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Introduction Hearing loss etiology depends on the population studied as well as on the ethnicity and the socio-economic condition of the analyzed region. Etiological diagnosis contributes to the improvement of preventive measures and to the early identification of this deficiency. Objective To identify the etiological factors of hearing loss and its prevalence in a tertiary hospital in southern Brazil, to verify the frequency of mutations in GJB2 and GJB6 genes, and to correlate the degree of hearing loss with the etiological factors of deafness. Methods This prevalence study involved 140 children with bilateral sensorineural or mixed hearing loss. Medical history, physical examination, audiometry, and evoked auditory brainstem response were conducted. Imaging and genetic examinations were also performed. Results Etiologies and their prevalence were as follows: (a) indeterminate causes, 31.4%; (b) conditions related to neonatal period, 22.1%; (c) genetic, 22.1%; (d) auditory neuropathy, 10%; (e) other factors (cortical malformation, intracranial hemorrhage, and internal ear malformations), 7.9% and (f) congenital infections, 6.4%. Within the genetic cases, ten homozygous and seven heterozygotes of the 35delG mutation were identified, besides two cases of rare variants of GJB2: p.Try172* and p.Arg184Pro. One case with homozygosis of del(GJB6-D13S1830) was found. Regarding severity of hearing loss, in 78.6% of the cases the degree of hearing loss was profound and there were no significant differences when comparing between etiologies. Conclusion The number of indeterminate etiologies is still high and congenital CMV infection may be a possible cause of undiagnosed etiology for hearing loss. The predominance of etiologies related to neonatal conditions and infectious causes are characteristic of developing countries. The most prevalent mutation was 35delG, the main GJB2 gene, probably because of the European influence in the genotype of our population. Resumo Introdução A etiologia da perda auditiva depende da população estudada, da etnia e da condição socioeconômica da região analisada. O diagnóstico etiológico contribui para o aprimoramento das medidas preventivas e para a identificação precoce dessa deficiência. Objetivos Identificar os fatores etiológicos da perda auditiva e sua prevalência em um hospital terciário do sul do Brasil, verificar a frequência de mutações nos genes GJB2 e GJB6 e correlacionar o grau da perda auditiva com os fatores etiológicos da deficiência auditiva. Método Este estudo de prevalência avaliou 140 crianças com perda auditiva neurossensorial bilateral ou mista. Foram submetidos a anamnese com histórico médico, exame físico, audiometria e potencial evocado auditivo de tronco encefálico. Exames de imagem e genéticos também foram feitos. Resultados As etiologias e sua prevalência foram as seguintes: (a) causas indeterminadas, 31,4%; (b) condições relacionadas ao período neonatal, 22,1%; (c) genética, 22,1%; (d) neuropatia auditiva, 10%; (e) outros fatores (malformação cortical, hemorragia intracraniana e malformações da orelha interna), 7,9% e (f) infecções congênitas, 6,4%. Entre os casos genéticos, foram identificados dez casos homozigotos e sete heterozigotos da mutação 35delG, além de dois casos de variantes raras do GJB2: p.Try172* e p.Arg184Pro. Foi encontrado um caso homozigoto da mutação del (GJB6‐D13S1830). Em relação à gravidade da perda auditiva, em 78,6% dos casos o grau da perda auditiva foi profundo e não houve diferenças significantes na comparação entre as etiologias. Conclusão O número de etiologias indeterminadas ainda é elevado e a infecção congênita por CMV pode ser uma possível causa de etiologia não diagnosticada para perda auditiva. A predominância das etiologias relacionadas às condições neonatais e às causas infecciosas são características de países em desenvolvimento. A mutação mais prevalente foi a 35delG e o principal gene foi o GJB2, provavelmente devido à influência europeia no genótipo de nossa população.

Introduction Noise-induced hearing loss is one of the most common forms of sensorineural hearing loss. Nevertheless, the mechanisms of noise-induced hearing loss are still not fully understood. Objective To investigate the dynamics of inflammatory responses in the mammalian cochlea following noise trauma at two different times, once during the light cycle and once during the dark. Methods We challenged C57BL/6J mice with moderate, continuous noise trauma at either 9 a.m. or 9 p.m. Auditory function, histological changes in hair cells, and modifications in gene expression levels of inflammatory mediators were assessed at specific time points. Shifts in auditory brainstem response thresholds were measured at 1, 3, 7 and 14 days after noise exposure to measure potential noise-induced hearing loss. Cochlear basilar-membrane immunofluorescent staining was performed at 3 and 14 days after noise exposure. The mRNA levels of several inflammatory mediators were measured via quantitative real-time polymerase chain reaction before (pre) and after (0, 3, 12, 24 and 72 h) noise exposure. Results We found that all noise-exposed mice developed a temporary threshold shift and that there were no significant differences between daytime and nighttime noise exposures in terms of inducing hearing-threshold shifts. Similarly, we did not detect significant histological changes in hair cells between these two groups. However, we discovered an interesting phenomenon in that the peak mRNA levels of IL-1β, IL-6, CCL2 and TNF-α were higher in day noise-exposed mice compared to those in night noise-exposed mice, and these mRNA levels subsided more slowly in day noise-exposed mice. Conclusion Overall, these observations suggest that the circadian timing of noise exposure has a significant effect on noise-induced inflammatory responses in the mouse cochlea and that a greater inflammatory response might occur after daytime exposure.

Background There is a growing number of pediatric procedures requiring sedation outside the operating room. Among these are auditory brainstem response (ABR) tests, the gold standard for objective hearing evaluation in infants and toddlers. Recently, a nurse-led pediatric sedation service based on a structured protocol has been developed for ABR testing. Objectives To retrospectively analyze the safety and efficacy of the pediatric nurse-led sedation protocol (PNLSP) in a tertiary medical center using Chloral Hydrate (CH) in children undergoing ABR testing. Methods Data from medical charts of children who underwent sedation for ABR testing between January 2014 and December 2017, were retrieved. Analysis of sedation success/failure rates, sleep induction time (SIT), sleep duration time (SDT), and adverse events (AE), was performed. Findings 1348 children with a mean age of 13.4 months (range 3–42 months), classified by the American Society of Anesthesiologists Physical Status Classification System (ASA score) 1–3, were included in the analysis. All children received a fixed dose of 75 mg / kg CH orally or rectally. Sedation success rate was 98.7% and enabled completion of ABR testing. Failure to sedate was evident in 17 children (1.3%), all classified as ASA score 1–2. Median SIT and SDT were 25 and 100 min, respectively. Mild AE occurred in 9 children (0.67%), none of which required further intervention. Conclusions Findings support the use of a structured PNLSP using CH as safe and efficient. The suggested protocol is an effective alternative for general anesthesia (GA) for ABR testing in healthy young children.

Objectives: the primary objective of this study was to train and test machine learning algorithms to be able to detect accurately whether EEG data contains an auditory brainstem response (ABR) or not and recommend suitable machine learning methods. In addition, the performance of the best machine learning algorithm was compared with that of prominent statistical detection methods.Design: four machine learning algorithms were trained and evaluated using nested k-fold cross-validation: a random forest, a convolutional long short-term memory network, a stacked ensemble, and a multilayer perceptron. The best method was evaluated on a separate test set and compared with conventional detection methods: Fsp, Fmp, q-sample uniform scores test, and Hotelling’s T2 test. The models were trained and tested on simulated data that were generated based on recorded ABRs collected from 12 normal-hearing participants and no-stimulus EEG data from 15 participants. Simulation allowed the ground truth of the data (“response present” or “response absent”) to be known.Results: the sensitivity of the best machine learning algorithm, a stacked ensemble, was significantly greater than that of the conventional detection methods evaluated. The stacked ensemble, evaluated using a bootstrap approach, consistently achieved a high and stable level of specificity across ensemble sizes.Conclusions: the stacked ensemble model presented was more effective than conventional statistical ABR detection methods and the alternative machine learning approaches tested. The stacked ensemble detection method may have potential both in automated ABR screening devices as well as in evoked potential software, assisting clinicians in making decisions regarding a patient’s ABR threshold. Further assessment of the model’s generalizability using a large cohort of subject recorded data, including participants of different ages and hearing status, is a recommended next step.

