Auditory Brainstem Response Evaluation Research Articles

An infant with congenital heart defects and proteinuria: a case report

BackgroundBranchio-Oto-Renal (BOR) Syndrome is a rare autosomal disorder with a wide variety of clinical manifestations and a high degree of heterogeneity. Typical clinical manifestations of BOR syndrome include deafness, preauricular fistula, abnormal gill slits, and renal malformations. However, atypical phenotypes such as congenital hip dysplasia, congenital heart anomaly or facial nerve paresis are rare in BOR syndrome, and this might be easily misdiagnosed with other congenital disorders.Case presentationWe report a 5-month-old boy of BOR syndrome with "congenital heart defects and proteinuria" as clinical features. Initially, as this case mainly presented with symptoms of recurrent respiratory infections and was found to be with congenital heart disease and proteinuria at the local hospital, but he only was diagnosed with congenital heart disease combined with pulmonary infection and anti-infective and supportive treatment was given. Subsequently, during the physical examination at our hospital, left side preauricular pit and branchial fistulae on the right neck were found. Subsequent evaluation of auditory brainstem response and distortion product otoacoustic emission were revealed sensorineural hearing impairment. Results of renal ultrasonography showed small kidneys. Genetic analysis revealed a microdeletion at chromosome 8q13.2-q13.3 encompassing EYA1 gene, this patient was finally diagnosed with BOR syndrome. Then, this patient received transcatheter patent ductus arteriosus closure and hearing aid treatment. Proteinuria, renal function and hearing ability are monitoring by nephrologist and otologist. The patient is currently being followed up until 3 months after discharge and his condition is stable.ConclusionCareful physical examination, detailed history and the implementation of diagnostic laboratory tests can reduce the incidence of misdiagnosis. Genetic sequencing analysis of patients is a key guide to the differential diagnosis of BOR syndrome.

QOL-23. Expanded protocols for hearing loss related cisplatin-based therapy in childhood cancer patients.

Abstract BACKGROUND: Most children who require cisplatin chemotherapy incur hearing loss. The basal end of the cochlea, corresponding to high frequency sound perception, is typically affected first, with progression along the basilar membrane and to lower frequencies over time. Typical audiologic protocols for children are often restricted to the speech frequencies (500-4000Hz). However, reliable responses to higher frequencies can be obtained using specialized electrophysiologic measures or adapted behavioral test procedures, which may lead to earlier identification of hearing loss during ototoxicity monitoring. METHODS: Auditory Brainstem Response (ABR) and behavioral threshold assessments were completed for patients during cisplatin treatment at Cincinnati Children’s Hospital between 2017 and 2021. High frequency ABR protocols were established to include 6000 and 8000 Hz and behavioral testing protocols were expanded to include frequencies 8000 through 16000 Hz. Hearing loss was defined as >20 dB eHL at any frequency. The typical and high frequency protocols were compared to determine if higher frequency measurement provides a more sensitive means to detect the onset of hearing loss. RESULTS: One-hundred and fifty-three patients receiving cisplatin were assessed audiometrically. For patients who required ABR evaluations, 38% were identified with hearing loss when using the typical test protocol, where 79% of the patients were identified with hearing loss when using the high frequency protocol. For patients who were able to complete behavioral audiometric evaluations, 42% were identified with hearing loss with the typical protocol while 84% were identified with the high frequency protocol. CONCLUSIONS: The addition of higher frequencies to audiologic evaluation protocols for both ABR and behavioral audiometry significantly increases sensitivity to detect hearing loss during ototoxicity monitoring of cisplatin treatment and is a feasible strategy in pediatric cancer patients. Audiologically, the increased sensitivity to detect hearing loss may lead to earlier intervention regarding hearing and communication for the patient/family.

