Hearing and anatomy of the ear of the European hedgehog Erinaceus europaeus.

Auditory brainstem response (ABR) testing is considered to be relatively resistant to effects of volatile anesthetics. The impact of newer anesthetics on interpretability of ABR testing is unknown. This study compared sevoflurane versus propofol anesthesia on qualitative interpretability of ABR click-testing in children. This prospective double-blind crossover study enrolled children (≤18 years old) receiving general anesthesia for elective ABR testing. All subjects received both sevoflurane and propofol anesthesias in the same ABR testing session. Deidentified ABR data were reviewed by 5 audiologists (blinded to anesthetic and patient) to determine threshold levels for hearing loss. The primary outcome was qualitative interpretability (false positive) of ABR click-testing. Each patient was tested at 4 different intensities in each ear: generating 624 records under each anesthetic, for a total of 1248 records. A few patients were tested at 5 different intensities in a single ear accounting for the additional 11 records, yielding 1259 records. Under sevoflurane anesthesia, 21 of the same patients (37 ears) were identified with abnormal ABR levels consistent with hearing loss (one or both ears). The probability of a patient being diagnosed with hearing "loss" in one or both ears was significantly less with propofol versus sevoflurane anesthesia (mid P =.0312). If patients with bilateral loss are compared, the mid P value is 0.0098. The effect size based on patients was medium to large, with a minimum value of Cohen w = 0.320. Sevoflurane produced more false positives for hearing loss and suggested more severe hearing loss than propofol. False-positive ABR tests, produced by certain anesthetic agents, can have significant life-long impact and negative psychosocial and developmental implications. Use of the intravenous anesthetic propofol is superior to sevoflurane for ABR testing in children.

Efficacy of melatonin for auditory brainstem response testing in children: A systematic review

As a common debilitating disorder worldwide, tinnitus requires objective assessment. In the auditory brainstem response (ABR) test, auditory potentials can be evoked by acoustic or optoacoustic (induced by laser light) stimulations. In order to use the ABR test in the objective assessment of tinnitus, in this study, acoustic ABR (aABR) and optoacoustic ABR (oABR) were compared in the control and tinnitus groups to determine the changes caused by sodium salicylate (SS)-induced tinnitus in rat. In both aABR and oABR, wave II was the most prominent waveform, and the amplitude of wave II evoked by oABR was significantly higher than that of aABR. Brainstem transmission time (BTT), which represents the time required for a neural stimulation to progress from the auditory nerve ending to the inferior colliculus, was significantly shorter in oABR. In the tinnitus group, there was a significant increase in the threshold of both ABRs and a significant decrease in the amplitude of wave II only in the oABR. Based on our findings, the ABR test has the potential to be used in the assessment of SS-induced tinnitus, but oABR has the advantages of producing more prominent waveforms and significantly reducing the amplitude of wave II in tinnitus.

Objective:The auditory brainstem response (ABR) test is usually applied during natural sleep, but it can also be conducted under anesthesia. This retrospective study aimed to compare the ABR findings of a general anesthesia group and a control group that underwent ABR test during natural sleep.Methods:The anesthesia group consisted of 42 (mean age 44.5±20.3 months) children, and the control group included 58 children (36.1±16.1 months). The results of the click ABR test of the two groups were compared in terms of amplitude, latency, interpeak latencies, and hearing thresholds.Results:The amplitudes of waves III and V were significantly decreased in the general anesthesia group compared with that in the control group. The ABR latencies of waves I and V and the interpeak latencies for I-V and III-V were prolonged in the anesthesia group compared with that in the control group. Moreover, the click threshold obtained in the anesthesia group was significantly higher than those of the control group.Conclusions:Clinicians and audiologists should advise families to know the effects of general anesthesia on ABR and be cautious in interpreting the results obtained in ABR test performed under anesthesia.

Impact of anesthetics choice on auditory brainstem response testing in children: A systematic review.

Chloral hydrate sedation for auditory brainstem response (ABR) testing in children: Safety and effectiveness

The viability of applying Sensorineural Acuity Level (SAL) audiometry to auditory brain stem response (ABR) testing was investigated using 38 subjects with normal hearing, conductive, sensorineural, and mixed hearing losses. The stimuli were clicks, 4000, 2000, and 1000 Hz tone-pips. After ABR thresholds (ABRt) were obtained, bone-conducted noise was used to mask the response to a stimulus 5 dB above ABR threshold (ABRt + 5). Estimates of behavioral bone-conduction thresholds were made by observing the amount of noise needed to mask ABRt + 5. Estimates of behavioral air-conduction thresholds were based upon ABRt. Results indicated that ABRt was within +/- 10 dB of behavioral air-conduction threshold across subject groups at least 74% of the time for all tone-pip stimuli. ABRt was within +/- 15 dB of the pure-tone average of 1000, 2000, and 4000 Hz 75% of the time when click stimuli were used. Derived bone-conduction thresholds were within +/- 10 dB of the actual bone-conduction threshold at least 73% of the time for all stimuli. It was concluded that, when used in a conservative manner, the application of SAL audiometry to ABR testing may increase the reliability and confidence with which decisions are made concerning the type and degree of hearing loss in difficult-to-test patients.