Background Tietz syndrome is a very rare clinical entity characterized by the association of profound bilateral congenital sensorineural deafness and generalized hypopigmentation of skin, eyes, and integuments (snow white appearance). It is an autosomal dominant syndrome due to a mutation in the melanocyte inducing transcription factor (MITF) gene. The association of a heart malformation has never been reported in this syndrome. Case presentation We report two cases of two cousins aged 5 years and 20 months respectively with a history of first degree consanguineous parents. Both girls presented with diffuse hypopigmentation of the skin, blond hair, blue eyes, and bilateral diffuse retinal hypopigmentation at ocular fundus exam. Bilateral profound sensorineural hearing loss was confirmed by auditory brainstem response in both cases. Echocardiography revealed a cardiac malformation such as interventricular communication in the older cousin and interatrial communication in the younger cousin. The family investigation did not reveal a similar case among ancestors. The diagnosis of Tietz syndrome was based on clinical criteria and pedigree. The older cousin underwent a total optical correction and a right unilateral cochlear implantation followed by speech therapy with a satisfactory result after a follow-up of two years. Unfortunately, the little cousin died following a head trauma. Conclusions Tietz syndrome is a rare autosomal dominant genetic disorder, characterized by generalized albinism with bilateral profound hearing loss. It results from a nontruncating mutation in the basic domain of in the MITF gene. Its management must include, in addition to hearing and ophthalmic rehabilitation, the research and treatment of cardiac malformations which may be life-threatening.

Auditory Neuropathy Spectrum Disorder is a rare condition wherein neural transmission through the VIIIth nerve and auditory brainstem is disrupted with intact peripheral hearing. Most frequently reported symptoms by individuals suffering from such conditions include impaired speech discrimination especially in presence of background noise. The aim of this single case study is to emphasize the effectiveness of channel-free technology as a rehabilitative option and to demonstrate the improvement in speech perception in noise with noise desensitisation training. A 24-year-old male patient reported to the National Institute of Speech and Hearing with the complaint of poor speech comprehension. The audiological profile revealed, bilateral moderate sensorineural hearing loss in pure tone audiometry with poor speech discrimination scores, bilateral ‘A’ type tympanogram with absent acoustic reflexes, good signal to noise ratio in otoacoustic emissions, and absent Auditory Brainstem Response at 95 dBnHL bilaterally suggestive of auditory neuropathy spectrum disorder in both the ears. As a part of rehabilitation, hearing aids with multiple channels and channel-free technology were tried and better speech discrimination scores were obtained with channel-free technology. In order to address poor speech discrimination in presence of noise, noise desensitisation training was given at different Signal to Noise Ratio with channel-free hearing aids and was found to be effective in improving the speech discrimination scores especially in adverse listening conditions. Key words: Auditory neuropathy spectrum disorder, Channel free hearing aid, Noise desensitisation.

Since its inception by Jewett and Williston in the late 1960s, the auditory brainstem response (ABR) has been an indispensable diagnostic tool, used by audiologists around the world. Click-evoked ABR testing proves to be a reliable tool, as it provides an objective representation of the auditory function, an estimate of hearing thresholds and the ability to pinpoint a potential issue in the auditory neural pathway. The present study describes state-of-the-art ABR analytics-related platforms and provides an overview of their functionality. In conjunction, we introduce the design and development of a newly developed, user-friendly web application, built in R language. This application provides several well-known and newly key characteristics for the analysis of ABR waveforms. These include absolute peak latencies, amplitudes, and interpeak latencies.

Background and Objectives: To investigate the diagnostic validity of auditory brainstem response (ABR) in the screening of vestibular schwannoma (VS). Subjects and Methods: Forty patients diagnosed with VS using magnetic resonance imaging who had undergone ABR before treatment between 2005 and 2015 were included. ABR results were considered positive when findings met at least one of the following criteria: 1) absent evoked response, 2) desynchronization of waves other than wave I, 3) interpeak latency (IPL) between waves I and III >2.5 ms, 4) IPL between waves I and V >4.4 ms, 5) wave V interaural latency difference >0.2 ms, and 6) interaural difference in IPL between waves I and V >0.2 ms. Results: The overall sensitivity of ABR was 85.0%. For tumors measuring 10 mm. The sensitivity of tumors confined to the internal acoustic canal was 73.3% compared with 100.0% for tumors confined to the cerebellopontine angle. In patients with serviceable hearing, the mean tumor size was 7.8±2.9 mm in patients with a normal ABR and 15.1±9.4 mm in patients with an abnormal ABR, indicating a significant difference (p10 mm in patients with serviceable hearing, supporting the need for further active diagnostic and treatment modalities in clinical practice.

ObjectiveOtological complications are considered early symptoms of severe acute respiratory syndrome coronavirus-2; however, it is unknown how long these symptoms last and whether the virus leaves any hearing disorders post-recovery.MethodsThis prospective cohort study comprised 31 mild or moderate confirmed coronavirus disease 2019 patients and 26 age-matched control peers (21–50 years old). Patients were questioned about their otological symptoms, and their hearing status was assessed during one month post-diagnosis.ResultsPatients showed a significantly higher rate of otological symptoms (hearing loss, ear fullness, ear pain, dizziness or vertigo, communication difficulties, and hyperacusis) versus the control group (p ≤ 0.022). The symptoms resolved early, between 2 and 8 days after their appearance. No significant differences were observed between the two groups in pure tone and extended high-frequency audiometry, transient evoked otoacoustic emissions, distortion product otoacoustic emissions, or auditory brainstem response following recovery.ConclusionThe findings indicate that, in mild to moderate coronavirus disease 2019 cases, otological symptoms resolve within a week, and the virus has no lasting impact on the auditory system.

Introduction Aminoglycosides are widely known for their ototoxic side effects. Nevertheless, they are potent antibiotics used in the treatment of life-threatening conditions because of the current concern for antibiotic resistance. We hypothesized that creatine supplements which are believed to improve mitochondrial antioxidant defense system and maintain optimal energy homeostasis may improve the ototoxic side effects. Objective This study aimed to investigate the protective effects of creatine monohydrate against ototoxicity induced by amikacin in rats in an experimental animal model, using distortion product otoacoustic emissions and auditory brainstem response. Methods Twenty healthy rats were assigned to four groups (5 rats in each): the control group, the creatine monohydrate group, the amikacin group and the amikacin + creatine monohydrate group. The creatine monohydrate group received creatine at a dose of 2 g/kg once daily via gastric gavage for 21 days. The amikacin group received amikacin at a dose of 600 mg/kg by intramuscular injections once daily for 21 days. The amikacin + creatine monohydrate group received intramuscular injections of amikacin (600 mg/kg) once daily for 21 days and creatine monohydrate (2 g/kg) once daily via gastric gavage for 21 days. The control group received nothing. The distortion product otoacoustic emissions and auditory brainstem response measurements were performed on all rats on days 0, 7, 21. Results Regarding auditory brainstem response values, a significant increase in the auditory threshold was observed in the amikacin group on day 21 (p < 0.001). The amikacin+creatine monohydrate group showed significantly lower levels of auditory brainstem response auditory thresholds on day 21 in comparison to the amikacin group (p < 0.001). Additionally, the control group and the amikacin+creatine monohydrate group did not differ significantly with respect to auditory brainstem response thresholds on treatment day 21 (p > 0.05). When we compare distortion product otoacoustic emissions values, there was no significant difference between the amikacin and amikacin+creatine monohydrate groups on day 7 (p > 0.05), However significantly greater distortion product otoacoustic emissions values were observed in the amikacin+creatine monohydrate group on day 21 compared to the amikacin group (p < 0.001). Conclusion Our findings demonstrate that creatine treatment protects against amikacin ototoxicity when given at a sufficient dose and for an adequate time period.

Introduction: The effect of orally consumed monosodium glutamate (MSG), which is a common additive in the food industry, on the cochlea has not been investigated. The present study aimed to investigate the possible cochleotoxic effects of oral MSG in guinea pigs using electrophysiological, biochemical, and histopathological methods. Methods: Thirty guinea pigs were equally divided into control and intervention groups (MSG 100 mg/kg/day; MSG 300 mg/kg/day). At 1 month, 5 guinea pigs from each group were sacrificed; the rest were observed for another month. Electrophysiological measurements (distortion product otoacoustic emission [DPOAE] and auditory brainstem response [ABR]), glutamate levels in the perilymph and blood samples, and histopathological examinations were evaluated at 1 and 2 months. Results: Change in signal-to-noise ratio at 2 months was significantly different in the MSG 300 group at 0.75 kHz and 2 kHz (p = 0.013 and p = 0.044, respectively). There was no statistically significant difference in ABR wave latencies of the guinea pigs given MSG compared to the control group after 1 and 2 months; an increase was noted in ABR thresholds, although the difference was not statistically significant. In the MSG groups, moderate-to-severe degeneration and cell loss in outer hair cells, support cells, and spiral ganglia, lateral surface junction irregularities, adhesions in stereocilia, and partial loss of outer hair cell stereocilia were noted. Conclusion: MSG, administered in guinea pigs at a commonly utilized quantity and route of administration in humans, may be cochleotoxic.

