Search

Introduction Current Brazilian legislation requires that all workers exposed to noise are to be given an audiogram upon hiring, after 6 months of employment (first periodic test), and annually after the first periodic test. In other countries, the regulations of hearing conservation programs do not include the requirement for audiometric testing at 6 months of employment, but only annually. There is no evidence that the periodicity adopted by Brazilian legislation is the most appropriate. Objective The present study aimed to evaluate the first 3 occupational audiometric tests of workers exposed to noise. Methods Historical cohort study with cross-sectional analysis. Participants were all male metallurgy workers aged up to 40 years. The first 3 audiograms of each worker were analyzed: pre-employment audiometric test, periodic audiometric test 1, and periodic audiometric test 2. For each worker, mean frequency thresholds were calculated at 3, 4, and 6 kHz in the left and right ears for each test. Statistical analysis was performed using the nonparametric Wilcoxon test. Results A total of 988 workers were included. There was a significant difference in auditory thresholds between the pre-employment test and the 2 subsequent periodic tests for the right and left ears. There was no significant difference between Test1 and Test2 in either ear. Conclusion Given the lack of difference between the first 2 periodic tests, we believe that they could be merged into a single test, i.e., first periodic audiometric testing could be performed at 12 months of employment without compromising workers’ health.

OBJECTIVES In adult cochlear implant patients, conventional audiometry is used to measure postoperative residual hearing which requires active listening and patient feedback. However, audiological measurements in pediatric cochlear implant patients are both challenging as well as time consuming. Intracochlear electrocochleography (ECOG) offers an objective and a time-efficient method to measure frequency-specific cochlear microphonic or difference thresholds (CM/DIF) thresholds that closely approximate auditory thresholds in adult cochlear implant patients. The correlation between CM/DIF and behavioral thresholds has not been established in pediatric cochlear implant patients. In the present study, CM/DIF thresholds were compared with audiometric thresholds in pediatric cochlear implant patients with postoperative residual hearing. DESIGN Thirteen (11 unilateral and 2 bilateral) pediatric cochlear implant patients (mean age = 9.2 years ± 5.1) participated in this study. Audiometric thresholds were estimated using conventional, condition play, or visual reinforcement audiometry. A warble tone stimulus was used to measure audiometric thresholds at 125, 250, 500, 1000, and 2000 Hz. ECOG waveforms were elicited using 50-msec acoustic tone-bursts. The most apical intracochlear electrode was used as the recording electrode with an extra-cochlear ground electrode. The ECOG waveforms were analyzed to determine CM/DIF thresholds that were compared with pediatric cochlear implant patients' audiometric thresholds. RESULTS The results show a significant correlation (r = 0.77, p < 0.01) between audiometric and CM/DIF thresholds over a frequency range of 125 to 2000 Hz in pediatric cochlear implant patients. Frequency-specific comparisons revealed a correlation of 0.82, 0.74, 0.69, 0.41, and 0.32 between the audiometric thresholds and CM/DIF thresholds measured at 125, 250, 500, 1000, and 2000 Hz, respectively. An average difference of 0.4 dB (±14 dB) was measured between the audiometric and CM/DIF thresholds. CONCLUSIONS Intracochlear ECOG can be used to measure CM/DIF thresholds in pediatric cochlear implant patients with residual hearing in the implanted ear. The CM/DIF thresholds are similar to the audiometric thresholds at lower test frequencies and offer an objective method to monitor residual hearing in difficult-to-test pediatric cochlear implant patients.

Objectives - to study hearing thresholds at high frequencies in elderly and senile patients, taking into account the age norm and the presence of comorbid diseases. Material and methods. 111 patients aged from 50 to 97 years (mean age 70.5 ± 2.1) were examined, their age, auditory function, and concomitant diseases were also registered. Results. The measured average auditory thresholds at high frequencies, if compared to the age-related standards for auditory sensitivity, have revealed an underestimated hearing loss in 12.6% of patients. The presence of concomitant diseases has a significant impact on the development of chronic sensorineural hearing loss in each age group. Conclusion. Audiometry in an extended frequency range in elderly patients with concurrent diseases can improve the hearing examination algorithm.

Introduction Cortical auditory evoked potentials (CAEPs) can be used to evaluate both peripheral and cortical components of auditory function, and contribute to the assessment of functional sensitivity and auditory thresholds, especially in neonates and infants. Auditory evoked potentials reflect auditory maturity and precede the acquisition of more complex auditory and cognitive skills, and are therefore crucial for speech and language development. Objective The aim of the present study was to determine the presence, latency and amplitude of CAEP components in response to verbal stimuli in children aged 2 years old. Methods The sample consisted of 19 subjects, 10 of whom were male while 9 were female. All of the participants were 24 months old at the time of assessment. Results A total of 17 of the participants displayed all components of the CAEP. Additionally, no significant differences were observed between genders or ears in the present sample. The presence of all components of the CAEP in subjects aged 2 years old confirms the existence of a critical period for the maturation of auditory pathways in the first 2 years of life. Conclusion In the present study, in addition to the P1/N1 components, it was possible to observe the presence of the CAEP P2/N2 components in individuals aged 24 months, confirming the existence of a critical period for the maturation of the auditory pathways in the first 2 years of life.

Belgian Waterslager song canaries, bred for hundreds of years for a low-pitched song, have also acquired an inherited high-frequency hearing loss associated with hair cell abnormalities. Here, auditory thresholds measured using auditory brainstem responses and psychophysical methods in three different strains of canaries are compared: Belgian Waterslagers, American Singers, and Borders. Border canaries have not been bred for song characteristics while American Singer canaries have been bred for song only since the 1930s. Results show that American Singer canaries also have elevated high frequency thresholds that are similar to those of the Belgian Waterslager, while Border canaries have normal thresholds. These results strengthen the case that song canary breeders in selecting for song characteristics may have inadvertently selected for hearing abnormalities.

Brainstem auditory evoked potentials (BAEP) are useful to diagnose neurologic and genetic disorders in cattle but normal parameters and its application to detect changes in hearing are not demonstrated. The aims of this study were to develop a protocol for obtaining BAEP in Holstein calves and to establish the normal parameters of peak latencies, interpeak latencies (IPL) and waveforms of BAEP in this species. Ten male Holstein calves, aged 2.5 months and weighting 90.7 ± 4.0 kg were used. All animals were previously sedated with 0.08 mg/kg xylazine hydrochloride administered intramuscularly. The BAEP analysis was recorded using the IHS SmartEP-ASSR program connected with electrode needles placed on the standardized locations of the animal's head. Monoaurally presented broadband click stimuli (0.1 ms) were used for BAEP stimulation, with contralateral masking of 30 dB SPL. Stimuli were presented at a rate of 35.5 pulses per second (PPS) and evoked responses were collected and averaged 450–1500 times for each sound intensity. Earphones were inserted into the ear canal to present the acoustic stimulus and to attenuate environmental noise. Peak latencies, IPL, waveforms and auditory thresholds were recorded and analyzed in the right ear and were like those described in previous papers in adult male bulls. Auditory thresholds obtained in all animals were 33 ± 1.5 dB SPL. Peak latencies were 1.4 ± 0.07 ms (Peak I), 2.4 ± 0.10 ms (Peak II), 3.3 ± 0.10 ms (Peak III), 4.4 ± 0.19 ms (Peak IV) and 5.6 ± 0.28 ms (Peak V). IPL were 1.9 ± 0.12 ms (IPL I-III), 4.1 ± 0.29 ms (IPL I-V), 2.2 ± 0.19 ms (IPL II-V) and 2.2 ± 0.19 ms (IPL III-V). Brainstem auditory evoked potentials are a minimally-invasive method to evaluate level of audition in Holstein calves. In addition, BAEP is a method that can be applied in young calves and it would work on-farm to select the animals with better conditions.

