Correlation Analysis and Comparison of Adult CE-Chirp ABR Response Threshold and Pure Tone Hearing Threshold.

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

Complete Restoration of Hearing Loss and Cochlear Synaptopathy via Minimally Invasive, Single-Dose, and Controllable Middle Ear Delivery of Brain-Derived Neurotrophic Factor-Poly(dl-lactic acid-co-glycolic acid)-Loaded Hydrogel.

Noise-induced hearing loss (NIHL) often accompanies cochlear synaptopathy, which can be potentially reversed to restore hearing. However, there has been little success in achieving complete recovery of sensorineural deafness using nearly noninvasive middle ear drug delivery before. Here, we present a study demonstrating the efficacy of a middle ear delivery system employing brain-derived neurotrophic factor (BDNF)-poly-(dl-lactic acid-co-glycolic acid) (PLGA)-loaded hydrogel in reversing synaptopathy and restoring hearing function in a mouse model with NIHL. The mouse model achieved using the single noise exposure (NE, 115 dBL, 4 h) exhibited an average 20 dBL elevation of hearing thresholds with intact cochlear hair cells but a loss of ribbon synapses as the primary cause of hearing impairment. We developed a BDNF-PLGA-loaded thermosensitive hydrogel, which was administered via a single controllable injection into the tympanic cavity of noise-exposed mice, allowing its presence in the middle ear for a duration of 2 weeks. This intervention resulted in complete restoration of NIHL at frequencies of click, 4, 8, 16, and 32 kHz. Moreover, the cochlear ribbon synapses exhibited significant recovery, whereas other cochlear components (hair cells and auditory nerves) remained unchanged. Additionally, the cochlea of NE treated mice revealed activation of tropomyosin receptor kinase B (TRKB) signaling upon exposure to BDNF. These findings demonstrate a controllable and minimally invasive therapeutic approach that utilizes a BDNF-PLGA-loaded hydrogel to restore NIHL by specifically repairing cochlear synaptopathy. This tailored middle ear delivery system holds great promise for achieving ideal clinical outcomes in the treatment of NIHL and cochlear synaptopathy.

Gaussian Processes for Hearing Threshold Estimation Using Auditory Brainstem Responses.

The Auditory Brainstem Response (ABR) plays an important role in diagnosing and managing hearing loss, but can be challenging and time-consuming to measure. Test times are especially long when multiple ABR measurements are needed, e.g., when estimating hearing threshold at a range of frequencies. While many detection methods have been developed to reduce ABR test times, the majority were designed to detect the ABR at a single stimulus level and do not consider correlations in ABR waveforms across levels. These correlations hold valuable information, and can be exploited for more efficient hearing threshold estimation. This was achieved in the current work using a Gaussian Process (GP), i.e., a Bayesian approach for non-linear regression. The function to estimate with the GP was the ABR's amplitude across stimulus levels, from which hearing threshold was ultimately inferred. Active learning rules were also designed to automatically adjust the stimulus level and efficiently locate hearing threshold. Simulation results show test time reductions of up to  âˆ¼ 50% for the GP compared to a sequentially applied Hotelling's T2 test, which does not consider correlations across ABR waveforms. A case study was also included to briefly assess the GP approach in ABR data from an adult volunteer.

Magnetic resonance spectroscopy and auditory brain-stem response audiometry as predictors of bilirubin-induced neurologic dysfunction in full-term jaundiced neonates.