Background Click-evoked auditory brainstem response (ABR) alterations are associated with autism spectrum disorder (ASD), but the specificity of these findings to the disorder is unclear. We therefore performed a meta-analysis on ABRs and attention-deficit/hyperactivity disorder (ADHD), a neurodevelopmental disorder that shares some etiologic and symptom overlap with ASD. Methods Seven papers compared ABR latency components (I, III, V, I-III, III-V, and I-V) between participants with and without ADHD. We used random-effects regression to generate component-specific estimates (Hedges's g) that adjusted for study sample sizes and the number of studies contributing to each estimate. We compared these estimates to our recently published meta-analysis of ABRs and ASD. Results All ADHD studies employed cross-sectional designs. ADHD was associated with longer latencies for waves III and V (g = 0.6, 95% confidence interval (CI) 0.3, 1.0 and g = 0.6, 95% CI 0.3, 0.9) and waves I-III and I-V (g = 0.7, 95% CI 0.2, 1.3 and g = 0.6, 95% CI 0.3, 1.0). Effect sizes from the ASD and ADHD meta-analyses did not differ from each other. Conclusions Similar patterns of ABR alterations are observed in ADHD and ASD. However, studies rarely screen for middle ear dysfunction or hearing loss and rely upon cross-sectional designs. Addressing these issues will inform the viability of ABRs as a prognostic and/or etiologic biomarker for these disorders. Impact Click-evoked ABR alterations are associated with ASD, but the specificity of these findings to the disorder is unclear. We therefore performed a meta-analysis of the association between ABRs and ADHD, a disorder that shares some etiologic and symptom overlap with ASD. ADHD was associated with longer ABR latencies for several components. These components are identical to those implicated in ASD. Effect sizes were similar in magnitude across disorders. The viability of ABRs as prognostic and/or etiologic biomarkers for neurodevelopmental risk requires addressing limitations in the literature (e.g., cross-sectional data, non-standardized ABR protocols, minimal characterization of symptom heterogeneity).

We have clarified the role of Universal Neonatal Hearing Screening (UNHS) for both early diagnosis and rapid treatment in order to improve the prognosis of the deaf child and reduce patient management costs. Although in Sicily UNHS has been progressively implemented, there is scarce data in the literature on this matter. Therefore, the main objective was to collect in the year 2018 the following data: number of newborns screened for hearing loss, number of infants "referred" to transiently evoked otoacoustic emissions (TEOAE), number of infants with pathologic auditory brainstem response (ABR) and number of infants affected by permanent hearing loss.UNHS monitoring was conducted through the collection of data through a questionnaire, which was analysed evaluating the effectiveness and adherence to the screening program prepared by the Department for Health Activities and the Epidemiological Observatory (DASOE).In 2018, there were 40,243 newborns in Sicily. A total of 37,562 newborns were screened (93.3%). There were 1,328 "referred" infants with TEOAE (3.5%). On the 2The monitoring of the UNHS in Sicily has allowed obtaining the data of individual centres, absent in the literature to date, to verify the effectiveness of the screening, according to JCIH criteria, to highlight some criticalities and, finally, to propose possible solutions.Screening uditivo neonatale universale nella regione Sicilia nel 2018.Abbiamo chiarito il ruolo dello screening uditivo neonatale universale (UNHS) sia come diagnosi precoce che come trattamento rapido al fine di migliorare la prognosi del bambino sordo e ridurre i costi di gestione del paziente. Anche se in Sicilia l’UNHS è stato progressivamente attuato, vi sono scarsi dati nella letteratura in materia. Pertanto, l’obiettivo principale è stato quello di raccogliere nell’anno 2018 i seguenti dati: numero di neonati sottoposti a screening per la perdita dell’udito, numero di neonati risultati “refer” alle TEOAE, numero di lattanti con ABR patologico e numero di lattanti affetti da perdita permanente dell’udito.Il monitoraggio del UNHS è stato condotto attraverso la raccolta dei dati forniti dal questionario, che valuta l’efficacia dello screening e l’aderenza alle fasi successive.Nel 2018, i nati in Sicilia sono stati 40.243. Sono stati sottoposti a screening 37.562 neonati, pari al 93,3%. Sono risultati “refer” con le TEOAE 1.328 neonati (pari al 3,5%). Al 2° livello, i neonati “refer” esaminati sono stati 1.080 su 1.328 attesi (dispersi 248 neonati refer, pari al 18,6%). I neonati “refer” confermati con le TEOAE sono stati 113 su 1.080, mentre i neonati “refer” confermati con ABR sono stati 71. Al 3° livello, i bambini esaminati sono stati 67 su 71 previsti: ventotto bambini soffrivano di perdita monolaterale dell’udito (13 lieve, 13 moderata, 1 grave e 1 profonda) e trentanove soffrivano di perdita bilaterale dell’udito (1 lieve, 19 moderata, 13 grave e 7 profonda). Escludendo 7 bambini provenienti dalla NICU, i bambini con perdita dell’udito sono stati 60 su 37.562 (pari all’1,5‰).Il monitoraggio dell’UNHS in Sicilia ha permesso di ottenere i dati dei singoli centri, dati assenti nella letteratura, di verificare l’efficacia dello screening, secondo criteri JCIH, di evidenziare alcune criticità e, infine, di proporre possibili soluzioni.

Objectives. Diabetic auditory neuropathy is a common complication of diabetes mellitus that has a major impact on patients’ quality of life. In this study, we assessed the efficacy of rutin in treating diabetic auditory neuropathy in an experimental rat model.Methods. Forty Sprague-Dawley rats were randomly assigned to the following groups: group 1, control; group 2, diabetic rats; and groups 3–5, rats treated with rutin (at doses of 50, 100, and 150 mg/kg, respectively). We used auditory brain stem response, stereology of the spiral ganglion, and measurements of superoxide dismutase (SOD) and malondialdehyde (MDA) to evaluate the effects of treatment.Results. Significant improvements in auditory neuropathy were observed in the rutin-treated groups in comparison with the diabetic group (P

OBJECTIVE To examine the prevalence of hearing impairment in children with hypothyroidism, and to characterize clinical and subclinical hearing loss by examining cochlear function, auditory brainstem pathways, and integration of the auditory system as a whole. DESIGN An electronic search was conducted using PubMed, Scopus, and Cochrane Library databases. This systematic review was performed in accordance with the PRISMA guidelines. Original observational studies that utilized audiological tests for auditory system evaluations in hypothyroidism were included. A total of 2004 studies were found in the search, with 23 studies meeting the inclusion criteria. RESULTS The pooled prevalence of hearing loss was 16.1% [95% confidence interval 10.7, 22.4] for children with congenital hypothyroidism. Hearing thresholds at pure-tone averages (0.5-2 kHz) were 1.6 dB [95% confidence interval 1.7, 4.8] higher for children with hypothyroidism compared to age-matched controls. Cochlear dysfunction was detected at middle frequencies (1-3 kHz) by otoacoustic emission testing, indicating abnormalities of hair cell function or cochlear integration. Retrocochlear involvement was detected on auditory brainstem response (ABR), with prolonged Wave I indicating a peripheral conduction abnormality localized to the middle or inner ear and eighth cranial nerve. CONCLUSIONS Children with hypothyroidism have a higher prevalence of hearing loss than children without hypothyroidism. For children with congenital hypothyroidism, evidence of subclinical abnormalities at the level of the cochlea and eighth cranial nerve are present despite early initiation of levothyroxine therapy. Dysfunction of the auditory system might begin with predominance of peripheral conduction abnormalities early in development.

Objective: The auditory brainstem response (ABR) test has been widely used in childhood. Although it is a painless procedure, sedation can be needed in pediatric patients. Thus, this study aimed to evaluate safety and complications of sedation anesthesia applied in pediatric patients during ABR testing. Methods: Medical records of 75 children who underwent ABR testing between 2018 and 2020 were evaluated retrospectively in terms of applicability, safety, and complications of sedation anesthesia. Results: The ages ranged from 3 to 9 (mean 6.2) years. Comorbidity was detected in 20% (n = 15); 3 had multiple comorbidities, and the most common comorbidity was Down syndrome (4%). The drugs used in sedation anesthesia were midazolam in 81.3% (n = 61), a combination of propofol and ketamine in 14.7% (n = 11), and only propofol in 4% (n = 3) of the patients. An additional drug use was needed in 44% (n = 33). The mean procedure time was 40 (range 30–55) min. The mean anesthesia duration was 45 (range 35–60) min. The mean recovery time was 10 (range 5–15) min. Complications related to anesthesia developed in 4 (5.33%) of the patients; respiratory distress, agitation, cough, and nausea-vomiting were seen in one of the patients, respectively. Complications like bradycardia and respiratory or cardiac arrest were not seen at all. Conclusions: The complication rate of sedation anesthesia performed during ABR testing of pediatric patients is quite low. It may be more beneficial to use combinations of sedation drugs instead of using a single sedation drug. Although sedation anesthesia appears to be safe in general, the potentially life-threatening complications of sedative agents should be remembered, especially in children who have comorbidities.