Auditory brain stem response (ABR) testing can provide valuable information about hearing in neonates. However, it is subject to a number of interpretive errors, not all of which have yet been resolved. Collapsing ear canals are one of these, as this report documents. We hypothesize that the quite common incidence of canal collapse in this age group, along with other transient conductive defects, may help to explain the 1:10 and 1:20 incidences of significantly abnormal ABRs in neonatal screening.

To compare hypothetical costs for identification of acoustic tumors when using magnetic resonance imaging with gadolinium Gd 64 (MRI-(64)Gd) as a sole diagnostic test and when using auditory brainstem response (ABR) testing followed by MRI-( 64)Gd (ABR + MRI-(64)Gd) for those with positive ABR findings. Retrospective review of the medical records of 75 patients having surgically confirmed acoustic neuromas to categorize them into 3 subgroups relative to their risk of having a cerebellopontine angle tumor based on history, symptoms, and routine pure-tone and speech audiometric findings. Hypothetical costs associated with identification of patients with acoustic neuroma in each subgroup were calculated for MRI-(64)Gd alone and ABR + MRI-( 64)Gd. Auditory brainstem response sensitivity and specificity data for the 75 patients with acoustic neuroma and 75 patients without a tumor matched for hearing loss were applied to the hypothetical subgroups. Tumor size was considered also. Tertiary care center. Comparison of costs for MRI-(64)Gd and ABR + MRI-(64)Gd. Fouteen patients with acoustic neuroma were assigned to the high-risk category (30% probability); 45 were in the intermediate-risk category (5% probability); and 16 were in the low-risk category (1% probability). Auditory brainstem response testing correctly identified 100% of the large tumors (>2.0 cm), 93% of the medium-sized tumors (1.1-2.0 cm), and 82% of the small tumors (<1.0 cm). The hypothetical costs for identifying 14 patients with acoustic neuroma among 47 patients in the high-risk category using MRI-(64)Gd would be $70,500; ABR + MRI-(64)Gd costs for the 13 patients identified by ABR would be $39,600. Hypothetically 900 patients would be tested to identify the 45 acoustic neuromas in the intermediate-risk category. Magnetic resonance imaging with (64)Gd screening would reach $1.35 million for this sample. Auditory brainstem response testing and MRI-(64)Gd would be $486,000, but 4 acoustic neuromas would be missed. For the low-risk subgroup MRI-6(4)Gd screening of 1600 patients to identify 16 acoustic neuromas would total $2.4 million; ABR + MRI-(64)Gd to identify 15 of them would be $787,500. In this sample of 75 acoustic neuromas, large tumors were more prevalent in the low-risk subgroup than in the high- or intermediate-risk subgroups. Decisions regarding assessment of patients at risk for acoustic neuromas must be made on a case-by-case basis. Use of ABR + MRI-( 64)Gd allows considerable savings when patients are in the intermediate- or low-risk subgroups. New MRI and ABR testing techniques offer promise for reducing costs.

Background: Esophageal atresia (EA) is a congenital malformation occurring in approximately 1 in 4,000 births, with an unknown etiology. Some studies have reported an association between EA, cleft palate, and conductive hearing loss. This study investigates the potential involvement of the middle ear and auditory dysfunction in infants and children with EA (ages 0 - 15 years) using audiological assessments, particularly distortion product otoacoustic emissions (DPOAE) and auditory brainstem response (ABR) tests. Objectives: This study aims to assess the prevalence and characteristics of auditory dysfunction in infants and children with EA (ages 0 - 15 years) through electrophysiological tests (ABR and DPOAE), identifying potential correlations between EA and hearing impairments. Methods: This study was designed as a retrospective analysis of the medical records of 150 infants and children diagnosed with EA who were referred to Mofid Hospital in Tehran between 2018 and 2023. Auditory function was evaluated using ABR and DPOAE tests. Data on patient demographics, clinical history, and auditory test results were collected and statistically analyzed to determine the prevalence and patterns of hearing impairment in this population. Results: The results indicated a significant difference in the ABR test between the test group (n = 150) and the control group (n = 150), with a higher prevalence of conductive hearing loss in the test group (62 out of 150 cases; 41.3%, P ≤ 0.01, independent t-test). Additionally, 40% (60 out of 150) of children with EA had cleft palate lesions, which were strongly associated with conductive hearing loss (chi-square test, P &lt; 0.05). Tympanometry results showed that 41 cases (27.3%) had type B curves, and 21 cases (14%) had type C curves, indicating middle ear dysfunction. Acoustic reflex testing revealed that all 41 cases with type B tympanograms had absent reflexes, while in the 21 cases with type C tympanograms, reflexes were either absent or elevated depending on the severity of negative middle ear pressure. Conclusions: The study findings indicate a significant prevalence of conductive hearing loss in children with EA, particularly among those with cleft palate. Middle ear dysfunction, as evidenced by abnormal tympanometry and absent acoustic reflexes, suggests that structural and physiological factors associated with EA contribute to auditory impairment. These results highlight the need for routine audiological screening in children with EA to facilitate early intervention and improve long-term auditory outcomes.