The purpose of this research was to define the functions of MRS and ABR as predictors of bilirubin-induced neurologic dysfunction (BIND) in full-term neonates who required intervention (phototherapy and/or exchange transfusion). This prospective cohort study was done at the NICU of Tanta University Hospitals over a 2-year duration. Fifty-six full-term neonates with pathological unconjugated hyperbilirubinemia were divided according to MRS and ABR findings into 2 groups: group (1) included 26 cases with mild acute bilirubin encephalopathy (BIND-M score 1-4). Group (2) included 30 cases with neonatal hyperbilirubinemia only. In addition, 20 healthy neonates with similar ages were employed as the controls. When compared to group 2 and the control group, group 1's peak-area ratios of NAA/Cr and NAA/Cho were found to be significantly reduced (P < 0.05). As compared to group 2 and the control group, group 1's Lac/Cr ratio was significantly greater (P < 0.05), but the differences were not significant for group 2 when compared to the control group. Waves III and V peak latencies, I-III, and I-V interpeak intervals were significantly prolonged in group 1 in comparison to group 2 and controls (P < 0.05) with no significant difference between group 2 and control group.   Conclusion: When the symptoms of ABE are mild and MRI does not show any evident abnormalities, MRS and ABR are helpful in differentiating individuals with ABE from patients with neonatal hyperbilirubinemia.    Trial registration:  ClinicalTrials.gov , Identifier: NCT06018012. What is Known: • MRS can be used as a diagnostic and prognostic tool for the differential diagnosis of patients with acute bilirubin encephalopathy, from patients with neonatal hyperbilirubinemia What is New: • ABR is a useful diagnostic and prognostic tool in the care and management of neonates with significantly raised bilirubin. It can be used as early predictor of acute bilirubin encephalopathy in the earliest stage of auditory damage caused by bilirubin.

Comparison of ASSR and frequency specificity ABR induced by NB CE-Chirp for prediction of behavioral hearing thresholds in children with conductive hearing loss.

BACKGROUND: Electrophysiological tests are often used to evaluate hearing loss in infants and young children with conductive hearing loss, no matter to quantify or characterize. However, there are advantages and disadvantages associated with the various electrophysiological tests that are currently available. Therefore, there is no gold standard test. This study aimed to compare the value of narrow-band (NB) CE-Chirp-induced auditory steady-state response (ASSR) and auditory brainstem response (ABR) for assessing hearing thresholds in children with conductive hearing loss. We hope to identify an effective electrophysiological testing method to evaluate conductive hearing loss and provide a reference for clinical hearing assessment of infants with conductive hearing loss. SUBJECTS: and Methods: We selected 27 children (41 ears) aged 3-6 years with otitis media with effusion (OME). Within 1 day, they underwent behavioral audiometry and NB CE-Chirp-induced ASSR and ABR tests in sequence. Pearson's correlation analysis was performed to compare behavioral audiometry thresholds and ASSR and ABR response thresholds at 500, 1000, 2000, and 4000 Hz. RESULTS: The behavioral audiometry thresholds of all children were strongly correlated with the response thresholds of the two electrophysiological tests, with correlation coefficients of 0.659, 0.605, 0.723, and 0.857 for ASSR, and 0.587, 0.684, 0.753, and 0.802 for ABR. The proportion of children with a difference of ≤10 dB between ASSR and behavioral audiometry thresholds or between ABR and behavioral audiometry thresholds was not high, especially in the low frequencies. ABR results were superior to ASSR results in terms of predicting actual hearing levels. At 0.5, 1, 2, and 4 kHz, the average differences between the behavioral hearing thresholds and ASSR thresholds in the 41 ears were 5.6, 5.7, 2, and 5.6 dB, respectively. The average differences between behavioral hearing thresholds and ABR thresholds was -5.6, -1.4, -6.8, and 3.2 dB, respectively. The hearing loss configuration of the ASSR exhibited a peaked pattern, similar to behavioral audiometry, whereas the ABR exhibited an ascending pattern. The time to perform the single-ear ASSR test was 5.9 min, whereas the ABR test took 17.0 min. CONCLUSION: ASSR and ABR induced by the NB CE-Chirp correlated well with behavioral audiometry in children with conductive hearing loss. The NB CE-Chirp ASSR has advantages in terms of testing time and hearing configuration evaluation, whereas ABR has better reliability than ASSR. However, the stability of ASSR and ABR induced by the NB CE-Chirp is poor, and the thresholds obtained cannot replace behavioral audiometry in evaluating the true hearing of children with conductive hearing loss. However, ASSR and ABR can be used as auxiliary tests for cross-validation.

Reliability and Accuracy of Chirp Based Multiple Auditory Steady State Response (MSSR) and Auditory Brainstem Response (ABR) in Children.