Earlier studies disputed the influence of higher-order function such as attention or cognitive inhibition on the auditory brainstem response (ABR) result. In short, the ABR result was considered similar with or without the subject paying attention. However, in the last few years, there has been growing evidence that the higher-order function may influence the ABR findings provided the sensory gating system of the brain is triggered by any cognitive interference activities. This chapter will explain the concept of auditory sensory gating, a method to measure auditory sensory gating, and at the end of the chapter, preliminary findings concerning the ABR with cognitive interference among ten normally developing children are presented. This chapter will also share a case study that compared auditory sensory gating capacity in normal and children with mild autism spectrum disorder (ASD).

Human hearing loss is often accompanied by comorbidities like tinnitus. This perception of phantom sounds without external stimulation is affecting up to 15% of the adult population and can lead to psychological disorders like depression. Animal studies in rodents could show that tinnitus may not only be a result of hearing loss due to cochlear hair cell damage but can also be a consequence of synaptopathy at the inner hair cells already induced by moderate sound traumata (hidden hearing loss). In this study we investigate the synaptopathy previously shown in mice in our animal model, the Mongolian gerbil, and relate it to behavioral signs of tinnitus in this species. Tinnitus was induced by a mild monaural acoustic trauma leading to a monaural noise induced hearing loss in the animals quantified by auditory brainstem response audiometry. Behavioral signs of tinnitus percepts were detected by measurement of pre-pulse inhibition of the acoustic startle response in a gap-noise paradigm in about two-thirds of the animals. 14 days after trauma the cochleae of traumatized and non-traumatized ears were isolated and inner hair cell synapses were counted within several spectral regions of the cochlea. In the here presented preliminary data inner hair cell synaptopathy was only found in animals with behavioral signs of tinnitus, independent of type of hearing loss. On the other hand, animals with apparent hearing loss but without behavioral signs of tinnitus showed a reduction in amplitudes of auditory brainstem response waves I/II (cochlear nerve and dorsal cochlear nucleus) but no significant changes in the number of synapses at the inner hair cells. We conclude – in line with the literature – that hearing loss is caused by damage to the inner and / or outer hair cells but that the development of tinnitus, at least in our animal model is closely linked to synaptopathy at the inner hair cells.

International audience; Post-operative outcomes for hearing after resection surgery to remove cerebellopontine angle (CPA) tumors other than vestibular schwannomas (VS) are not well understood. This study presents a series of patients with significant postoperative hearing recovery, trying to define the incidence among all patients operated on for removal of non-VS CPA tumors. Methods: This is a retrospective observational case series of 8 patients among 69 operated on for removal of non-VS CPA tumors between 2012 and 2020. All patients had pre-and post-operative hearing measurement with pure-tone average (PTA) and speech discrimination score (SDS), according to the American Academy of Otolaryngology-Head and Neck Surgery recommendations, auditory brainstem response (ABR) measurements and imaging. Results: Six meningiomas and two lower cranial nerve schwannomas operated on with a retrosigmoid approach were included for analysis. The mean pre-operative PTA and SDS were 58±20.7 dB and 13±17.5%, respectively. All patients had pre-operative class D hearing and asynchronous ABRs. They all showed significant hearing recovery, with an improvement of 36±22.2 dB (p=0.0025) and 85±16.9% (p=0.0001) in PTA and SDS, respectively, with mean follow-up of 21±23.5 months. Seven patients recovered to a class A hearing level and one patient to class B. The ABRs became synchronous for three patients. The incidence of auditory recovery was 13% for patients operated on with a conservative approach (n=60). Conclusion: A significant post-operative improvement in hearing could be a reasonable expectation in non-VS tumors extending into the CPA and a retrosigmoid approach should always be considered regardless of pre-operative hearing status.

Tinnitus is hypothesized to be an auditory phantom phenomenon resulting from spontaneous neuronal activity somewhere along the auditory pathway. The neural abnormalities underlying tinnitus are largely unknown. We evaluated the functional characteristics and the auditory system synchronization using Auditory Brainstem Response (ABR) in normal hearing tinnitus patients. In this observational comparative cross-sectional study, patients with chief complaints of Tinnitus and equal number of age and sex matched controls without hearing loss and tinnitus were enrolled. All patients underwent a full ENT assessment, pure tone audiometry and Brainstem evoked response audiometry (BERA) tests. The study population consisted of 100 patients with tinnitus, 55 controls without tinnitus and 45 controls with tinnitus. Statistical analysis showed significant relation (p

Purpose In this study, the efficacy and feasibility of melatonin in young children with and without comorbidities, undergoing auditory brainstem response audiometry (ABR) was evaluated. The aim of this study was primarily to evaluate the use of melatonin for ABR investigations in children with comorbidities. Second, the efficacy of melatonin was evaluated based on several factors like sleep-onset latency, sleep duration, frequency of awakenings as well as adverse events. Methods Click-induced ABR tests were performed at the outpatient clinic between January, 2018 and August, 2020. Investigations were considered successful when binaural testing was completed. A dose of melatonin depending on age, 5 mg for children younger than 6 years and 10 mg if older than 6 years, was administered after placement of electrodes. Results 131 children were included in this study. 87% of all ABR investigations were performed successfully. Comorbidities such as neurodevelopmental disorders or developmental delays were present in 70% of all children. There was no significant difference in age (p = 0.36) or gender (p = 0.97) between the success and failed group. In addition, comorbidities were equally distributed between both groups. Mean sleep duration was 38 (SD 21) min and sleep-onset latency was 28 (SD 20) min No adverse events were documented. Conclusion Melatonin is effective for ABR examinations in infants and children with and without comorbidities. Furthermore, it allows for sequential testing in those at risk for progressive hearing loss. Clear instructions to caregivers and expertise of audiologists are a prerequisite for optimal outcomes.

Background Various extratympanic recording electrodes have been used to make electrocochleography (ECochG) and auditory brainstem response (ABR) measurements in clinics, translational research, and basic science laboratories. However, differences may exist in ECochG and ABR measurements depending on the different types of extratympanic electrodes that are used. Purpose The purpose of this research is to compare simultaneously recorded ECochG and ABR responses using three different extratympanic electrodes. This research helps clinicians and researchers to understand how electrode types and recording sites influence EcochG and ABR results. In addition, our findings could provide more normative data to the ECochG and ABR literature as well as give perspective on a preferred electrode approach when performing simultaneous ECochG and ABR testing. Research Design Ours was a repeated-measures study with measurements being made from individual participants on two separate sessions. Study Sample Twenty young adult females with normal hearing. Procedure A three-channel recording system was used to simultaneously record ECochG and ABR measurements in response to alternating polarity click stimuli. In each session, measurements were simultaneously recorded with a TipTrode electrode and one of the tympanic membrane (TM) electrodes. Data Collection and Analysis Suprathreshold summating potential (SP) and action potential (AP) of the ECochG and waves I, III, and V of the ABR, and threshold responses (AP and wave V) were identified. Results Compared with the ear canal TipTrode electrode, TM electrodes yielded suprathreshold amplitudes that were larger than those from the ear canal electrode, smaller SP–AP ratios, lower AP thresholds, and less variability. These findings can help guide choices made by clinicians, translational investigators, and basic science researchers on which type of extra-tympanic electrode to use for their intended purpose.

