How to perform ABR in young children

Preserved Auditory Steady State Response and Envelope-Following Response in Severe Brainstem Dysfunction Highlight the Need for Cross-Checking

OBJECTIVES

Commercially available auditory steady state response (ASSR) systems are widely used to obtain hearing thresholds in the pediatric population objectively. Children are often examined during natural or induced sleep so that the recorded ASSRs are of subcortical origin, the inferior colliculus being often designated as the main ASSR contributor in these conditions. This report presents data from a battery of auditory neurophysiological objective tests obtained in 3 cases of severe brainstem dysfunction in sleeping children. In addition to ASSRs, envelope-following response (EFR) recordings designed to distinguish peripheral (cochlear nerve) from central (brainstem) were recorded to document the effect of brainstem dysfunction on the two types of phase-locked responses.

DESIGN

Results obtained in the 3 children with severe brainstem dysfunctions were compared with those of age-matched controls. The cases were identified as posterior fossa tumor, undiagnosed (UD), and Pelizaeus-Merzbacher-Like Disease. The standard audiological objective tests comprised tympanograms, distortion product otoacoustic emissions, click-evoked auditory brainstem responses (ABRs), and ASSRs. EFRs were recorded using horizontal (EFR-H) and vertical (EFR-V) channels and a stimulus phase rotation technique allowing isolation of the EFR waveforms in the time domain to obtain direct latency measurements.

RESULTS

The brainstem dysfunctions of the 3 children were revealed as abnormal (weak, absent, or delayed) ABRs central waves with a normal wave I. In addition, they all presented a summating and cochlear microphonic potential in their ABRs, coupled with a normal wave I, which implies normal cochlear and cochlear nerve function. EFR-H and EFR-V waveforms were identified in the two cases in whom they were recorded. The EFR-Hs onset latencies, response durations, and phase-locking values did not differ from their respective age-matched control values, indicating normal cochlear nerve EFRs. In contrast, the EFR-V phase-locking value and onset latency varied from their control values. Both patients had abnormal but identifiable and significantly phase-locked brainstem EFRs, even in a case with severely distorted ABR central waves. ASSR objective audiograms were recorded in two cases. They showed normal or slightly elevated (explained by a slight transmission loss) thresholds that do not yield any clue about their brainstem dysfunction, revealing the method's lack of sensitivity to severe brainstem dysfunction.

CONCLUSIONS

The present study, performed on 3 sleeping children with severe brainstem dysfunction but normal cochlear responses (cochlear microphonic potential, summating potential, and ABR wave I), revealed the differential sensitivity of three auditory electrophysiological techniques. Estimated thresholds obtained by standard ASSR recordings (cases UD and Pelizaeus-Merzbacher-Like Disease) provided no clue to the brainstem dysfunction clearly revealed by the click-evoked ABR. EFR recordings (cases posterior fossa tumor and UD) showed preserved central responses with abnormal latencies and low phase-locking values, whereas the peripheral EFR attributed to the cochlear nerve was normal. The one case (UD) for which the three techniques could be performed confirms this sensitivity gradient, emphasizing the need for applying the Cross-Check Principle by avoiding resorting to ASSR recording alone. The entirely normal EFR-H recordings observed in two cases further strengthen the hypothesis of its cochlear nerve origin in sleeping children.

Confirmatory Auditory Brainstem Responses Testing Results in Discordant Outcomes: Implications for Timely Care

OBJECTIVES

The purpose of this study is to evaluate for discrepancies in diagnostic auditory brainstem responses (ABR) between Children's National Hospital (CNH), a pediatric medical center, and outside facilities (OSF) that referred patients to CNH for confirmatory evaluation. Such discrepancies impact early hearing detection and intervention (EHDI) timelines.

METHODS

A retrospective chart review was conducted from an internal database of patients who underwent diagnostic ABR from 2017 to 2021. Only patients with ABR results from both CNH and OSF were analyzed. Demographic data, external and internal test results, and intervention data were obtained. Hearing loss (HL) severity was graded on a scale of 0 to 8, where 0 indicated normal hearing and 8 indicated profound. Each ear was analyzed separately.

