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The matched filter hypothesis proposes a close match between senders and receivers and is supported by several studies on variation in signal properties and sensory-processing mechanisms among species and populations. Importantly, within populations, individual variation in sensory processing may affect how receivers perceive signals. Our main goals were to characterize hearing sensitivity of Pacific treefrogs (Pseudacris regilla), assess patterns of individual variation in hearing sensitivity, and evaluate how among-individual variation in hearing sensitivity and call frequency content affect auditory processing of communication signals. Overall, males and females are most sensitive to frequencies between 2.0 and 2.5 kHz, which matches the dominant frequency of the call, and have a second region of high sensitivity between 400 and 800 Hz that does not match the fundamental frequency of the call. We found high levels of among-individual variation in hearing sensitivity, primarily driven by subject size. Importantly, patterns of among-individual variation in hearing differ between males and females. Cross-correlation analyses reveal that among-individual variation in hearing sensitivity may lead to differences on how receivers, particularly females, perceive male calls. Our results suggest that individual variation in sensory processing may affect signal perception and influence the evolution of sexually selected traits. [ABSTRACT FROM AUTHOR]

Objective To investigate the significance of auditory brainstem response （ABR） combined with auditory steady-state response （ASSR） for the assessment of mild sensorineural hearing loss in infants. Methods Data from 114 infants with mild sensorineural hearing loss were retrospectively analyzed， and their ABR and ASSR results were collected for rank sum test and correlation analysis. Results In the rank sum test， the difference in thresholds between tone-burst ABR （Tb-ABR） and ASSR at 0.5，1，2，4 kHz was statistically significant （P < 0.05）， and they were also correlated at 0.5， 1，2，4 kHz （P < 0.05）， r = 0.613， 0.569， 0.616， 0.71. After grouping by gender and ear， there was a correlation between ABR and ASSR at 0.5， 1，2， and 4 kHz， male: r = 0.61， 0.56， 0.671， 0.774； female: r = 0.581， 0.558， 0.546， 0.608； left ear: r = 0.61， 0.558， 0.576， 0.715； right ear: r = 0.631， 0.581， 0.662， 0.71. And after grouping by age at diagnosis， only infants diagnosed from 7 ~ 12 months of age did not correlate at 0.5 kHz and 1 kHz（ P > 0.05）， while the rest of the groups had a good correlation（ P < 0.05），0 ~ 3 months: r = 0.686， 0.643， 0.671， 0.742； 4 ~ 6 months: r = 0.671， 0.626， 0.616， 0.693； 7 ~ 12 months at 2 kHz and 4 kHz: r = 0.571， 0.706. Conclusion In infants with mild sensorineural hearing loss， ABR and ASSR correlate in assessing hearing thresholds at all frequencies， and the combination of the two tests could provide a more accurate assessment of the subject's true hearing. [ABSTRACT FROM AUTHOR]

AbstractObjectivesDesignStudy SampleResultsConclusionsStandard diagnostic measures focus on threshold elevation but hearing concerns may occur independently of threshold elevation – referred to as “hidden hearing loss” (HHL). A deeper understanding of HHL requires measurements that locate dysfunction along the auditory pathway. This study aimed to describe the relationship and interdependence between certain behavioural and physiological measures of auditory function that are thought to be indicative of HHL.Data were collected on a battery of behavioural and physiological measures of hearing. Threshold-dependent variance was removed from each measure prior to generating a multiple regression model of the behavioural measures using the physiological measures.224 adults in the United States with audiometric thresholds ≤65 dB HL.Thresholds accounted for between 21 and 60% of the variance in our behavioural measures and 5–51% in our physiological measures of hearing. There was no evidence that the behavioural measures of hearing could be predicted by the selected physiological measures.Several proposed behavioural measures for HHL: thresholds-in-noise, frequency-modulation detection, and speech recognition in difficult listening conditions, are influenced by hearing sensitivity and are not predicted by outer hair cell or auditory nerve physiology. Therefore, these measures may not be able to assess threshold-independent hearing disorders. [ABSTRACT FROM AUTHOR]

Background: No studies to date have compared audiologic characteristics in patients with continuous and intermittent tinnitus. The present study classified tinnitus patients into continuous and intermittent groups based on tinnitus duration and compared their audiologic characteristics. Methods: This study enrolled 604 patients with tinnitus from January 2019 to December 2022. Clinical manifestations, PTA results, the frequency and loudness of tinnitus, ABR, DPOAE, and TEOAE tests were compared in patients with continuous and intermittent tinnitus. Results: Of the 604 patients, 231 (38.2%) had continuous and 373 (61.8%) had intermittent tinnitus. There were no significant between-group differences in otologic symptoms, tinnitus onomatopoeia. PTA showed that hearing thresholds, except at 125 Hz, were significantly higher in patients with continuous rather than intermittent tinnitus. The loudness of tinnitus was significantly greater in patients with continuous rather than intermittent tinnitus. ABR tests showed that the absolute latency of wave V was significantly longer in continuous than in intermittent tinnitus. Signal-to-noise ratios on TEOAE tests were significantly lower in patients with continuous rather than intermittent tinnitus at all frequencies tested (1, 1.5, 2, 3, and 4 kHz). Response rates to sound stimuli at all frequencies, except for 1 kHz, were significantly lower on DPOAE tests in patients with continuous rather than intermittent tinnitus. Conclusions: Continuous tinnitus is more common in males, more persistent over time, and is associated with a higher rate of hearing loss. In contrast, intermittent tinnitus is more common in women, appears acutely, and is associated with a relatively lower rate of hearing loss. Based on the findings of the current paper, it seems that audiologic characteristics may differ between patients with continuous and intermittent tinnitus. [ABSTRACT FROM AUTHOR]

The present study sought to determine the cochlear frequency regions represented by Auditory Brainstem Responses (ABRs) obtained using the high-pass noise/derived response (HP/DR) technique. Broadband noise sufficient to mask the ABR to 50 dB nHL clicks was HP filtered (96 dB/oct) at 8000, 4000, 2000, 1000 and 500 Hz. Mixed with the clicks and HP noise masker was narrowband noise. Three derived response bands, denoted by the upper and lower high-pass noise frequencies, were obtained: DR4000-2000, DR2000-1000, and DR1000-500. Ten adults with normal hearing, aged 19–27 years (mean age: 22.4 years), were recruited from the community. Frequencies contributing to each DR were determined from the wave V percent amplitude (or latency shift) vs narrowband masker frequency profiles (relative to a no-narrowband-noise condition). Overall, results indicate derived band centre frequencies were closer to the lower HP cut-off frequencies for DR4000-2000 and DR2000-1000, and approximately halfway between the lower HP cut-off and the geometric mean of the two HP frequencies for DR1000-500, with bandwidths of 0.5-1 octave in width. These results confirm the validity of the HP/DR technique for assessing narrow cochlear regions (≤1.0 octave wide), with centre frequencies within ½-octave of the lower HP frequency. [ABSTRACT FROM AUTHOR]