Background: Aim: To compare the response of human auditory brain stem evoked by clicks stimuli and chirps. Patients and Methods: A study of cross-sectional design was chosen to evaluate the objective of the study. Children between 1-10 years were enrolled from the attendants of the Dept. of Surgery and Audiology, Al-Jamhoori Teaching Hospital, Ministry of Health /Nineveh health Directorate, and the outpatient clinics in al-alwiyah teaching hospital for children and done in the privet clinics of the researchers. The data collection extended over the period from 2019 January to 2020 August. A total number of 70 children involved in the study according to the parents’ complaints, full history taken and the clinical examination by otoscopy. The probable conductive problem excluded by using the Tympanometry. Moreover, free field test was done before chirp and click. Paired t-test was used for the statistical analysis. Results: The males represent (44.3%) and the females (55.7%). The mean age of children included was 49 months ± 27.7 SD. Wave V of the chirp shows lower latency means in all intensities in comparison with that of click stimuli. While waves I and III, show longer latency as the intensity go down, but the differences between chirp and click are insignificant. Wave V amplitudes getting lower values as the intensity decreasing in both chirp and click and become significantly higher than that of click. Wave I and III show decreasing amplitudes with the decreasing intensity in both chirp and click, with higher amplitudes in click in comparing with that of chirp, which are insignificant statistically down to below 70 dBnHL. Conclusions: The chirp stimuli are highly significant and more efficient from the click in the detection of hearing loss among the children regarding both latency and amplitude particularly at wave V.

Hearing is an important sense organ for human beings essential for speech, language and overall development. Universal neonatal hearing screening programmes are mandatory in many developed countries. In India out of 1000 neonates approximately 5–6 infants are diagnosed with hearing impairment but still universal neonatal hearing screening programme is in its infancy. To screen all neonates delivered at our centre in three years, with secondary objective of determining the significance of risk factors with neonatal hearing loss and to provide appropriate intervention following the detection of a permanent hearing impairment. It is a non-randomised prospective cohort study conducted at a tertiary care centre to screen all neonates born between Jan 2017 and Dec 2019 with 2 stage protocol using distortion product otoacoustic emission and auditory brainstem response. The study population was also divided into two groups, ‘‘at risk’’ and ‘‘no risk’’ groups to determine the significance of risk factors on neonatal hearing loss. Total 2676 neonates were screened, OAE referral rate was 1.53%. There was a 94.12% follow up. The incidence of hearing impairment was found to be 7 per 1000(In the “no risk” group, 2.9 per 1000 and in the “at risk” group, 41.38 per 1000). Statistically, a significant difference was found in the incidence of hearing impairment between the two groups (p

Introduction: Congenital deafness is a hearing loss that occurs at birth. Congenital deafness in neonates can be caused by risk factors during pregnancy and during the birth process. The tests carried out for hearing screening for neonates in hospital up to 1 month old are Otoaccoustic Emission (OAE) and Auditory Brainstem Response (ABR) examinations. Objective: Determining the relationship between family history of deafness, syndromes associated with sensorineural hearing loss, TORCH infection and prenatal syphilis, use of ototoxic drugs during pregnancy, prematurity, low birth weight, asphyxia, and hyperbilirubinemia with the incidence of congenital deafness in children Methods: This cross-sectional study was conducted based on medical record datas from children who underwent OAE and ABR examinations at Dr. Mohammad Hoesin Palembang hospital from January 2019 to February 2021. Results: From the 349 children, 180 (51.6%) had bilateral OAE and ABR pass results, 161 (46.1%) had bilateral referrals and 8 (2.3%) children received unilateral refer results. From 122 children with risk factors, 38 (31.1%) children with bilateral passes, 81 (66.4%) children with bilateral referrals and 3 (2.5 %) children with unilateral refer. From 227 children without risk factors, 142 (62.6 %) children with a bilateral pass, 80 (35.2 %) children with bilateral referrals and 5 (2.2%) children with unilateral refer. The most common risk factor was LBW of 41 (11.7%) children. Chi square test and logistic regression analysis results showed a significant relationship between ototoxic drugs during pregnancy and congenital deafness (p = 0.001) with referral results, the value of Odd Ratio (OR) 9.651. Conclusions: There is a significant relationship between risk factors for ototoxic drugs during pregnancy, TORCH and syphilis infection during pregnancy, asphyxia, congenital syndrome, LBWand hyperbilirubinemia with congenital deafness.

TORCH group of infections are one of the most common causes of bilateral profound hearing loss in a developing country like ours. Seroprevalance is quite high in eastern part of our country. Screening for TORCH infections in children’s with profound hearing loss has significant prognostic, planning and policy forming implications. To evaluate the seroprevalance of TORCH infections in prospective cochlear implant children and its significance. Ours is a retrospective study conducted from 2017 to 2018 on 50 children with bilateral profound hearing loss attending the Department of ENT at AIIMS, Patna. Thorough clinical and audiological assessment of the patients was done using objective tests like OAE (otoacoustic emission), ABR (auditory brainstem response) and subjective tests like BOA(behavioural audiometry) and PTA (puretone audiometry) wherever feasible. Blood samples were collected and serotesting was done using ELISA for Toxoplasma, Rubella, Cytomegalovirus (CMV) and Herpes Simplex Virus (HSV) (TORCH). We found that IgM was negative for all patients. Seroprevalance for IgG was 16.3% for toxoplasma, 74.4% for rubella, 69.8% for CMV and 20.9% for HSV. All the children had bilateral severe to profound loss on ABR and bilateral REFER on OAE. As prevalence of TORCH infection is quite common in India and is an established risk factor for sensorineural hearing loss with multisystem involvement screening for the same will help in early identification and in decision making for cochlear implantation thus improving the prognosis and also aid in policy making.

Sensorineural hearing loss is an intractable disease. Acoustic overstimulation creates hearing loss; many patients exhibit social and emotional dysfunctions. In a model of noise-induced hearing loss (NIHL), low-level laser photobiomodulation (PBM) at a near-infrared wavelength significantly improved auditory brainstem response (ABR) thresholds. In addition, both N-acetyl-L-cysteine (NAC) and acetyl-L-carnitine (ALCAR) attenuated NIHL, reducing the effects of noise trauma in the cochlea and the central auditory system. Here, we combined PBM with antioxidants to explore hearing threshold recovery and morphological hair cell changes after rats were exposed to noise. The average auditory brainstem response thresholds after PBM/NAC combination treatment were reduced from the apex to the basal turn at all of 8, 16, and 32 kHz compared to the noise-only group. The PBM/NAC combination treated group exhibited intact outer hair cells in all turns, and significantly greater hair cell numbers in the middle and basal cochlear turns, than did controls. Thus, PBM/NAC treatment may prevent hearing dysfunction caused by NIHL.

Background Contralateral noise masking is an important aspect of auditory brainstem response (ABR) measurements. Purpose The primary aim of this study is to determine how contralateral white noise (WN) masking influences the amplitude and the latency of V wave generated during ABR measurements, using tone burst (TB), in adult ears with normal hearing (NH). The secondary aim of this study is to ascertain the need of contralateral masking in ABR measurements with the TB stimuli using a 3A insertion earphone, and to propose the applicability of WN masking in unilateral sensorineural hearing loss (USNHL). Research Design It is a cross-sectional observational and descriptive study. Study Sample Experiment 1: Thirty individuals, without any otologic, psychological, or neurological dysfunction, were selected. Experiment 2: Fifteen individuals with previous audiological diagnoses of severe and profound USNHL were considered. Intervention The study involves ABR TB at specific frequencies of 0.5, 1, 2, and 4 kHz. Data Collection and Analysis Experiment 1: The evaluation was performed at the fixed intensity of 80 dB nHL (decibel normalized hearing level) on the tested ear, followed by the application of simultaneous masking to the nontested ear, intensity ranged from 0 to 80 dB. Experiment 2: ABR threshold measurements were first performed on the ear with hearing loss (HL) at the frequencies of 1, 2, and 4 kHz. The results were subsequently confirmed using contralateral masking. Results Experiment 1: At any given frequency, there were no statistically significant differences in the amplitude and latency of V wave with increase in the intensities of WN masking. Experiment 2: Cross-hearing was observed at least once in all frequencies analyzed through the occurrence of V wave. Conclusion In conclusion, the contralateral WN masking at the maximum intensity of 80 dB does not affect the amplitude and latency of V wave of the ABR TB at 1, 2, and 4 kHz. Contralateral masking for the ABR TB presented using 3A insertion earphones is necessary at 1, 2, and 4 kHz in individuals with severe or profound degrees of USNHL and at intensities of 15, 20, and 10 dB above the ABR threshold of the nontested ear.