RESULTS

Forty-nine patients met the inclusion criteria, and each ear was evaluated separately. Median HL severity was 1.0 [0.0, 4.3] at CNH compared to 3.0 [1.8, 6] at OSF (p = 0.004). Forty-seven ears (48.0%) showed lower severity at CNH. Twenty-seven patients (55%) received hearing amplification devices. The median age at time of hearing intervention was 220 days.

CONCLUSION

Our results showed statistical significance in the median severity of HL between CNH and OSF. A substantial proportion (70%) of children in our dataset who received amplification via cochlear implant or hearing aids were shown to have discrepancies in ABR findings from CNH and OSF. These findings have implications with regards to the appropriate usage of health care resources and maintaining EDHI timelines.

LEVEL OF EVIDENCE

4 (Retrospective Cohort Study) Laryngoscope, 133:3571-3574, 2023.

Bats experience age-related hearing loss (presbycusis)

Hearing loss is a hallmark of aging, typically initially affecting the higher frequencies. In echolocating bats, the ability to discern high frequencies is essential. However, nothing is known about age-related hearing loss in bats, and they are often assumed to be immune to it. We tested the hearing of 47 wild Egyptian fruit bats by recording their auditory brainstem response and cochlear microphonics, and we also assessed the cochlear histology in four of these bats. We used the bats' DNA methylation profile to evaluate their age and found that bats exhibit age-related hearing loss, with more prominent deterioration at the higher frequencies. The rate of the deterioration was ∼1 dB per year, comparable to the hearing loss observed in humans. Assessing the noise in the fruit bat roost revealed that these bats are exposed to continuous immense noise-mostly of social vocalizations-supporting the assumption that bats might be partially resistant to loud noise. Thus, in contrast to previous assumptions, our results suggest that bats constitute a model animal for the study of age-related hearing loss.

Efficiency of Melatonin as a Sedative for Auditory Brainstem Response in Children

Introduction-Although auditory brainstem response (ABR) testing is among the most frequently used investigations in pediatric audiology and it often requires sedation or general anesthesia. In recent years, melatonin has been successfully used as an alternative way of inducing sleep, particularly in children undergoing magnetic resonance imaging (MRI) or electroencephalography (EEG). Purpose-To assess the effectiveness of orally administered melatonin as an alternative to sedation or general anesthesia during ABR testing. Method-In total, 33 children with suspected hearing loss underwent ABR tests in melatonin-induced sleep. Each patient received an initial dose of 5 mg, which was re-administered in case of failure to obtain sleep. Click-induced ABR tests were performed on both ears. Results-ABR tests were successfully performed in 72.7% of the patients. The average total length of time needed to obtain sleep and complete the ABR testing was 45 min. There was no significant difference between the patients who completed the examination and those who did not in terms of age or psychomotor development. There was a statistically significant association between receiving a maintenance dose and successful completion of the test (p < 0.001). There was also a significant connection between the degree of hearing loss and the success rate of the ABR tests (p < 0.001). Conclusions-Melatonin-induced sleep is a good and safer alternative to anesthesia to perform ABR testing in young children. It is easily administered, tolerated by the patients, and accepted by parents.

Melatonin is useful alternative for sedation in children undergoing auditory brainstem responses testing