OBJECTIVE: The purpose of this study was to compare the reliability and accuracy of chirp-based Multiple Auditory Steady State Response (MSSR) and Auditory Brainstem Response (ABR) in children. METHODS: The prospective clinical study was conducted at Selayang Hospital (SH) and Hospital Canselor Tuanku Muhriz (HCTM) within one year. A total of 38 children ranging from 3 to 18 years old underwent hearing evaluation using ABR tests and MSSR under sedation. The duration of both tests were then compared. RESULTS: The estimated hearing threshold of frequency specific chirp MSSR showed good correlation with ABR especially in higher frequencies such as 2000 Hz and 4000Hz with the value of cronbach alpha of 0.890, 0.933, 0.970 and 0.969 on 500Hz, 1000Hz, 2000Hz and 4000Hz. The sensitivity of MSSR is 0.786, 0.75, 0.957 and 0.889 and specificity is 0.85, 0.882, 0.979 and 0.966 over 500Hz, 1000Hz, 2000Hz and 4000Hz. The duration of MSSR tests were shorter than ABR tests in normal hearing children with an average of 35.3 minutes for MSSR tests and 46.4 minutes for ABR tests. This can also be seen in children with hearing loss where the average duration for MSSR tests is 40.0 minutes and 52.0 minutes for ABR tests. CONCLUSION: MSSR showed good correlation and reliability in comparison with ABR especially on higher frequencies. Hence, MSSR is a good clinical test to diagnose children with hearing loss.

Investigating the optimal stimulus to evoke the binaural interaction component of the auditory brainstem response.

Objective assessment of spatial and binaural hearing deficits remains a major clinical challenge. The binaural interaction component (BIC) of the auditory brainstem response (ABR) holds promise as a non-invasive biomarker for diagnosing such deficits. However, while comparative studies have reported robust BIC in animal models, BIC in humans can sometimes be unreliably evoked even in subjects with normal hearing. Here we explore the hypothesis that the standard methodology for collecting monaural ABRs may not be ideal for electrophysiological assessment of binaural hearing. This study aims to improve ABR BIC measurements by determining more optimal stimuli to evoke it. Building on previous methodology demonstrated to enhance peak amplitude of monaural ABRs, we constructed a series of level-dependent chirp stimuli based on empirically derived latencies of monaural-evoked ABR waves I, IV and the binaural-evoked BIC DN1, the most prominent BIC peak, in a cohort of ten chinchillas. We hypothesized that chirps designed based on BIC DN1 latency would specifically enhance across-frequency temporal synchrony in the afferent inputs leading to the binaural circuits that produce the BIC and would thus produce a larger DN1 than either traditional clicks or chirps designed to optimize monaural ABRs. Compared to clicks, we found that level-specific chirp stimuli evoked significantly greater BIC DN1 amplitudes, and that this effect persisted across all stimulation levels tested. However, we found no significant differences between BICs resulting from chirps created using binaural-evoked BIC DN1 latencies and those using monaural-evoked ABR waves I or IV. These data indicate that existing level-specific, monaural-based chirp stimuli may improve BIC detectability and reduce variability in human BIC measurements.

Enhanced Place Specificity of the Parallel Auditory Brainstem Response: A Modeling Study.

While each place on the cochlea is most sensitive to a specific frequency, it will generally respond to a sufficiently high-level stimulus over a wide range of frequencies. This spread of excitation can introduce errors in clinical threshold estimation during a diagnostic auditory brainstem response (ABR) exam. Off-frequency cochlear excitation can be mitigated through the addition of masking noise to the test stimuli, but introducing a masker increases the already long test times of the typical ABR exam. Our lab has recently developed the parallel ABR (pABR) paradigm to speed up test times by utilizing randomized stimulus timing to estimate the thresholds for multiple frequencies simultaneously. There is reason to believe parallel presentation of multiple frequencies provides masking effects and improves place specificity while decreasing test times. Here, we use two computational models of the auditory periphery to characterize the predicted effect of parallel presentation on place specificity in the auditory nerve. We additionally examine the effect of stimulus rate and level. Both models show the pABR is at least as place specific as standard methods, with an improvement in place specificity for parallel presentation (vs. serial) at high levels, especially at high stimulus rates. When simulating hearing impairment in one of the models, place specificity was also improved near threshold. Rather than a tradeoff, this improved place specificity would represent a secondary benefit to the pABR's faster test times.