Prospective Evaluation of Auditory Brainstem Response against Hearing Loss Risk Factrs. A Clinical Based Study

Objective: The purpose of this study is to determine the improvement of auditory brainstem response against hearing loss risk factors among new born babies. Study Design: Prospective study Place and Duration: Bahawalpur Medical and Dental College, Bahawalpur and General Hospital, Lahore. Jan, 2021 to June, 2021 Methods: There were one hundred and thirty high risk infants were presented in this study. Birth weight and gestational age as well as transfusion and asphyxiation rates were documented once the parents provided written permission. Included patients had absent ABR or ABR thresholds ≥80 dBnHL. ABR testing during natural or chloral hydrate-induced sleep was part of the audiologist's examination. Patients with aberrant ABR responses underwent further testing, including optical absorption empiricism (OAE). Measurements of immittance were performed as necessary. All data was analyzed by using SPSS 22.0. Results: Among 130 cases, majority of the infants were males 85 (65.4%) and 45 (34.6%) infants were females. Mean gestational age of the infants was 35.11± 6.42 weeks. Mean weight of the infants was 1899.1± 2.654 grams. Frequency of severe birth asphyxia was seen in 65 (50%) cases. We found exchange transfusion in 25 (19.2%) cases. Improvement in ABR threshold was seen in 70 (53.8%) cases, partial improvement in 27 (20.8%) cases and no improvement was seen in 33 (25.4%) cases. After 3-4 months among patients of no/partial improvement, 42 (70%) patients were improved and no improvement was seen in 18 (30%) cases. Conclusion: We concluded in this study that the hearing loss can be improved in infants by early ear screening by using ABR thresholds. Re-screening of ABR thresholds provided better results among infants. Staged further hearing testing of babies is needed to monitor hearing development at an early age utilizing repeated ABR measures to identify hearing impairment and detect threshold changes crucial for treatment decision-making. Keywords: Infants, ABR thresholds, Improvement, OAE

Evaluation of Auditory Brainstem Response in Chicken Hatchlings.

The auditory brainstem response (ABR) is an invaluable assay in clinical audiology, non-human animals, and human research. Despite the widespread use of ABRs in measuring auditory neural synchrony and estimating hearing sensitivity in other vertebrate model systems, methods for recording ABRs in the chicken have not been reported in nearly four decades. Chickens provide a robust animal research model because their auditory system is near functional maturation during late embryonic and early hatchling stages. We have demonstrated methods used to elicit one or two-channel ABR recordings using subdermal needle electrode arrays in chicken hatchlings. Regardless of electrode recording configuration (i.e., montage), ABR recordings included 3-4 positive-going peak waveforms within the first 6 ms of a suprathreshold click stimulus. Peak-to-trough waveform amplitudes ranged from 2-11 µV at high-intensity levels, with positive peaks exhibiting expected latency-intensity functions (i.e., increase in latency as a function of decreased intensity). Standardized earphone position was critical for optimal recordings as loose skin can occlude the ear canal, and animal movement can dislodge the stimulus transducer. Peak amplitudes were smaller, and latencies were longer as animal body temperature lowered, supporting the need for maintaining physiological body temperature. For young hatchlings (<3 h post-hatch day 1), thresholds were elevated by ~5 dB, peak latencies increased ~1-2 ms, and peak to trough amplitudes were decreased ~1 µV compared to older hatchlings. This suggests a potential conductive-related issue (i.e., fluid in the middle ear cavity) and should be considered for young hatchlings. Overall, the ABR methods outlined here permit accurate and reproducible recording of in-vivo auditory function in chicken hatchlings that could be applied to different stages of development. Such findings are easily compared to human and mammalian models of hearing loss, aging, or other auditory-related manipulations.