OBJECTIVES/HYPOTHESIS Previous studies have demonstrated that electrocochleography (ECochG) measurements made at the round window prior to cochlear implant (CI) electrode insertion can account for 47% of the variability in 6-month speech perception scores. Recent advances have made it possible to use the apical CI electrode to record intracochlear responses to acoustic stimuli. Study objectives were to determine 1) the relationship between intracochlear ECochG response amplitudes and 6-month speech perception scores and 2) to determine the relationship between behavioral auditory thresholds and ECochG threshold estimates. The hypothesis was that intracochlear ECochG response amplitudes made immediately after electrode insertion would be larger than historical controls (at the extracochlear site) and explain more variability in speech perception scores. STUDY DESIGN Prospective case series. METHODS Twenty-two adult CI recipients with varying degrees of low-frequency hearing had intracochlear ECochG measurements made immediately after CI electrode insertion using 110 dB SPL tone bursts. Tone bursts were centered at five octave-spaced frequencies between 125 and 2,000 Hz. RESULTS There was no association between intracochlear ECochG response amplitudes and speech perception scores. But, the data suggest a mild to moderate relationship between preoperative behavioral audiometric testing and intraoperative ECochG threshold estimates. CONCLUSION Performing intracochlear ECochG is highly feasible and results in larger response amplitudes, but performing ECochG before, rather than after, CI insertion may provide a more accurate assessment of a patient's speech perception potential. LEVEL OF EVIDENCE 4 Laryngoscope, 131:E2681-E2688, 2021.

It has been suggested that infants respond preferentially to infant-directed speech because their auditory sensitivity to sounds with extensive frequency modulation (FM) is better than their sensitivity to less modulated sounds. In this experiment, auditory thresholds for FM tones and for unmodulated, or pure, tones in a background of noise were measured for 4-month-old infants using a conditioned response procedure. The FM tones swept from 150 to 275 Hz or from 150 to 550 Hz. The frequency of the pure tone was either 275 or 550 Hz. The results showed that infants were slightly, but significantly, more sensitive to the sounds that included 550 Hz than they were to the lower frequency sounds, whether or not the sound was frequency modulated. It appears that infants could be somewhat more sensitive to infant-directed than to adult-directed speech, not because of FM per se, but because the fundamental frequency excursions in infant-directed speech extend into a higher frequency range than those in adult-directed speech.

Purpose This article investigates the validity of a smartphone-based audiometry for hearing screening to identify hearing loss in workers exposed to noise. Research Design This is a validation study comparing hearing screening with the hearTest to conventional audiometry. The study population included all workers who attended the Brazilian Social Service of Industry to undergo periodic examinations. Sensitivity, specificity, the Youden index, and positive (PPV) and negative predictive values (NPV) for hearing screening obtained by the hearTest were estimated according to three definitions of hearing loss: any threshold greater than 25 dB hearing level (HL), the mean auditory thresholds for 0.5, 1, 2, and 4 kHz greater than 25 dB HL, and the mean thresholds for 3, 4, and 6 kHz greater than 25 dB HL. Note that 95% confidence intervals were calculated for all measurements. Results A total of 232 workers participated in the study. Hearing screening with the hearTest presented good sensitivity (93.8%), specificity (83.9%), and Youden index (77.7%) values, a NPV (97.2%), and a low PPV (69.0%) for the identification of hearing loss defined as any auditory threshold greater than 25 dB HL. For the other definitions of hearing loss, we observed high specificity, PPV and NPV, as well as low sensitivity and Youden index. Conclusion The hearTest is an accurate hearing screening tool to identify hearing loss in workers exposed to noise, including those with noise-induced hearing loss, although it does not replace conventional audiometry.

Purpose Auditory threshold estimation using the auditory brainstem response or auditory steady state response is limited in some populations (e.g., individuals with auditory neuropathy spectrum disorder [ANSD] or those who have difficulty remaining still during testing and cannot tolerate general anesthetic). However, cortical auditory evoked potentials (CAEPs) can be recorded in many such patients and have been employed in threshold approximation. Thus, we studied CAEP estimates of auditory thresholds in participants with normal hearing, sensorineural hearing loss, and ANSD. Method We recorded CAEPs at varying intensity levels to speech (i.e., /ba/) and tones (i.e., 1 kHz) to estimate auditory thresholds in normal-hearing adults ( n = 10) and children ( n = 10) and case studies of children with sensorineural hearing loss and ANSD. Results Results showed a pattern of CAEP amplitude decrease and latency increase as stimulus intensities declined until waveform components disappeared near auditory threshold levels. Overall, CAEP thresholds were within 10 dB HL of behavioral thresholds for both stimuli. Conclusions The above findings suggest that CAEPs may be clinically useful in estimating auditory threshold in populations for whom such a method does not currently exist. Physiologic threshold estimation in difficult-to-test clinical populations could lead to earlier intervention and improved outcomes.

Animal hearing has long served as a model for understanding human hearing. Yet conversely, animal hearing can only be imagined through human hearing. This chapter shows how, building on techniques for testing human hearing, experimental psychologists in the 1930s and 1940s turned to determining the absolute (upper) frequencies of hearing for various other mammal subjects. Showing the domains of animal auditory perception to be overlapping but rarely congruous with that of humans, these measurements began to lead lives of their own in the subsequent decades. Propelled by various scientific, military, and commercial interests, fascination with the ultrasonic stirred imaginaries of sonic control. The threshold of hearing, this chapter argues, is also a threshold to the imagination, as expressed in the simultaneous success and failure of mundane technologies such as the “Ultrasonic Pied Piper” or the “Bird-E-Vict.”

Background Sensory gating is a measure used to evaluate inhibitory deficits underlying neurological disorders. However, the effects of hearing loss (HL), thought to decrease inhibition, remain unknown on gating function. Purpose The goal of this study was to investigate gating performance in HL. Research Design This was a prospective, cross-sectional study with independent group comparison and correlational design. Study Sample Eleven adults (mean age/standard deviation = 47.546 ± 7.967 years) with normal hearing (NH) and 11 adults (mean age/standard deviation = 56.273 ± 13.871 years) with mild–moderate high-frequency HL. Data Collection and Analysis Cortical auditory evoked potentials (CAEPs) were recorded in response to tonal pairs via high-density electroencephalography. The CAEP response to the second tone in the pair (S2) was compared with the response to the first tone in the pair (S1) within groups. Amplitude gating indices were compared between groups and correlated with auditory behavioral measures. Current density reconstructions were performed to estimate cortical gating generators. Results Amplitude gating indices were decreased and correlated with elevated auditory thresholds. Gating generators in temporal, frontal, and prefrontal regions were localized in the NH group, while HL gating was localized in mainly temporal and parietal areas. Conclusions Reduced inhibition may be associated with compensatory cortical gating networks in HL and should be considered when utilizing gating in clinical populations.

