Otoacoustic Emissions in Early Noise-Induced Hearing Loss

The Effects of Burr-Assisted Rhinoplasty on Hearing

AIM

The aim of this study is to examine the effects of the burr used for hump reduction and osteoplasty on cochlear function.

MATERIALS AND METHODS

The design of this study was prospective, randomized, and controlled. Twenty patients who underwent burr-assisted septorhinoplasty were included in the study group. The control group consisted of 20 patients who underwent septoplasty. Pure tone audiometry, distortion product otoacoustic emission test, and tympanometry were performed to determine the auditory functions.

RESULTS

No significant difference was observed between the bone conduction thresholds of the right and left ears in both groups, except for a single frequency (1000 Hz in the left ear) in the control group. There was no significant difference between the 2 groups' air conduction thresholds at frequencies of 500, 1000, 2000, 4000, 6000, and 8000 Hz preoperatively and postoperatively. In addition, the study and control group did not differ significantly in signal-to-noise ratio measurements at frequencies of 500, 1000, 2000, and 4000 Hz. The comparison of preoperative and postoperative otoacoustic emission measurement results of the study group revealed a statistically significant difference only at the frequencies of 2000 Hz in the right ear and 500 Hz in the left ear. Despite those differences, otoacoustic emissions were still present at those frequencies postoperatively.

CONCLUSIONS

Our study showed that using burrs during rhinoplasty slightly impacts hearing, but it does not cause significant hearing loss. Burr-assisted rhinoplasty appears to be a safe operation regarding the auditory functions.

The short-term effect of COVID-19 on the cochleovestibular system in pediatric patients

OBJECTIVES

The audio-vestibular equivalent of neurological symptoms secondary to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been discussed; however, it has not been fully clarified. Although it has been reported that the vestibulocochlear system is affected in adult coronavirus disease-2019 (COVID-19) patients, there is no study in the literature in which the pediatric patient group with COVID-19 was evaluated comprehensively with auditory and vestibular tests. In this study, the short-term damage caused by SARS-CoV-2 in the vestibulocochlear system in pediatric patients was examined.

METHODS

This study aimed to evaluate the vestibulocochlear system of pediatric patients (aged 9-15 years) with a recent history of COVID-19. The study included 35 individuals with a recent history of COVID-19 and 35 age-gender-matched healthy individuals (control group). Pure tone audiometry, suppressed otoacoustic emission (OAE), video head impulse test (VHIT), and cervical and ocular vestibular evoked myogenic potentials (c/o-VEMP) tests were administered to all participants following their otoscopic examinations, and the obtained data were compared between the two groups.

RESULTS

When the data obtained with pure tone audiometry were compared, statistically significant differences were found between the groups at four different frequencies (1000, 2000, 4000, and 8000 Hz) in favor of the control group. There was a statistically significant difference between the groups in the signal-to-noise ratio (SNR) values obtained before noise at 2800 Hz and before and after noise at 4000 Hz. VHIT lateral gain, LARP gain, and RALP gain were statistically significantly lower in the COVID-19 group than in the control group (p < 0.05). VHIT lateral asymmetry parameter was measured higher in the COVID-19 group than in the control group, and this difference was statistically significant (p < 0.05). In the VHIT test, the asymmetry parameter was significantly higher in the COVID-19 group (p < 0.05). In the o-VEMP test, n10 latency, p15 latency, n10-p15 interlatency, n10-p15 interpeak amplitude, and asymmetry parameters were measured, and no statistically significant difference was found between the COVID-19 group and the control group (p > 0.05).

CONCLUSION

Evidence was obtained that the cochleovestibular system was damaged in pediatric patients in the early post-COVID-19 period.

Evaluatıon of the hearıng status ın carpenters

PURPOSE

Carpenters are constantly exposed to a noise level of 82-100 dB(A) in their professional lives. The aim of this study is to evaluate the hearing status of carpenters with pure -tone audiometry and transient evoked otoacoustic emissions test.

METHODS

A total of 62 individuals were enrolled. The study group consisted of 31 carpenters and the controls were age and sex matched healthy individuals who were not exposed to continuous or sudden noise.

RESULTS

The average age of the carpenters is 44.58 ± 10.33, the average age of the control group is 41.84 ± 8.65 and there was no statistically significant difference (p = 0.262). There was a significant hearing loss in the study group nearly at all frequencies when compared to the control group (p < 0.05). The emission values of the right and left ears of the carpenters were significantly lower than the controls at 2000 and 2800 Hz (p < 0.05).

CONCLUSION

Accordingly, carpenters seem to be susceptible to the development of noise-induced hearing loss.

Evaluation of cochlear functions in infants exposed to SARS-CoV-2 intrauterine

Purpose

The novel coronavirus (SARS-CoV-2) caused an acute respiratory illness named COVID-19 and the disease spread all over the World. Fever, cough, fatigue, gastrointestinal infection symptoms form the main clinical symptoms. Pregnants and newborns form a vulnerable population and urgent measures must be addressed. Studies about the effect of COVID-19 on pregnant women, developing fetuses, and infants are limited. Various viral diseases can cause congenital or acquired, unilateral or bilateral hearing loss.