Evaluation of Auditory Brainstem Response in Chicken Hatchlings

The auditory brainstem response (ABR) is an invaluable assay in clinical audiology, non-human animals, and human research. Despite the widespread use of ABRs in measuring auditory neural synchrony and estimating hearing sensitivity in other vertebrate model systems, methods for recording ABRs in the chicken have not been reported in nearly four decades. Chickens provide a robust animal research model because their auditory system is near functional maturation during late embryonic and early hatchling stages. We have demonstrated methods used to elicit one or two-channel ABR recordings using subdermal needle electrode arrays in chicken hatchlings. Regardless of electrode recording configuration (i.e., montage), ABR recordings included 3-4 positive-going peak waveforms within the first 6 ms of a suprathreshold click stimulus. Peak-to-trough waveform amplitudes ranged from 2-11 µV at high-intensity levels, with positive peaks exhibiting expected latency-intensity functions (i.e., increase in latency as a function of decreased intensity). Standardized earphone position was critical for optimal recordings as loose skin can occlude the ear canal, and animal movement can dislodge the stimulus transducer. Peak amplitudes were smaller, and latencies were longer as animal body temperature lowered, supporting the need for maintaining physiological body temperature. For young hatchlings (<3 h post-hatch day 1), thresholds were elevated by ~5 dB, peak latencies increased ~1-2 ms, and peak to trough amplitudes were decreased ~1 µV compared to older hatchlings. This suggests a potential conductive-related issue (i.e., fluid in the middle ear cavity) and should be considered for young hatchlings. Overall, the ABR methods outlined here permit accurate and reproducible recording of in-vivo auditory function in chicken hatchlings that could be applied to different stages of development. Such findings are easily compared to human and mammalian models of hearing loss, aging, or other auditory-related manipulations.

Auditory brainstem response in preterm infants with bilirubin encephalopathy

AimTo clarify auditory brainstem response (ABR) in preterm infants with bilirubin encephalopathy and the relationships between ABR and clinical variables. MethodWe retrospectively reviewed the ABR waveforms of 56 preterm infants with BE and graded them as “no response”, “abnormal interwave separation”, or “normal”. Patient backgrounds, the peak total bilirubin level, the bilirubin/albumin ratio, verbal communication ability, and newborn hearing screening test results from an automated ABR evaluation had been collected during an earlier nationwide survey. ResultsThe frequency of abnormal ABR findings decreased with age. Verbal communication tended to be poorer in patients with more severe ABR abnormalities. ABR findings improved in 7 of 29 infants with available serial ABR data. Both gestational age and the peak total bilirubin level were relatively lower in patients with than in those without improved ABR findings. Newborn hearing screening using automated ABR evaluation yielded data consistent with manual ABR findings in 16 of 20 patients who underwent both examinations. ConclusionsABR abnormalities in preterm infants with bilirubin encephalopathy may improve over time, especially in those with a lower gestational age and peak total bilirubin level. Newborn hearing screening using automated ABR may fail to detect abnormalities in some infants.

Evaluation of Auditory Brainstem Response (ABR) in Vitamin B12 Deficiency.

Changes in the central nervous system are observed due to vitamin B12 deficiency. The purpose of this study is to assess the effects of vitamin B12 deficiency on the central auditory tracks utilizing ABR. 30 individuals (16 females, 14 males) with vitamin B12 deficiency and 30 individuals (17 females, 13 males) without any hearing problem and B12 deficiency have participated in the study. The ages of the individuals with vitamin B12 deficiency varied between 18 and 39, with a mean of 28±5.6, The ages of the individuals with normal hearing in the control group were between 18 and 42, with a mean of 30±6.2. The I, III and V. wave latencies and I-III, I-V and III-V inter-wave latencies and amplitudes of the participants with vitamin B12 deficiency and with normal hearing were evaluated using click stimulus. No statistically significant change was observed between the group with vitamin B12 deficiency and the normal group in the I, III and V. wave latencies and the I-III, I-V and III-V inter-latency values and amplitudes. Although vitamin B12 deficiency effects the central nervous system, normal latencies and amplitudes were obtained in the ABR test. It was especially observed that the brainstem region, where the I, III ve V. Waves originate, is not effected by vitamin B12 deficiency.

Acellular Collagen Scaffold With Basic Fibroblast Growth Factor for Repair of Traumatic Tympanic Membrane Perforation in a Rat Model.