BACKGROUND Several health conditions among professional fishermen have been reported. Among the risks to the health of fishermen, it should be noted that high noise levels cause hearing loss and general health problems. OBJECTIVE to investigate the effects of exposure to occupational noise on hearing in professional fishermen at the main large-scale commercial fishing center in Brazil. METHODS A cross-sectional study, 466 Brazilian commercial fishermen participated in the study, all males, ages range 18-67 years. A total of 15 vessels were included in the study. The first phase involved assessment of the sound pressure levels (SPLs) in the vessels, the second phase involved the use of a questionnaire and audiological assessment. RESULTS Most compartments registered SPLs greater than 80 dBA and the noisiest compartment was the engine-room, where the vessel pilot works. Among the fishermen, tinnitus was the most commonly reported symptom (48.63%). A higher prevalence of hearing loss was observed in engine-room keepers. Longer the length of time in service, and consequently, exposure to noise (in years), were associated with higher auditory thresholds. CONCLUSION the tolerance limits to noise exposure were exceeded according to legislation. Fishing activities are associated with noise-induced hearing loss, with the risk increasing with the length of service.

Background Auditory evoked potentials (AEPS) constitutes the most commonly used neurophysiological test to assess the functional development of the auditory brainstem in infants and allows the evaluation of hearing for high frequencies. Methods An observational, descriptive, cross-sectional and retrospective study was conducted. The AEPS results for 186 infants (372 ears) with a history of prematurity were examined. The bioelectrical response, morphology, amplitude, latencies I, III and V, and intervals I-III, III-V and I-V were compared, as well as auditory thresholds between two groups of premature infants Results The bioelectrical response, latencies I, III and V, and intervals I-III and III-V were similar between the two groups of premature infants according to their corrected age; no statistically significant differences were found (p > 0.05) for these variables. The amplitude, morphology, and the I-V interval were more affected in the group of premature infants Conclusions The functional development of the auditory brainstem was similar between the groups of premature infants and within the normal range for the respective corrected age. Prematurity produced a directly proportional and statistically significant increase in the frequency of hearing loss for high frequencies.

Background: Auditory steady-state response (ASSR) is a test for the estimation of auditory thresholds. It is used in infants, children, and adults. This case report presented unusual ASSR results in an elderly person. The Case: Pure tone and speech audiometry, tympanometry and acoustic reflexes showed a moderate sensorineural hearing loss in both ears. However, the patient did not respond in the ASSR test to different carrier frequencies with frequency modulations of 40 and 80 Hz. Conclusion: To date, the results of the different effects of the aging process obtained from ASSR responses have been reported. However, the absence of any response in the ASSR test has never been reported. The patient in this case report may have these results because of a neural deficit. Keywords: Sensorineural hearing loss; aging; auditory steady-state response

We aimed to evaluate whether electrophysiological auditory thresholds (EATs) before 3 month of age, as assessed by the auditory brainstem responses (ABR) test and the auditory steady state responses (ASSR) test, can predict hearing outcome at 3 years of age among children born with congenital cytomegalovirus (cCMV) infection. Audiological assessment was performed before 3 months of age, and every 6 months thereafter until 3 years of age, in a population of 63 children (126 ears). EATs before 3 months of age and at 3 years of age were compared. No ear with an EAT of ≤30 dBHL (i.e. normal hearing) before 3 months of age showed worsening EATs at 3 years of age. An EAT of ≤30 dBHL obtained by ABR and ASSR tests before 3 months of age is predictive of a normal hearing at 3 years of age in children born with cCMV.

Purpose: to describe the audiological profile of professional disc jockeys acting in cities of the Brazilian Federal District. Methods: audiometry, tympanometry, transient evoked emissions, and distortion product evoked emissions exams were conducted, as well as interviews, in order to identify auditory symptoms. Appropriate statistical tests were applied, adopting a significance level lower than 0.05. Results: a total of 21 disc jockeys, aged between 20 and 45 years, were evaluated. The most cited auditory complaints were feeling of ear fullness (86%) and tinnitus (57%). Auditory thresholds remained predominantly within normal range (90%), but thresholds were increased in frequencies from 3 KHz to 6 KHz (38%). Only 42% of the sample presented a pass response in transient evoked emissions, and 81% in distortion product evoked emissions, in both ears. Conclusion: the research identified auditory thresholds predominantly within standards of normality, though with increased high frequencies, that may be associated with noise exposure. The otoacoustic emissions presented alterations both in the transient ones and in the distortion product. RESUMO Objetivo: descrever o perfil audiológico de profissionais disc jockeys atuantes em cidades do Distrito Federal. Métodos: foram realizados os exames de audiometria, timpanometria, emissões evocadas por estímulo transiente e emissões evocadas - produto de distorção, e entrevista para identificar sintomas auditivos. Foram aplicados os testes estatísticos pertinentes adotando o nível de significância menor que 0,05. Resultados: foram avaliados 21 disc jockeys com faixa etária entre 20 e 45 anos. As queixas auditivas mais citadas foram sensação de plenitude auricular (86%) e zumbido (57%). Os limiares auditivos mantiveram-se predominantemente dentro da normalidade (90%), mas houve aumento dos limiares nas frequências de 3.000 a 6.000 Hz (38%). Apenas 42% da amostra apresentaram resposta “passa” nas emissões evocadas por estímulo transiente e 81% nas emissões evocadas - produto de distorção em ambas as orelhas. Conclusão: a pesquisa identificou limiares auditivos predominantemente dentro dos padrões de normalidade, entretanto com aumento das frequências altas, que podem estar associadas à exposição ao ruído. As emissões otoacústicas apresentaram alterações tanto nas transientes quanto nas por produto de distorção.

Naked mole-rats are extremely social and extremely vocal rodents, displaying a wide range of functionally distinct call types and vocalizing almost continuously. Their vocalizations are low frequency, and a behavioral audiogram has shown that naked mole-rats, like other subterranean mammals, hear only low frequencies. Hence, the frequency range of their hearing and vocalizations appears to be well matched. However, even at low frequencies, naked mole-rats show very poor auditory thresholds, suggesting vocal communication may be effective only over short distances. However, in a tunnel environment where low frequency sounds propagate well and background noise is low, it may be that vocalizations travel considerable distances at suprathreshold intensities. Here, we confirmed hearing sensitivity using the auditory brainstem response; we characterized signature and alarm calls in intensity and frequency domains and we measured the effects of propagation through tubes with the diameter of naked mole-rat tunnels. Signature calls-used for intimate communication-could travel 3-8 m at suprathreshold intensities, and alarm calls (lower frequency and higher intensity), could travel up to 15 m. Despite this species' poor hearing sensitivity, the naked mole-rat displays a functional, coupled auditory-vocal communication system-a hallmark principle of acoustic communication systems across taxa.