Attentional Modulation of the Cortical Contribution to the Frequency-Following Response Evoked by Continuous Speech.

Selective attention to one of several competing speakers is required for comprehending a target speaker among other voices and for successful communication with them. It moreover has been found to involve the neural tracking of low-frequency speech rhythms in the auditory cortex. Effects of selective attention have also been found in subcortical neural activities, in particular regarding the frequency-following response related to the fundamental frequency of speech (speech-FFR). Recent investigations have, however, shown that the speech-FFR contains cortical contributions as well. It remains unclear whether these are also modulated by selective attention. Here we used magnetoencephalography to assess the attentional modulation of the cortical contributions to the speech-FFR. We presented both male and female participants with two competing speech signals and analyzed the cortical responses during attentional switching between the two speakers. Our findings revealed robust attentional modulation of the cortical contribution to the speech-FFR: the neural responses were higher when the speaker was attended than when they were ignored. We also found that, regardless of attention, a voice with a lower fundamental frequency elicited a larger cortical contribution to the speech-FFR than a voice with a higher fundamental frequency. Our results show that the attentional modulation of the speech-FFR does not only occur subcortically but extends to the auditory cortex as well.SIGNIFICANCE STATEMENT Understanding speech in noise requires attention to a target speaker. One of the speech features that a listener can use to identify a target voice among others and attend it is the fundamental frequency, together with its higher harmonics. The fundamental frequency arises from the opening and closing of the vocal folds and is tracked by high-frequency neural activity in the auditory brainstem and in the cortex. Previous investigations showed that the subcortical neural tracking is modulated by selective attention. Here we show that attention affects the cortical tracking of the fundamental frequency as well: it is stronger when a particular voice is attended than when it is ignored.

A multi-channel EEG mini-cap can improve reliability for recording auditory brainstem responses in chinchillas.

BACKGROUND: Disabling hearing loss affects nearly 466 million people worldwide (World Health Organization). The auditory brainstem response (ABR) is the most common non-invasive clinical measure of evoked potentials, e.g., as an objective measure for universal newborn hearing screening. In research, the ABR is widely used for estimating hearing thresholds and cochlear synaptopathy in animal models of hearing loss. The ABR contains multiple waves representing neural activity across different peripheral auditory pathway stages, which arise within the first 10 ms after stimulus onset. Multi-channel (e.g., 32 or higher) caps provide robust measures for a wide variety of EEG applications for the study of human hearing. However, translational studies using preclinical animal models typically rely on only a few subdermal electrodes. NEW METHOD: We evaluated the feasibility of a 32-channel rodent EEG mini-cap for improving the reliability of ABR measures in chinchillas, a common model of human hearing. RESULTS: After confirming initial feasibility, a systematic experimental design tested five potential sources of variability inherent to the mini-cap methodology. We found each source of variance minimally affected mini-cap ABR waveform morphology, thresholds, and wave-1 amplitudes. COMPARISON WITH EXISTING METHOD: The mini-cap methodology was statistically more robust and less variable than the conventional subdermal-needle methodology, most notably when analyzing ABR thresholds. Additionally, fewer repetitions were required to produce a robust ABR response when using the mini-cap. CONCLUSIONS: These results suggest the EEG mini-cap can improve translational studies of peripheral auditory evoked responses. Future work will evaluate the potential of the mini-cap to improve the reliability of more centrally evoked (e.g., cortical) EEG responses.

Interaural frequency mismatch jointly modulates neural brainstem binaural interaction and behavioral interaural time difference sensitivity in humans.