Methods

37 infants whose mother was pregnant between March 2020 and December 2020 and were born after the diagnosis of COVID- 19 during pregnancy and 36 healthy infants were included in the study. Transient evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE) and contralateral suppression of OAE (CLS OAE) tests were performed on all infants.

Results

According to the TEOAE results of patients and controls in the silent a statistically significant difference was observed between the two groups at 3 kHz and 4 kHz (p < 0.05). Contralateral suppression of OAE test results of patients and controls a statistically significant difference was found in all frequencies (p< 0.05). Suppression was much more effective at all frequencies in the normal group than patient group. This difference was found to be more significant at higher frequencies (2,3 and 4 kHz) (p < 0.001).

Conclusions

Our results suggest an insufficiency in medial olivocochlear efferent system in infants exposed to SARS-CoV-2 intrauterine. Cochlear functions should be examined in infants whose mothers had COVID-19.

The Immediate and Long-Term Impact of Military Aircraft Noise on Hearing: A Cross-Sectional Comparison of Fighter Pilots and Ground Staff

We examined the immediate and long-term impacts of military aircraft noise exposure on noise-induced hearing loss (NIHL) in fighter pilots and ground staff. We recruited 40 pilots, 40 ground staff, and 136 age-matched controls; all participants underwent hearing tests, including conventional pure-tone audiometry (PTA) (0.25–8.0 kHz), extended high-frequency (EHF) audiometry (9.0–18.0 kHz), and distortion-product otoacoustic emission (DPOAE) as a recent reference. A subsequent hearing test immediately after flight-mission noise exposure was requested. The results revealed higher recent hearing thresholds in pilots and ground staff than in controls. Threshold shifts at many octave band frequencies were also significantly elevated in ground staff. The grouped frequency threshold was significantly elevated in the 4–8 kHz high-frequency range. After a single flight-mission noise exposure, both ground staff and pilots showed decreased signal-to-noise ratios for DPOAE (1–8 kHz), whereas only ground staff showed significantly elevated left-ear hearing thresholds at 3, 11.2, and 12.5 kHz by conventional and EHF PTA. Fighter pilots and ground staff serve in hazardous noise-exposed environments that cause hearing damage and subsequent NIHL, but ground staff may be more vulnerable. A comprehensive hearing conservation program should be implemented to protect high-risk service members, and especially ground staff, from high-intensity noise exposure.

Effects of primary arterial hypertension on cochlear function

BACKGROUND

Hypertension (HT) is one of the most common chronic diseases. The existing literature on HT and hearing contains conflicting results, and no consensus has been reached yet.

OBJECTIVES

This study aimed to investigate cochlear function in hypertensive and normotensive groups.

METHODS

This study was conducted on 34 patients with primary HT and 17 healthy adults. The Cochlear function was assessed with conventional audiometry (0.125-8 kHz), ultra-high frequency audiometry (10-16 kHz), the transient evoked otoacoustic emission (TEOAE) test, and the distortion product otoacoustic emission (DPOAE) test.

RESULTS

Hearing thresholds at 8, 10, 12.5, 14, and 16 kHz were significantly poorer in the HT group than in the control group (p < .05). There was no significant difference in the mean conventional thresholds between the groups. Compared to the control group, the patient group exhibited statistically significant lower amplitudes of TEOAE and DPOAE.

CONCLUSION

This study demonstrated significantly poorer high-frequency hearing and lower otoacoustic emission amplitudes for adults with HT. Impairment in hearing thresholds associated with HT begins at ultra-high frequencies in the cochlea. HT may be a potential risk factor for the development of hearing loss; therefore, individuals with HT should be screened for auditory function.

Otoacoustic Emissions in Children with Long-Term Middle Ear Disease

Introduction: Otoacoustic emissions (OAEs) evaluate the functional status of the cochlea. Repeated otitis media (OM) can cause changes in the peripheral structures of the auditory system, and, in this way, middle ear infection may irreversibly damage the middle ear, or even the cochlea. Objectives: To analyze the results of transiently evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) in individuals with a history of OM. Method: Participants with 8 to 16 years of schooling were split into two groups: a control group (CG) of 50 subjects who had no history of otological disease and an experimental group (EG) of 50 subjects who had a history of recurrent otitis in childhood and had consequently undergone myringotomy to insert bilateral ventilation tubes. All children underwent basic audiological assessment (tonal audiometry, speech audiometry, and immittance testing) and otoacoustic emission testing (TEOAEs and DPOAEs). Results: There were no significant differences between the groups when audiometrically tested via air and bone conduction. OAEs were found in all CG subjects. For the EG, there were no TEOAE responses in 17 ears and no DPOAEs in nine ears; response amplitudes were lower at all frequencies. The emission level and the signal-to-noise ratio were statistically different between the two groups, and OAEs in the EG were statistically smaller compared to the GC. Conclusion: In the EG, responses were more likely to be absent and were of statistically smaller amplitude compared to the CG. A history of repeated OM apparently interferes with the generation and transmission of TEOAEs and DPOAEs.