To evaluate the efficacy of acellular collagen scaffold (ACS) in combination with basic fibroblast growth factor (bFGF) for the repair of traumatic tympanic membrane (TM) perforation in a rat model. A prospective controlled animal study in a rat model of traumatic TM perforation. Tertiary medical center. Sprague-Dawley rats (N = 84) with unilateral traumatic perforation of the right TMs were randomized to receive ACS, bFGF, ACS in combination with bFGF (ACS/bFGF), or nothing (spontaneous healing without any interventions as a control group). The healing outcomes were evaluated by otoscopy, optical coherence tomography, histology, and transmission electron microscopy at 1, 2, and 4 weeks postoperatively. The hearing outcomes were assessed with auditory brainstem response testing. ACS/bFGF resulted in higher perforation closure rates at an earlier stage than spontaneous healing, ACS, and bFGF. Based on histology, optical coherence tomography, and transmission electron microscopy, a trilaminar structure and uniform thickness with mature, densely packed collagen fibers were seen in the ACS/bFGF group. Auditory brainstem response evaluation also showed that ACS/bFGF treatment promoted faster functional hearing recovery as compared with the control group. ACS is an effective TM scaffold and a carrier for bFGF. ACS/bFGF improves the TM closure rate, results in better-reconstructed TMs, and improves hearing. ACS/bFGF serves as a potential substitute for TM perforations in clinical settings.

Examining the Early Period Effect of Nilotinib on Hearing: An Experimental Study.

Nilotinib has very few side effects, including neutropenia, thrombocytopenia, cardiotoxicity, high pancreatic lipase, ischemia, and vascular occlusion. We aimed to investigate whether short-term administration of nilotinib had ototoxic effects in rats. Wistar-albino rats were categorized into three groups: group C (administered 0.25 mL of distilled water, no nilotinib), group N-20 (administered 20 mg/kg/day of nilotinib dissolved in distilled water), and group N-50 (administered 50 mg/kg/day of nilotinib dissolved in distilled water). A single dose was administered once per day, at the same hour, over 21 days. Auditory brainstem response (ABR) thresholds were recorded on day 0 and day 21. There were no changes in ABR threshold values obtained on day 0 (baseline) and on day 21 across all three groups. A statistically significant difference was not found in terms of the mean latency of waves V and III, interpeak latency values of waves III-V, and amplitude ratios of waves III-V and V/Va at baseline and on day 21 across all three groups on within-group or between-group evaluation. Consequently, further studies are needed that involve different drug doses, prolonged administration of drugs, as well as distortion otoacoustic emission test for the evaluation of cochlear activation and ABR. Furthermore, histopathological studies are needed to indicate whether the cochlea is affected to prove that nilotinib has definitively no ototoxic effect.

Early detection of neonatal hearing loss by otoacoustic emissions and auditory brainstem response over 10 years of experience

ObjectivesA number of different screening protocols for detecting neonatal hearing loss currently exist. We present our 10 years of experience with using auditory brainstem response (ABR) complementary to otoacoustic emissions (OAEs) in the three phases hearing screening process in our hospital. Furthermore, we want to demonstrate the usefulness of these screening techniques used in combination, that remain valid to identify cases of neonatal hearing loss and meet the well-established program quality criteria for these screening protocols. MethodsData were collected retrospectively from patient record forms completed on 9698 newborns from 2007 to 2017. The screening protocol for neonatal hearing loss in our centre is carried out in three phases. First phase, prior to discharge from the hospital, consists of carrying out the OAE evaluation on the newborn. Second phase is carried out in the paediatric consultation department. There, the newborns who did not pass the first phase are again studied with OAE. If this phase is not passed either, the child is referred to a third phase for the realization of ABR, in the clinical neurophysiology service. Newborns with risk factors for hearing loss, identified in the first phase, also go on to this third phase. When this hearing threshold exceeds 30 dB, it is considered abnormal. Cases with abnormal ABR, has a re-test conducted within the next six months from the initial ABR assessment. ResultsA total of 9390 (97.1%) OAEs were performed during first phase, with 8245 newborns (87.8%) passing the screening test, while 1145 children (12.1%) presented an abnormal OAE and were included in the second screening phase. Second phase involving a repeat OAE examination performed on 1077 newborns (94%). In this second phase, 941 newborns (87.3%) passed the test. Nevertheless, 136 newborns (12.6%) failing the retest and were referred to continue on to phase three. Furthermore, 181 newborns (1.8%) presented high-risk factors at birth and were also included in this third phase. However, in the registries of children referred to this phase, only 255 (80%) ABR evaluations were confirmed. In total, 227 newborns (2.3%) were missed from the first to third phases of the screening process. According to the database of the clinical neurophysiology service, ABRs evaluations were performed in 352 newborns referred between December 2007 and December 2017. Of this sample, 38.9% were boys and 61.1% were girls. From among cases underwent ABR, 34% of newborns did not pass the OAEs. The most common risk factor was prematurity (with admission to the neonatal intensive care unit for more than five days), affecting 28%. Abnormal ABRs waveforms were found in 43.9%, with 12.3% having a sensorineural hearing loss, 26.5% showing mixed hearing loss and, conductive hearing loss being present in 61.9%. Considering sensorineural hearing loss and other types of severe hearing loss, affected patients constituted only 1.7% of the total number of individuals studied. Finally, regarding quality control of the program participation in the first phase of care included 97.2% of all newborns, yielding a third phase referral rate of 2.9%, confirmation of a diagnosis before the fourth month of life in more than 90% of cases with an average of 3.4 months of age, and a hearing impairment detection rate as an outcome indicator of 4.5%. ConclusionsOur data are similar to those of previous studies on screening for hearing loss in newborns. We have demonstrated the advantages of carrying out this protocol in three phases using the otoacoustic emissions together with auditory brainstem response, diagnostic tools that remain as a Gold Standard. Also, we want to highlight and demonstrate the importance of interdisciplinary coordination between the paediatric and clinical neurophysiology services in the implementation of this screening protocol. The foregoing has allowed us to comply with the proposed quality indicators, reaching coverage percentages of more than 95%, confirming the diagnosis of hearing loss within the first six months of life and making timely referrals to benefit the newborns with hearing impairment by way of treatment and follow-up in the early stages of development, avoiding future disabilities.

