is over-decreased after the small fenestra technique.

Otoacoustic emissions in newborn hearing screening: a systematic review of the effects of different protocols on test outcomes

BACKGROUND AND OBJECTIVES

Otoacoustic emission (OAE) tests are currently used to screen newborns for congenital hearing loss in many Universal Newborn Hearing Screening programs. However, there are concerns about high referral and false-positive rates. Various protocols have been used to address this problem. The main objective of this review is to determine the effects of different screening protocols on the referral rates and positive predictive values (PPV) of the OAE newborn screening test.

METHODS

Eligible studies published in English from January 1990 until August 2012 were identified through searches of MEDLINE, Medline In-Process, Embase, PubMed (NCBI), ISI Web of Science, and the Cochrane Central Register of clinical controlled trials. Two reviewers independently screened the data sources, using pre-defined inclusion criteria to generate a list of eligible articles. Data extracted included the number of newborns screened, age at screening, OAE pass criteria, frequencies screened, number of retests, referral rates, and the number of newborns identified with permanent congenital hearing loss.

RESULTS

Ten articles met the inclusion criteria, with a total of 119,714 newborn participants. The pooled referral rate was 5.5%. Individual referral rates ranged from 1.3% to 39%; the PPV from 2 to 40%. Increasing the age at initial screening and performing retests reduced the referral rate. Likewise, screenings involving higher frequencies had lower referral rates.

CONCLUSION

Delaying newborn hearing screening improves test results but may not be practical in all contexts. The use of higher frequencies and more sophisticated OAE devices may be useful approaches to ensure better performance of the OAE test in newborn hearing screening.