The binaural interaction component (BIC) of the auditory brainstem response (ABR) is the difference obtained after subtracting the sum of right and left ear ABRs from binaurally evoked ABRs. The BIC has attracted interest as a biomarker of binaural processing abilities. Best binaural processing is presumed to require spectrally-matched inputs at the two ears, but peripheral pathology and/or impacts of hearing devices can lead to mismatched inputs. Such mismatching can degrade behavioral sensitivity to interaural time difference (ITD) cues, but might be detected using the BIC. Here, we examine the effect of interaural frequency mismatch (IFM) on BIC and behavioral ITD sensitivity in audiometrically normal adult human subjects (both sexes). Binaural and monaural ABRs were recorded and BICs computed from subjects in response to narrowband tones. Left ear stimuli were fixed at 4000 Hz while right ear stimuli varied over a ∼2-octave range (re: 4000 Hz). Separately, subjects performed psychophysical lateralization tasks using the same stimuli to determine ITD discrimination thresholds jointly as a function of IFM and sound level. Results demonstrated significant effects of IFM on BIC amplitudes, with lower amplitudes in mismatched conditions than frequency-matched. Behavioral ITD discrimination thresholds were elevated at mismatched frequencies and lower sound levels, but also more sharply modulated by IFM at lower sound levels. Combinations of ITD, IFM and overall sound level that resulted in fused and lateralized percepts were bound by the empirically-measured BIC, and also by model predictions simulated using an established computational model of the brainstem circuit thought to generate the BIC.

Which stimulus should be used for auditory brainstem response in newborns; CE-Chirp® level specific versus Click stimulus.

OBJECTIVES: Auditory Brainstem Response (ABR), the electrical responses in the neuronal pathways extending from the inner ear to the auditory cortex, are evaluated with auditory stimuli. ABR analysis evaluates waves I, III and V's absolute-latencies, amplitude values, interpeak-latencies, interaural-latency differences, and morphologies. This study aims to reveal the advantages of CE-Chirp® LS stimulus and its clinical uses to increase by comparing the amplitude, latency, and interpeak-latency differences of waves I, III, and V at 80 dB nHL and wave V at 60, 40, 20 dB nHL by using click and CE-Chirp® LS stimuli. METHODS: 100 (54 boys, 46 girls) infants with normal hearing were included in the National Newborn Hearing Screening Program. With the click and CE-Chirp® LS ABR, the absolute latency and amplitude values of wave V at 20, 40, and 60 dB nHL, and the absolute-latency, interpeak-latency, and amplitude values of waves I, III, and V at 80 dB nHL are determined between stimuli and right-left ear. RESULTS: When the wave V latency and amplitudes obtained at 80, 60, 40, and 20 dB nHL levels were examined between genders, and according to the risk factor, no significant difference was found between click and CE-Chirp® LS stimuli (p > 0.05). Waves I, III, and V absolute-latency, amplitudes were compared at 80 dB nHL and wave V absolute-latency, amplitudes at 60, 40, and 20 dB nHL; the amplitudes measured with CE-Chirp® LS were significantly higher than the click stimulus (p < 0.05). When two stimuli were compared for I-III and III-V interpeak-latency values at 80 dB nHL level, no significant difference was found between the two stimuli (p > 0.05). However, the I-V interpeak-latency value was statistically significantly decreased for two stimuli, regardless of the ear (p < 0.05). CONCLUSIONS: It is suggested to increase the use of CE-Chirp® LS stimulus with better morphology and amplitude in clinics, believing that it facilitates clinicians' interpretation.

Middle Ear Muscle Reflex in Normal-Hearing Individuals with Occupational Noise Exposure.

Objectives: Noise-induced cochlear synaptopathy is studied extensively in animal models. The diagnosis of synaptopathy in humans is challenging and the roles of many noninvasive measures in identifying synaptopathy are being explored. The acoustic middle ear muscle reflex (MEMR) can be considered as a vital tool since noise exposure affects the low-spontaneous rate fibers that play an important role in elicitation of MEMR. The present study aimed at measuring MEMR threshold and MEMR strength. Design: The study participants were divided into two groups. All the participants had normal-hearing thresholds. The control group consisted of 25 individuals with no occupational noise exposure whereas noise exposure group had 25 individuals who were exposed to occupational noise of 85 dBA for a minimum period of 1 year. MEMR threshold and strength was assessed for pure tones (500 Hz and 1000 Hz) and broadband noise. Results: The results showed that the MEMR threshold was similar in both the groups. MEMR strength was reduced in noise exposure group compared to control group. Conclusions: The results of the study suggest that MEMR strength could be used as a sensitive measure in identifying cochlear synaptopathy with careful consideration of the stimulus characteristics.

Auditory brainstem response: Key parameters for good-quality recording.

