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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.

With developments in science and technology, the number of electric vehicles will increase, and they will even replace ICE vehicles. Thus, perceiving the presence of approaching electric vehicles on the road has become an important issue. In this study, the auditory detectability of the electric vehicle warning sound at different volumes, distances, and environmental noise levels was investigated. To this end, the detection rate was recorded in experiments with three environmental noise levels (50, 60, and 70 dBA), two sound pressure levels (SPLs) of the warning sound (46 and 51 dBA), three frequency combinations of the warning sound (5000, 2500, 1250, and 630 Hz for high frequencies, 2500, 1250, 630, and 315 Hz for medium frequencies, and 1250, 630, 315, and 160 Hz for low frequencies), and five distances (2, 4, 6, 8, and 10 m). The main results showed that the detection rate at 51 dBA was significantly higher than that at 46 dBA under a high-frequency warning sound, however, the detection rates were similar under medium- and low-frequency warning sounds. The participants’ rates of detection for warning sounds were less than 20% under all experimental conditions, and a high-frequency warning sound was not affected by environmental noise. With regard to distances, no significant effects were observed between the distances and the detection rate at any of the three frequencies. In addition, auditory thresholds based on high-, medium-, and low-frequency warning sounds were found through logistic regression analysis results. The results of this study can be used as a reference for the future design of warning sounds.

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.

Purpose: to investigate the auditory recognition of intermittent speech in relation to different modulation rates and ages. Methods: 20 young people, 20 middle-aged adults, and 16 older adults, all of them with auditory thresholds equal to or lower than 25 dB HL up to the frequency of 4000 Hz. The participants were submitted to intermittent speech recognition tests presented in three modulation conditions: 4 Hz, 10 Hz, and 64 Hz. The percentages of correct answers were compared between age groups and modulation rates. ANOVA and post hoc tests were conducted to investigate the modulation rate effect, and the mixed linear regression model (p < 0.001). Results: regarding the age effect, the data showed a significant difference between young people and older adults, and between middle-aged and older adults. As for the modulation rate effect, the indexes of correct answers were significantly lower at the slower rate (4 Hz) in the three age groups. Conclusion: an age effect was verified on intermittent speech recognition: older adults have greater difficulty. A modulation rate effect was also noticed in the three age groups: the higher the rate, the better the performance. RESUMO Objetivo: investigar o reconhecimento auditivo da fala intermitente em função de diferentes taxas de modulação e em função da idade. Métodos: participaram do estudo vinte jovens, vinte adultos de meia idade, e dezesseis idosos, todos com limiares auditivos iguais ou menores que 25 dB NA até a frequência de 4000 Hz. Os participantes foram submetidos a testes de reconhecimento da fala intermitente apresentada em três condições de modulação: 4 Hz, 10 Hz e 64 Hz. Percentuais de acerto foram comparados entre grupos etários e taxas de modulação. Para a investigação do efeito da taxa de modulação foi realizada ANOVA e testes Post Hoc, enquanto para a investigação do efeito da idade, utilizou-se o modelo de regressão linear misto (p

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.

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.

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.

Introduction: Auditory Steady State Response (ASSR) is an objective method for determining the auditive threshold, applicable and necessary especially in children. The test is extremely important for recommending cochlear implant in children. The aim of the study was to compare pure tone audiometry responses and auditory steady-state thresholds. Materials and method: The study was performed on a group including both patients with normal hearing and with hearing loss. The main inclusion criteria accepted only patients with normal otomicroscopic aspect, normal tympanogram, capable to respond to pure tone audiometry, and with ear conduction thresholds between 0 and 80 dB NHL. The patients with suppurative otic processes or ear malformations were excluded. The research protocol was followed, the tests being performed in soundproofed rooms, starting with pure tone audiometry followed, after a pause, by ASSR determinations at frequencies of 0.5, 1.2 and 4 KHz. The audiological instruments were provided by a single manufacturer. ASSR was recorded at least two times for both borderline intensities, namely the one defining the auditory threshold and the first no-response intensity. The recorded responses were stored in a database and further processed in Excel. Discussion: The differences observed between pure tone audiometry and ASSR thresholds are important at 500 Hz and insignificant at the other frequencies. When approaching the PTA-ASSR relation, whatever the main characteristic between the PTA and ASSR thresholds in one ear, the profile of the lines gap maintains the same shape on the opposite ear. Conclusions: ASSR is a confident objective test, maintaining attention to low frequencies, where some differences might occur.