Introduction: This study investigates the comparative effectiveness of Click Auditory Brainstem Response (Click ABR) and Multiple Auditory Steady-State Response (Multi-ASSR) in identifying hearing impairments in infants. Recognizing auditory issues early is crucial for a child's cognitive and language development, as emphasized by the Joint Committee on Infant Hearing (JCIH) and the American Academy of Audiology (AAA). While Click ABR is widely utilized, Multi-ASSR offers a modern technique for detailed hearing assessment. Methods: A comparative analysis was conducted on 111 infants aged 1–6 months, previously screened for hearing at a tertiary care centre. The study employed both Click ABR and Multi-ASSR to evaluate their respective efficacy in assessing infant hearing. Results: Click ABR detected normal hearing in 87.4% of the infants, slightly higher than Multi-ASSR's 84.7%. A noteworthy finding was the higher incidence of bilateral versus unilateral hearing loss, with Click ABR identifying bilateral loss in 10 infants and unilateral loss in 4, compared to Multi-ASSR, which found bilateral loss in 12 infants and unilateral loss in 5. There was a minor but significant difference in auditory thresholds between the methods, with a mean discrepancy of 1.2 dB and a significant statistical variance (t-value of 15; p < 0.001), indicating variations in sensitivity. Conclusion: Both Click ABR and Multi-ASSR are indispensable tools in paediatric audiology, each with unique advantages. Click ABR excels in efficiency, suitable for rapid assessments and early detection. In contrast, Multi-ASSR offers comprehensive frequency-specific data, facilitating thorough evaluations. Healthcare professionals must grasp these methods' strengths to optimize infant hearing screenings and enhance early intervention strategies, aligning with JCIH and AAA guidelines. [ABSTRACT FROM AUTHOR]

Objective: To investigate the audiological characteristics of vestibular schwannoma (VS) patients with normal pure‐tone audiometry (PTA) results. Study Design: A retrospective study. Setting: Forty‐two VS patients with normal PTA results from October 2016 to October 2022 were included. Methods: Normal PTA was defined when the hearing threshold is ≤25 dB hearing loss (HL) in each test frequency and the PTA is ≤25 dB HL. Results of multiple audiological tests such as the auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), multiple auditory steady‐state responses threshold (ASSR), and speech discrimination score were retrospectively reviewed. Demographic data of these patients were also been collected. Results: According to our results, the ABR and average ASSR threshold of the affected side were statistically significantly higher in VS patients with normal PTA. ABR waveforms on the affected side also showed more abnormalities. The DPOAE pass rates of the affected side were lower than the unaffected side while the amplitude and signal‐to‐noise ratio rate was also lower. In addition, we used magnetic resonance imaging 3‐dimensional reconstruction images to measure the volume of tumors in these patients. We also found that higher ABR threshold means lager tumor size in patients with normal PTA. Conclusion: VS patients with normal PTA result cannot be assumed to have no impairment of hearing function. ABR, DPOAE, and ASSR results showed the characteristic changes in the affect ear. ABR threshold has the highest sensitivity for hearing abnormalities and is strong relative with tumor size in patients with normal PTA. [ABSTRACT FROM AUTHOR]

Simple Summary: Background noise poses a significant detriment to speech perception. Here, as a continuation of our prior work, we provide biological evidence that cognitively-based auditory training lessens the physiologic impact of background noise, resulting in shorter (i.e., earlier) frequency-following response latencies after 20 training sessions. Background noise disrupts the neural processing of sound, resulting in delayed and diminished far-field auditory-evoked responses. In young adults, we previously provided evidence that cognitively based short-term auditory training can ameliorate the impact of background noise on the frequency-following response (FFR), leading to greater neural synchrony to the speech fundamental frequency(F0) in noisy listening conditions. In this same dataset (55 healthy young adults), we now examine whether training-related changes extend to the latency of the FFR, with the prediction of faster neural timing after training. FFRs were measured on two days separated by ~8 weeks. FFRs were elicited by the syllable "da" presented at a signal-to-noise ratio (SNR) of +10 dB SPL relative to a background of multi-talker noise. Half of the participants participated in 20 sessions of computerized training (Listening and Communication Enhancement Program, LACE) between test sessions, while the other half served as Controls. In both groups, half of the participants were non-native speakers of English. In the Control Group, response latencies were unchanged at retest, but for the training group, response latencies were earlier. Findings suggest that auditory training can improve how the adult nervous system responds in noisy listening conditions, as demonstrated by decreased response latencies. [ABSTRACT FROM AUTHOR]

Background and Aim: It is important to know how much are the auditory electrophysiological tests affected by sleep and wakefulness to be employed in different situations. This problem is more important for the speech-evoked Auditory Brainstem Response (speechABR) test that is affected by higher-level processing. This study aimed to compare the results of the speech-ABR test between wakefulness and sleep states. Methods: Sixteen young male adults (aged 20–28 years) with normal hearing participated in this study. The speech-ABR to the /da/ syllable was recorded during wakefulness and sleep. Electroencephalography (EEG) and behavioral tests (eyes position, body movements, etc.) were monitored during the test time to confirm the sleep state. Results: The speech-ABR test parameters showed significant changes during sleep compared to wakefulness (latencies of waves V and A were longer and the amplitudes of waves V and A, the slope of V-A complex, and the spectral magnitude of F1 were lower). However, the spectral magnitude of higher frequencies was not significantly different. In addition, no significant statistical difference was observed in speech-ABR parameters between right and left ears. Conclusion: Although the speech-ABR originates from brainstem centers, unlike conventional click-evoked ABR, it is affected by sleep as it is affected by the higher-level auditory processing functions. Although, further studies are needed. However, our study opens the way for many applied auditory studies about the possibility to use speech-ABR for auditory processing assessments in sleep state of different population groups, such as neonates. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to compare auditory brainstem response (ABR) findings of normal-hearing preschool children with different types of speech and language pathology. Methods: This retrospective, non-randomized, cohort study was conducted at a tertiary speech and hearing rehabilitation institution according to STROBE guidelines. The study enrolled 123 preschool children diagnosed with speech language pathology and normal hearing. The participants included children with developmental language disorder, autism spectrum disorder, isolated articulation pathology, organic brain lesions, cognitive delay, and a group of very young children with clinically significant speech development delay. All patients underwent standard ABR procedures. Results: The latencies were the longest in the group of children with organic lesion, followed by the group of children with autism spectrum disorder, then the group with developmental language disorder, and the young children group. In the group of children with articulation pathology and the cognitive delay group, the latencies were the shortest. Conclusion: This study showed a connection between several groups of children with language pathology that includes comprehension problems and prolongation of ABR latencies. [ABSTRACT FROM AUTHOR]

Introduction: Aging deteriorates peripheral and central auditory structures and functions. In elders, for an accurate audiological evaluation, it is important to explore beyond the cochlear receptor. Audiograms provide an estimation of hearing thresholds, while the amplitudes and latencies of supra-threshold auditory brainstem response (ABR) can offer noninvasive measures of the auditory pathways functioning. Regarding ABR, in young populations, level-specific chirp (LS CE-chirp) stimulus has been proposed as an alternative synchronizing method to obtain larger ABR responses than those evoked by clicks. However, the supra-threshold characteristics of chirp evoked ABR, and their association to hearing thresholds is relatively unknown in the elderly. The aim of this study was to evaluate supra-threshold LS CE-chirp ABRs in an aged population by comparing their features with click ABRs, and evaluating their relationship with audiometric hearing thresholds. Methods: We carried out a cross-sectional study to characterize the hearing of 125 adults aged over 65 years. We determined the audiometric hearing thresholds and supra-threshold ABRs elicited by LS CE-chirp and click stimuli at 80 dB nHL. We evaluated associations by means of partial correlations and covariate adjustment. We performed specific frequencies' analysis and subgroup analysis per hearing level. Results: Wave V responses had significantly shorter latencies and larger amplitudes when elicited by LS CE-chirp as compared to click-evoked responses. Audiometric hearing thresholds correlated with age, but ABR characteristics did not. We found mild correlations between hearing thresholds and ABR characteristics, predominantly at higher frequencies and with chirp. We found scarce evidence of correlation between ABR characteristics and the average of behavioral hearing thresholds between 0.5 to 4 kHz (0.5–4 kHz PTA). After subgroup analysis according to the hearing level, no stronger or more significant correlations were found between ABR characteristics and 0.5–4 kHz PTA. Discussion: In this study, we found that supra-threshold LS CE-chirp ABR presented some of the previously described similitudes and differences with supra-threshold click ABR in younger populations. Although, the average amplitude and latency of wave V evoked by LS CE-chirp were larger and faster than those evoked by clicks, these results should be taken with caution at the individual level, and further studies are required to state that LS CE-chirp ABRs are better than click ABRs in elders for clinical evaluations. We did not find consistent associations between hearing thresholds and supra-threshold wave V features, suggesting that these measures should be considered independently in the elderly. [ABSTRACT FROM AUTHOR]