Stroke risk in African Americans with subclinical auditory dysfuntion evidenced by Distortion Product Otoacoustic Emissions: the Jackson heart study

Objective: Distortion product otoacoustic emissions (DPOAEs) are sensitive to early indices of cochlear pathology. Pathology to the cochlea is in part mediated by ischaemic related mechanisms. We propose that DPOAEs may provide an objective measure of cardiovascular risk.Design: Cross-sectional.Study sample: The relationships between stroke risk and DPOAEs of 1,107 individuals from the Jackson Heart Study (JHS), an all-African-American cohort, were assessed. Linear regression models were used for analysis among all participants and delimited to normal hearing, defined as either a pure-tone threshold average of 500, 1000, 2000, and 4000 Hz (PTA4) ≤ 25 dBHL or pure-tone thresholds for all individual tested frequencies for each ear (500, 1000, 2000, 4000, and 8000 Hz) ≤ 25 dBHL.Results: We observed a significant inverse relationship between DPOAE amplitudes and stroke risk scores in the pooled cohort and in the subgroups with normal hearing defined by pure tone thresholds. Participants in the high-risk group had significantly lower DPOAE amplitudes than those in the low stroke risk group.Conclusions: Our results indicate that auditory dysfunction as measured by DPOAEs are related to stroke risk. Further prospective studies are needed to determine if DPOAEs could be used as a predictive tool for cardiovascular disease.

Detection of Age-Related Hearing Losses (ARHL) via Transient-Evoked Otoacoustic Emissions

PURPOSE

The objective of the study was to identify subjects presenting hearing deficits, specifically age-related hearing losses (ARHL), via objective assessment methodologies.

MATERIALS AND METHODS

Initially, 259 subjects (165 men, 94 women) were enrolled in the study. After the application of inclusion criteria, the final number was reduced to 88 subjects (49.8 ± 19.1 ys) subdivided into 64 normal and 83 ARHL cases. The subjects were assessed with traditional audiometry tests and with transiently evoked otoacoustic emissions (TEOAEs). Since each ear has its own acoustic signature, the TEOAE analyses were conducted in terms of ears and not subjects. The TEOAE data were processed by traditional and recurrence quantification analyses, leading to the estimation of the WWR (whole waveform reproducibility) and the new RAD2D (2-dimensional radius) parameters. A plot of WWR vs RAD2D was used to optimize the classification of the cases presenting ARHL.

RESULTS

By using a WWR value of 70% as a classifier, the sensitivity of TEOAEs was estimated as 75.9% and the specificity as 89.1%. By using the RAD2D parameter (with a cut-off value of 1.78), a sensitivity value of 80.7% and a specificity value of 71.9% were obtained. When both parameters were used, a sensitivity value of 85.5% and a specificity value of 92.2% were estimated. In the latter classification paradigm, the number of false negatives decreased from 20 to 12 out of 83 ears (14%).

CONCLUSION

In adult hearing screening assessments, the proposed method optimizes the identification of subjects with a hearing impairment correlated to the presence of age-related hearing loss.

Cochlear dysfunction is associated with styrene exposure in humans

AIM

Occupational exposure to styrene has been shown to be associated with an increased probability of developing hearing loss. However, the sites of lesions in the auditory system in humans remain unknown. The aim of this study was to investigate the possible adverse effects of styrene exposure on the cochlea of human subjects.

DESIGN

The hearing function of 98 styrene-exposed male workers from the glass fibre-reinforced plastics industry (mean concentration of 55 mg/m3) was evaluated bilaterally using pure-tone audiometry (1000-16000 Hz), distortion product otoacoustic emissions (DPOAEs), and auditory brainstem response (ABR). The results were compared to a group of 111 male workers exposed to noise (above 85 dBA) and 70 male white-collar workers exposed to neither noise nor solvents. Age and noise exposure levels were accounted for as confounding variables in all statistical models.

RESULTS

Styrene exposure was significantly associated with poorer pure-tone thresholds (1-8 kHz), lower DPOAE amplitudes (5-6 kHz), and shorter wave V latencies in both ears compared to control-group subjects. Similar results were found among noise-exposed subjects. A further analysis with wave V latency showed that styrene-exposed subjects showed significantly shorter latencies than expected according to normative data. These results suggest that occupational exposure to styrene at moderate concentrations is associated with cochlear dysfunction, at least at high frequencies. DPOAEs may be considered a valuable diagnostic tool in hearing conservation programs in workers exposed to styrene.