Auditory brainstem response (ABR) is widely used in ENT to investigate hearing loss. This test evaluates the response of the ascending auditory pathway, from cochlea to mesencephalon, following auditory stimulation. It provides precise analysis of waves numbered I to V according to location on the auditory pathway, in terms of amplitude, latency and inter-wave interval. Good-quality assessment requires familiarity with the parameters to be used and the factors likely to modify response. We describe the procedure for ABR examination and the recorded responses, with particular attention to factors influencing response to which the examiner must be vigilant. These factors are related to the individual (age, gender, hearing loss, body temperature, drug treatments), transducer (air or bone conduction), stimulation parameters (type, polarity, intensity, calibration, duration, cadence, number of clicks, background noise) and acquisition parameters (analysis window, scale, electrodes). We also briefly describe the clinical applications of this examination.

Envelope following responses for hearing diagnosis: Robustness and methodological considerations.

Recent studies have found that envelope following responses (EFRs) are a marker of age-related and noise- or ototoxic-induced cochlear synaptopathy (CS) in research animals. Whereas the cochlear injury can be well controlled in animal research studies, humans may have an unknown mixture of sensorineural hearing loss [SNHL; e.g., inner- or outer-hair-cell (OHC) damage or CS] that cannot be teased apart in a standard hearing evaluation. Hence, a direct translation of EFR markers of CS to a differential CS diagnosis in humans might be compromised by the influence of SNHL subtypes and differences in recording modalities between research animals and humans. To quantify the robustness of EFR markers for use in human studies, this study investigates the impact of methodological considerations related to electrode montage, stimulus characteristics, and presentation, as well as analysis method on human-recorded EFR markers. The main focus is on rectangularly modulated pure-tone stimuli to evoke the EFR based on a recent auditory modelling study that showed that the EFR was least affected by OHC damage and most sensitive to CS in this stimulus configuration. The outcomes of this study can help guide future clinical implementations of electroencephalography-based SNHL diagnostic tests.

The middle ear muscle reflex: Current and future role in assessing noise-induced cochlear damage.

The middle ear muscle reflex (MEMR) in humans is a bilateral contraction of the middle ear stapedial muscle in response to moderate-to-high intensity acoustic stimuli. Clinically, MEMR thresholds have been used for differential diagnosis of otopathologies for decades. More recently, changes in MEMR amplitude or threshold have been proposed as an assessment for noise-induced synaptopathy, a subclinical form of cochlear damage characterized by suprathreshold hearing problems that occur as a function of inner hair cell (IHC) synaptic loss, including hearing-in-noise deficits, tinnitus, and hyperacusis. In animal models, changes in wideband MEMR immittance have been correlated with noise-induced synaptopathy; however, studies in humans have shown more varied results. The discrepancies observed across studies could reflect the heterogeneity of synaptopathy in humans more than the effects of parametric differences or relative sensitivity of the measurement. Whereas the etiology and degree of synaptopathy can be carefully controlled in animal models, synaptopathy in humans likely stems from multiple etiologies and thus can vary greatly across the population. Here, we explore the evolving research evidence of the MEMR response in relation to subclinical noise-induced cochlear damage and the MEMR as an early correlate of suprathreshold deficits.

[Evolution of auditory brainstem response in 0-6 years old normal hearing children and characteristics of children with abnormal acoustic conduction].

Objective:To explore the normal reference range of Click-ABR latency and interwave period in 0-6 years old children, and to analyze the clinical characteristics of Click-ABR in children with sound transmission function is abnormal. Methods:A total of 1791（3582 ears） normal hearing children aged 0-6 years and 176（258 ears） conductive hearing loss children were selected for Click-ABR. The differences of Click-ABR parameters in children of different months were analyzed, and the correlation between the degree of conductive hearing loss and Click-ABR parameters was explored. Results:The incubation period of wave Ⅰ was not correlated with the age of month, while the incubation period of wave Ⅲ, wave Ⅴ, waveⅠ-Ⅲ and wave Ⅰ-Ⅴ were highly correlated with the age of month. There was a positive correlation between the latency of wave Ⅰ and hearing threshold in the children with sound transmission function is abnormal under 80 dB nHL stimulation, and there was no difference between the standard values of wave Ⅰ-Ⅲ and Ⅰ-Ⅴ in the children with sound transmission function is abnormal and normal children. Conclusion:The latency of ABR wave Ⅲ and Ⅴ, and the interval between wave Ⅰ-Ⅲ and Ⅰ-Ⅴ shorten with the increase of age in children aged 0-6 years. The normal ABR values of children of different ages should be established in each hearing clinic for children as a reference. Combined with Click-ABR threshold and 80 dB nHL acoustic subwave Ⅰlatency, the abnormal conduction function can be preliminatively screened out, which should be further supplemented with other combinations of hearing diagnosis.