Background: Hearing loss is an unknown complication of diabetes mellitus (DM). The aim of this study was to evaluate hearing function using auditory brainstem response (ABR) in diabetic patients. Methods: The present case-control study was performed on thirty diabetic patients as a case group and thirty healthy individuals as a control group. Baseline demographic information, HbA1c level, and duration of diabetes were obtained from all diabetic patients. In all subjects, the ABR and pure-tone audiometry (PTA) tests were performed and the results were analyzed using the t-test and logistic regression. Results: The absolute latency of I was significantly lower in diabetes patients. The absolute latency of III and the interpeak latencies (IPL) I-III were significantly higher in diabetic patients. No significant relationship was noticed in the absolute latency of V and the IPL I-V among diabetic patients in the right and left ears (P>0.05). Conclusion: The results of this study suggested that diabetes may cause central auditory dysfunction manifested on the absolute latency of III, the IPL I-III and III-V. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate how prosthetic management affects the otological and audiological state of infants with cleft lip and palate by preventing or treating otitis media (OM). Materials and Methods: Thirty infants with cleft lip and palate (L/P) were assigned to three equal groups according to the age of prosthetic intervention; Group I: immediately after birth, Group II: 2 months old, Group III: 5 months old. Assessment of middle ear function by tympanometry and hearing quality by auditory brainstem response (ABR) under natural sleep was conducted before and after prosthetic treatment every month till 10 months of age. Data from the study groups were compared. Results: No statistically significant differences were found between Gp I and Gp II in the 2nd, 3rd, and 4th months for right and left ears (p > 0.05). In the 5th month, statistically significant differences between the three groups were found in tympanometry for right (p = 0.011) and left (p = 0.024) ears also, in ABR for right (p = 0.007) and left (p = 0.011) ears. Tympanometric readings starting from the 6th till the 10th month showed no statistically significant differences between the three groups (p >0.05). The final ABR outcomes of the 10th month indicated statistically significant differences between the three groups for both ears (p = 0.027). Conclusions: Early prosthetic care could delay the development of OM, so it could potentially improve the otological and audiological state in infants with cleft L/P. However, prosthetic treatment may not be able to completely prevent or eliminate middle ear disorders. [ABSTRACT FROM AUTHOR]

Objective To investigate the electrophysiological characteristics and clinical significance of unilateral tinnitus with normal hearing threshold. Methods A total of 34 patients with normal hearing but unilateral tinnitus admitted to our department from May 2022 to February 2023 were recruited as the study subjects. Pure tone hearing threshold detection, distortion product otoacoustic emission (DPOAE), auditory brainstem response (ABR) detection and extended high-frequency pure tone audiometry were performed on both ears (affected side and healthy side) of every patient. The data of the affected side group and those of healthy side group were compared. Results The Ⅰ-wave latency of ABR was significantly shorter (1.60 vs 1.73 ms, P=0.018), and its amplitude was obviously decreased (0.19 vs 0.23 μV, P=0.003) in the affected side group when compared with the healthy side group. In the affected group (34 ears), there were 18 ears (52.94%) having amplitude of wave Ⅲ greater than that of wave Ⅴ, while in the healthy group, no such difference in the amplitude between wave Ⅲ and wave Ⅴ was observed. There was statistical significance between the 2 groups (Chi-square=24.480, P < 0.001). In the 12.5, 14.0, 16.0, 18.0 and 20.0 kHz conditions, the average hearing threshold of extended high-frequency audiometry was all significantly higher in the affected side group than the healthy group (P < 0.05). Conclusion For subjective tinnitus patients with normal hearing threshold, ABR examination is helpful in preliminarily determining whether there are hidden functional changes in the auditory pathway. Decreased Ⅰ-wave amplitude, shortened Ⅰ-wave latency, and wave Ⅲ amplitude greater than wave Ⅴ amplitude can be used as objective reference indicators.

Background: No studies to date have compared audiologic characteristics in patients with continuous and intermittent tinnitus. The present study classified tinnitus patients into continuous and intermittent groups based on tinnitus duration and compared their audiologic characteristics. Methods: This study enrolled 604 patients with tinnitus from January 2019 to December 2022. Clinical manifestations, PTA results, the frequency and loudness of tinnitus, ABR, DPOAE, and TEOAE tests were compared in patients with continuous and intermittent tinnitus. Results: Of the 604 patients, 231 (38.2%) had continuous and 373 (61.8%) had intermittent tinnitus. There were no significant between-group differences in otologic symptoms, tinnitus onomatopoeia. PTA showed that hearing thresholds, except at 125 Hz, were significantly higher in patients with continuous rather than intermittent tinnitus. The loudness of tinnitus was significantly greater in patients with continuous rather than intermittent tinnitus. ABR tests showed that the absolute latency of wave V was significantly longer in continuous than in intermittent tinnitus. Signal-to-noise ratios on TEOAE tests were significantly lower in patients with continuous rather than intermittent tinnitus at all frequencies tested (1, 1.5, 2, 3, and 4 kHz). Response rates to sound stimuli at all frequencies, except for 1 kHz, were significantly lower on DPOAE tests in patients with continuous rather than intermittent tinnitus. Conclusions: Continuous tinnitus is more common in males, more persistent over time, and is associated with a higher rate of hearing loss. In contrast, intermittent tinnitus is more common in women, appears acutely, and is associated with a relatively lower rate of hearing loss. Based on the findings of the current paper, it seems that audiologic characteristics may differ between patients with continuous and intermittent tinnitus.