The Effect of Short-Term Noise Exposure on Audiometric Thresholds, Distortion Product Otoacoustic Emissions, and Electrocochleography

Purpose The purpose of the study was to examine the effect of short-term noise exposure on audiometric thresholds, distortion product otoacoustic emissions (DPOAEs), and electrocochleography (ECochG) as a function of ear and sex. Method Preexposure and postexposure measures of audiometric thresholds, DPOAEs, and ECochG indices were examined. Sixteen male and 16 female adults participated. Participants were exposed to a 2000-Hz narrowband noise presented at 105 dBA for 10 min. Results Following noise exposure, significantly ( p < .0001) larger auditory threshold differences were observed for left ears. Larger auditory threshold differences were also observed for 3000 and 4000 Hz versus 2000 and 6000 Hz. DPOAE absolute amplitude differences increased with decreasing L ₁, L ₂ level ( p < .0001). DPOAE absolute amplitude differences also significantly rose with increasing f₂ frequencies ( p < .0001). Females generally had larger DPOAE absolute amplitude differences than males ( p < .05). Summating potential amplitudes were significantly larger for female left ears following noise exposure ( p = .03). Left-ear summating potential/action potential amplitude ratios and summating potential/action potential area ratios were increased following noise exposure ( p < .05). Conclusions Utilizing a test battery to examine the effects of short-term noise exposure can reveal the functional status of different structures in the cochlea. There appears to be a susceptibility of the left ear to short-term loud noise exposure. Findings with respect to a sex susceptibility to short-term loud noise exposure were not strong, as sex differences were only observed for a subset of the conditions.

Utility of otoacoustic emissions and olivocochlear reflex in predicting vulnerability to noise-induced inner ear damage

Aim:

The aim of the present study was to explore the possible utility of otoacoustic emissions (OAEs) and efferent system strength to determine vulnerability to noise exposure in a clinical setting.

Materials and Methods:

The study group comprised 344 volunteers who had just begun mandatory basic training as Hellenic Corps Officers Military Academy cadets. Pure-tone audiograms were obtained on both ears. Participants were also subjected to diagnostic transient-evoked otoacoustic emissions (TEOAEs). Finally, they were all tested for efferent function through the suppression of TEOAEs with contralateral noise. Following baseline evaluation, all cadets fired 10 rounds using a 7.62 mm Heckler & Koch G3A3 assault rifle while lying down in prone position. Immediately after exposure to gunfire noise and no later than 10 h, all participants completed an identical protocol for a second time, which was then repeated a third time, 30 days later.

Results:

The data showed that after the firing drill, 280 participants suffered a temporary threshold shift (TTS) (468 ears), while in the third evaluation conducted 30 days after exposure, 142 of these ears still presented a threshold shift compared to the baseline evaluation [permanent threshold shift (PTS) ears]. A receiver operating characteristics curve analysis showed that OAEs amplitude is predictive of future TTS and PTS. The results were slightly different for the suppression of OAEs showing only a slight trend toward significance. The curves were used to determine cut points to evaluate the likelihood of TTS/PTS for OAEs amplitude in the baseline evaluation. Decision limits yielding 71.6% sensitivity were 12.45 dB SPL with 63.8% specificity for PTS, and 50% sensitivity were 12.35 dB SPL with 68.2% specificity for TTS.

Conclusions:

Interestingly, the above data yielded tentative evidence to suggest that OAEs amplitude is both sensitive and specific enough to efficiently identify participants who are particularly susceptible to hearing loss caused by impulse noise generated by firearms. Hearing conservation programs may therefore want to consider including such tests in their routine. As far as efferent strength is concerned, we feel that further research is due, before implementing the suppression of OAEs in hearing conservations programs in a similar manner.

Disorders induced by direct occupational exposure to noise: Systematic review

Background:

To review the available scientific literature about the effects on health by occupational exposure to noise.

Materials and Methods:

A systematic review of the retrieved scientific literature from the databases MEDLINE (via PubMed), ISI-Web of Knowledge (Institute for Scientific Information), Cochrane Library Plus, SCOPUS, and SciELO (collection of scientific journals) was conducted. The following terms were used as descriptors and were searched in free text: “Noise, Occupational,” “Occupational Exposure,” and “Occupational Disease.” The following limits were considered: “Humans,” “Adult (more than 18 years),” and “Comparative Studies.”

Results:

A total of 281 references were retrieved, and after applying inclusion/exclusion criteria, 25 articles were selected. Of these selected articles, 19 studies provided information about hearing disturbance, four on cardiovascular disorders, one regarding respiratory alteration, and one on other disorders.

Conclusions:

It can be interpreted that the exposure to noise causes alterations in humans with different relevant outcomes, and therefore appropriate security measures in the work environment must be employed to minimize such an exposure and thereby to reduce the number of associated disorders.

Decreased Speech-In-Noise Understanding in Young Adults with Tinnitus

OBJECTIVES

Young people are often exposed to high music levels which make them more at risk to develop noise-induced symptoms such as hearing loss, hyperacusis, and tinnitus of which the latter is the symptom perceived the most by young adults. Although, subclinical neural damage was demonstrated in animal experiments, the human correlate remains under debate. Controversy exists on the underlying condition of young adults with normal hearing thresholds and noise-induced tinnitus (NIT) due to leisure noise. The present study aimed to assess differences in audiological characteristics between noise-exposed adolescents with and without NIT.