OBJECTIVE. Inventing of the system of auditory brainstem implantation. MATERIAL AND METHODS. 3 patients were chosen for study: 2 adults with neurofibromatosis of type II and a 2 years old child with bilateral cochlea aplasia. RESULTS. In the end of the first rehabilitation, the auditory thresholds accounted 45–50 dB. In 2 years after surgery, the adults differentiate words from the closed set. Passive vocabulary of the child amounted for 200 words. Speech intelligibility was 30–70 % in these patients. CONCLUSION. Wearing of auditory processor for five months led to significant dynamics.

This study was performed to assess whether there is an association between elevated Fasting Blood Glucose (FBG) and hearing impairment in Bangladeshi population. A total of 142 subjects (72 with elevated FBG; 70 control) were included in the study. The mean auditory thresholds of the control subjects at 1, 4, 8 and 12 kHz frequencies were 6.35 ± 0.35, 10.07 ± 0.91, 27.57 ± 1.82, 51.28 ± 3.01 dB SPL (decibel sound pressure level), respectively and that of the subjects with elevated FBG were 8.33 ± 0.66, 14.37 ± 1.14, 38.96 ± 2.23, and 71.11 ± 2.96 dB, respectively. The auditory thresholds of the subjects with elevated FBG were significantly (p 10 years) showed significantly (p 40 years) and younger (≤40 years) age groups compared to the respective controls. The binary logistic regression analysis showed a 5.79-fold increase in the odds of extra-high frequency hearing impairment in diabetic subjects after adjustment for age, gender and BMI. This study provides conclusive evidence that auditory threshold at an extra-high frequency could be a sensitive marker for hearing impairment in diabetic subjects.

Military operations often require Service Members (SMs) to make life-and-death decisions based on information they can only obtain auditorily. However, the wide variety of critical sounds, essential spoken messages, and masking environments encountered while performing military missions makes it difficult to use clinical tests to predict the operational performance of hearing-impaired SMs. In this study, ≈2400 SMs performed listening tasks derived from binaural recordings made during realistic battlefield exercises at the US Army Joint Readiness Training Center. The listening tasks included standardized speech recognition tasks based on the Oldenburg Matrix Test and Modified Rhyme Test (MRT), as well as scenario-based multiple-choice tasks where questions were asked about unmodified verbal exchanges that occurred between SMs engaged in the battlefield simulation. The scores SMs achieved on these operational tasks were then compared to their hearing thresholds and to their scores on the MRT80. The results show that an auditory fitness-for-duty standard that requires individuals with thresholds that exceed the values defined in the new US Army H3 Profile to obtain a minimum score on the MRT80 is generally able to identify individuals who are most at risk of performing abnormally poorly on militarily relevant listening tasks. [The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of the Army, Department of Defense, or U.S. Government.]

Perinatal hypothyroidism causes serious damage to auditory functions that are essential for vocalization development. In rat pups, perinatal hypothyroidism potentially affects the development of ultrasonic vocalization (USV) as a result of hearing deficits. This study examined the effect of perinatal hypothyroidism on the development of USVs in rat pups. Twelve pregnant rats were divided into three groups and treated with the anti-thyroid drug methimazole (MMI) via drinking water, from gestational day 15 to postnatal day (PND) 21. The MMI concentration (w/v) was 0% (control group), 0.01% (low-dose group), or 0.015% (high-dose group). After birth, the pups were individually separated from the dam and littermates on PNDs 5, 10, 15, and 20, and their USVs were recorded for 5 min. On PNDs 5 and 10, compared with the control group, the low- and high-dose groups exhibited reductions of both frequency modulated and downward USVs. On PND 15, however, the low- and high-dose groups displayed increases in number, duration, and amplitude of USVs compared with those in the control group. Lower body weights were observed for the low- and high-dose groups than for the control group. Total thyroxine concentrations in plasma were dose-dependently reduced. The onset of auditory functions appeared on PNDs 11-14. Thus, the rat pups were unable to hear externally produced USVs before PND 11. USVs emitted on PNDs 5 and 10 might have been spontaneous and independent of the pups' own or littermate-emitted USVs. The developmental retardation of vocalization-related organs or muscles might underlie the acoustic alterations of USVs on PNDs 5 and 10. The greater number, duration, and amplitude of USVs on PND 15, after which the hearing onset occurred, suggested that the elevation of auditory thresholds occurred as a result of hearing deficits in the low- and high-dose groups. Perinatal hypothyroidism appears to have caused acoustic alterations in the USV development. (C) 2016 Elsevier B.V. All rights reserved.

As of yet there is no literature record of the hearing range of the Eurasian otter (Lutra lutra, L. 1758), a key species for natural conservation efforts in Europe. We recorded in-air pure tone hearing thresholds of anaesthetized otters using auditory brainstem responses (ABR) and report the results of the Eurasian otter. The recorded potentials showed the typical mammalian auditory brainstem response consisting of 5 distinct positive peaks during the first 10 ms after stimulus onset. At 80 dB SPL the hearing ranged from around 200 Hz to 32 kHz, with lowest thresholds around 4 kHz.

Introduction. Exposure to high intensity noise produced by MRI is a cause for concern. This study was conducted to determine the temporary and permanent effects of exposure to noise created by performing MRI on the hearing threshold of the subjects using conventional and extended high frequency audiometry. Methods. This semiexperimental study was performed on 35 patients referred to Shahid Rahnemoun Hospital for head and neck MRI due to different clinical conditions. The hearing threshold of patients was measured before, immediately after, and 24 hours after performing 1.5 Tesla MRI using conventional and extended high frequency audiometry. SPSS version 18 was used to compare the mean hearing thresholds before and after MRI using paired T test and repeated measures analysis. Results. Comparison of auditory thresholds in conventional and extended high frequencies before and immediately after MRI showed a significant shift at 4 KHz (P = 0.008 and P = 0.08 for right and left ears), 6 KHz (P = 0.03 and P = 0.01 for right and left ears), and 14 KHz (P =0.03 and P = 0.31 for right and left ears). However, there was no significant difference between audiometric thresholds before and 24 hours after MRI. Conclusion. Noise due to 1.5 Tesla MRI can only cause transient threshold shift.

Objective: To verify auditory thresholds at conventional and high frequencies and the presence of distortion product otoacoustic emissions in sickle cell patients, analyzing the age group variable. Method: Observational, prospective, analytical cohort for diagnostic purposes. Conventional audiometry, high frequency audiometry and distortion product otoacoustic emissions were performed in patients with the disease. Results: 38 patients were evaluated, 16 (42.1%) in the age group from 7 to 20 years old and 22 (57.9%), from 21 to 35 years old. Hearing impairment in conventional audiometry was 6.3% in the age group of 7 to 20 years and 13, 6%, between 21 and 35 years. There was no statistically significant difference between the age groups (p = 0.624). In high frequency audiometry, changes in 25% of children and adolescents and in 68.2% of adults. Adults had greater hearing loss (p = 0.021). There was no significant difference when comparing the distortion product otoacoustic emissions signal / noise ratio measurements between the ears, both in the total sample and by age group (p> 0.05). There was no significant association between the results of the distortion product otoacoustic emissions changes and hearing loss at ultra-high frequencies both in children and adolescents (p = 0.250) and in adults (p = 0.121). When comparing the sensitivity of the high frequency audiometry and distortion product otoacoustic emissions exams, there was a significant difference between them only in adults (p = 0.004). Conclusions: Adults with a longer duration of exposure to the disease showed increased thresholds in high frequency audiometry, as well as changes in distortion product otoacoustic emissions.