Pediatric Audiology Productivity: Results From a Multicenter Survey.

Purpose This report focuses on audiology productivity measures and targets, impacting variables, and implementation of productivity in pediatric settings and "life span facilities" with a significant population of pediatric patients. Research Design A questionnaire was sent to 116 facilities in geographically diverse locations. Results Of the 116 surveys sent, 25 surveys were returned (response rate of 21.5%) and 22 had sufficient data to be included for analyses. The majority of the sites measure productivity at the individual and/or department level. No predominant productivity measurement method was reported. Measurement methods included the following: appointment length (n = 6), weighting Current Procedural Terminology codes (n = 6), relative value units (n = 5), a combination of methods (n = 1), and other specific parameters (n = 1). Thirteen sites measured productivity as a percentage of scheduled worked time with a target of 69% (ranged from 40% to 85%). Many variables thought to impact productivity were evaluated: age of the patient, scheduling, use of a 2nd tester, no-show rate, hearing aid status, components of auditory brainstem response evaluation, documentation time, and monaural or binaural services. Schedule review and adjustment, efficiency, and communication with staff were methods reported to increase productivity. Conclusion Most surveyed facilities measure productivity at the individual and/or department levels. However, there is no standard method. Current productivity measures include time-based measures based on appointment length, time-based measures assigned to Current Procedural Terminology codes, relative value units, combined approaches, and individual site developed programs. Many variables impact productivity measurements. Further study and discussion are needed to develop an optimal method for productivity measurement in audiology.

Clinical Practice Guideline: Sudden Hearing Loss (Update) Executive Summary.

ObjectiveSudden hearing loss is a frightening symptom that often prompts an urgent or emergent visit to a health care provider. It is frequently, but not universally, accompanied by tinnitus and/or...

Clinical Practice Guideline: Sudden Hearing Loss (Update).

ObjectiveSudden hearing loss is a frightening symptom that often prompts an urgent or emergent visit to a health care provider. It is frequently but not universally accompanied by tinnitus and/or v...

Hearing loss in very preterm infants: should we wait or treat?