METHODS

A group of 87 young adults with a history of recreational noise exposure was investigated by use of the following tests: otoscopy, impedance measurements, pure-tone audiometry including high-frequencies, transient and distortion product otoacoustic emissions, speech-in-noise testing with continuous and modulated noise (amplitude-modulated by 15 Hz), auditory brainstem responses (ABR) and questionnaires.Nineteen students reported NIT due to recreational noise exposure, and their measures were compared to the non-tinnitus subjects.

RESULTS

No significant differences between tinnitus and non-tinnitus subjects could be found for hearing thresholds, otoacoustic emissions, and ABR results.Tinnitus subjects had significantly worse speech reception in noise compared to non-tinnitus subjects for sentences embedded in steady-state noise (mean speech reception threshold (SRT) scores, respectively -5.77 and -6.90 dB SNR; p = 0.025) as well as for sentences embedded in 15 Hz AM-noise (mean SRT scores, respectively -13.04 and -15.17 dB SNR; p = 0.013). In both groups speech reception was significantly improved during AM-15 Hz noise compared to the steady-state noise condition (p < 0.001). However, the modulation masking release was not affected by the presence of NIT.

CONCLUSIONS

Young adults with and without NIT did not differ regarding audiometry, OAE, and ABR.However, tinnitus patients showed decreased speech-in-noise reception. The results are discussed in the light of previous findings suggestion NIT may occur in the absence of measurable peripheral damage as reflected in speech-in-noise deficits in tinnitus subjects.

[A survey of the otoacoustic emissions (OAEs) of workers exposed to noise in manufacturing factories]

OBJECTIVES

Otoacoustic emission (OAE) testing is not widespread in Japanese industrial health. This study examined the association between hearing thresholds (HTs) and OAEs among workers exposed to noise in actual workplaces.

METHODS

In two metal products manufacturing factories, 34 workers with noise exposure in the workplace (exposure group, mean age 40.6 ± 9.4 years), and 9 workers with no noise exposure (control group, 49.0 ± 14.3 years) were surveyed. The time-weighted average (LAeq) and maximum (LAMAX) of environmental noise monitoring (ENM), and the time-weighted average (LTWA) and sound exposure level (LAE) of personal noise monitoring (PNM) were measured for each subject at the same time. As hearing effect indicators of noise exposure levels, HTs (0.5, 1, 2, 4 and 8 kHz) and distortion product OAEs (DPOAEs) (2, 3 and 4 kHz) were performed before and after 5 days of work. The results of the ENM, PNM, HTs and OAEs were compared between the groups using Student's t test, and their correlations were investigated using Pearson correlation coefficients.

RESULTS

Noise exposure levels of the exposure group were significantly higher than those of the control group. In the exposure group, LAeq, LAMAX, LTWA and LAE were respectively 84.5 ± 4.1 dB(A),89.5 ± 6.3 dB(A), 83.4 ± 4.7 dB(A) and 153.1 ± 15.7 dB(A), and in the control group, they were 53.2 ± 2.6 dB(A), 56.4 ± 2.4 dB(A), 67.8 ± 5.6 dB(A) and 119.5 ± 5.6 dB(A). There was no difference between hearing effect indicators (HTs and OAEs) before and after work in either group. There was no correlation between the noise exposure level (LAeq, LTWA, LTWA and LAE) and HTs or OAEs, but there was a significant correlation between the HTs and OAEs at most of frequencies. The HTs and OAEs of subjects with noise-induced hearing loss (NIHL) were significantly lower than those of subjects without NIHL.

CONCLUSIONS

This study revealed there is a significant correlation of the HTs and OAEs before and after 5 days of work. In the future, OAE is expected to be used as a screening test of hearing management of noise-exposed workers in Japan.

Influence of sound-conditioning on noise-induced susceptibility of distortion-product otoacoustic emissions

Cochlear damage caused by loud sounds can be attenuated by "sound-conditioning" methods. The amount of adaptation for distortion product otoacoustic emissions (DPOAEs) measured in alert rabbits previously predicted an ear's susceptibility to a subsequent noise exposure. The present study investigated if sound-conditioning influenced the robustness of such DPOAE adaptation, and if such conditioning elicited more protection by increasing the amount of DPOAE adaptation. Toward this end, rabbits were divided into two study groups: (1) experimental animals exposed to a sound-conditioning protocol, and (2) unconditioned control animals. After base-line measures, all rabbits were exposed to an overstimulation paradigm consisting of an octave band noise, and then re-assessed 3 weeks post-exposure to determine permanent changes in DPOAEs. A major result was that prior sound-conditioning protected reductions in DPOAE levels by an average of 10-15 dB. However, DPOAE adaptation decreased with sound-conditioning, so that such conditioning was no longer related to noise-induced reductions in DPOAEs. Together, these findings suggest that sound-conditioning affected neural pathways other than those that likely mediate DPOAE adaptation (e.g., medial olivocochlear efferent and/or middle-ear muscle reflexes).