OBJECTIVE: The aim of the study was to evaluate the results of neonatal hearing screening in our hospital with the help of literature and to question and reveal the risk factors to gain healthy individuals and to raise awareness for all health workers and the public who are interested in this subject. METHODS: A total of 16,388 newborn infants were evaluated between October 2009 and January 2018. All newborns were screened with transient evoked otoacoustic emissions (TEOAEs) test. Risk factors were investigated. The test repetition and auditory brainstem response (ABR) measurements were performed on newborns who could not pass the TEOAE test and the newborns in the risky group after 15 days. RESULTS: A total of 116 newborns (0.7%) were suspected to have hearing loss. Twenty-seven newborns (0.16%) were found to be in intensive care unit. Twelve newborns (0.07%) had permanent hearing loss. Then, in order: 9 newborns (0.05%) had received phototherapy and 7 newborns (0.04%) were born to consanguineous marriages. In addition, 3 newborns (0.02%) had a low birth weight and 1 newborn (0.006%) had a history of fever. CONCLUSION: Screening tests should be performed in all newborns for early detection of hearing loss. Even though frequency of hearing loss is higher in newborns with risk factors, the treatment should be started within 6 months, the latest, and newborns should be referred for rehabilitation and training.

Objective To study the pathophysiology of Charcot-Marie-Tooth disease (CMT) with auditory neuropathy (AN) and to follow up cochlear implant or hearing aid use over the long term. Study design Clinical capsule report. Patients Two adult CMT patients with AN. Intervention Cochlear implantation for case 1 and hearing aid use for case 2. Result Case 1 was a 50-year-old man who was diagnosed as having CMT at 15 years of age. He noted his hearing impairment at the age of 22. We considered that he had AN as a complication on the basis of the findings of normal distortion product otoacoustic emission and the absence of auditory brainstem response on both ears. We performed cochlear implantation for his progressive hearing loss when he was 41 years old. His postoperative discrimination scores for words and sentences in the CI-2004 test 4 years after cochlear implantation were 80% and 93%, respectively. His sound discrimination scores were 23/24 in the test with picture matching and 9/24 in that without picture matching 8 years after cochlear implantation.Case 2 was a 38-year-old woman who was neurologically diagnosed as having CMT with AN as a complication on the basis of auditory brainstem response and distortion product otoacoustic emission test findings. During 15 years of follow-up, her discrimination score decreased gradually. She is currently wearing a hearing aid. Conclusions We found a significant improvement in case 1 and a slight increase in hearing level in case 2. The pathoneurological findings of CMT might be either demyelination or axonal degeneration depending on the type of genetic abnormality (e.g., PMP22 and MPZ mutations). The symptoms and courses vary among patients with CMT. Therefore, the selection of an appropriate intervention for hearing loss depending on the severity and course is very important.

Objective To identify intraoperative neurophysiologic measures predictive of delayed progressive sensorineural hearing loss in the operative ear after a middle fossa approach (MCF) for resection of vestibular schwannoma (VS). Study design Retrospective review. Setting Academic, tertiary referral center. Patients Subjects with vestibular schwannoma who underwent a MCF microsurgical resection of VS were analyzed for individuals whose hearing was initially preserved but subsequently developed progressive sensorineural hearing loss in the operative ear. Thirty-seven patients were identified for whom audiologic and neurophysiologic data was available. Intervention Intraoperative neurophysiologic changes will correlate with delayed sensorineural hearing loss in the operative ear. Main outcome measures Audiometric evaluations, intraoperative electrocochleography (ECoG), and auditory brainstem response (ABR) measures. Results Twenty-five subjects experienced stable hearing or hearing loss in the operative ear comparable to the contralateral ear. Twelve subjects suffered a significant increase in the hearing asymmetry between ears. Deterioration in the amplitude of wave V of the ABR persisting at the close of tumor resection correlated with delayed sensorineural hearing loss in the operative ear (p 0.02, 5% mean improvement in the stable hearing group, versus a 14% decline with progressive asymmetry), but changes in ECoG or other auditory brainstem response parameters (p > 0.05) were not predictive. Conclusions Persisting amplitude reduction of wave V of the intraoperative ABR best correlates with delayed progressive sensorineural hearing loss in the operative ear. Neither persistent changes in ECoG, other ABR parameters, nor transient changes, correlated with delayed progressive sensorineural hearing loss in the operative ear.

Auditory neural impairment is a key clinical feature of Friedreich’s Ataxia (FRDA). We aimed to characterize the phenotypical spectrum of the auditory impairment in FRDA in order to facilitate early identification and timely management of auditory impairment in FRDA patients and to explore the relationship between the severity of auditory impairment with genetic variables (the expansion size of GAA trinucleotide repeats, GAA1 and GAA2), when controlled for variables such as disease duration, severity of the disease and cognitive status. Twenty-seven patients with genetically confirmed FRDA underwent baseline audiological assessment (pure-tone audiometry, otoacoustic emissions, auditory brainstem response). Twenty of these patients had additional psychophysical auditory processing evaluation including an auditory temporal processing test (gaps in noise test) and a binaural speech perception test that assesses spatial processing (Listening in Spatialized Noise-Sentences Test). Auditory spatial and auditory temporal processing ability were significantly associated with the repeat length of GAA1. Patients with GAA1 greater than 500 repeats had more severe auditory temporal and spatial processing deficits, leading to poorer speech perception. Furthermore, the spatial processing ability was strongly correlated with the Montreal Cognitive Assessment (MoCA) score. To our knowledge, this is the first study to demonstrate an association between genotype and auditory spatial processing phenotype in patients with FRDA. Auditory temporal processing, neural sound conduction, spatial processing and speech perception were more severely affected in patients with GAA1 greater than 500 repeats. The results of our study may indicate that auditory deprivation plays a role in the development of mild cognitive impairment in FRDA patients.

Introduction The effects of increasing stimulus repetition rate on the ABR using click stimuli have been investigated in normal and hearing impaired subjects with neurologic abnormality but there is limited study on the effect of stimulus repetition rate on ABR using chirp stimuli. The present study aims to compare the chirp evoked auditory brainstem responses with reference to changes in latency of peaks, interaural latency differences and interwave latency intervals as a function of rate and compare those responses with the click evoked auditory brainstem responses, in normal hearing subjects. Materials and Methods Total 30 normally hearing adults were considered for this study. All participants were screened for normal hearing sensitivity upto 8 kHz in pure tone audiometry for middle ear pathology and central auditory processing disorder. Four parameters of ABR were considered to assess in this study including absolute latency, interwave latency intervals, latency-rate function and interaural latency. ABR was done based on the protocol of this study. Results Results revealed that there was a significant difference in the absolute latency and interwave intervals when the stimulus repetition rate was increased. Conclusion The latencies of wave III and V increases and waveform morphology changed as the stimulus repetition rate increased above 20/sec. The absolute latency of wave III and V was found to be shorter than clicks and can be used especially in newborn hearing evaluation assuming in shorter time window.

Smith–Lemli–Opitz syndrome (SLOS) is an autosomal recessive multiple congenital malformation and intellectual disability syndrome resulting from variants in DHCR7. Auditory characteristics of persons with SLOS have been described in limited case reports but have not been systematically evaluated. The objective of this study is to describe the auditory phenotype in SLOS. Age- and ability-appropriate hearing evaluations were conducted on 32 patients with SLOS. A subset of 21 had auditory brainstem response testing, from which an auditory neural phenotype is described. Peripheral or retrocochlear auditory dysfunction was observed in at least one ear of 65.6% (21) of the patients in our SLOS cohort. The audiometric phenotype was heterogeneous and included conductive, mixed, and sensorineural hearing loss. The most common presentation was a slight to mild conductive hearing loss, although profound sensorineural hearing loss was also observed. Abnormal auditory brainstem responses indicative of retrocochlear dysfunction were identified in 21.9% of the patients. Many were difficult to test behaviorally and required objective assessment methods to estimate hearing sensitivity. Individuals with SLOS are likely to have hearing loss that may impact communication, including speech and language development. Routine audiologic surveillance should be conducted to ensure prompt management of hearing loss.

The peripheral auditory and vestibular systems rely on sensorineural structures that are vulnerable to ototoxic agents that cause hearing loss and/or equilibrium deficits. Although attention has focused on hair cell loss as the primary pathology underlying ototoxicity, evidence from the peripheral vestibular system indicates that hair cell loss during chronic exposure is preceded by synaptic uncoupling from the neurons and is potentially reversible. To determine if synaptic pathology also occurs in the peripheral auditory system, we examined the extent, time course, and reversibility of functional and morphological alterations in cochleae from mice exposed to 3,3′-iminodipropionitrile (IDPN) in drinking water for 2, 4 or 6 weeks. Functionally, IDPN exposure caused progressive high- to low-frequency hearing loss assessed by measurement of auditory brainstem response wave I absolute thresholds and amplitudes. The extent of hearing loss scaled with the magnitude of vestibular dysfunction assessed behaviorally. Morphologically, IDPN exposure caused progressive loss of outer hair cells (OHCs) and synapses between the inner hair cells (IHCs) and primary auditory neurons. In contrast, IHCs were spared from ototoxic damage. Importantly, hearing loss consistent with cochlear synaptopathy preceded loss of OHCs and synapses and, moreover, recovered if IDPN exposure was stopped before morphological pathology occurred. Our observations suggest that synaptic uncoupling, perhaps as an early phase of cochlear synaptopathy, also occurs in the peripheral auditory system in response to IDPN exposure. These findings identify novel mechanisms that contribute to the earliest stages of hearing loss in response to ototoxic agents and possibly other forms of acquired hearing loss. Supplementary Information The online version contains supplementary material available at 10.1007/s00204-020-02962-5.