SUMMARYThis study investigated hearing threshold changes during the first year of corrected age (CA) in infants admitted in a neonatal intensive care unit (NICU). In 5 years, 239 infants with birth weight (BW) ≤ 1,000 gm and/or gestational age (GA) ≤ 30 weeks were enrolled. Hearing was evaluated by oto-acoustic emission (OAEs) before discharge and auditory brainstem response (ABR) within 3 months of CA. Infants affected by unilateral or bilateral hearing loss were addressed to audiological follow-up until definitive diagnosis (within 6 months of CA). Changes in hearing threshold were also carefully analysed. 207 (86.6%) infants had normal hearing while 32 infants (13.4%) showed hearing loss (HL) at the confirmative ABR evaluation (9 mild, 16 moderate, 4 severe, 3 profound). The latter showed lower GA (27.7 ± 2 vs 28.4 ± 1.2; p = 0.0061) and BW (950 ± 390 vs 1,119 ± 326 gm; p = 0.0085). At final evaluation, 15 infants (47%) recovered a normal hearing. HL was confirmed in 17 patients. Among these, 3 infants were addressed to audiological follow-up (one case of mild unilateral hearing loss (UHL) and two with moderate UHL), while in 14 cases (44%) with bilateral sensory neural hearing loss (SNHL) (7 moderate, 4 severe, 3 profound) hearing aids were prescribed. They showed significantly lower GA and longer hospital stay in the NICU in comparison with infants without indication for audiological habilitation (18 infants) (GA 26.2 ± 2.2 weeks vs 28.4 ± 2.4; p = 0.01; NICU stay 132 ± 67 vs 59 ± 7; p = 0.0002). Definitive diagnosis was obtained at 5.9 ± 1.3 months of CA. Our study confirms the importance of audiological surveillance in preterm newborns. Hearing thresholds of preterm infants with hearing loss can change during the first year of CA and we observed normalisation in 47% of our patients. Most vulnerable to permanent SNHL were very preterm infants with a longer NICU stay, while a shorter stay represents a favourable prognostic factor for hearing improvement.

The Effects of Riluzole on Cisplatin-induced Ototoxicity.

Introduction Riluzole (2-amino-6-trifluoromethoxy benzothiazole) is known as a neuroprotective, antioxidant, antiapoptotic agent. It may have beneficial effects on neuronal cell death due to cisplatin-induced ototoxicity. Objective To evaluate the effect of riluzole on cisplatin-induced ototoxicity in guinea pigs. Methods Twenty-four guinea pigs, studied in three groups, underwent auditory brainstem response evaluation using click and 8 kHz tone burst stimuli. Subsequently, 5 mg/kg of cisplatin were administered to all animals for 3 days intraperitoneally (i.p.) to induce ototoxicity. Half an hour prior to cisplatin, groups 1, 2 and 3 received 2 ml of saline i.p., 6 mg/kg of riluzole hydrochloride i.p., and 8 mg/kg of riluzole hydrochloride i.p., respectively, for 3 days. The auditory brainstem responses were repeated 24 hours after the last drug administration. The cochleae were analyzed by transmission electron microscopy (TEM). Results After drug administiration, for 8,000 Hz stimulus, group 1 had significantly higher threshold shifts when compared with groups 2 ( p < 0.05) and 3 ( p < 0.05), and there was no significant difference in threshold shifts between groups 2 and 3 ( p > 0.05). Transmission electron microscopy findings demonstrated the protective effect of riluzole on the hair cells and the stria vascularis, especially in the group treated with 8 mg/kg of riluzole hydrochloride. Conclusion We can say that riluzole may have a protective effect on cisplatin- induced ototoxicity. However, additional studies are needed to confirm these results and the mechanisms of action of riluzole.

Comparison of Neural Response Telemetry (NRT) results of cochlear implanted children in view of pre-operative Auditory Brainstem Response (ABR)

To compare the Neural Response Telemetry (NRT) results of the cochlear implanted children who showed wave 5 and who could not, in preimplantation ABR. 24 children (11 boys, 13 girls) with bilateral profound sensorineural hearing loss participated in this study. Age of children ranged between 13 and 60 months (mean 30 months). All participated children were implanted with Cochlear® Nucleus brand devices. In preoperative ABR evaluation with click stimulus in 100 dBnHL intensity level, 9 children showed wave V and 15 children did not. We compared intraoperative NRT results of 1st, 6th, 11th, 16th and 22nd electrodes, those were selected from 22 electrodes, of the two groups. There was no statistically significant difference between the children who showed wave V and who did not in preoperative ABR, when compared the intraoperative NRT results of 1st, 6th, 11th, 16th and 22nd electrodes (p>0,05). intraoperative NRT was obtained in all the implanted children with bilateral profound sensorineural hearing loss, even if they received wave V or not in preoperative ABR. There was no difference between any of the parameters of the test results of the two groups. Normal NRT results can be achievable when there is no wave V in preoperative ABR.