Insurance coverage for oral valganciclovir (VGCV) began in Japan in April 2023 on the basis of results, including our clinical trials for symptomatic congenital cytomegalovirus (CMV) disease. The VGCV treatment is available throughout Japan, so clinicians must consider the likelihood of hearing improvement and the possibility of neutropenia before dosing. We performed a substudy of an investigator-initiated, single-arm, prospective, multicenter, clinical trial in which 24 infants with symptomatic congenital CMV disease were orally administered 16 mg/kg VGCV twice daily for 6 months as an intervention. We examined the infants' baseline characteristics associated with improved hearing impairment or a severely reduced neutrophil count. Of the 24 patients, 4 had normal hearing on assessment of their ear with the best hearing. Hearing impairment improved in 14 patients and did not respond to VGCV treatment in 6 patients at the 6-month hearing assessment. CMV DNA levels in plasma at baseline were higher in patients in whom hearing did not respond to treatment. A neutrophil count <500/mm3 occurred in 5 (21%) patients for the first 6 weeks and in 8 (33%) patients for the first 6 months. A neutrophil count at screening and the lowest neutrophil count over the 6 months showed the highest correlation (r = 0.477, p = 0.019). Infants with a low plasma viral load at screening tend to have an improvement in hearing impairment. Clinicians should be aware of neutropenia during VGCV treatment particularly in patients with a low neutrophil count during screening. [ABSTRACT FROM AUTHOR]

Background: Essential tremor (ET) is a common chronic progressive disease, characterized by postural and action tremor. Abnormalities within the cerebello-thalamocortical pathways are thought to be involved in ET. In some studies, it was reported that there is an association between ET and hearing loss. Objective: In this study, our goal is to examine the electrophysiological changes of the structures forming the auditory pathway in ET cases, and the relationship of these changes with clinical findings and understand if the pathology underlying hearing loss in ET is cochlear or retrocochlear. Materials and Methods: One hundred sequential ET patients who had referred to Mersin University Faculty of Medicine Neurology Department, and 100 healthy individuals that are equivalent in terms of age and gender were conducted to investigate this association. Detailed medical history, neurologic examination, audiologic examination, pure-tone audiometry (PTA), tympanometry, and auditory brainstem response (ABR) analyses also known as brainstem auditory-evoked potentials were applied to all patients and controls. Results: The mean age of patients with ET was 56.38 ± 16.73, and the mean age of individuals in the control group was 56.47 ± 16.86. Nineteen of the patients with ET, and two healthy individuals from the control group had hearing problems (P < 0.001). In this study, there were no significant differences found in audiometric and ABR examinations in terms of hearing loss between the ET group and control group. However, in audiometric and ABR analyses, an increase in hearing loss was found to be correlated with an increase in tremor severity. In PTA test, hearing loss was higher in those with high-intensity tremor severity than in the group with mild tremor severity. This was statistically significant. P (KW)

Background: Hearing loss is an unknown complication of diabetes mellitus(DM). The aim of this study was to evaluate hearing function using auditory brainstem response (ABR) in diabetes patients. Methods: The present case-control study was performed on thirty diabetic patients as a case group and thirty healthy individuals as a control group. Baseline demographic information, HbA1c level, and duration of diabetes were obtained from all diabetic patients. In all subjects, the ABR and pure-tone audiometry (PTA) tests were performed and the results were analyzed using the t-test and logistic regression. Results: The absolute latency of I was significantly lower in diabetes patients. The absolute latency of III and the interpeak latencies (IPL) I-III were significantly higher in diabetic patients. No significant relationship was noticed in the absolute latency of V and the IPL I-V among diabetic patients in the right and left ears (P>0.05). Conclusion: The results of this study suggested that diabetes may cause central auditory dysfunction manifested on the absolute latency of III, the IPL I-III and III-V.

This study evaluates the efficacy of several Convolutional Neural Network (CNN) models for the classification of hearing loss in patients using preprocessed auditory brainstem response (ABR) image data. Specifically, we employed six CNN architectures—VGG16, VGG19, DenseNet121, DenseNet-201, AlexNet, and InceptionV3—to differentiate between patients with hearing loss and those with normal hearing. A dataset comprising 7990 preprocessed ABR images was utilized to assess the performance and accuracy of these models. Each model was systematically tested to determine its capability to accurately classify hearing loss. A comparative analysis of the models focused on metrics of accuracy and computational efficiency. The results indicated that the AlexNet model exhibited superior performance, achieving an accuracy of 95.93%. The findings from this research suggest that deep learning models, particularly AlexNet in this instance, hold significant potential for automating the diagnosis of hearing loss using ABR graph data. Future work will aim to refine these models to enhance their diagnostic accuracy and efficiency, fostering their practical application in clinical settings. [ABSTRACT FROM AUTHOR]

Temperature is a critical factor in shaping the physiological and metabolic processes of animals, notably impacting their auditory systems. Particularly, ectotherms face heightened vulnerability to temperature fluctuations. To comprehend the impact of rapid temperature changes on the auditory sensitivity of ectotherms, we measured the auditory sensitivity of Xenopus laevis at 10°C, 20°C, and 30°C respectively, using the auditory brainstem response. Our results reveal a significant decrease in auditory sensitivity of X. laevis at 10°C, with auditory thresholds markedly higher than those observed at 20°C and 30°C. Conversely, as the test temperature increased from 20°C to 30°C, their hearing sensitivity did not decline but tended to become more sensitive. In conclusion, our results suggest that rapid temperature changes have a discernible impact on the hearing sensitivity of X. laevis, particularly at low temperatures. These rapid environmental temperature changes significantly impact the sensory capabilities and courtship behaviours of animals, thereby influencing their population dynamics. Hence, revealing the consequences of rapid temperature fluctuations on sensory sensitivity in ectotherms is crucial for understanding the repercussions of climate change on animal population dynamics. These insights have profound implications for both environmental management and animal conservation. [ABSTRACT FROM AUTHOR]

Glenis Long championed the application of quantitative psychophysical methods to understand comparative hearing abilities across species. She contributed the first psychophysical studies of absolute and masked hearing sensitivities in an auditory specialist, the echolocating horseshoe bat. Her data demonstrated that this bat has hyperacute frequency discrimination in the 83-kHz range of its echolocation broadcast. This specialization facilitates the bat's use of Doppler shift compensation to separate echoes of fluttering insects from concurrent echoes of non-moving objects. In this review, we discuss another specialization for hearing in a species of echolocating bat that contributes to perception of echoes within a complex auditory scene. Psychophysical and behavioral studies with big brown bats show that exposures to long duration, intense wideband or narrowband ultrasonic noise do not induce significant increases in their thresholds to echoes and do not impair their ability to orient through a naturalistic sonar scene containing multiple distracting echoes. Thresholds of auditory brainstem responses also remain low after intense noise exposures. These data indicate that big brown bats are not susceptible to temporary threshold shifts as measured in comparable paradigms used with other mammals, at least within the range of stimulus parameters that have been tested so far. We hypothesize that echolocating bats have evolved a decreased susceptibility to noise-induced hearing losses as a specialization for echolocation in noisy environments. [ABSTRACT FROM AUTHOR]

The auditory brainstem response (ABR) is a valuable clinical tool for objective hearing assessment, which is conventionally detected by averaging neural responses to thousands of short stimuli. Progressing beyond these unnatural stimuli, brainstem responses to continuous speech presented via earphones have been recently detected using linear temporal response functions (TRFs). Here, we extend earlier studies by measuring subcortical responses to continuous speech presented in the sound-field, and assess the amount of data needed to estimate brainstem TRFs. Electroencephalography (EEG) was recorded from 24 normal hearing participants while they listened to clicks and stories presented via earphones and loudspeakers. Subcortical TRFs were computed after accounting for non-linear processing in the auditory periphery by either stimulus rectification or an auditory nerve model. Our results demonstrated that subcortical responses to continuous speech could be reliably measured in the sound-field. TRFs estimated using auditory nerve models outperformed simple rectification, and 16 minutes of data was sufficient for the TRFs of all participants to show clear wave V peaks for both earphones and sound-field stimuli. Subcortical TRFs to continuous speech were highly consistent in both earphone and sound-field conditions, and with click ABRs. However, sound-field TRFs required slightly more data (16 minutes) to achieve clear wave V peaks compared to earphone TRFs (12 minutes), possibly due to effects of room acoustics. By investigating subcortical responses to sound-field speech stimuli, this study lays the groundwork for bringing objective hearing assessment closer to real-life conditions, which may lead to improved hearing evaluations and smart hearing technologies. [ABSTRACT FROM AUTHOR]

