Click Auditory Brainstem Response Research Articles

Fundamental frequency predominantly drives talker differences in auditory brainstem responses to continuous speech.

Deriving human neural responses to natural speech is now possible, but the responses to male- and female-uttered speech have been shown to differ. These talker differences may complicate interpretations or restrict experimental designs geared toward more realistic communication scenarios. This study found that when a male and female talker had the same fundamental frequency, auditory brainstem responses (ABRs) were very similar. Those responses became smaller and later with increasing fundamental frequency, as did click ABRs with increasing stimulus rates. Modeled responses suggested that the speech and click ABR differences were reasonably predicted by peripheral and brainstem processing of stimulus acoustics.

An eight-year follow-up on auditory outcomes after neonatal hearing screening.

The aim of this study is to assess the neonatal click Auditory Brainstem Response (ABR) results in relation to the subsequently determined mean hearing loss (HL) over 1, 2 and 4 kHz, as well as over 2 and 4 kHz. Between 2004-2009, follow-up data were collected from Visual Reinforcement Audiometry (VRA) at 1 and 2 years and playaudiometry at 4 and 8 years of newborns who had failed neonatal hearing screening in the well-baby clinics and who had been referred to a single Speech and Hearing center. Hearing Level data were compared with ABR threshold-levels established during the first months of life. The Two One-Sided Tests equivalence procedure for paired means was applied, using a region of similarity equal to 10 dB. Initially, in 135 out of 172 children referred for diagnostic procedures hearing loss was confirmed in the neonatal period. In 106/135 of the HL children the eight-year follow-up was completed. Permanent conductive HL was established in 5/106 cases; the hearing thresholds were predominantly stable over time. Temporary conductive HL was found in 48/106 cases and the loss disappeared by 4 years of age at the latest. Sensorineural hearing loss (SNHL) was found in 53/106 cases, of which 13 were unilateral and 40 bilateral. ABR levels were equivalent (within a 10 dB range) to VRA levels at age 1 and 2 and play audiometry levels at age 4 and 8, both when VRA and play audiometry were averaged over both frequency ranges. Long term follow-up data of children with SNHL suggest that the initial click ABR level established in the first months of life, are equivalent to the hearing threshold measured at the age of 1, 2, 4 and 8 years for both mean frequency ranges. Click ABR can reliably be used as starting point for long-term hearing rehabilitation.

Supra-Threshold LS CE-Chirp Auditory Brainstem Response in the Elderly

Introduction: Aging deteriorates peripheral and central auditory structures and functions. In elders, for an accurate audiological evaluation, it is important to explore beyond the cochlear receptor. Audiograms provide an estimation of hearing thresholds, while the amplitudes and latencies of supra-threshold auditory brainstem response (ABR) can offer noninvasive measures of the auditory pathways functioning. Regarding ABR, in young populations, level-specific chirp (LS CE-chirp) stimulus has been proposed as an alternative synchronizing method to obtain larger ABR responses than those evoked by clicks. However, the supra-threshold characteristics of chirp evoked ABR, and their association to hearing thresholds is relatively unknown in the elderly. The aim of this study was to evaluate supra-threshold LS CE-chirp ABRs in an aged population by comparing their features with click ABRs, and evaluating their relationship with audiometric hearing thresholds. Methods: We carried out a cross-sectional study to characterize the hearing of 125 adults aged over 65 years. We determined the audiometric hearing thresholds and supra-threshold ABRs elicited by LS CE-chirp and click stimuli at 80 dB nHL. We evaluated associations by means of partial correlations and covariate adjustment. We performed specific frequencies’ analysis and subgroup analysis per hearing level. Results: Wave V responses had significantly shorter latencies and larger amplitudes when elicited by LS CE-chirp as compared to click-evoked responses. Audiometric hearing thresholds correlated with age, but ABR characteristics did not. We found mild correlations between hearing thresholds and ABR characteristics, predominantly at higher frequencies and with chirp. We found scarce evidence of correlation between ABR characteristics and the average of behavioral hearing thresholds between 0.5 to 4 kHz (0.5–4 kHz PTA). After subgroup analysis according to the hearing level, no stronger or more significant correlations were found between ABR characteristics and 0.5–4 kHz PTA. Discussion: In this study, we found that supra-threshold LS CE-chirp ABR presented some of the previously described similitudes and differences with supra-threshold click ABR in younger populations. Although, the average amplitude and latency of wave V evoked by LS CE-chirp were larger and faster than those evoked by clicks, these results should be taken with caution at the individual level, and further studies are required to state that LS CE-chirp ABRs are better than click ABRs in elders for clinical evaluations. We did not find consistent associations between hearing thresholds and supra-threshold wave V features, suggesting that these measures should be considered independently in the elderly.