Dietary carotenoids lutein (L) and zeaxanthin (Z) have been linked to improved visual and cognitive function. These effects are thought to be mediated by the presence of these pigments in critical regions of the retina and brain. There, it has been postulated that L and Z mediate improved performance by enhancing neural efficiency. The auditory system also relies on efficient segregating of signals and noise and LZ are also found in the auditory cortex. The purpose of the present study was to investigate the influence of LZ status (as assessed by the measuring levels in retina) on auditory thresholds in young non-smokers (N = 32, M = 20.72 ± 3.28 years).LZ status was determined by measuring macular pigment (MP) optical density using a standardized psychophysical technique (customized heterochromatic flicker photometry). Auditory thresholds were assessed with puretone thresholds and puretone auditory thresholds in white noise.MP density was related to many, but not all, of the puretone thresholds we tested: 250 Hz (F(6,32) = 4.36, P 0.01), 500 Hz (F(6,32) = 2.25, P 0.05), 1000 Hz (F(6,32) = 3.22, P 0.05), and 6000 Hz (F(6,32) = 2.56, P 0.05).The overall pattern of results is consistent with a role for L and Z in maintaining optimal auditory function.

Background: The aim of the present study was to compare the hearing thresholds between pure tone audiometry (PTA) and auditory brainstem response (ABR) from level-specific (LS) CE-Chirp® and click stimuli in normal adult subjects. Materials and Methods: Twenty-four adults with normal audiometric thresholds participated in the study. The ABR was recorded from the study participants at 80 dBnHL until their respective auditory thresholds using both the LS CE-Chirp® and click stimuli. Study Design and Statistical Analysis: A quasi-experimental study design was used. Audiometric thresholds (low frequencies [LFs], mid frequencies [MFs], and high frequencies [HFs]) and the ABR thresholds from both stimuli were compared using the Friedman test with Wilcoxon signed-rank test as the post hoc analysis. Results: No statistically significant difference was identified between the PTA and the ABR to LS CE-Chirp® thresholds at LFs and only small differences (

The plainfin midshipman fish (Porichthys notatus) is a species of marine teleost that produces acoustic signals that are important for mediating social behavior. The auditory sensitivity of the saccule is well established in this species, but the sensitivity and function of the midshipman’s putative auditory lagena are unknown. Here, we characterize the auditory-evoked potentials from hair cells in the lagena of reproductive type I males to determine the frequency response and auditory sensitivity of the lagena to behaviorally relevant acoustic stimuli. Lagenar potentials were recorded from the caudal and medial region of the lagena, while acoustic stimuli were presented by an underwater speaker. Our results indicate that the midshipman lagena has a similar low-frequency sensitivity to that of the midshipman saccule based on sound pressure and acceleration (re: 1 µPa and 1 ms(−2), respectively), but the thresholds of the lagena were higher across all frequencies tested. The relatively high auditory thresholds of the lagena may be important for encoding high levels of behaviorally relevant acoustic stimuli when close to a sound source.

Vocalizations play a critical role in mate recognition and mate choice in a number of taxa, especially, but not limited to, orthopterans, frogs, and birds. But receivers can only recognize and prefer sounds that they can hear. Thus a fundamental question linking neurobiology and sexual selection asks—what is the threshold for detecting acoustic sexual displays? In this study, we use 3 methods to assess such thresholds in túngara frogs: behavioral responses, auditory brainstem responses, and multiunit electrophysiological recordings from the midbrain. We show that thresholds are lowest for multiunit recordings (ca. 45 dB SPL), and then for behavioral responses (ca. 61 dB SPL), with auditory brainstem responses exhibiting the highest thresholds (ca. 71 dB SPL). We discuss why these estimates differ and why, as with other studies, it is unlikely that they should be the same. Although all of these studies estimate thresholds they are not measuring the same thresholds; behavioral thresholds are based on signal salience whereas the 2 neural assays estimate physiological thresholds. All 3 estimates, however, make it clear that to have an appreciation for detection and salience of acoustic signals we must listen to those signals through the ears of the receivers.

Background and objectives Numerous studies have indicated deterioration of speech perception in noisy conditions among the elderly even those with normal hearing capabilities. The aim of this study was to investigate the effects of age on the speech-in-noise identification by speech-in-noise (SIN) test, subjective ratings of hearing difficulties by speech, spatial, and qualities of hearing scale (SSQ) questionnaire and encoding of fundamental frequency (F0) by Speech auditory brainstem response (ABR) in the elderly and comparing the results with young people. Subjects and methods The present study was conducted on 32 elderly people aged over 60 years old (17 male and 15 female) with the mean age of 68.9 (standard deviation=6.33) possessing normal peripheral hearing and 32 young subjects (16 male and 16 female) aged 18-25 years old. Results Findings showed that the score of SIN test is lower among the elderly people as compared with young people in signal-to-noise ratios of 0 and -10 based on Iranian version of SSQ questionnaire (pl0.001). The range of F0 amplitude in the elderly people is also lower than young people (pl0.001) in Speech ABR. Conclusions It seems that speech processing in older people is deteriorated comparing with young people regardless of their normal peripheral auditory thresholds. This decrease will result in weaker perception and improper segregation of speech from other competing sources.

The clinical uses of electrocochleography are reviewed with some technical notes on the apparatus needed to get clear recordings under different conditions. Electrocochleography can be used to estimate auditory thresholds in difficult to test children and a golf club electrode is described. The same electrode can be used to obtain electrical auditory brainstem responses (EABR). Diagnostic testing in the clinic can be performed with a transtympanic needle electrode, and a suitable disposable monopolar electrode is described. The use of tone bursts rather than click stimuli gives a better means of diagnosis of the presence of endolymphatic hydrops. Electrocochleography can be used to monitor the cochlear function during surgery and a long coaxial cable, which can be sterilized, is needed to avoid electrical artifacts. Recently electrocochleography has been used to monitor cochlear implant insertion and to record residual hearing using an electrode on the cochlear implant array as the non-inverting (active) electrode.

We used a cross-modal dual task to examine how changing visual-task demands influenced auditory processing, namely auditory thresholds for amplitude- and frequency-modulated sounds. Observers had to attend to two consecutive intervals of sounds and report which interval contained the auditory stimulus that was modulated in amplitude (Experiment 1) or frequency (Experiment 2). During auditory-stimulus presentation, observers simultaneously attended to a rapid sequential visual presentation-two consecutive intervals of streams of visual letters-and had to report which interval contained a particular color (low load, demanding less attentional resources) or, in separate blocks of trials, which interval contained more of a target letter (high load, demanding more attentional resources). We hypothesized that if attention is a shared resource across vision and audition, an easier visual task should free up more attentional resources for auditory processing on an unrelated task, hence improving auditory thresholds. Auditory detection thresholds were lower-that is, auditory sensitivity was improved-for both amplitude- and frequency-modulated sounds when observers engaged in a less demanding (compared to a more demanding) visual task. In accord with previous work, our findings suggest that visual-task demands can influence the processing of auditory information on an unrelated concurrent task, providing support for shared attentional resources. More importantly, our results suggest that attending to information in a different modality, cross-modal attention, can influence basic auditory contrast sensitivity functions, highlighting potential similarities between basic mechanisms for visual and auditory attention.