A method for testing the health of ear's peripheral auditory nerve and its connection to the brainstem is called an auditory brainstem response (ABR). Manual quantification of ABR tests by an audiologist is not only costly but also time-consuming and susceptible to errors. Recently in machine learning have prompted a resurgence of research into ABR classification. This study presents an automated ABR recognition model. The initial step in our design process involves collecting a dataset by extracting ABR test images from sample test reports. Subsequently, we employ an elastic distortion approach to generate new images from the originals, effectively expanding the dataset while preserving the fundamental structure and morphology of the original ABR content. Finally, the Vision Transformer method was exploited to train and develop our model. In the testing phase, the incorporation of both the newly generated and original images yields an impressive accuracy rate of 97.83%. This result is noteworthy when benchmarked against the latest research in the field, underscoring the substantial performance enhancement achieved through the utilization of generated data. [ABSTRACT FROM AUTHOR]

AbstractObjectiveDesignStudy sampleResultsConclusionsTo investigate the reliability of tone-burst auditory brainstem response (TB-ABR) latencies and thresholds in pre-term and full-term infants.TB-ABRs to 500 Hz and 4000 Hz tone-burst stimuli were recorded at two-week intervals over the first six weeks of life in a group of full-term infants (40–46 weeks gestational age [GA]) and over ten weeks (36–46 weeks gestation) in a group of preterm infants. Linear mixed model analyses evaluated within-subject changes and the effects of the subject group, age at assessment, and stimulus frequency on ABR latency and threshold.Twenty-four infants participated. Nine were full-term (GA: 39–41 weeks) and fifteen were healthy pre-term (GA: 28–34 weeks) at birth.TB-ABR wave V latencies at 70 dBnHL decreased throughout the study (p < 0.001) in pre-term babies for both test frequencies by approximately 0.5 ms. There were, however, no group or GA (at birth) effects indicating that response latency normalized in these children by the due date. Similarly, TB-ABR threshold levels in the premature group were elevated (p = 0.001) by approximately 5 dB in pre-term evaluation but were equivalent to those of full-term participants in the post-term assessment period.In healthy, pre-term infants, tone-burst ABR testing is reliable from 36 weeks gestation. [ABSTRACT FROM AUTHOR]

Background: Auditory neuropathy (AN) is a hearing disorder that affects neural activity in the VIIIth cranial nerve and central auditory pathways. Progressive forms have been reported in a number of neurodegenerative diseases and may occur as a result of both the deafferentiation and desynchronisation of neuronal processes. The purpose of this study was to describe changes in auditory function over time in a patient with axonal neuropathy and to explore the effect of auditory intervention. Methods: We tracked auditory function in a child with progressive AN associated with Charcot–Marie–Tooth (Type 2C) disease, evaluating hearing levels, auditory-evoked potentials, and perceptual abilities over a 3-year period. Furthermore, we explored the effect of auditory intervention on everyday listening and neuroplastic development. Results: While sound detection thresholds remained constant throughout, both electrophysiologic and behavioural evidence suggested auditory neural degeneration over the course of the study. Auditory brainstem response amplitudes were reduced, and perception of auditory timing cues worsened over time. Functional hearing ability (speech perception in noise) also deteriorated through the first 1.5 years of study until the child was fitted with a "remote-microphone" listening device, which subsequently improved binaural processing and restored speech perception ability to normal levels. Conclusions: Despite the deterioration of auditory neural function consistent with peripheral axonopathy, sustained experience with the remote-microphone listening system appeared to produce neuroplastic changes, which improved the patient's everyday listening ability—even when not wearing the device. [ABSTRACT FROM AUTHOR]

Background: In order to better understand the pathophysiology of surgically induced hearing loss after vestibular schwannoma (VS) surgery, we postoperatively analyzed the hearing status in a series of patients where hearing was at least partially preserved. Methods: Hearing was assessed through tonal audiometry, speech discrimination score, maximum word recognition score (dissyllabic word lists—MaxIS), otoacoustic emissions (OAEs), and auditory brainstem response (ABR). The magnetic resonance imaging (MRI) tumor characterization was also noted. Results: In a series of 24 patients operated on for VS over 5 years, depending on the results of this triple hearing exploration, we could identify, after surgery, patients with either a myelin alteration or partial damage to the acoustic fibers, others with a likely partial cochlear ischemia, and some with partial cochlear nerve ischemia. One case with persisting OAEs and no preoperative ABR recovered hearing and ABR after surgery. Long follow-up (73 ± 57 months) revealed a mean hearing loss of 30 ± 20 dB with a drastic drop of MaxIS. MRI revealed only 25% of fundus invasion. Conclusion: a precise analysis of hearing function, not only with classic audiometry but also with ABR and OEAs, allows for a better understanding of hearing damage in VS surgery. [ABSTRACT FROM AUTHOR]

Introduction NB CE-Chirp LS was developed to improve the audiogram estimation by auditory brainstem response (ABR) thresholds during audiological assessment of infants and difficult to test children. However, before we know how the stimulus behaves in several types of hearing loss, it is important we know how the stimulus behaves in normal hearing infants. Objective To describe ABR thresholds with NB CE-Chirp LS stimulus for 500, 1,000, 2,000, and 4,000 Hz, as well as the amplitude and absolute latency for ABR thresholds. Methods Auditory brainstem response thresholds were evaluated with the Eclipse EP25 system. NB CE-Chirp LS was presented using an ER-3A insert earphone. EEG filter was 30 Hz high-pass and 1,500 Hz low-pass. The ABR threshold was defined as the lowest intensity capable of clearly evoke wave V, accompanied by an absent response 5 dB below. Results Eighteen normal hearing infants were evaluated. The mean and standard deviation (SD) of the ABR threshold (dB nHL) were: 23.8 (±4.2); 14.4 (±5.7); 6.0 (±5.0); and 7.0 (±5.9). The mean and SD of the absolute latency (ms) were: 8.86 (±1.12); 9.21 (±0.95); 9.44 (±0.78); and 9.64 (±0.52). The mean amplitude (nV) and SD were: 0.123 (±0.035); 0.127 (±0.039); 0.141 (±0.052); and 0.105 (±0.028), respectively, for 500, 1,000, 2,000 and 4,000 Hz. Conclusion Auditory brainstem response threshold with NB CE-Chirp LS reaches low levels, in special for high frequencies. It provides absolute latencies similar between frequencies with robust amplitude. The results obtained brings to the examiner more confidence in the results registered. [ABSTRACT FROM AUTHOR]

Genuine concerns are being increased regarding potential health risks associated with the radiation exposure while using mobile devices. To study the effects of mobile phone usage on auditory functions. The detailed history of the patient was obtained with special emphasis on total cumulative usage [in years], average daily use [in minutes]. According to the years of exposure, subjects were divided into Group A (< 5 years of exposure) and Group B (> 5 years of exposure) and according to the average daily usage of mobile phones, subjects were divided into Group 1 (< 60 min daily usage) and Group 2 (> 60 min of daily usage). After that systemic examination was done. Audiological testing included pure tone audiometry (PTA) with extended high frequencies (0.250–12 kHz), Otoacoustic emissions (OAE) and Auditory Brainstem response (ABR) testing and middle latency response (MLR) were performed. Out of 100 subjects, maximum subjects (38%) in the present study were in the age group of 21–30 years with male: female ratio of 1.6:1. The main associated complaints in the subjects at the time of enrolment in the study included ear warmth (34%) followed by aural fullness (20%) and tinnitus (17%). In Group A, mild SNHL was seen in 3 (11.54%) subjects in whom 2 had > 60 min average daily use and 1 had < 60 min daily use. In Group B 19 (25.68%) subjects had mild SNHL out of which 6 were in Group 2 and 13 were in Group 1. In group B 2 (2.7%) subjects had moderate SNHL. Increase in latencies of Na and Pa were noted with prolonged and frequent exposure to mobile phones in MLR. It is advised to limit the usage of mobile phones so as to reduce the damage caused by EMRs to the auditory system. [ABSTRACT FROM AUTHOR]

Hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome is an autosomal dominant disorder. Because HDR syndrome is caused by haploinsufficiency in GATA3, it exhibits variation in the onset and progression of hearing loss. In previous reports, the automated auditory brainstem response (AABR) was considered insufficient to detect sensorineural hearing loss caused by HDR syndrome. We report a case of HDR syndrome whose congenital hearing loss was detected by newborn hearing screening (NHS) using AABR. In this case, HDR syndrome was suspected due to hearing loss, hypocalcemia, and her family history. Genetic testing confirmed the diagnosis of HDR syndrome at 5 months of age. Because the phenotype of hearing loss due to HDR syndrome is variable and includes progressive hearing loss, these cases may not be detected by the HNS. However, most of the previous reports were published before the NHS became common and given the frequency of hearing loss complications in HDR syndrome. We consider that there is a reasonable number of HDR syndrome cases with abnormalities on the NHS. We believe that the NHS may also be useful for early detection of hearing loss due to HDR syndrome. [ABSTRACT FROM AUTHOR]

IntroductionThe Newborn Hearing Screening (NHS) program was officially launched in Jordan in 2021. Since its inception, no studies have examined the effectiveness of the program. This study seeks to assess the effectiveness and outcomes of the NHS program in Jordan.MethodsA retrospective cross-sectional study was conducted to investigate the program coverage rate, referral rate, loss to follow-up rate and the hearing status of newborns who successfully completed the necessary diagnostic assessment. Live births in all hospitals administered by the Ministry of Health (MoH) in Jordan from July 2021 to November 2023 were included.ResultsOut of 25,825 newborns delivered, 99.4% (25,682) were screened. A referral rate of 0.7% (189) was recorded. Approximately 61.9% of those referred (n = 117) had normal hearing, while 31.7% (60 infants) were diagnosed with hearing loss. The prevalence of congenital hearing loss was 0.14%, and the mean age for identifying hearing loss was 11 months.DiscussionThe current status of the NHS program in Jordan is promising. The program has achieved most benchmarks recommended by the Joint Committee on Infant Hearing (JCIH), demonstrating encouraging outcomes. There is a need to investigate and address the factors causing delays in the identification of hearing loss in Jordan.

Objective To study the application of CE-Chirp in the evaluation of hearing impairment in forensic medicine by testing the auditory brainstem response （ABR） in adults using CE-Chirp to analyze the relationship between the V-wave response threshold of CE-Chirp ABR test and the pure tone hearing threshold. Methods Subjects （aged 20-77 with a total of 100 ears） who underwent CE-Chirp ABR test in Changzhou De’an Hospital from January 2018 to June 2019 were selected to obtain the V-wave response threshold， and pure tone air conduction hearing threshold tests were conducted at 0.5， 1.0， 2.0 and 4.0 kHz， respectively， to obtain pure tone listening threshold. The differences and statistical differences between the average pure tone hearing threshold and V-wave response threshold were compared in different hearing levels and different age groups. The correlation， differences and statistical differences between the two tests at each frequency were analyzed for all subjects. The linear regression equation for estimating pure tone hearing threshold for all subjects CE-Chirp ABR V-wave response threshold was established， and the feasibility of the equation was tested. Results There was no statistical significance in the CE-Chirp ABR response threshold and pure tone hearing threshold difference between different hearing level groups and different age groups （P>0.05）. There was a good correlation between adult CE-Chirp ABR V-wave response threshold and pure tone hearing threshold with statistical significance （PPConclusion The use of CE-Chirp ABR V-wave response threshold can be used to evaluate subjects’ pure tone hearing threshold under certain conditions， and can be used as an audiological test method for forensic hearing impairment assessment.

Newborn hearing screening (NHS) programs are essential to identify hearing loss early in life and to improve outcomes in children. In Saudi Arabia, the national NHS program has been operational since 2016; however, few studies have evaluated its status, and none have covered all provinces across the country. This cross-sectional retrospective study provides an overview of the program's status across all provinces, focusing on screening coverage rates, referral/fail rates, and follow-up procedures. In 2021, 199,034 newborns were screened, with a coverage rate of 92.6% and an overall referral/fail rate of 1.87%. These performance measures provide a foundation for future progress and improvements. This study highlights the importance of ongoing efforts to enhance the program's effectiveness and sustainability.

Abstract Objective This study aimed to compare and analyze the expression and significance of the GRP78 protein in cochlear cell injury induced by a high glucose and high-fat diet in obese and diabetic rats. Methods Male SD rats were randomly divided into two groups: normal (NC) and high-fat (HF) groups. The NC group was fed a standard diet for eight weeks, while the HF group received a high-glucose, high-fat diet. The HF group was further categorized into the obesity group (OB group) and the type II diabetes mellitus group (T2DM group). To induce a type II diabetes mellitus (T2DM) model, the T2DM group received an intraperitoneal injection of a small dose of STZ (45 mg/kg). After four weeks on the original diet, body weight, blood glucose, blood lipid levels, and auditory brainstem response (ABR) thresholds were measured. The cochlea was dissected, and its morphology was observed using HE staining. Immunohistochemistry and western blotting were utilized to examine the expression level of the GRP78 protein in the cochlea. Results (1) The ABR threshold demonstrated a statistically significant difference between the T2DM group and the OB group (P

Background: Auditory brainstem response (ABR) to the level-specific (LS) CE-Chirp has been reported to provide optimum neural synchrony along cochlear partitions, theoretically improving ABR waveform resolution. Despite this promising finding, limited studies have been conducted to contrast the results between LS CE-Chirp and Click stimuli. The current study aimed to compare the results of ABR between the two stimuli (Click and LS CE-Chirp). Method: Sixty-seven normal-hearing infants, both with and without risk factors, aged less than 7 months old, participated in this study. The ABR test was conducted at 70 dBnHL using 33.3 stimulus repetition rates with both Click and LS CE-Chirp stimuli. The signal averaging was stopped at a maximum fixed signal average of 2,500 sweeps. Data were statistically compared between the two stimuli using the Wilcoxon signed-rank test. Results: The waves I and V ABRs elicited by LS CE-Chirp exhibited significantly larger amplitudes than the Click stimulus. However, the amplitude of wave III and absolute latencies were similar in both stimuli at a supra-threshold level. Conclusion: LS CE-Chirp has the advantage of larger amplitudes than the ABR from Click at the supra-threshold level (70 dBnHL) in normal-hearing infants. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the safety and efficacy of chloral hydrate in auditory brainstem response (ABR) tests. Setting and Design: In this study, the authors systematically searched both English (Embase, PubMed, and Web of Science) and Chinese (Chinese National Knowledge Infrastructure, Wanfang Data, and VIP Chinese Science) databases. Two authors independently performed data extraction and quality assessment. The pooled sedation failure rate and the pooled incidence of adverse events were calculated via a random‐effects model. Sensitivity and subgroup analyses were performed to explore the sources of heterogeneity, and the PRISMA guideline was followed. Participants: Patients with ABR tests receiving chloral hydrate sedation. Main outcome measures: The pooled sedation failure rate and the pooled incidence of adverse events. Results: A total of 23 clinical studies were included in the final analysis. The pooled sedation failure rate of patients who received chloral hydrate sedation before ABR examination was 10.0% [95% confidence interval (CI) (6.7%, 15.0%), I2 = 95%, p <.01]. There were significant differences in the prevalence of sedation failure between sample sizes greater than 200 and those less than or equal to 200 (5.6% vs. 19.6%, p <.01) and between the studies that reported sleep deprivation and those that did not report sleep deprivation (7.1% vs. 18.9%, p <.01). The pooled incidence of adverse events was 10.32% [95% CI (5.83%, 14.82%), I2 = 98.1%, p <.01]. Conclusions: Chloral hydrate has a high rate of sedation failure, adverse events, and potential carcinogenicity. Therefore, replacing its use in ABR tests with safer and more effective sedatives is warranted. [ABSTRACT FROM AUTHOR]