Measuring parent satisfaction is an important factor in pediatric health care service programs because parents play a major role in their child's life. The parental decisions are a basis for the success or failure of the child's treatment in many cases. The purpose of this study was to determine levels of parents' satisfaction following the implementation of universal newborn hearing screening (UNHS) program in Iran. In this study, the Persain version of the parent satisfaction questionnaire with neonatal hearing screening program (PSQ-NHSP) was used to measure parents' satisfaction on information of newborn hearing screening program, personnel in charge of the hearing testing, hearing screening activities, and overall satisfaction. Newborns were screened using transient evoked otoacoustic emissions and automatic auditory brainstem response tests within the first 48 h of life for each ear. Of the 312 questionnaires distributed, 217 parents (67%) responded. The mean scores of the "overall satisfaction" items ranged from 4.07 to 4.29, demonstrating high levels of parent satisfaction with this aspect of the program. More than 86% of parents were overally satisfied with the hearing screening program. In open-ended items, 84% of parents comments showed their satisfaction. The findings of the present study revealed that parents were generally satisfied with the UNHS program. The PSQ-NHSP questionnaire is easily employed and effective method for assessing parental satisfaction with newborn hearing screening programs.

Cisplatin chemotherapy often causes permanent hearing loss, which leads to a multifaceted decrease in quality of life. Identification of early cisplatin-induced cochlear damage would greatly improve clinical diagnosis and provide potential drug targets to prevent cisplatin’s ototoxicity. With improved functional and immunocytochemical assays, a recent seminal discovery revealed that synaptic loss between inner hair cells and spiral ganglion neurons is a major form of early cochlear damage induced by noise exposure or aging. This breakthrough discovery prompted the current study to determine early functional, cellular, and molecular changes for cisplatin-induced hearing loss, in part to determine if synapse injury is caused by cisplatin exposure. Cisplatin was delivered in one to three treatment cycles to both male and female mice. After the cisplatin treatment of three cycles, threshold shift was observed across frequencies tested like previous studies. After the treatment of two cycles, beside loss of outer hair cells and an increase in high-frequency hearing thresholds, a significant latency delay of auditory brainstem response wave 1 was observed, including at a frequency region where there were no changes in hearing thresholds. The wave 1 latency delay was detected as early cisplatin-induced ototoxicity after only one cycle of treatment, in which no significant threshold shift was found. In the same mice, mitochondrial loss in the base of the cochlea and declining mitochondrial morphometric health were observed. Thus, we have identified early spiral ganglion-associated functional and cellular changes after cisplatin treatment that precede significant threshold shift.

We describe a dominant Japanese patient with progressive conductive hearing loss who was diagnosed with NOG-related symphalangism spectrum disorder (NOG-SSD), a spectrum of congenital stapes fixation syndromes caused by NOG mutations. Based on the clinical features, including proximal symphalangism, conductive hearing loss, hyper­opia, and short, broad middle, and distal phalanges of the thumbs, his family was diagnosed with stapes ankylosis with broad thumbs and toes syndrome (SABTT). Genetic analysis revealed a heterozygous substitution in the NOG gene, c.645C>A, p.C215* in affected family individuals. He had normal hearing on auditory brainstem response (ABR) testing at ages 9 months and 1 and 2 years. He was followed up to evaluate the hearing level because of his family history of hearing loss caused by SABTT. Follow-up pure tone average testing revealed the development of progressive conductive hearing loss. Stapes surgery was performed, and his post-operative hearing threshold improved to normal in both ears. According to hearing test results, the stapes ankylosis in our SABTT patient seemed to be incomplete at birth and progressive in early childhood. The ABR results in our patient indicated the possibility that newborn hearing screening may not detect conductive hearing loss in patients with NOG-SSD. Hence, children with a family history and/or known congenital joint abnormality should undergo periodic hearing tests due to possible progressive hearing loss. Because of high success rates of stapes surgeries in cases of SABTT, early surgical interventions would help minimise the negative effect of hearing loss during school age. Identification of the nature of conductive hearing loss due to progressive stapes ankylosis allows for better genetic counselling and proper intervention in NOG-SSD patients.

Background: Central auditory processing disorders (CAPDs) tend to affect an individual’s ability to understand speech, especially in difficult listening conditions.Objective: To study speech-in-noise (SIN) ability in cases of central auditory processing disorders (CAPDs) subjectively by Arabic Hearing in Noise Test (A-HINT) and objectively by Speech-evoked auditory brainstem response (S-ABR) with ipsilateral noise.Patients and Methods: Subjects included in this study will be divided into 2 groups: a control group which included 30 normal hearing subjects (17 males and 13 females). Their age ranged from 6 to 17 years. All subjects had normal developmental milestones and normal speech development. The Study group included 30 normal hearing subjects (18 males and 12 females). Their age ranged from 7 to 16 years. These subjects had central auditory processing disorders (CAPDs) diagnosed by central auditory screening tests. Both groups were tested using Arabic HINT and Speech-evoked auditory brainstem response (S-ABR) with ipsilateral noise.Results: Comparison between control and study groups as regards the Arabic HINT revealed statistically significant differences in noise conditions. Using S-ABR significant difference was found in onset and offset response waves latency in noise conditions also.Conclusion: Patients with CAPDs have speech in noise ability affection proved by affected HINT in noise conditions and by delayed S- ABR with ipsilateral noise latencies in onset- offset responses.

Prenatal exposures to alcohol (PAE) and tobacco (PTE) are known to produce adverse neonatal and childhood outcomes including damage to the developing auditory system. Knowledge of the timing, extent, and combinations of these exposures on effects on the developing system is limited. As part of the physiological measurements from the Safe Passage Study, Auditory Brainstem Responses (ABRs) and Transient Otoacoustic Emissions (TEOAEs) were acquired on infants at birth and one-month of age. Research sites were in South Africa and the Northern Plains of the U.S. Prenatal information on alcohol and tobacco exposure was gathered prospectively on mother/infant dyads. Cluster analysis was used to characterize three levels of PAE and three levels of PTE. Repeated-measures ANOVAs were conducted for newborn and one-month-old infants for ABR peak latencies and amplitudes and TEOAE levels and signal-to-noise ratios. Analyses controlled for hours of life at test, gestational age at birth, sex, site, and other exposure. Significant main effects of PTE included reduced newborn ABR latencies from both ears. PTE also resulted in a significant reduction of ABR peak amplitudes elicited in infants at 1-month of age. PAE led to a reduction of TEOAE amplitude for 1-month-old infants but only in the left ear. Results indicate that PAE and PTE lead to early disruption of peripheral, brainstem, and cortical development and neuronal pathways of the auditory system, including the olivocochlear pathway.

Recent advances in machine learning have led to a surge of interest in classification of the auditory brainstem response. In this work, we conducted a search in the PubMed, Google Scholar, SpringerLink, ScienceDirect, and Scopus databases, and identified twelve studies that explored the use of machine learning to classify the auditory brainstem response as a complementary and objective method to (a) help clinicians better diagnose hearing impairment by discerning between healthy and pathological auditory brainstem response waveforms, (b) present a neural marker for potential applications in hearing aid tuning, and (c) provide a biometric marker for discriminating between subjects. A comparison between the studies presented in this review is not possible as they used different test subjects, group sizes, and stimuli, and evaluated auditory brainstem response differently. Instead, the result of these studies will be presented and their limitations as well as their potential applications will be discussed. Overall, the findings of these studies suggest that ABR classification using machine learning is a promising tool for assessing patients with hearing loss, optimizing technologies for tuning hearing aids, and discriminating between subjects.