The olivocochlear system and protection from acoustic trauma: a mini literature review

Large intersubject variability in the susceptibility to noise-induced hearing loss (NIHL) is known to occur in both humans and animals. It has been suggested that the olivocochlear system (OCS) plays a significant role in protecting the cochlea from exposure to high levels of noise. A mini literature review about the scientific evidence from animal and human studies about the association between the function of the OCS and susceptibility to NIHL was carried out. Animal data consistently show that de-efferented ears exhibit larger temporary threshold shift (TTS) and permanent threshold shift (PTS) than efferented ears. Data from human studies do not consistently show a correlation between the strength of the OCS function and amount of TTS. Further research on human subjects is required to determine how the OCS function could be used to predict susceptibility to NIHL in individual subjects.

Analysis of subtle auditory dysfunctions in young normal-hearing subjects affected by Williams syndrome

OBJECTIVE

To assess if young subjects affected by Williams syndrome (WS) with normal middle ear functionality and normal hearing thresholds might have subtle auditory dysfunctions that could be detected by using clinically available measurements.

METHODS

Otoscopy, acoustic reflexes, tympanometry, pure-tone audiometry, and distortion product otoacoustic emissions (DPOAEs) were measured in a group of 13 WS subjects and in 13 age-matched, typically developing control subjects. Participants were required to have normal otoscopy, A-type tympanogram, normal acoustic reflex thresholds, and pure-tone thresholds≤15 dB HL at 0.5, 1, and 2 kHz bilaterally. To limit the possible influence of middle ear status on DPOAE recordings, we analyzed only data from ears with pure-tone thresholds≤15 dB HL across all octave frequencies in the range 0.25-8 kHz, middle ear pressure (MEP)>-50 daPa, static compliance (SC) in the range 0.3-1.2 cm3, and ear canal volume (ECV) in the range 0.2-2 ml, and we performed analysis of covariance to remove the possible effects of middle ear variables on DPOAEs.

RESULTS

No differences in mean hearing thresholds, SC, ECV, and gradient were observed between the two groups, whereas significantly lower MEP values were found in WS subjects as well as significantly decreased DPOAEs up to 3.2 kHz after adjusting for differences in middle ear status.

CONCLUSIONS

Results revealed that WS subjects with normal hearing thresholds (≤15 dB HL) and normal middle ear functionality (MEP>-50 daPa, SC in the range 0.3-1.2 cm3, ECV in the range 0.2-2 ml) might have subtle auditory dysfunctions that can be detected by using clinically available methods. Overall, this study points out the importance of using otoacoustic emissions as a complement to routine audiological examinations in individuals with WS to detect, before the onset of hearing loss, possible subtle auditory dysfunctions so that patients can be early identified, better monitored, and promptly treated.

Otoacoustic-emission-based medial-olivocochlear reflex assays for humans

Otoacoustic emission (OAE) tests of the medial-olivocochlear reflex (MOCR) in humans were assessed for viability as clinical assays. Two reflection-source OAEs [TEOAEs: transient-evoked otoacoustic emissions evoked by a 47 dB sound pressure level (SPL) chirp; and discrete-tone SFOAEs: stimulus-frequency otoacoustic emissions evoked by 40 dB SPL tones, and assessed with a 60 dB SPL suppressor] were compared in 27 normal-hearing adults. The MOCR elicitor was a 60 dB SPL contralateral broadband noise. An estimate of MOCR strength, MOCR%, was defined as the vector difference between OAEs measured with and without the elicitor, normalized by OAE magnitude (without elicitor). An MOCR was reliably detected in most ears. Within subjects, MOCR strength was correlated across frequency bands and across OAE type. The ratio of across-subject variability to within-subject variability ranged from 2 to 15, with wideband TEOAEs and averaged SFOAEs giving the highest ratios. MOCR strength in individual ears was reliably classified into low, normal, and high groups. SFOAEs using 1.5 to 2 kHz tones and TEOAEs in the 0.5 to 2.5 kHz band gave the best statistical results. TEOAEs had more clinical advantages. Both assays could be made faster for clinical applications, such as screening for individual susceptibility to acoustic trauma in a hearing-conservation program.

Prevention of Cisplatin-Induced Hearing Loss by Intratympanic Dexamethasone

Objective

To examine the role of intratympanic Dexamethasone (ITD) in the prevention of Cisplatin-induced hearing loss.

Study Design

Prospective randomized controlled clinical trial.

Setting

Tertiary referral center.

Subjects and Methods

Twenty-six patients suffering from a neoplastic disease for which the treatment protocol included Cisplatin were recruited. Prior to each Cisplatin treatment session ITD was injected to the baseline randomly assigned ear while the other ear of the same patient served as the control. Audiometry and Distortion Product Otoacoustic Emissions (DPOAEs) test results of the baseline and follow-up examinations were compared within and between the study and control ears.