Introduction: Mefloquine is an antimalarial medicine used to prevent and treat malaria. This medicine has some side effects, including ototoxicity. This study, which was designed in two phases, aimed to investigate the side effects of mefloquine and evaluate the preventive effects of electrical stimulation on these side effects. Methods: In the first phase, two doses of mefloquine (50 and 200 μM) were injected into male rats, and after 7 days, they were evaluated by an auditory brainstem response (ABR) test. In the second phase, electrical stimulation was applied for 10 days, and then a toxic dose of mefloquine was injected. Similar to the first phase of the study, the animals were evaluated by an ABR test after 7 days. Results: In the first phase, the results showed that a high dose of mefloquine increased the ABR threshold and wave I latency; however, these changes were not observed in the second phase. Conclusion: Application of electrical stimulation could prevent the ototoxic effects of mefloquine. According to the findings of the present study, electrical stimulation can be used as a preconditioner to prevent the ototoxic effects of mefloquine. [ABSTRACT FROM AUTHOR]

Hearing loss is a common manifestation of Hunter's syndrome, with reported rates ranging from 67.3 to 94%. The aim is to highlight the audiological profile and pathophysiology of mixed hearing loss in individuals with hunter's syndrome. A 7.6-year-old male child was brought to the department of audiology with a complaint of not responding to name call and regression in the speech and language skills. Detailed audiological showed severe to profound mixed hearing loss. REELS and 3DLAT results showed RLA to be 9 to 10 months and ELA to be 6 to 7 months. Owing to the progressive nature and high prevalence of hearing loss in hunter's syndrome, this case report highlights the importance of middle ear evaluation in the pediatric hearing assessment apart from OAE and ABR. Speech- language therapy must be considered with a focus on functional communication. [ABSTRACT FROM AUTHOR]

The mitochondrial disorder–Leigh syndrome is a neurodegenerative disorder often manifested with brainstem abnormalities. The case report highlights the auditory brainstem response in a child with medical findings suggestive of Leigh syndrome. The case report also emphasizes the importance of ruling out any underlying neural pathology before making a clinical impression in children with developmental delays. [ABSTRACT FROM AUTHOR]

Long-term exposure to noise can cause irreversible hearing loss. Considering that there is no effective drug treatment, it is important to seek preventive treatment for noise-induced hearing loss (NIHL). Although astragaloside IV (AS-IV) protects against NIHL by reducing serum inflammatory factors, there is scarce information on the regulation of inflammatory factors by AS-IV to prevent NIHL. We investigated the hearing thresholds and relationship between the serum levels of inflammatory cytokines and intestinal microbiota of c57bl/6j mice exposed to noise (103 dB SPL 4 h·d−1) for 7 days, treated with or without AS-IV. Our results revealed a lower hearing threshold and lower serum levels of TNF-α, TNF-γ, IL-6, IL-1β, and IFN-γ in the mice treated with AS-IV. Additionally, AS-IV increased the abundance levels of the phylum Firmicutes, class Bacillus, order Lactobacillus, and family Lactobacillus (p < 0.05), and decreased those of the phylum Bacteroidetes and order Bacteroidales (p < 0.05). Lactobacillus and Bacilli negatively correlated with TNF-α, TNF-γ, and IL-1β; Erysipelotrichaceae negatively correlated with INF-γ; and Clostridiales positively correlated with IL-1β. In conclusion, AS-IV reduces the elevation of hearing thresholds in mice, preventing hearing loss in mice exposed to noise, and under the intervention of AS-IV, changes in the levels of inflammatory factors correlate with intestinal flora. We suggest that AS-IV improves intestinal flora and reduces inflammation levels in c57bl/6j mice exposed to noise. [ABSTRACT FROM AUTHOR]

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The auditory brainstem response (ABR) is important for both clinical and basic auditory research. It is a non-invasive measure of hearing function with millisecond-level precision. The ABR can not only measure the synchrony, speed, and efficacy of auditory physiology but also detect different modalities of hearing pathology and hearing loss. ABRs are easily acquired in vertebrate animal models like reptiles, birds, and mammals, and complement existing molecular, developmental, and systems-level research. One such model system is the chicken; an excellent animal for studying auditory development, structure, and function. However, the ABR for chickens was last reported nearly 4 decades ago. The current study examines how decades of ABR characterization in other animal species support findings from the chicken ABR. We replicated and expanded on previous research using 43 chicken hatchlings 1- and 2-day post-hatch. We report that click-evoked chicken ABRs presented with a peak waveform morphology, amplitude, and latency like previous avian studies. Tone-evoked ABRs were found for frequencies from 250 to 4000 Hertz (Hz) and exhibited a range of best sensitivity between 750 and 2000 Hz. Objective click-evoked and tone-evoked ABR thresholds were comparable to subjective thresholds. With these revisited measurements, the chicken ABR still proves to be an excellent example of precocious avian development that complements decades of molecular, neuronal, and systems-level research in the same model organism. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to compare and analyze the expression and significance of the GRP78 protein in cochlear cell injury induced by a high glucose and high-fat diet in obese and diabetic rats. Methods: Male SD rats were randomly divided into two groups: normal (NC) and high-fat (HF) groups. The NC group was fed a standard diet for eight weeks, while the HF group received a high-glucose, high-fat diet. The HF group was further categorized into the obesity group (OB group) and the type II diabetes mellitus group (T2DM group). To induce a type II diabetes mellitus (T2DM) model, the T2DM group received an intraperitoneal injection of a small dose of STZ (45 mg/kg). After four weeks on the original diet, body weight, blood glucose, blood lipid levels, and auditory brainstem response (ABR) thresholds were measured. The cochlea was dissected, and its morphology was observed using HE staining. Immunohistochemistry and western blotting were utilized to examine the expression level of the GRP78 protein in the cochlea. Results: (1) The ABR threshold demonstrated a statistically significant difference between the T2DM group and the OB group (P < 0.05), as well as between the OB group and the NC group (P < 0.05). (2) Based on morphological comparisons from HE-stained sections, the T2DM group exhibited the most significant alterations in the number of cells in the spiral ganglion, the organ of Corti, and the stria vascularis of the cochlea. (3) The expression level of the GRP78 protein in the cochlea was higher in the T2DM group compared to the OB group (P < 0.05) and higher in the OB group compared to the NC group (P < 0.05). Conclusion: The findings indicate that the GRP78 protein plays a role in hearing loss caused by T2DM and hyperlipidemia. Moreover, T2DM is more likely than hyperlipidemia to be associated with hearing impairment. [ABSTRACT FROM AUTHOR]