OBJECTIVES Pure-tone auditory thresholds in children are below the standardized hearing threshold levels described by ). The development of hearing ability in Chinese and German children at different ages is analyzed and compared with data in the literature. Extended high frequencies above 8 kHz are included due to their vulnerability to noise. DESIGN Ninety-one children in China and 197 children at a typical primary school in Germany underwent audiometric tests at 17 frequencies ranging from 125 Hz to 16 kHz. To analyze effects of age the children were assessed in age groups of 6 to 9, 9 to 12, and 13 to 16 years of age. RESULTS Children in China and Germany have the poorest hearing sensitivity at low frequencies (below 1 kHz) and the best sensitivity at the extended high frequencies above 8 kHz. The mean deviations (both ears) from the standard thresholds for adults 18 to 25 years of age, averaged over all frequencies, are 6.7 dB for Chinese and 7.1 dB for German children in the youngest age groups. In the Chinese age group of 9- to 12-year olds the averaged threshold is 4.5 dB and for the same German age group 3.6 dB. For the Chinese age group of 13- to 16-year olds the averaged threshold is 3.3 dB. The improvements of the older German age group compared with the younger are significant at p < 0.05 and are nearly twice as high compared with the comparable Chinese age groups. CONCLUSIONS Age-dependent improvements of hearing ability are evident in children and should be considered in evaluating audiometric test results. Audiometric tests in the extended high-frequency range could be used as an early warning system for future degeneration of hearing ability.

While hearing is the primary sensory modality for odontocetes, there are few data addressing variation within a natural population. This work describes the hearing ranges (4–150 kHz) and sensitivities of seven apparently healthy, wild beluga whales (Delphinapterus leucas) during a population health assessment project that captured and released belugas in Bristol Bay, Alaska. The baseline hearing abilities and subsequent variations were addressed. Hearing was measured using auditory evoked potentials (AEPs). All audiograms showed a typical cetacean U-shape; substantial variation (>30 dB) was found between most and least sensitive thresholds. All animals heard well, up to at least 128 kHz. Two heard up to 150 kHz. Lowest auditory thresholds (35–45 dB) were identified in the range 45–80 kHz. Greatest differences in hearing abilities occurred at both the high end of the auditory range and at frequencies of maximum sensitivity. In general, wild beluga hearing was quite sensitive. Hearing abilities were similar to those of belugas measured in zoological settings, reinforcing the comparative importance of both settings. The relative degree of variability across the wild belugas suggests that audiograms from multiple individuals are needed to properly describe the maximum sensitivity and population variance for odontocetes. Hearing measures were easily incorporated into field-based settings. This detailed examination of hearing abilities in wild Bristol Bay belugas provides a basis for a better understanding of the potential impact of anthropogenic noise on a noise-sensitive species. Such information may help design noise-limiting mitigation measures that could be applied to areas heavily influenced and inhabited by endangered belugas.

Tinnitus is often related to auditory dysfunction. We hypothesised that, among individuals with normal auditory thresholds, the mechanism of frequency selectivity might differ between subjects with and without tinnitus. Our objective was to identify any differences between normal-hearing individuals with tinnitus and those without in terms of psychophysical tuning curves (PTCs) and threshold-equalising noise (TEN) test results. Design: We determined PTCs and performed the TEN test. Study sample: We evaluated 57 individuals, 16 with bilateral tinnitus (tinnitus-group) and 41 without tinnitus (control-group). Results: We found signifi cant differences between tinnitus and control groups regarding the following: 2 kHz PTCs obtained in noise at 6 and 8 kHz; 4 kHz PTCs obtained in noise at 2 and 8 kHz; and 6 and 8 kHz PTCs obtained in noise at 2 and 3 kHz. The TEN test revealed differences between groups in terms of auditory thresholds, which were signifi cantly higher in the tinnitus group. In addition, none of the individuals in the tinnitus group were found to have dead regions in the cochlea. Conclusions: Despite having normal auditory thresholds, individuals with tinnitus have auditory patterns that differ signifi cantly from those seen in individuals without tinnitus, such differences being suggestive of cochlear impairment.

Summary Introduction: Chronic otitis media (COM) is an inflammatory condition associated with otorrhea as well as large and persistent perforations of the tympanic membrane in some cases. COM can also lead to cholesteatoma. Surgical treatment with canal wall-down and canal wall-up tympanomastoidectomy is considered for both types of illness. The choice of technique is controversial and is dependent on several factors, including the extent of disease. Objective: We aimed to evaluate surgical outcomes in COM patients with and without cholesteatoma treated with canal wall-down and canal wall-up tympanomastoidectomy. Disease eradication and post-operative auditory thresholds were assessed. Method: Patient records from the otorhinolaryngology department of a tertiary hospital were assessed retrospectively. Results: Patients who underwent canal wall-up tympanomastoidectomy had a higher rate of revision surgery, especially those with cholesteatoma. However, there were no statistically significant differences in post-operative hearing thresholds between the two techniques. Conclusion: The canal wall-down technique is superior to the canal wall-up technique, especially for patients with cholesteatoma.

BACKGROUND: Noise pollution in urban cities is a serious problem and steadily increasing over the years. Literature states that the noise pollution has negative effect on the child's intellectual ability. So the present study was undertaken to find the effect of noise pollution on the auditory thresholds of school children using pure tone audiometer so that appropriate preventive measures can be undertaken in the initial stages. OBJECTIVES: 1. To make pure tone audiometric assessment of auditory acuity in school children situated in a noise polluted area. 2. To make pure tone audiometric assessment of auditory acuity in school children situated in a less noisy area. 3. To compare these two groups to find out the effect of noise pollution on auditory thresholds.

It is not clear how audio-visual temporal perception develops in children with restored hearing. In this study we measured temporal discrimination thresholds with an audio-visual temporal bisection task in 9 deaf children with restored audition, and 22 typically hearing children. In typically hearing children, audition was more precise than vision, with no gain in multisensory conditions (as previously reported in Gori et al. (2012b)). However, deaf children with restored audition showed similar thresholds for audio and visual thresholds and some evidence of gain in audio-visual temporal multisensory conditions. Interestingly, we found a strong correlation between auditory weighting of multisensory signals and quality of language: patients who gave more weight to audition had better language skills. Similarly, auditory thresholds for the temporal bisection task were also a good predictor of language skills. This result supports the idea that the temporal auditory processing is associated with language development.

Auditory thresholds were measured in three bottlenose dolphins before and after exposure to ten impulses from a seismic air gun. Thresholds were measured using behavioral and electrophysiological methods to determine the amount of temporary threshold shift induced. The results suggest that the potential for seismic surveys using air guns to cause auditory effects on dolphins may be lower than previously predicted; however, two of the three dolphins exhibited "anticipatory" behavioral changes at the highest exposure condition that suggested they were attempting to mitigate the effects of the exposures.