Results

The cumulative dose of Cisplatin was greater than 400 mg for the 15 subjects who completed the study. The pure tone threshold at 8000 Hz and pure tone average threshold at 4000 to 8000 Hz significantly increased in both the study ( P < .005, P < .03, respectively) and control ears ( P < .01, P < .005, respectively). Significant increase in the pure tone threshold for 6000 Hz was observed in the control ( P < .02) but not in the study group. Within the groups comparison also revealed significant decrease in the DPOAE average signal-to-noise ratio (SNR) for the f2 frequencies 7031 ( P < .04) and 8391 Hz ( P < .04) and SNR average for 4000 to 8000 Hz in the control ( P < .04) but not in the study ears.

Conclusions

ITD significantly attenuated hearing loss at 6000 Hz and decreased the outer hair dysfunction in the DPOAE f2 range of 4000 to 8000 Hz. ITD might have potential in the reduction of Cisplatin-induced hearing loss.

Conventional Audiometry, Extended High-Frequency Audiometry, and DPOAE for Early Diagnosis of NIHL

Background:

Noise most frequently affects hearing system, as it may typically cause a bilateral, progressive sensorineural hearing loss at high frequencies.

Objectives:

This study was designed to compare three different methods to evaluate noise-induced hearing loss (conventional audiometry, high-frequency audiometry, and distortion product otoacoustic emission).

Material and Methods:

This was a cross-sectional study. Data was analyzed by SPSS (ver. 19) using chi square, T test and repeated measures analysis. Study samples were workers from tile and ceramic industry.

Results:

We found that conventional audiometry, extended high-frequency audiometry, low-tone distortion product otoacoustic emission and high-tone distortion product otoacoustic emission had abnormal findings in 29 %, 69 %, 22 %, and 52 % of participants. Most frequently affected frequencies were 4000 and 6000Hz in conventional audiometry, and 14000 and 16000 in extended high-frequency audiometry.

Conclusions:

Extended high-frequency audiometry was the most sensitive test for detection of hearing loss in workers exposed to hazardous noise compared with conventional audiometry and distortion product otoacoustic.

A longitudinal study of changes in distortion-product otoacoustic emissions and pure-tone thresholds in an industrial setting

In a longitudinal study of 76 noise-exposed industrial workers, 34 (68 ears) of them were available for final evaluation after 9 years of observation. Distortion-product otoacoustic emissions (DP) at 65/55 dB SPL and pure-tone audiometry were used to detect noise-induced inner ear changes. Repeated measures analyses of variance were made on the subjects and in a control group, whereas significant threshold shifts (STS) and significant emission shifts (SES) were calculated. Both hearing thresholds and DP showed a high-frequency deterioration, but there was absence of statistical correlation between elevation of hearing thresholds and decrease of DP. There was no clear pattern between individual changes in audiometric thresholds and DP, and all combinations were present: ears with only STS, ears with only SES, ears with both STS and SES and ears with absence of STS and SES. Audiometric changes were maximal at 4 and 6 kHz and DP changes at 2 and 3 kHz. Since significant individual emission changes do not necessarily follow the same pattern as the group-averaged results, the use of DP for monitoring of individual subjects is not advised. However, its use in conjunction with audiometry in hearing conservation programs is highly recommended.

Post-processing analysis of transient-evoked otoacoustic emissions to detect 4 kHz-notch hearing impairment--a pilot study

Background

To identify a parameter to distinguish normal hearing from hearing impairment in the early stages. The parameter was obtained from transient-evoked otoacoustic emissions (TEOAEs), overcoming the limitations of the usually adopted waveform descriptive parameters which may fail in standard clinical screenings.

Material/Methods

Audiometric examinations and TEOAE analysis were conducted on 15 normal ears and on 14 hearing-impaired ears that exhibited an audiometric notch around 4 kHz. TEOAE signals were analyzed through a multivariate technique to filter out the individual variability and to highlight the dynamic structure of the signals. The new parameter (named radius 2-dimension – RAD2D) was defined and evaluated for simulated TEOAE signals modeling a different amount of hearing impairment.

Results

Audiometric examinations indicated 14 ears as impaired-hearing (IH), while the TEOAE ILO92 whole reproducibility parameter (WWR) indicated as IH 7 signals out of 14 (50%). The proposed new parameter indicated as IH 9 signals out of 14 (64%), reducing the number of false negative cases of WWR.

Conclusions

In this preliminary study there is evidence that the new parameter RAD2D defines the topology and the quantification of the damage in the inner ear. The proposed protocol can be useful in hearing screenings to identify hearing impairments much earlier than conventional pure tone audiometry and TEOAE pass/fail test.