Improving acquisition time of the frequency-specific auditory brainstem response through simultaneous independently random toneburst sequences

The frequency-specific auditory brainstem response (ABR) is an objective electroencephalographic (EEG) method for estimating auditory thresholds when behavioral thresholds are not attainable, primarily in infants and toddlers. It is recorded by repeatedly presenting brief, band-limited tonebursts and averaging the scalp potential response. In a typical ABR evaluation, measurements are made at multiple intensities, at multiple frequencies, and in both ears, leading to a large combinatorial space and long test times. Here, we present a method of recording the responses at five frequencies in both ears simultaneously, along with preliminary data demonstrating its effectiveness. We created ten toneburst trains—five octave frequencies (500–8000 Hz) by two ears—for simultaneous presentation. Importantly, the toneburst timing for each train was dictated by an independent random process, rather than being periodic. Independent sequences allow separate computation of the ABR to each of the toneburst trains as the cross-correlation of its timing sequence and the EEG recording. Early results suggest substantial improvements in recording time, particularly at lower stimulus intensities. It also appears that cochlear spread of excitation—a problem at high intensities—is mitigated by our method. This improvement in place specificity is predicted by modeling of auditory nerve activity.

A relationship between brainstem auditory evoked potential and vagal control of heart rate in adult women

Numerous studies have investigated the connection between autonomic control of heart rate (HR) and auditory stimulus. Yet, the literature lacks evidence of a close association between auditory brainstem processing and HR autonomic control. We aimed to evaluate and verify the relationship between auditory brainstem response (ABR) and HR variability (HRV) in healthy women. Forty‑six healthy female subjects, between the ages of 18 and 30 years old participated in the study. They were subjected to an audiometry examination, followed by rest for 10 minutes for HR recording. Next, ABR evaluation was completed discretely in both ears, with I, III and V wave components. Linear regression revealed that the root‑mean square of differences between adjacent normal RR intervals (RMSSD) and the triangular interpolation of RR interval (TINN) exhibited a significant association with Wave I in the right ear. These variables contributed to 28.2% (R²) of Wave I. In conclusion, there was a significant interaction between the autonomic control of HR and auditory processing in the right ear, suggesting that vagal tone interacts with the cochlear nerve.

Effects of phototherapy on outer hair cell function in infants with hyperbilirubinemia

Introduction: Hyperbilirubinemia in newborns has been hypothesized to cause damage to inner ear, thus leading to sensorineural hearing loss. Phototherapy is treatment protocol in most of the hospitals for newborns with high bilirubin levels. The present study aimed to determine the effects of phototherapy on outer hair cell (OHC) function of cochlea. Methods: Twenty-two neonates with hyperbilirubinemia undergoing phototherapy and 22 neonates without any high-risk registers were included in the study. Distortion product otoacoustic emission (DPOAE) was administered before and after phototherapy. Auditory brainstem response (ABR) evaluation was done during the postphototherapy recording. Results: Results showed that DP amplitude and signal-to-noise ratio improved significantly after phototherapy. ABR evaluation revealed; 19 neonates had significantly prolonged wave V latency compared to normal, whereas no peaks were identified among three neonates. Most of the infantile hyperbilirubinemia are found to be harmless until and unless treatment is not initiated at the earliest, but still it is found that short-term increase in bilirubin level can induce temporary changes in OAEs and ABR measures. ABR needs to be repeated over a period of time for these three neonates to rule out auditory dyssynchrony (AD). Conclusion: The results indicate that phototherapy has temporary effects on OHC function and can improve as the bilirubin levels reduce. Follow-up testing over a period of time helps in discriminating the sensory pathology and AD.

Auditory brainstem response evaluations in cynomolgus macaques: Considerations for anesthesia and waveform data collection and analysis

Auditory brainstem response evaluations in cynomolgus macaques: Considerations for anesthesia and waveform data collection and analysis