The purpose of the study was to which investigate whether dexamethasone, which has anti-inflammatory and immune response suppression roles, could treat noise-induced hearing loss caused by damage to hair cells in the cochlea. The experiment used 8-week-old CBA mice exposed to white noise at an intensity of 110 dB SPL for 2 h, with hearing loss confirmed by the auditory brainstem response test. Dexamethasone was administered by intraperitoneal injection for 5 days, and the therapeutic effect was investigated for 3 weeks. The experimental groups were 3 mg/kg of dexamethasone (3 mpk) and 10 mg/kg of dexamethasone (10 mpk), and the control group was a saline-administered group. The results showed that compared to the control group, the hearing threshold value was recovered by 10 dB SPL compared to the saline group from the 14th day in the 3 mpk group. In the 10 mpk group, thresholds were recovered from the 7th day compared to the saline group. This difference was similar at 4 kHz, and in the case of the 10 mpk group, the threshold was recovered by 20 dB SPL compared to the saline group. The study also confirmed the restoration of nerve cell activity and showed a recovery effect of about 20 µV in the amplitude value change in the 10 mpk group. In conclusion, the study suggests that dexamethasone has a therapeutic effect for noise-induced hearing loss by increasing the activity of nerve cells and showing a recovery effect from hair cells damaged by noise. [ABSTRACT FROM AUTHOR]

Introduction NB CE-Chirp LS was developed to improve the audiogram estimation by auditory brainstem response (ABR) thresholds during audiological assessment of infants and difficult to test children. However, before we know how the stimulus behaves in several types of hearing loss, it is important we know how the stimulus behaves in normal hearing infants.

Cochlear synaptic loss (termed cochlear synaptopathy) has been suggested to contribute to suprathreshold hearing difficulties. However, its existence and putative effects in humans remain inconclusive, largely due to the heterogeneous methods used across studies to indirectly evaluate the health of cochlear synapses. There is a need to standardize proxies of cochlear synaptopathy to appropriately compare and interpret findings across studies. Early auditory evoked potentials (AEPs), including the compound action potential (AP)/Wave I of the auditory brainstem response are a popular proxy, yet remain variable based on technical considerations. This study evaluated one such consideration—electrode array (i.e., montage)—to optimize the use of early AEP waveforms. In 35 young adults, electrocochleography (ECochG) responses were collected using vertical and horizontal montages. Standard ECochG measures and AP/Wave I and Wave II peak-to-trough amplitudes and latencies were compared between montages. Vertical montage recordings consistently produced significantly larger AP/Wave I peak-to-trough amplitudes compared to horizontal recordings. These findings support the use of a vertical electrode montage for optimal recordings of peripheral cochlear nerve activity. As cochlear synaptopathy continues to be explored in humans, the methods highlighted here should be considered in the development of a standardized assessment.

Background noise disrupts the neural processing of sound, resulting in delayed and diminished far-field auditory-evoked responses. In young adults, we previously provided evidence that cognitively based short-term auditory training can ameliorate the impact of background noise on the frequency-following response (FFR), leading to greater neural synchrony to the speech fundamental frequency(F0) in noisy listening conditions. In this same dataset (55 healthy young adults), we now examine whether training-related changes extend to the latency of the FFR, with the prediction of faster neural timing after training. FFRs were measured on two days separated by ~8 weeks. FFRs were elicited by the syllable “da” presented at a signal-to-noise ratio (SNR) of +10 dB SPL relative to a background of multi-talker noise. Half of the participants participated in 20 sessions of computerized training (Listening and Communication Enhancement Program, LACE) between test sessions, while the other half served as Controls. In both groups, half of the participants were non-native speakers of English. In the Control Group, response latencies were unchanged at retest, but for the training group, response latencies were earlier. Findings suggest that auditory training can improve how the adult nervous system responds in noisy listening conditions, as demonstrated by decreased response latencies.

Cochlear synaptic loss (termed cochlear synaptopathy) has been suggested to contribute to suprathreshold hearing difficulties. However, its existence and putative effects in humans remain inconclusive, largely due to the heterogeneous methods used across studies to indirectly evaluate the health of cochlear synapses. There is a need to standardize proxies of cochlear synaptopathy to appropriately compare and interpret findings across studies. Early auditory evoked potentials (AEPs), including the compound action potential (AP)/Wave I of the auditory brainstem response are a popular proxy, yet remain variable based on technical considerations. This study evaluated one such consideration—electrode array (i.e., montage)—to optimize the use of early AEP waveforms. In 35 young adults, electrocochleography (ECochG) responses were collected using vertical and horizontal montages. Standard ECochG measures and AP/Wave I and Wave II peak-to-trough amplitudes and latencies were compared between montages. Vertical montage recordings consistently produced significantly larger AP/Wave I peak-to-trough amplitudes compared to horizontal recordings. These findings support the use of a vertical electrode montage for optimal recordings of peripheral cochlear nerve activity. As cochlear synaptopathy continues to be explored in humans, the methods highlighted here should be considered in the development of a standardized assessment. [ABSTRACT FROM AUTHOR]

Introduction: Coronavirus disease (COVID-19), considered to be caused by a novel coronavirus (SARS-CoV-2), is an acute respiratory disease which was declared a pandemic by the World Health Organization. Previously published reports have shown contradictory findings on the involvement of the auditory system in individuals infected with COVID-19. The present study aims to assess auditory system functioning in individuals post-COVID-19 infection and compare the results with individuals without COVID-19 infection. Material and methods: Participants in this study were 30 individuals who had experienced mild COVID-19 infection and 30 individuals who never had COVID-19. Participants were aged between 18 and 40 years. Testing was done 1 to 6 months after infection, and involved conventional and extended high-frequency audiometry, speech perception in quiet and at different signal-to-noise ratios (SPIN), transient evoked otoacoustic emissions (TEOAEs) in quiet and in the presence of contralateral noise, and auditory brainstem response (ABR) in the ipsilateral and contralateral mode. Results: None of the tests -- pure-tone thresholds, speech perception in quiet and in noise, TEOAE with and without contralateral noise, and ABR -- showed any significant difference between individuals who never had COVID-19 infection and those who had recovered from the infection. Both afferent and efferent auditory pathways showed normal findings in individuals post-COVID-19 infection. Conclusions: Individuals who have been infected with mild COVID-19 did not show any significant deficit in any of the audiological tests, suggesting that the disease does not cause any permanent harm to the auditory system after the infection has subsided. [ABSTRACT FROM AUTHOR]

The auditory brainstem response (ABR) to tone burst stimuli of thirteen frequencies ranging from 0.5 to 48 kHz was recorded in the nine-banded armadillo (Dasypus novemcinctus), the only extant member of the placental mammal superorder Xenarthra in North America. The armadillo ABR consisted of five main peaks that were visible within the first 10 ms when stimuli were presented at high intensities. The latency of peak I of the armadillo ABR increased as stimulus intensity decreased by an average of 20 ms/dB. Estimated frequency-specific thresholds identified by the ABR were used to construct an estimate of the armadillo audiogram describing the mean thresholds of the eight animals tested. The majority of animals tested (six out of eight) exhibited clear responses to stimuli from 0.5 to 38 kHz, and two animals exhibited responses to stimuli of 48 kHz. Across all cases, the lowest thresholds were observed for frequencies from 8 to 12 kHz. Overall, we observed that the armadillo estimated audiogram bears a similar pattern as those observed using ABR in members of other mammalian clades, including marsupials and later-derived placental mammals. [ABSTRACT FROM AUTHOR]