Extending Subcortical EEG Responses to Continuous Speech to the Sound-Field.

The auditory brainstem response (ABR) is a valuable clinical tool for objective hearing assessment, which is conventionally detected by averaging neural responses to thousands of short stimuli. Progressing beyond these unnatural stimuli, brainstem responses to continuous speech presented via earphones have been recently detected using linear temporal response functions (TRFs). Here, we extend earlier studies by measuring subcortical responses to continuous speech presented in the sound-field, and assess the amount of data needed to estimate brainstem TRFs. Electroencephalography (EEG) was recorded from 24 normal hearing participants while they listened to clicks and stories presented via earphones and loudspeakers. Subcortical TRFs were computed after accounting for non-linear processing in the auditory periphery by either stimulus rectification or an auditory nerve model. Our results demonstrated that subcortical responses to continuous speech could be reliably measured in the sound-field. TRFs estimated using auditory nerve models outperformed simple rectification, and 16 minutes of data was sufficient for the TRFs of all participants to show clear wave V peaks for both earphones and sound-field stimuli. Subcortical TRFs to continuous speech were highly consistent in both earphone and sound-field conditions, and with click ABRs. However, sound-field TRFs required slightly more data (16 minutes) to achieve clear wave V peaks compared to earphone TRFs (12 minutes), possibly due to effects of room acoustics. By investigating subcortical responses to sound-field speech stimuli, this study lays the groundwork for bringing objective hearing assessment closer to real-life conditions, which may lead to improved hearing evaluations and smart hearing technologies.

Comparison of Click and Level-Specific (LS) CE Chirp-Stimulated Auditory Brainstem Responses in Adults with Hearing Loss.

Background The CE-Chirp stimulus used in the ABR was developed to compensate for the cochlear wave delay. As a version of broadband CE-Chirp stimulus, the use of level-specific (LS) CE-Chirp stimuli, which are created with varying delay models suitable for the intensity levels at which the sound is transmitted, is becoming increasingly common. Purpose The aim of this study was to compare click auditory brainstem responses (ABRs) with LS CE-Chirp ABR thresholds in adults with sensorineural hearing loss. Research Design The research is a cross-sectional-analytical research. Study Sample Twenty-two adult patients (n = 44 ears) with bilateral sensorineural hearing loss were included in the study. Data Collection and Analysis Pure Tone Audiometry (PTA), click ABR and LS CE-Chirp ABR tests were performed on adult (13 male, 9 female) (42.86± 14.50 years) patients with bilateral sensorineural hearing loss. Click ABR and LS CE-Chirp ABR thresholds were compared in terms of proximity to behavioral hearing thresholds of 2 kHz, 4 kHz, and 2-4 kHz averages. Results: Both types of ABR stimuli were able to identify with total hearing loss (n = 6). A statistically significant difference was found between LS CE-Chirp ABR thresholds (53.81±20.28 dB nHL) and click ABR thresholds (58.81±19.11 dB nHL) in the other ears (n = 38) with hearing loss (p=0.00). When both ears were evaluated together and the right and left ears were evaluated separately, no difference was found between LS CE-Chirp ABR thresholds and 4 kHz behavioral hearing thresholds (p: 0.66, p:0.80, p: 0.69, respectively). Conclusion: We determined that in adults with hearing loss, the LS CE-Chirp provides ABR thresholds closer to the behavioral hearing thresholds of 2 kHz, 4 kHz compared to the click stimulus. Notably, there was no difference between LS CE-Chirp ABR thresholds and the 4 kHz behavioral hearing thresholds. We concluded that the LS CE-Chirp stimulus can be used effectively in the estimation of behavioral hearing thresholds in adults with hearing loss Keywords: Auditory Brainstem Response, Hearing loss, Click, Level specific CE-Chirp.