RESUMO Objetivo Analisar o impacto da exposição à música na audição e na qualidade de vida de músicos de uma orquestra sinfônica brasileira. Métodos Trata-se de um estudo quantitativo transversal, descritivo, sobre os aspectos da saúde auditiva de 30 músicos da orquestra sinfônica do Paraná, com idade entre 33 e 54 anos. Foram medidos os níveis de pressão sonora a que os músicos estão expostos durante um ensaio da orquestra e os participantes responderam a um questionário sobre a prática musical e o questionário SF-36, que investiga a qualidade de vida. Foi realizada audiometria convencional e de altas frequências. Resultados Durante o ensaio da orquestra, foram observados níveis de pressão sonora que colocam a audição dos músicos em risco. Os sintomas auditivos mais relatados foram zumbido e intolerância a sons intensos. Na audiometria convencional, mais da metade dos músicos apresentou perda auditiva neurossensorial, com piores resultados nas frequências mais altas. Na audiometria de altas frequências, também foram encontrados limiares auditivos mais elevados nas frequências mais altas. Quanto à qualidade de vida, houve correlação significativa para os músicos com perda auditiva no domínio “limitação por aspectos emocionais”. Conclusão Os níveis de pressão sonora a que os músicos estão expostos são excessivos, colocando em risco a sua audição. A perda auditiva, juntamente com outros sintomas auditivos, pode interferir na qualidade de vida, uma vez que a audição é fundamental para essa categoria profissional. ABSTRACT Purpose To analyze the impact of exposure to music in the hearing process and quality of life in musicians of a symphony orchestra. Methods This is a descriptive, cross-cut, quantitative study on the aspects of hearing health in 30 musicians of the symphony orchestra of Paraná, ages between 33 and 54 years. The sound pressure levels that musicians are exposed to were measured during the orchestra rehearsal, and participants answered a questionnaire about the musical practice as well as the SF-36 questionnaire, which investigates the quality of life. Conventional audiometry and high-frequency audiometry were applied. Results During the orchestra rehearsal, hazardous sound pressure levels to musicians’ hearing health were observed. The commonest symptoms reported were tinnitus and intolerance to intense sounds. In the conventional audiometry test, more than half of the musicians featured sensorineural hearing loss, and the worst results were found in high frequencies. In the high -frequency audiometry test, higher auditory thresholds were also found in higher frequencies. As for quality of life, there was significant correlation for musicians with hearing loss in the domain “limitation due to emotional aspects”. Conclusion the sound pressure levels that musicians are exposed to are excessive and represent a risk to hearing health. Hearing loss and other auditory symptoms can interfere in their quality of life, once hearing is essential to this professional category.

Summary Introduction: With the technological advances and the changes in the productive processes, the workers are displayed the different physical and chemical agents in its labor environment. The toluene is solvent an organic gift in glues, inks, oils, amongst others. Objective: To compare solvent the literary findings that evidence that diligent displayed simultaneously the noise and they have greater probability to develop an auditory loss of peripheral origin. Method: Revision of literature regarding the occupational auditory loss in displayed workers the noise and toluene. Results: The isolated exposition to the toluene also can unchain an alteration of the auditory thresholds. These audiometric findings, for ototoxicity the exposition to the toluene, present similar audiograms to the one for exposition to the noise, what it becomes difficult to differentiate a audiometric result of agreed exposition - noise and toluene - and exposition only to the noise. Conclusion: The majority of the studies was projected to generate hypotheses and would have to be considered as preliminary steps of an additional research. Until today the agents in the environment of work and its effect they have been studied in isolated way and the limits of tolerance of these, do not consider the agreed expositions. Considering that the workers are displayed the multiples agent and that the auditory loss is irreversible, the implemented tests must be more complete and all the workers must be part of the program of auditory prevention exactly displayed the low doses of the recommended limit of exposition.

INTRODUCTION: One of the problems observed in pure-tone audiometry tonal has been the variation in test results of a same individual, particularly at frequencies of 4 kHz, 6 kHz and/or 8 kHz. Improper placement of headphones is one of the factors that can cause alterations in results. OBJECTIVE: To compare differences in auditory thresholds using earphones positioned by the examiner and by the worker. METHODS: Clinical and experimental study conducted in 2009, with 324 workers aged between 19 and 61 years, with a mean of 33.29 years and mean exposure time of 7.67 years. All subjects were familiar with audiometry procedures. Auditory thresholds were obtained at frequencies of 0.25-8 kHz, with earphones positioned by the examiners, and at frequencies of 4, 6 and 8 kHz, with earphones placed by workers in a comfortable position, following the examiner's instructions. The thresholds obtained in these two situations were compared. RESULTS: The three frequencies exhibited better responses with earphones placed by the workers themselves (p < 0.001). At a frequency of 8 kHz a greater difference was found (p < 0.001), with a mean of 13.89 dB and standard deviation of 6.07 dB. CONCLUSION: Earphone placement by the workers themselves under supervision of the examiner results in improved mean auditory thresholds at frequencies of 4, 6 and 8 kHz, the last one significantly higher than the other two.

Objectives: Multiple auditory steady state responses (ASSRs) will likely be included in the diagnostic test battery for estimating infant auditory thresholds in the near future; however, the effects of single- versus multiple-stimulus presentation in infants has never been investigated. In adults, there are no interactions (reduced amplitudes) between responses to multiple simultaneous stimuli presented at 60 dB SPL or lower. Maturational differences, however, may lead to greater interactions in infants; thus, it is unknown whether the single-stimulus technique or the multiple-stimulus technique is more efficient for testing infants. Two studies were carried out to address this issue. Design: All infants in study A participated in three stimulus conditions, which differed in the number of stimuli presented simultaneously. The monotic single (MS) condition consisted of 500, 1000, 2000, and 4000 Hz tones, which were presented singly to one ear. The monotic multiple (MM) condition was composed of four tones (500, 1000, 2000, and 4000 Hz) presented to one ear simultaneously. The dichotic multiple (DM) condition consisted of eight tones presented simultaneously to both ears (four tones to each ear). ASSR amplitudes were obtained from 15 normal infants (mean age: 23.1 wks) in response to multiple (MM, DM) and single (MS) air conduction amplitude-modulated (AM) tones (77 to 105 Hz modulation rates; 60 dB SPL). In study B, ASSR thresholds were determined for 500-Hz stimuli in the single- and DM-stimulus conditions (14 infants; mean age: 20.2 wks). Results: Mean single-stimulus ASSR amplitudes for 500, 1000, 2000, and 4000 Hz were 30, 39, 45 and 43 nV, respectively. Presentation of multiple AM tones (i.e., four octave-spaced frequencies) to one ear resulted in ASSR amplitudes that were 97%, 87%, 82%, and 70% (for 500, 1000, 2000, and 4000 Hz, respectively) of the single-stimulus ASSR amplitudes. Results for the dichotic presentation of eight AM tones show ASSR amplitudes that were 70%, 77%, 67%, and 67% relative to the MS condition. Although decreases in amplitude occurred using multiple stimuli in infants, the multiple ASSR remained more efficient than the single-stimulus ASSR (i.e., multiple-stimulus amplitudes were greater than single-stimulus amplitudes divided by √K, where K is the number of stimuli). Results from study B indicate that ASSR thresholds for 500 Hz presented in the DM condition were elevated 3 dB compared with that obtained in the 500-Hz single-stimulus condition. This statistically nonsignificant difference is within the range of acceptable test-retest variability and is thus not of clinical significance. Conclusions: The amplitude reductions seen in the multiple-stimulus conditions in infants, not seen in adults, could be related to maturational differences in the ear canal, middle ear, cochlea, and/or brain stem. Because greater interactions occur in the DM-stimulus condition compared with the monotic multiple-stimulus condition and baseline single-stimulus condition, brain stem origins of these interactions are likely. Study B revealed statistically nonsignificant differences between threshold for 500 Hz when presented in the single- and DM-stimulus conditions. In summary, as with adults, multiple-stimulus presentation in infants is more efficient than single AM tones, at least for 60 dB SPL stimuli.