The increasing rate of age-related hearing loss (ARHL), with its subsequent reduction in quality of life and increase in health care costs, requires new therapeutic strategies to reduce and delay its impact. The goal of this study was to determine if ARHL could be reduced in a rat model by administering a combination of antioxidant vitamins A, C, and E acting as free radical scavengers along with Mg++, a known powerful cochlear vasodilator (ACEMg). Toward this goal, young adult, 3 month-old Wistar rats were divided into two groups: one was fed with a diet composed of regular chow (“normal diet,” ND); the other received a diet based on chow enriched in ACEMg (“enhanced diet,” ED). The ED feeding began 10 days before the noise stimulation. Auditory brainstem recordings (ABR) were performed at 0.5, 1, 2, 4, 8, 16, and 32 kHz at 3, 6–8, and 12–14 months of age. No differences were observed at 3 months of age, in both ND and ED animals. At 6–8 and 12–14 months of age there were significant increases in auditory thresholds and a reduction in the wave amplitudes at all frequencies tested, compatible with progressive development of ARHL. However, at 6–8 months threshold shifts in ED rats were significantly lower in low and medium frequencies, and wave amplitudes were significantly larger at all frequencies when compared to ND rats. In the oldest animals, differences in the threshold shift persisted, as well as in the amplitude of the wave II, suggesting a protective effect of ACEMg on auditory function during aging. These findings indicate that oral ACEMg may provide an effective adjuvant therapeutic intervention for the treatment of ARHL, delaying the progression of hearing impairment associated with age.

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.

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.

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.

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.

Background/Purpose: With respect to follow-up from newborn hearing screening, click evoked auditory brainstem response provides relatively accurate estimates of auditory thresholds at a broad frequency range between 1000 Hz and 4000 Hz. Further on the frequency-specific hearing evaluation, recent studies conclude that tone burst auditory brainstem response estimates the behavioral thresholds reasonably well. This study reports the preliminary data of tone burst auditory brainstem response measurements of infants and young children with normal hearing in Taiwan. Methods: Ninety-four infants and young children aged from 3 months to 3 years of age were recruited as they were eventually determined to have normal hearing after a series of tests. They underwent tone burst auditory brainstem response measurements at four selected frequencies. Statistical methods were applied to study the relationship among recorded variables. Results: The results indicated that the averaged tone burst auditory brainstem response thresholds of infants and young children with normal hearing in Taiwan are typically 10-20 dB nHL at 500, 1000, 2000, and 4000 Hz, which is similar to the reported tone burst auditory brainstem response thresholds in adults with normal hearing. There was no statistically significant difference for the thresholds with regard to gender, laterality, and age distribution in this study. Conclusion: Based on the published research and our study, we suggest setting the normal criterion levels for infants and young children in Taiwan of the tone burst auditory brainstem response to air-conducted tones as 30 dB nHL for 500 and 1000 Hz, and 25 dB nHL for 2000 and 4000 Hz.

Background and Aim: Omega 3 of essential fatty acids, especially in fish oil form plays an important role in structural, functional, and biological aspects in body. Omega 3 deficiency can have devastating effects on the nervous system and auditory. This study aimed to evaluate auditory threshold in n-3 fatty acid-deficient rat pups following supplementation of fish oil consumption during the suckling period. Methods: One sources of omega 3 fatty acid were fed to rat pups of n-3 polyunsaturated fatty acids (PUFA)-deficient dams to compare auditory thresholds in 2, 4, 8, 12 and 16 kHz by auditory brainstem response (ABR) among this group, those with defects with placebo, and control groups. The pups' in supplement group were orally fed 5 mol/g weight of fish oil between the ages of 5 and 21 days. Results:Results showed significant differences in auditory threshold estimation in 2,4,8,12 and 16 kHz in ABR between study groups. The group with n-3 PUFA deficient with placebo showed a significant increase of the parameters indicated as p