Can auditory evoked responses elicited to click and/or verbal sound identify children with or at risk of central auditory processing disorder: A scoping review.

(Central) auditory processing disorders, (C)APDs are clinically identified using behavioral tests. However, changes in attention and motivation may easily affect true identification. Although auditory electrophysiological tests, such as Auditory Brainstem Responses (ABR), are independent of most confounding cognitive factors, there is no consensus that click and/or speech-evoked ABR can be used to identify children with or at-risk of (C)APDs due to heterogeneity among studies. This study aimed to review the possibility of using ABR evoked by click and/or speech stimuli to identify children with or at risk of (C)APDs. The online databases of PubMed, Web of Science, Medline, Embase, and CINAHL were explored using combined keywords for all English and French articles published until April 2021. Additional gray literature was also included such as conference abstracts, dissertations, and editorials in ProQuest Dissertations. Thirteen papers met the eligibility criteria and were included in the scoping review. Fourteen papers were cross-sectional and two were interventional studies. Eleven papers used click stimuli to assess children with/at risk of (C)APDs, and speech stimuli were utilized in the remaining studies. Despite the diversity of the results, especially in click ABR assessments, most studies indicated increases in the wave latencies and/or decreases in the wave amplitudes of click ABR in children with/at risk of (C)APDs. The results of speech ABR assessments were more consistent, as prolongation of the transient components of speech ABR was observed in these children, while sustained components remained almost unchanged. Although both click and speech-evoked ABRs could be used to assess children with (C)APDs, it appears that speech-evoked ABR assessments yield more reliable findings. These findings, however, should be interpreted with caution given the heterogeneity among studies. Well-designed studies on children with confirmed (C)APDs using standard diagnostic and assessment protocols are recommended.

Do cochlear microphonics evoked by narrow-band chirp stimuli affect the objective detection of auditory steady-state responses?

Objective It has recently been discussed whether hearing screening and hearing threshold assessment can accurately be completed using automated ASSR methods for children with auditory neuropathy spectrum disorder (ANSD). Possible causes for the claimed potential failures were investigated here. Design The study is based on the analysis of stored ASSR raw data. Study sample This study reviewed raw ASSR data from 274 patients with a total of 5809 individual recordings. Results Cochlear microphonics (CM) were found in 18 of the 274 patient records. Four of these 18 were obtained from patients with ANSD. One patient with ANSD without click auditory brainstem responses up to 100 dBnHL demonstrated clear ASSR responses from 65 dBnHL upwards. Where click stimulation suggests an auditory nerve defect, narrow-band chirps were shown to evoke ASSR in certain patients. CMs are elicited by narrow-band chirps in the same way as by broadband stimuli. CM residuals as well as a presumed enlarged wave I with absent neural responses, always accompanied by CM, were found as possible causes of misinterpretation at high stimulus levels. A CM detector was created. Conclusions The CM detector, indicating the presence of CM, will prevent misinterpretation of clinical ASSR results.