Conclusion: The findings from this study extend the use of the local application of D-methionine (D-met) to protect against acoustic trauma and demonstrate that D-met slowly diffuses from the perilymph. Objectives: The objectives of the study were to determine the effect of D-met on auditory function and morphology after acoustic trauma and to measure the concentration of D-met in perilymph. Methods: Auditory thresholds were determine before, immediately after, and 24 h after acoustic trauma. Cochleae were analyzed using immunocytochemistry for c-Fos, TUJI, and cytochrome c. The concentration of D-met was determined from perilymph. Results: Protection against acoustic trauma (immediately and 24 h post trauma) on auditory brainstem thresholds was found at a time when the concentration of D-met in perilymph showed a fivefold increase above basal levels. The local application of D-met to the guinea pig cochlea results in elevated D-met concentrations that are maintained in the perilymph for at least...

Introduction The techniques most frequently used within a screening context (otoacoustic emissions and click auditory brainstem response) have well-known limitations in hearing loss detection. Objective This study examines the feasibility of a semi-automated multiple auditory steadystate responses (MSSR) system designed for neonatal hearing screening. Methods A sample of 50 newborns without risk factors (well-babies) was tested within two weeks of birth. All had detectable auditory brainstem responses to clicks down to 40 dB nHL in both ears. Two amplitude modulated carrier tones of 500 and 2,000 Hz were mixed together and presented simultaneously. Each infant (and ear) was screened with the MSSR system; to simulate a hearing loss, a recording without stimulation was also obtained. Results Mean auditory thresholds were 42.5 ± 7 dB HL at 500 Hz and 35.5±6 dB HL at 2,000 Hz. The average duration of the MSSR recording was 2.6±1.6 minutes for each tested ear and the overall duration of the screening procedure (including electrode fitting and infant preparation) was 17.8±3.7 minutes. The diagnostic sensibility and the positive predictive values of the MSSR semi-automatic screening system was 100% and 96% respectively, with specificity of 96% and negative predictive values of 100%. Conclusions Although the diagnostic efficiency of the semi-automated MSSR system was found adequate, further technological improvements are still necessary to facilitate its use in the context of universal newborn hearing screening program.

Objectives: According to classic theories, auditory stimulation, whether air- or bone-conducted, has been thought to begin with sound-induced relative motion between the cochlear shell and the stapes footplate, producing a passive mechanical traveling wave along the basilar membrane. This study was designed to assess the effect of experimental mechanical manipulations of the cochlea on the auditory thresholds to air-conducted and bone-conducted stimulation. Methods: The left ear of Psammomys obesus (highest auditory sensitivity between 0.5 and 5.0 kHz) was initially ablated in all animals studied. After baseline recording of auditory nerve–brain stem evoked response (ABR) thresholds to air- and bone-conducted broadband click stimulation from the right ear, a hole was drilled in the vestibule of that ear in 3 animals. In 2 other animals, the round window of the animals was immobilized. In 3 additional animals, the round window was widely perforated. Repeat ABR thresholds were then determined. Results: There was no change in ABR thresholds to both air- and bone-conducted stimulation following these manipulations. The ABR wave latency also did not change. Conclusions: It is likely that an alternative mode of cochlear excitation is possible.

Objectives: We examined the relations between blood cadmium and lead exposure and hearing impairments in the Iraqi people.Methods: We analyzed data from 51 individual 13–75 ages who had been randomly dispensed to the audiometry examination center at Al-Hilla Teaching Hospital (Babel) for each Iraqi civilian who said, “I suffering from the hearing problem.” Pure-tone average (PTA) of auditory thresholds at frequencies of 0.5, 1, 2, and 4 kHz was calculated, and hearing impairment was described as a PTA >25 dB in either ear.Results: All patients who suffer from hearing impairment have serum lead level (23.14±1.76 μg/dL), which is a significantly elevated in comparison to control group (21.20±2.08 μg/dL). In addition to lead, the blood level of cadmium in people with hearing impairment was showed a significant elevation (0.28±0.05 μg/dL) in comparison to normal people (0.22±0.03 μg/dL). In general, this elevation remains within normal reference for the blood level of cadmium (0.5 μg/dL).Conclusions: The present study revealed that the environmental and occupational cadmium and lead coexposures lead to a significant elevation in the blood level of these metals and could have an essential part in the progression of hearing loss.

Introduction: The ability of temporal sequencing refers to the processing of two or more auditory stimuli in order of occurrence in time. Objective: To compare the skill of sequencing between musicians and non-musicians violinists from the frequency pattern test (FPT). Method: The prospective, constituted a group of 20 violinists and musicians non-musicians 20 participants, half matched for age and education, all males who underwent audiometric assessment and WPPT. Results: Comparing the performance in TFP between the groups was found statistically significant for the group of musicians in both ears, (p = 0.003) for the right ear (RE) and (p = 0.002) for the left ear (OE). The results of the PPT were correlated with the average frequencies, three-tone average and high frequencies mean obtaining a statistically significant only for OD being (p = 0.0047) for low frequencies, (p = 0.011) for average and tritonal (p = 0.02) for the average frequencies. The comparative analysis between the ears, the only group statistically significant variable was the mean of frequencies in the group of musicians (p Conclusion: The performance of the group of musicians in the TPF group was superior to non-musicians. Highlights the relevance of the auditory thresholds for low frequencies, acute tritonal average performance of TPF in OD.

The frequency-specific auditory brainstem response (ABR) is an objective electroencephalographic (EEG) method for estimating auditory thresholds when behavioral thresholds are not attainable, primarily in infants and toddlers. It is recorded by repeatedly presenting brief, band-limited tonebursts and averaging the scalp potential response. In a typical ABR evaluation, measurements are made at multiple intensities, at multiple frequencies, and in both ears, leading to a large combinatorial space and long test times. Here, we present a method of recording the responses at five frequencies in both ears simultaneously, along with preliminary data demonstrating its effectiveness. We created ten toneburst trains—five octave frequencies (500–8000 Hz) by two ears—for simultaneous presentation. Importantly, the toneburst timing for each train was dictated by an independent random process, rather than being periodic. Independent sequences allow separate computation of the ABR to each of the toneburst trains as the cross-correlation of its timing sequence and the EEG recording. Early results suggest substantial improvements in recording time, particularly at lower stimulus intensities. It also appears that cochlear spread of excitation—a problem at high intensities—is mitigated by our method. This improvement in place specificity is predicted by modeling of auditory nerve activity.