We investigated whether hearing advertisement calls over several nights, as happens in natural frog choruses, modified the responses of the peripheral auditory system in the green treefrog,Hyla cinerea. Using auditory evoked potentials (AEP), we found that exposure to 10 nights of a simulated male chorus lowered auditory thresholds in males and females, while exposure to random tones had no effect in males, but did result in lower thresholds in females. The threshold change was larger at the lower frequencies stimulating the amphibian papilla than at higher frequencies stimulating the basilar papilla. Suprathreshold responses to tonal stimuli were assessed for two peaks in the AEP recordings. For the peak P1 (assessed for 0.8–1.25 kHz), peak amplitude increased following chorus exposure. For peak P2 (assessed for 2–4 kHz), peak amplitude decreased at frequencies between 2.5 and 4.0 kHz, but remained unaltered at 2.0 kHz. Our results show for the first time, to our knowledge, that hearing dynamic social stimuli, like frog choruses, can alter the responses of the auditory periphery in a way that could enhance the detection of and response to conspecific acoustic communication signals.

The efficiency of acoustic communication depends on the power generated by the sound source, the attributes of the environment across which signals propagate, the environmental noise and the sensitivity of the intended receivers. Eupsophus emiliopugini, an anuran from the temperate austral forest communicates by means of an advertisement call of moderate intensity within the range for anurans. To estimate the range over which these frogs communicate effectively, we conducted measurements of call sound levels and of auditory thresholds to pure tones and to synthetic conspecific calls. The results show that E. emiliopugini produces advertisement calls of about 84 dB SPL at 0.25 m from the caller. The signals are affected by attenuation as they propagate, reaching average values of about 47 dB SPL at 8 m from the sound source. Midbrain multi-unit recordings show quite sensitive audiograms within the anuran range, with thresholds of about 44 dB SPL for synthetic imitations of conspecific calls, which would allow communication at distances beyond 8 m. This is an extended range as compared to E. calcaratus, a related syntopic species for which a previous study has shown to be restricted to active acoustic spaces shorter than 2 m. The comparison reveals divergent strategies for related taxa communicating amid the same environment.

Auditory neuropathy spectrum disorder (ANSD) is a clinical syndrome characterized by evidence of cochlear function in conjunction with an aberrant auditory neural system. The auditory brainstem response (ABR) cannot be recorded or is grossly abnormal in ANSD patients. Consequently, the fitting of amplification is delayed until behavioral testing is possible. For some ANSD children, behavioral testing is infeasible despite advanced age due to other comorbidities. Therefore, it is crucial to identify a reliable measure of auditory thresholds for ANSD children in order to provide appropriate and timely intervention. Despite an absent ABR, the cortical auditory evoked potential (CAEP) can be recorded from ANSD patients1-4. Previous studies have also shown that hearing thresholds can be reliably measured with the CAEP response in SNHL children5 and its accuracy is as good as or better than that of the ABR6. This report demonstrates the feasibility of using the CAEP to estimate hearing thresholds in ANSD children.

Postnatal development of masked auditory thresholds in the house mouse Mus musculus were behaviorally measured from the 10th to the 24th day. An unconditioned stop reflex and an unconditioned pinna reflex to tones were used for threshold determinations. Masked threshold levels first decrease from day 10 to day 12, then increase or remain constant until day 14, and finally decrease until day 16–18, where the adult levels are reached. The results are in agreement with anatomical and electrophysiological data in the literature. It was concluded that in the developing acoustical system of the mouse two effects superimpose: peripheral completion and central maturation. The data can be interpreted such that the peripheral development which lasts until day 14 dominates between the 12th and 14th postnatal day, whereas development in the central nervous system influences thresholds between day 10 and day 16–18. The widths of critical masking bands are assumed to be constant during development and determined by per...

Postnatal development of absolute auditory thresholds in the kitten was behaviorally measured from birth up to 1 mo of age. Unconditioned reactions to pure tones were observed for kittens up to Day 12, and conditioned responses were used for animals from Day 10 onward. At 1 day after birth, the first noticeable responses were obtained in 4 of 11 kittens at frequencies of .5-2 kHZ. At 2 days of age, 12 of 16 kittens responded. Thresholds remained high (above 100 dB SPL) up to the sixth day, but the range of behaviorally effective frequencies extended from .2 to 6 kHZ. All conditioned response thresholds at Day 10 and most at Day 12 were significantly lower than those measured by unconditioned reactions. From 10 days onward, all threshold curves showed a characteristic sensitivity optimum at 4 kHZ. For frequencies below 1 kHZ, maximum sensitivity was reached at Day 15; for frequencies up to 20 kHZ, at Day 20; and for even higher frequencies, at Day 30. At 1 mo of age, the frequency range is adultlike. The present behavioral results on developing acoustic function in the kitten closely followed structural maturation of the acoustic pathway and demonstrated limitations of the ability for acoustical communication during the first week of life.