Click-evoked auditory brainstem responses (ABRs) are intact in schizophrenia and not sensitive to cognitive training

Patients with schizophrenia have impairments in early auditory system functioning that relate to clinical, cognitive, and psychosocial functioning. Some neurophysiological biomarkers of auditory information processing are sensitive to and predictive of clinically relevant outcomes following auditory-based targeted cognitive training (TCT) in schizophrenia. It is not known, however, whether schizophrenia patients show abnormalities at the earliest stage of sensory processing reflecting the integrity of the ascending auditory pathway at the level of the brainstem, or whether such abnormalities can serve as biomarkers. This study aimed to determine whether click-evoked auditory brainstem responses (click ABRs) are 1) abnormal in schizophrenia patients relative to healthy comparison subjects (HCS), 2) acutely sensitive to or predictive of TCT response, and 3) associated with clinically relevant symptoms. We also sought to determine whether 4) click ABRs show adequate psychometric reliability. Click ABRs were examined in 52 patients with schizophrenia and 32 HCS. Patients were randomized to either TCT ( n = 30), which comprised 30 h of training, or treatment as usual (TAU; n = 23). Patients showed intact click ABRs relative to HCS and click ABRs did not change significantly after 1 or 30 h of TCT. Exploratory analyses revealed modest relationships between click ABRs and baseline measures of positive symptoms and speech-in-noise perception; acute changes in ABRs were modestly related to improvements on measures of cognition independent of treatment. ABR measurements showed adequate internal consistency indicating their suitability for cross-sectional studies of individual differences, but poor test-retest reliability indicating poor suitability for clinical trials. In contrast to a growing literature demonstrating the utility of later cortical neurophysiological measures for translational research, the present findings indicate that brainstem-mediated responses are intact in schizophrenia and are not sensitive to or predictive of clinical changes in the context of TCT. These data provide guidance for establishing future neurophysiology-guided interventions in schizophrenia.

Effect of General Anesthesia on Auditory Brainstem Response Testing.

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.

Effect of subject state on auditory brainstem response threshold using Kalman-weighted averaging

ObjectivesThis study aims to explore the impact of a subject's testing state on auditory brainstem response (ABR) thresholds using a novel ABR system (Vivosonic Integrity™), which incorporates Kalman-weighted averaging and bluetooth electrical isolation to address the limitation of conventional ABR limitation to obtain a stable result under non-sedated conditions, especially for infants and children. MethodTwenty-four adults (18–34 years old, 48 ears) with normal hearing were enrolled for ABR testing under three different states (lying quietly in the supine position or sleeping—lying; watching silent videos quietly in a seated position—sitting; and writing in a seated position—writing), which simulate the behaviors of young children most often encountered during non-sedated Kalman-weighted ABR testing in clinical practice. The click ABR (cABR) and tone-burst ABR (tbABR) thresholds (0.5, 1, 2, and 4 kHz) of each subject and the time taken to reach the monaural threshold for each kind of stimulus were recorded. Results(1) The cABR and tbABR thresholds were observed to increase in the following order: lying < sitting < writing. Significant threshold differences were found between any two states, except for between the sitting and lying states for the cABR and between sitting and writing for the 0.5 kHz tbABR. (2) The time required for cABR testing in the writing state was significantly longer than that in the lying and sitting states. The time required for 1 and 4 kHz tbABR testing in the lying state was significantly shorter than that in the sitting or writing state. For 2 KHz tbABR, only testing time under writing was significantly longer than that under lying. There were no significant differences in the time used for 0.5 kHz tbABR testing among different states. ConclusionsDifferent testing states have significant impacts on the thresholds of ABRs using Kalman-weighted averaging. A subject's state during ABR testing warrants consideration, and normal levels and correction values to estimate the hearing threshold from the ABR threshold should be determined for different testing states.