Introduction Repeated blast exposures result in structural damage to the peripheral auditory system (PAS) and the central auditory system (CAS). However, it is difficult to differentiate injuries between two distinct pathways: the mechanical damage in the PAS caused by blast pressure waves transmitted through the ear and the damage in the CAS caused by blast wave impacts on the head or traumatic brain injury. This article reports a preliminary study using a 3D printed chinchilla “helmet” as a head protection device associated with the hearing protection devices (e.g., earplugs) to isolate the CAS damage from the PAS injuries under repeated blast exposures. Materials and Methods A finite element (FE) model of the chinchilla helmet was created based on micro-computed tomography images of a chinchilla skull and inputted into ANSYS for FE analysis on the helmet’s protection against blast over pressure. The helmet was then 3D printed and used for animal experiments. Chinchillas were divided into four cases (ears open, with earplug only, with both earplug and helmet, and with helmet only) and exposed to three blasts at blast over pressure of 15 to 20 psi. Hearing function tests (e.g., auditory brainstem response) were performed before and after blast on Day 1 and Days 4 and 7 after blasts. Results The FE model simulation showed a significant reduction in intracranial stress with the helmet, and the animal results indicated that both earplug and helmet reduced the severity of blast-induced auditory injuries by approximately 20 dB but with different mechanisms. Conclusions The biomechanical modeling and animal experiments demonstrated that this four-case study in chinchillas with helmet and hearing protection devices provides a novel methodology to investigate the blast-induced damage in the PAS and CAS.

The purpose of this study was to use a murine model to determine if melatonin can protect the inner ear from radiation-induced damage. A total of 81 4-week-old Balb/c mice were randomly divided into five groups: control group; 50 mg/kg melatonin group; 5 mg/kg melatonin+radiotherapy group; 50 mg/kg melatonin+radiotherapy group; radiotherapy group. The radiotherapy groups received 16 Gy irradiation and melatonin was administered by intraperitoneal injection 30 min before radiotherapy. On days 3 and 7 after irradiation the function of outer hair cells was determined by auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs) testing, pathological changes of inner ear cells were observed by light microscopy, and the expression of prestin mRNA was determined. ABR thresholds were increased and wave I latencies were extended after radiotherapy; however, the increases were lower in the groups that received melatonin (P

Introduction: Diabetes mellitus (DM) is a systemic disease characterized by hyperglycemia and several pathological changes. DM-related hearing dysfunctions are associated with histological changes. Here, we explore hearing function and synaptic changes in the inner hair cells (IHCs) of rats with streptozotocin (STZ)-induced diabetes. Methods: STZ was injected to trigger diabetes. Rats with DM were exposed to narrow-band noise (105 dB SPL) for 2 h, and hearing function was analyzed 1, 3, 7, and 14 days later. Both the hearing threshold and the peak 1 amplitude of the tone auditory brainstem response were assessed. After the last functional test, animals were sacrificed for histological evaluation. Results: We found no changes in the baseline hearing threshold; however, the peak 1 amplitude at the low frequency (4 kHz) was significantly higher in both DM groups than in the control groups. The hearing threshold had not fully recovered at 14 days after diabetic rats were exposed to noise. The peak 1 amplitude at the higher frequencies (16 and 32 kHz) was significantly larger in both DM groups than in the control groups. The histological analysis revealed that the long-term DM group had significantly more synapses in the 16 kHz region than the other groups. Conclusions: We found that high blood glucose levels increased peak 1 amplitudes without changing the hearing threshold. Diabetic rats were less resilient in threshold changes and were less vulnerable to peak 1 amplitude and synaptic damage than control animals.

Purpose The objective of this study was to investigate the auditory pathway maturation monitored by auditory brainstem responses (ABR) in infants with hearing loss during the first year of life. ABR were used to estimate hearing thresholds and the effect of early intervention strategies using hearing aids (HA). Methods Click-evoked ABRs were measured in 102 infants aged from 0 to 12 months to determine their individual auditory threshold. Early therapy intervention was recommended before 12 months of age and analyzed. To evaluate the effect of hearing amplification on auditory maturation, different subgroups of infants with moderate hearing loss were analyzed and the auditory pathway maturation was determined based on IPL I–V shortening. Results Overall, 110 ears (54.0% of 204 ears) with mild to profound HL showed threshold changes of 10 dB up to 60 dB in the follow-up ABR testing. HA were prescribed at the age of 3.8 ± 3.9 months. Cochlear implantation (CI) was performed in cases of repeated profound HL at the age of 9.9 months ± 4.5 months. A significant shortening of IPL I–V in all subgroups of infants (with and without risk factors) who received HA was shown and assumed auditory pathway maturation. Conclusion An early intervention using optimally fitted HA influenced auditory pathway maturation and may lead to improvements of hearing thresholds during the first year of life in infants. This study underscores the importance of not only providing HAs to infants, but also controlling for hearing threshold changes ensuring that HAs provide the optimal level of intervention or CI is indicated.

Auditory brainstem response (ABR) is used to determine hearing thresholds in children who cannot undergo behavioural testing. Children must remain still during testing, with general anaesthesia (GA) in theatre required for those who cannot. We developed a protocol whereby an ABR was undertaken in a ward environment using only intranasal dexmedetomidine for sedation.Prospective data were collected including the time of sedation onset, ABR duration and arrival to discharge time was recorded and feedback was requested using a questionnaire.Twenty-nine consecutive patients routinely undergoing an ABR.From this pilot study, we demonstrated that intranasal dexmedetomidine could be used successfully to administer safe sedation to all twenty-nine children undergoing an ABR in a ward environment as opposed to theatre.This allowed for faster time to discharge compared to GA, produced what was felt to be a better quality ABR trace, better utilization of a theatre slot, negated the need for GA in a child and created a less stressful experience for both parent and child according to information from feedback questionnaires.

Purpose The study investigated whether the auditory brainstem response (ABR) at a baseline and at higher repetition rates can detect if neurodegeneration has occurred in adults living with HIV who present with normal behavioral pure-tone thresholds. Method An exploratory research design was used. Forty adults with HIV (80 ears, 57.5% female; M age = 26.3 years, SD = 3.68) and 20 adults without HIV participated. Phase 1 compared ABR absolute and interwave latencies at a baseline rate. Phase 2 examined the effect of HIV status and category of immunodeficiency on ABR absolute Wave V latency and Wave V latency shift at increased stimulus rates. Analysis included a two-way analysis of variance of the interaction between stimulus rate and HIV status and between CD4+ category and rate, and multiple regression analysis. Results In adults living with HIV, the baseline ABR yielded prolonged Wave III and V absolute latencies and interpeak prolongations in 22.5%. Interaural Wave V latency differences were present in 15% of participants. An additional 15% of ears presented with abnormal Wave V at increased rates. No significant interaction between HIV status and rate in either ear or between CD4+ category and rate was found in either ear ( p > .05). Although rate and gender contributed significantly to the prediction of Wave V latency of the rate study (left and right, p < .001), HIV status did not (left and right, p > .05). Conclusions Although the interaction of HIV status and CD4+ with rate was not significant, more ears were identified with abnormal results at increased stimulus rates than with the baseline ABR alone. The ABR at increased rates may therefore be a valuable addition for the identification of individuals living with HIV with auditory neural deficiencies.

Background Intraoperative auditory brainstem response (ioABR) testing under general anesthesia is commonly performed on children when sleep-deprived ABR and behavioral testing are not reliable or feasible. Several studies have reported potential confounding results when tube insertion is combined with ABR testing. Purpose This article evaluates whether a temporary threshold shift (TTS) occurs following placement of tympanostomy tubes (TTs) in children who undergo ioABR testing. Research Design A case–control prospective study. Patients scheduled for combined TT and ioABR procedures were enrolled into this study. Study Sample Twenty children (38 ears), ranging in age from 6 months to 10.5 years, were enrolled. Data Collection and Analysis ABR thresholds for tone bursts with center frequencies of 2 and 4 kHz were compared before and after tube insertion. The indication for surgery, comorbidities, and status of the middle ear were also recorded. A paired t-test was used to determine statistical significance. Results Data collection did not necessarily indicate suctioning and tube placement were causing a TTS; however, fluid present in the middle ear space prior to TT placement appeared to influence results. Although a paired t-test did not show statistically significant differences in ABR thresholds between groups of individuals with and without fluid and before and after tube placement, 50% of patients with mucoid fluid (two out of four patients) were noted to have 10 dB or greater worsening in ABR thresholds in two out of six ears. Twenty-nine percent of patients with serous fluid (two out of seven patients) were noted to have at least a 10 dB worsening in ABR threshold in 2 out of 10 ears. Further testing is needed to confirm these trends. Conclusion This pilot study indicates that children with mucoid or serous fluid may experience worse ABR thresholds following TT insertion. ioABR testing immediately after TT tube placement and in the presence of middle ear fluid should be interpreted with caution. Additional studies with a larger sample size are needed to confirm these results.