In this paper, we present MLP, a MATLAB toolbox enabling auditory\ud thresholds estimation via the adaptive Maximum Likelihood procedure proposed\ud by David Green (1990, 1993). This adaptive procedure is particularly appealing for\ud those psychologists that need to estimate thresholds with a good degree of accuracy\ud and in a short time. Together with a description of the toolbox, the current text\ud provides an introduction to the threshold estimation theory and a theoretical\ud explanation of the maximum likelihood adaptive procedure. MLP comes with a\ud graphical interface and it is provided with several built-in, classic psychoacoustics\ud experiments ready to use at a mouse click.

Summary Objective: To show the efficacy of intra-peritoneally administered trimetazidine to prevent gentamicin ototoxicity, which is still an important cause of profound deafness among children in different parts of the world. Methods: Two groups of Swiss albino mice received daily intra-muscular injections of gentamicin for 30 days. One of the groups received trimetazidine intra peritoneally in addition to the gentamicin. Auditory thresholds of the animals were measured by evoked brain stem response at the beginning and the end of the study. Results were compared to the results of the control group, which received intra peritoneal saline injections. Results: Both groups receiving gentamicin injections had significant auditory threshold shifts, but in the group receiving additional trimetazidine, the threshold shift was not statistically significant when compared to control group. Threshold shift in gentamicin group significantly differed from that of the control group (p = 0.0001) and gentamicin + trimetazidine group (p = 0.0001), on the other hand there was no statistically significant difference between control group and trimetazidine + gentamicin group (p = 0.102). Conclusion: Gentamicin ototoxicity can be prevented by intra peritoneal trimetazidine injections in animal model. This treatment modality may be a mode of protection from gentamicin ototoxicity in children.

Fishes have evolved a diversity of sound–generating organs and acoustic signals of various temporal and spectral content. Additionally, representatives of many teleost families such as otophysines, anabantoids, mormyrids and holocentrids possess accessory structures that enhance hearing abilities by acoustically coupling air–filled cavities to the inner ear. Contrary to the accessory hearing structures such as Weberian ossicles in otophysines and suprabranchial chambers in anabantoids, sonic organs do not occur in all members of these taxa. Comparison of audiograms among nine representatives of seven otophysan families from four orders revealed major differences in auditory sensitivity, especially at higher frequencies (> 1kHz) where thresholds differed by up to 50 dB. These differences showed no apparent correspondence to the ability to produce sounds (vocal versus non–vocal species) or to the spectral content of species–specific sounds. In anabantoids, the lowest auditory thresholds were found in the blue gourami Trichogaster trichopterus , a species not thought to be vocal. Dominant frequencies of sounds corresponded with optimal hearing bandwidth in two out of three vocalizing species. Based on these results, it is concluded that the selective pressures involved in the evolution of accessory hearing structures and in the design of vocal signals were other than those serving to optimize acoustic communication.

Purpose: to evaluate the perception of the level of quality of life in subjects with tinnitus, with and without hearing loss. Methods: a cross-sectional quantitative study. A total of 189 subjects (mean age 53.06 years) divided into four groups. Group 1: subjects with normal auditory thresholds without tinnitus complaint; Group 2: subjects with normal auditory thresholds and tinnitus complaint; Group 3: subjects with sensorineural hearing loss without tinnitus complaint; Group 4: subjects with sensorineural hearing loss and with tinnitus complaint. Levels of quality of life were investigated through the World Health Organization Quality Of Life (WHOQOL) website - brief and psycho-emotional and functional aspects of patients with tinnitus through the Tinnitus Handicap Inventory (THI). Statistical analyzes, comparisons among groups and descriptive analysis were performed, considering a significance level of 5%. Results: the overall mean scores of quality of life in group 4 (56.07) were smaller than those of group 1 (64.67) (p