Biallelic p.V37I variant in GJB2 is associated with increasing incidence of hearing loss with age

PurposeThis study aimed to quantitatively assess the incidence of hearing loss in relation to age in individuals with biallelic p.V37I variant in GJB2. MethodsPopulation screening of the biallelic p.V37I variant was performed in 30,122 individuals aged between 0 and 97 years in Shanghai. Hearing thresholds of the biallelic p.V37I individuals and the controls were determined by click auditory brainstem response or pure tone audiometry. ResultsBiallelic p.V37I was detected in 0.528% (159/30,122) of the subjects. Of the biallelic p.V37I newborns, 43.91% (18/41) passed their distortion-product otoacoustic emissions–based newborn hearing screening or had hearing thresholds lower than 20 decible above normal hearing level. The older newborns had elevated hearing thresholds, with increasing incidence of 9.52%, 23.08%, 59.38%, and 80.00% for moderate or higher grade of hearing loss in age groups of 7 to 15 years, 20 to 40 years, 40 to 60 years, and 60 to 85 years, respectively. Their hearing deteriorated at a rate of 0.40 dB hearing level per year on average; males were more susceptible, and deterioration occurred preferentially at higher sound frequencies. ConclusionThe biallelic p.V37I variant is associated with steadily progressive hearing loss with increasing incidence over the course of life. Most of the biallelic p.V37I individuals may develop significant hearing loss in adulthood and, can benefit from early diagnosis and intervention through wide-spread genetic screening.

Auditory neuropathy spectrum disorder in two siblings with congenital cytomegalovirus infections: Two rare cases

Auditory neuropathy spectrum disorder (ANSD) is a rare hearing disorder when signal transmission is disrupted on the auditory pathway. Infection is one of the multifactorial causes of ANSD. Only a few researchers have reported the cases of ANSD caused by congenital cytomegalovirus (CMV) infection, and fewer have presented cases involving siblings. In our study, the two patients were siblings, aged 3 years and 7 months and 8 months. They were born prematurely, had microcephaly; anti-CMV IgG levels were reactive. Distortion product otoacoustic emissions test was normal. A click auditory brainstem response showed that no wave was detected with an 80 dB stimulus, and a cochlear microphonic response was obtained. No abnormality in the middle ear was observed, and negative acoustic reflexes were noted. Hearing habilitation with a low-gain hearing aid, speech therapy, and motoric habilitation was planned, and the patients were referred to the pediatric neurology for CMV management.

Audiological findings of a patient with H syndrome: case report

BackgroundH syndrome is an autosomal recessive disorder caused by mutations in SLC29A3. Hyperpigmentation, hypertrichosis, hyperglycemia, and hearing loss are some characteristics of this disorder, and it has a prevalence of < 1/1000. The aim of this report is to spread awareness among otologists, audiologists, and pediatricians about this syndrome and its audiological features.Case presentationAn 8-year-old male with a diagnosed H syndrome registered to our clinic with a complaint of hearing loss. The patient was diagnosed with hearing loss in a different clinic using only the air-conducted click auditory brainstem response test which showed wave V at 60 dB nHL for the right ear and at 80 dB nHL for the left ear. The initially performed pure tone audiometry (PTA) test in our clinic revealed a bilateral asymmetric hearing loss with a moderate sensorineural hearing loss in the right ear and a profound mixed hearing loss in the left ear. The performed air conducted click auditory brainstem response (ABR) result showed wave V at 55 dB nHL for the right ear and at 70 dB nHL for the left ear. Then, the repeated PTA test revealed a mild-severe sensorineural sloping hearing loss in the right ear and a severe sensorineural hearing loss in the left ear.ConclusionAlthough hearing thresholds in H syndrome could be within normal limits in some patients, sensorineural hearing loss is an important characteristic feature for this syndrome. Sensorineural hearing loss could be progressive or of sudden onset and ranges from mild to profound. Thus, it must be taken into consideration to apply the audiological follow-up regularly and paying attention to the patient’s complaints; also, a regular follow-up for language development of children with H syndrome and for the hearing aids is advised.