Auditory Brainstem response electrophysiological thresholds with narrow band chirps stimuli in hearing infants.

OBJECTIVES: to describe reference values for the electrophysiological thresholds obtained in the frequency-specific Auditory Brainstem Response (fsABR) with the NB CE-Chirp® LS and NB iChirp stimuli in hearing infants and to compare the variables: Minimum Levels of Response (MLR), latency, amplitude and examination time. METHODS: the sample consisted of 74 full-term infants, with a mean age of 23.11 days, 29 females and 45 males. The participants underwent fsABR at the frequencies of 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz, to measure the MLR with the NB CE-Chirp® LS stimulus in the Eclipse equipment, and with the NB iChirp stimulus in the SmartEP, all in natural sleep and performed in the same session. The waveforms were evaluated by judges and later, for the comparison of thresholds and examination time, analyzed with the Wilcoxon test. To compare latency and amplitude, the Student's T Test and ANOVA were used for the same variables, but with the same stimulus. The Kruskal-Wallis test was used to compare the examination time at the different frequencies. RESULTS: The MLR and latency at 500 Hz and 1000 Hz showed a statistically significant difference between the stimuli, with lower thresholds and higher latencies for the NB iChirp. Higher amplitudes were obtained with the NB iChirp stimulus. The average examination time for the threshold investigation in the four frequencies was 40 min for each ear. CONCLUSION: it was possible to present reference values for the MLR and latencies for the NB CE-Chirp® LS and NB iChirp stimuli for hearing infants. In addition, with the NB iChirp, the latency of the responses was influenced by the frequency, but it was the stimulus that provided greater amplitudes. With the NB CE-Chirp® LS, the frequency did not influence latency, except at 500 Hz, and the stimulus provided recordings that facilitated the visualization of wave V. There was no difference in the examination time between the stimuli, nor between the test frequencies.

Newborn Auditory Brainstem Responses in Children with Developmental Disabilities.

We integrated data from a newborn hearing screening database and a preschool disability database to examine the relationship between newborn click evoked auditory brainstem responses (ABRs) and developmental disabilities. This sample included children with developmental delay (n = 2992), speech impairment (SI, n = 905), language impairment (n = 566), autism spectrum disorder (ASD, n = 370), and comparison children (n = 128,181). We compared the phase of the ABR waveform, a measure of sound processing latency, across groups. Children with SI and children with ASD had greater newborn ABR phase values than both the comparison group and the developmental delay group. Newborns later diagnosed with SI or ASD have slower neurological responses to auditory stimuli, suggesting sensory differences at birth.

Auditory brainstem responses obtained with randomised stimulation level.

OBJECTIVE: To present randomised stimulation level (RSL) - a stimulation paradigm in which the level of the stimuli is randomised, rather than presented sequentially as in the conventional paradigm. DESIGN: The value of RSL was evaluated by (i) comparing the morphology of auditory brainstem responses (ABRs) elicited by the conventional and RSL paradigms, and by (ii) an online survey investigating the hearing comfort of the stimulus sequence. STUDY SAMPLE: ABRs were obtained from 11 normal-hearing adults (8 females, 25-29 years). The online survey was administered to 238 adults from the general community. RESULTS: Results showed that (i) both stimulation paradigms elicit ABR signals of similar morphology, (ii) RSL provides a faster comprehensive representation of the ABR session, and that (iii) the general population found RSL stimuli to be more comfortable. CONCLUSIONS: The simultaneous evaluation of all ABR traces of the session provided by RSL has potential to improve the identification of ABR components by enabling clinicians to make use of the response tracking strategy from the start of the test, which is critical in situations where ABRs present an abnormal morphology. New research opportunities and the clinical potential of RSL are discussed.