Auditory brainstem responses testing (ABRs) is frequently required to assess auditory function in children. It is done usually in outpatient fashion and requires deep sleep to avoid artefacts. Sedation method used for the test should allow a deep sleep while avoiding general anaesthesia that requires special monitoring, dedicated staff and operating room availability. For this purpose, several sedation methods have been used, with the risk of respiratory depression and sides effects. We aim to assess the efficacy and the usefulness of melatonin in sedation for children undergoing auditory brainstem responses testing. We calculated success rate of complete bilateral ABR, sleep delay and quality of sleep of 247 children referred for ABR testing. Two hundred six children (83.4%) successfully underwent both ears testing. The delay to sleep was variable with a mean of 32 min. The quality of sleep was described as continuous in 156 infants (75.7%) and discontinuous in 50 infants (24.27%) requiring either simple nursing or a second dose of melatonin 30 min later.Conclusion: Melatonin has the advantages of inducing natural sleep and reducing sleep delay without adverse effects or respiratory depression risk. It is efficient and useful sedation method for ABRs in an outpatient setting. What Is Known? • Auditory brainstem responses test is the most used objective test to assess auditory function in children and requires deep sleep to avoid artefacts. • Melatonin is an endogenous pineal hormone used for sedation in electrophysiological testing and magnetic resonance imaging. What Is New? • 83.4% of children in our study successfully performed a bilateral ABR under melatonin-induced sleep with continuous sleep in 75.7%. • The use of melatonin to induce sleep for ABR tests is useful in an outpatient setting and it is a good alternative to general anaesthesia in Morocco.

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

OBJECTIVE

To examine the literature on pre-treatment with melatonin for successful completion of Auditory Brainstem Response (ABR) testing in pediatric patients and evaluate melatonin dosing protocols.

DATA SOURCES

The Cochrane Library, PubMed, Ovid MEDLINE, and Web of Science from inception through May 20th, 2019. In addition, a retrospective case series of pediatric patients (<18yr) who underwent melatonin assisted ABR testing between 2015 and 2018 was performed at our institution.

REVIEW METHODS

Prospective and retrospective studies involving melatonin use in pediatric patients (<18yrs) for auditory brainstem response testing were evaluated. Studies meeting inclusion/exclusion criteria reported success rate of ABR testing using melatonin pre-treatment, dosage of melatonin used, duration of sleep, and whether adverse events occurred.

RESULTS

43 studies were identified, 8 studies were selected, and finally 5 studies were included in the review. A total of 480 pediatric patients underwent ABR testing with pre-treatment of melatonin with success rates ranging from 65% to 86.7%. Age across studies ranged from 1 month to 14 years, 6 months. Dosage of melatonin varied from 0.25 mg for patients <3 months of age to 20 mg for patients >6 years of age, with one study using a weight-based approach. No significant adverse events were reported by any of the included studies.

CONCLUSION

Pre-medication with melatonin may be a useful option for obtaining successful results of non-sedated ABR testing in pediatric patients and may provide a useful alternative to sedation. Dosing patterns are highly variable. No adverse events were reported with any dosing strategy.

The Effects of Random Stimulation Rate on Measurements of Auditory Brainstem Response

Electroencephalography (EEG) signal is an electrophysiological recording from electrodes placed on the scalp to reflect the electrical activities of the brain. Auditory brainstem response (ABR) is one type of EEG signals in response to an auditory stimulus, and it has been widely used to evaluate the potential disorders of the auditory function within the brain. Currently, the ABR measurements in the clinic usually adopt a fixed stimulation rate (FSR) technique in which the late evoked response could contaminate the ABR signals and deteriorate the waveform differentiation after averaging, thus compromising the overall auditory function assessment task. To resolve this issue, this study proposed a random stimulation rate (RSR) method by integrating a random interval between two adjacent stimuli. The results showed that the proposed RSR method was consistently repeatable and reliable in multiple trials of repeated measurements, and there was a large amplitude of successive late evoked response that would contaminate the ABR signals for conventional FSR methods. The ABR waveforms of the RSR method showed better wave I–V morphology across different stimulation rates and stimulus levels, and the improved ABR morphology played an important role in early diagnoses of auditory pathway abnormities. The correlation coefficients as functions of averaging time showed that the ABR waveform of the RSR method stabilizes significantly faster, and therefore, it could be used to speed up current ABR measurements with more reliable testing results. The study suggests that the proposed method would potentially aid the adequate reconstruction of ABR signals towards a more effective means of hearing loss screening, brain function diagnoses, and potential brain–computer interface.