Relationships between click auditory brainstem response and speech frequency following response with development in infants born preterm

The speech evoked frequency following response (sFFR) is used to study relationships between neural processing and functional aspects of speech and language that are not captured by click or toneburst evoked auditory brainstem responses (ABR). The sFFR is delayed, deviant, or weak in school age children having a variety of disorders, including autism, dyslexia, reading and language disorders, in relation to their typically developing peers. Much less is known about the developmental characteristics of sFFR, especially in preterm infants, who are at risk of having language delays. In term neonates, phase locking and spectral representation of the fundamental frequency is developed in the early days of life. Spectral representation of higher harmonics and latencies associated with transient portions of the stimulus are still developing in term infants through at least 10 months of age. The goal of this research was to determine whether sFFR could be measured in preterm infants and to characterize its developmental trajectory in the time and frequency domain. Click ABR and sFFR were measured in 28 preterm infants at ages 33 to 64 weeks gestational age. The sFFR could be measured in the majority of infants at 33 weeks gestational age, and the detectability of all sFFR waves was 100% by 64 weeks gestational age. The latency of all waves associated with the transient portion of the response (waves V, A, and O), and most waves (waves D and E) associated with the quasi-steady state decreased with increasing age. The interpeak wave A-O latency did not change with age, indicating that these waves share a neural generator, or the neural generators are developing at the same rate. The spectral amplitude of F0 and the lower frequencies of the first formant increased with age, but that for higher frequencies of the first formant and higher harmonics did not. The results suggest that the sFFR can be reliably recorded in preterm infants, including those cared for in the neonatal intensive care unit. These findings support that in preterm infants, F0 amplitude continues to develop within the first 6 months of life and develops before efficient representation of higher frequency harmonics. Further research is needed to determine if the sFFR in preterm infants is predictive of long-term language or learning disorders.

Towards effective assessment of normal hearing function from ABR using a time-variant sweep-tone stimulus approach

Objective. The auditory brainstem response (ABR) audiometry is a means of assessing the functional status of the auditory neural pathway in the clinic. The conventional click ABR test lacks good neural synchrony and it mainly evaluates high-frequency hearing while the common tone-burst ABR test only detects hearing loss of a certain frequency at a time. Additionally, the existing chirp stimuli are designed based on average data of cochlear characteristics, ignoring individual differences amongst subjects. Approach. Therefore, this study designed a new stimulus approach based on a sweep-tone concept with a time variant and spectrum characteristics that could be customized based on an individual’s cochlear characteristics. To validate the efficiency of the proposed method, we compared its performance with the click and tone-bursts using ABR recordings from 11 normal-hearing adults. Main results. Experimental results showed that the proposed sweep-tone ABR achieved a higher amplitude compared with those elicited by the click and tone-bursts. When the stimulus level or rate was varied, the sweep-tone ABR consistently elicited a larger response than the corresponding click ABR. Moreover, the sweep-tone ABR appeared earlier than the click ABR under the same conditions. Specifically, the mean wave V peak-to-peak amplitude of the sweep-tone ABR was 1.3 times that of the click ABR at 70 dB nHL (normal hearing level) and a rate of 20 s−1, in which the former saved 40% of test time. Significance. In summary, the proposed sweep-tone approach is found to be more efficient than the traditional click and tone-burst in eliciting ABR.

Towards optimal selection of stimuli polarity method for effective evoking auditory brainstem responses.