Sensorineural hearing loss in high school teenagers in Mexico City and its relationship with recreational noise

The aim of this study was to measure the frequency of hearing loss in a sample of typical public high-school students exposed to recreational noise, and determine associated risk factors. The sample was made up of 214 teenagers from a high-school in Mexico City; subjects were selected randomly per strata. We applied a questionnaire to identify risk factors for hearing loss and performed a battery of audiologic tests consisting of otoscopy, tympanometry, and pure-tone audiometry. The mean age of the sample was 16 +/- 1.07 years; 73% were male and 27%, female. Hearing loss was found in 21% of students. The main hearing loss-related risk factor was exposure to recreational noise: frequent attendance at discotheques and pop-music concerts; use of personal stereos; and noise exposure in school workshops. The high frequency of hearing loss in high school students from one Mexico City school (nearly one fifth of the sample) was found to be related to noise exposure mainly during recreational activities.

Otoacoustic emissions in a hearing conservation program: general applicability in longitudinal monitoring and the relation to changes in pure-tone thresholds

The hearing status of workers (N = 233) in a printing office was assessed twice within seventeen months by pure-tone audiometry and otoacoustic emissions (OAEs). One of the questions was how a quality criterion of OAE-measurements based on a minimum signal-to-noise-ratio (SNR) would affect the applicability on the entire population. Secondly, effects of noise exposure were investigated in overall changes in audiogram and OAE-measurements. For TEOAEs (transient evoked OAEs) in the frequency band of 4 kHz, only 55% of the data points meet the SNR-inclusion criterion. For DPOAEs (distortion product OAEs) around 6 kHz approximately 80% of the data points satisfy the criterion. Thus OAEs have a limited applicability for monitoring the hearing status of this entire population. Audiometry shows significant deteriorations at 6 and 8 kHz. TEOAEs show a significant decline at all frequency bands (1-4 kHz), DPOAEs between 4 and 8 kHz and less pronounced between 1 and 2 kHz. On group level, OAEs show a decline in a larger frequency region than the audiogram, suggesting an increased sensitivity of OAEs compared to audiometry.

Distortion product otoacoustic emissions following stapedectomy versus stapedotomy

Objectives:

To evaluate distortion product otoacoustic emissions following stapes surgery in patients with otosclerosis, and to compare in this respect two surgical techniques used in our department.

Method:

This retrospective study included 17 stapedectomy and 23 stapedotomy patients aged 16–68 years who had been followed up for at least 12 months. Distortion product otoacoustic emission results at 2, 3, 4 and 5 kHz (i.e. =f2, with 2f1 − f2 = 0.6f2) were obtained pre-operatively and four weeks post-operatively. The control group included 13 volunteers aged 18–50 years with normal hearing and normal otoscopic findings.

Results:

Distortion product otoacoustic emissions were detected pre-operatively in 34.8 per cent of stapedotomy patients and 29.4 per cent of stapedectomy patients, and post-operatively in 91.3 per cent of stapedotomy patients and 88.2 per cent of stapedectomy patients. The differences between the stapedotomy and stapedectomy groups were statistically insignificant for each tested frequency, both pre- and post-operatively. The patients' post-operative distortion product otoacoustic emission amplitudes were less than those of normal hearing individuals, even in patients with complete air–bone gap closure and a significant improvement in hearing.

Conclusion:

Distortion product otoacoustic emissions were detected in most of our patients following successful stapes surgery, and appeared to be unaffected by the surgical technique or prosthesis used.

Estudo das emissões otoacústicas - produto de distorção durante a prática esportiva associada à exposição à música

OBJETIVO: estudar a audição dos alunos de uma academia de ginástica durante o exercício físico, analisando os resultados das emissões otoacústicas - produto de distorção (EOAPD), antes e após a exposição à música eletronicamente amplificada. MÉTODOS: foi aplicado um questionário em 20 indivíduos, sendo os mesmos avaliados por meio das EOAPD, antes e após a execução do exercício físico e exposição à música. RESULTADOS: uma elevada porcentagem de exposições extra-ocupacionais e de lazer (65%) foi encontrada ao analisar as queixas. Observou-se que 40% dos alunos de academia de ginástica apresentaram dores de cabeça e insônia; sete, intolerância para sons intensos; cinco, plenitude auricular e irritabilidade; cinco, nervosismo; quatro, tontura; e três relataram apresentar zumbidos após as aulas. No teste de EOPD, houve presença de respostas em 100% das orelhas testadas no momento 1 (M1), porém, no momento 2 (M2), houve presença de resposta em 75%. As frequências que apresentaram maior percentual de falhas no momento 2 (M2) foram 3KHz, 4KHz e 5 KHz. CONCLUSÃO: exercício físico associado a elevados níveis de pressão sonora de música provocam alterações nas EOA-PD, principalmente nas frequências de 3000Hz, 4000Hz e 5000Hz. Desse modo, alunos de academia de ginástica que ficam expostos à música eletronicamente amplificada podem estar prejudicando a audição. Há necessidade, portanto, das academias avaliarem as condições acústicas de suas salas de aulas, a partir da análise de profissionais especializados no intuito de verificarem os níveis sonoros, desse modo, observando se estes (NPS) estão compatíveis com os valores recomendados pela lei.