Auditory brainstem response testing is typically done under sedation in the pediatric sedation unit but often requires tympanostomy tube placement, typically done under general anesthesia in the operating room (OR), to be performed first to obtain accurate results. This is the first report on the feasibility of performing tympanostomy tube placement in combination with auditory brainstem response testing under sedation provided by pediatric critical care medicine and hospitalist physicians outside the OR. A retrospective review was performed of cases at two children's hospitals in the United States, between July 2021 and February 2024. A total of 28 cases of tympanostomy tube placement in conjunction with auditory brainstem response testing under sedation provided by pediatric critical care medicine and hospitalist physicians outside the OR were identified. All the sedative regimens utilized propofol. All procedures were successful, but 6 patients experienced adverse events, with 5 patients experiencing only minor respiratory adverse events. One patient experienced laryngospasm, requiring unplanned intubation and Pediatric Intensive Care Unit admission. Lower direct facility costs and wait times were noted in a convenience sample of cases under sedation outside the OR compared to cases under general anesthesia in the OR.

Ultra high resolution nonenhanced fast spin echo magnetic resonance imaging: Cost-effective screening for acoustic neuroma in patients with sudden sensorineural hearing loss

Purpose Simulation is a tool commonly used in the clinical training of students within the health professions fields, such as medicine and nursing. The effectiveness of simulation as a teaching technique has been extensively documented in numerous health care professions; however, little is known about the effectiveness of simulation techniques in audiology education. This study assesses the effectiveness of a simulation activity focused on auditory brainstem response (ABR) testing conducted with students of an applied doctoral program in audiology. Method Twelve 2nd year audiology graduate students enrolled in the auditory electrophysiology course at Towson University in Fall 2018 participated in this pre-post study. Over a 3-week period, each student (a) received didactic instruction in ABR testing, (b) underwent a presimulation exercise skills assessment, (c) participated in a simulation exercise, and (d) underwent a postsimulation exercise skills assessment. Results Significant improvements were observed in clinical skill level for the ABR tasks evaluated in terms of both accuracy and efficiency (time in seconds needed to complete the task). The tasks evaluated included skin preparation, identification of scalp electrode placement sites, and scalp electrode placement in a variety of configurations (single- and two-channel arrays, horizontal and vertical electrode montages). Benefits associated with simulation-based instruction varied by clinical skill as well as by student. Conclusions The data described in this study reinforce the need to incorporate simulation in audiology training programs, especially for complex clinical skills. It also emphasizes the need for additional research that can be useful in the design and implementation of simulation-based exercises.

The levels of noise necessary to effectively mask the stimuli commonly used in auditory brainstem response (ABR) tests were determined. The relative masking level (RLM) of twenty normally-hearing volunteers was measured behaviourally using ipsilaterally presented unfiltered noise in the presence of ABR stimuli. The upper limit for RLM was found to be typically 30 dB above the stimulus level when the stimulus was calibrated in dBnHL to ISO 389-6 (2007) and the noise was measured in dBSPL. This value is recommended when calculating the level of noise necessary to prevent cross-hearing during ABR testing.SumarioSe determinaron los niveles de ruido necesarios para enmascarar efectivamente los estímulos comúnmente utilizados en las pruebas de respuestas auditivas del tallo cerebral (ABR). Se midió en forma conductual el nivel de enmascaramiento relativo (RLM) de veinte voluntarios con audición normal, usando ruido no filtrado presentado ipsilateralmente en presencia de estímulos para ABR. Se encontró que el límite superior del RLM típicamente era de 30 dB por encima de nivel del estímulo cuando el estímulo estaba calibrado en dB nHL para ISO 389-6 (2007) y el ruido era medido en dB SPL. Este valor es recomendado cuando se calcula el nivel de ruido necesario para prevenir audición cruzada durante la evaluación con ABR.

Transiently evoked otoacoustic emissions (TEOAE) and auditory brainstem response (ABR) tests were used in parallel to screen 862 neonates with risk factors for hearing loss. Seven neonates (0.81%) passed on TEOAE screen yet failed on ABR in one ear (six neonates) or both ears (one neonate). This combination of results has been termed 'anomalous'. Examination of audiometric results obtained on follow-up shows that in one ear of one neonate the result was consistent with the later confirmed audiogram shape. The explanation for the anomalous results in the remaining ears is unclear although neural maturation and the effects of hyperbilirubinaemia are possibilities. There were no instances of progressive or retrocochlear hearing loss identified. None of the seven neonates had better ear hearing loss of > or = 40 dB on long term follow-up.