Towards eliminating stimulus artifacts, alternating polarity stimuli have been widely adopted in eliciting the auditory brainstem response. However, considering the difference in the physiologic basis of the positive and negative polarity stimuli on the auditory system, it is unclear whether alternating polarity stimuli would adversely affect the auditory brainstem response characteristics. This research proposes a new polarity method for stimulus artifacts elimination, Sum polarity, that separately utilized the rarefaction and condensation stimuli and then summed the two evoked responses. We compared the waveform morphology and latencies of the auditory brainstem responses evoked by familiar stimuli (including click, tone-burst, and chirp) with different polarity methods in normal-hearing subjects to investigate the new method's effectiveness. The experimental results showed that alternating polarity of the click and chirp had little effect on the auditory brainstem response. In contrast, alternating polarity affected the waveform morphology and latencies of the auditory brainstem responses to the low-frequency tone-burst, with the effect decreasing as the stimulus frequency increased. These results demonstrated the performance of any polarity method is related to the characteristics of the stimulus signal itself, and no polarity method is optimal for all types of stimuli. Based on the analysis of experimental results, a fixed polarity and alternating polarity were recommended for the click and chirp auditory brainstem responses, respectively. Furthermore, considering the apparent latency differences between the responses to opposite polarity stimuli, the Sum polarity was suggested for the tone-burst auditory brainstem responses. Moreover, this work verified the feasibility of the Sum polarity, which offers another choice for eliminating stimulus artifacts in an evoked potential acquisition.

Click-evoked and speech-evoked auditory brainstem responses from individuals with multiple sclerosis

PurposeTo determine whether speech-evoked auditory brainstem response (ABR) is more sensitive to the effects of multiple sclerosis (MS) than click-evoked ABR. Materials and MethodsEleven previously-confirmed MS patients (8 females, 3 males) and nine controls (7 females, 2 males), matched in age and gender, participated in a repeated-measures design. Stimuli were presented monaurally to the right ear via insert earphone. All evoked potential responses were collected by a single-channel montage where three electrodes were placed on the center of the head (Cz: non-inverting/ active), the ipsilateral earlobe (inverting/ reference) and the contralateral earlobe (ground). Rarefaction clicks of 0.1 ms duration were presented at rates of 13.30 and 91.1 clicks per second. Speech-evoked ABRs were obtained using the BioMARK software and the Bio-Logic Navigator PRO hardware. A synthesized /da/ syllable of 40-ms duration was presented via alternating polarity and at a rate of 10.9 stimuli per second. Stimuli were presented at 80 dB SPL. Speech-evoked ABR responses were obtained in quiet and in noise. ResultsConventional click ABR responses were absent more often at high presentation rates in control subjects than in MS patients. Speech-evoked ABR peak amplitudes, wave E latency and VA complex slope variables separated the MS patients from controls. Group differences were also found in speech-evoked ABR response correlations in quiet versus noise conditions. ConclusionsThe speech-evoked ABR is as or more sensitive to MS than conventional ABR measures without resort to simply noting missing peaks. Comparison of speech-evoked ABR responses in quiet and in noise highlight loss of neural synchrony in MS.

Analysis of Click and Swept-Tone Auditory Brainstem Response Results for Moderate and Severe Sensorineural Hearing Loss

Introduction: Auditory brainstem response (ABR) is one of the commonly used methods in clinical settings to evaluate the hearing sensitivity and auditory function. The current ABR measurement usually adopts click sound as the stimuli. However, there may be partial ABR amplitude attenuation due to the delay characteristics of the cochlear traveling wave along the basilar membrane. To solve that problem, a swept-tone method was proposed, in which the show-up time of different frequency components was adjusted to compensate the delay characteristics of the cochlear basilar membrane; therefore, different ABR subcomponents of different frequencies were synchronized. Methods: The normal hearing group, moderate sensorineural hearing loss group, and severe sensorineural hearing loss group underwent click ABR and swept-tone ABR with different stimulus intensities. The latencies and amplitudes of waves I, III, and V in 2 detections were recorded. Results: It was found that the latency of each of the recorded I, III, and V waves detected by swept-tone ABR was shorter than that by click ABR in both the control group and experimental groups. In addition, the amplitude of each of the recorded I, III, and V waves, except V waves under 60 dB nHL in the moderate sensorineural hearing loss group, detected by swept-tone ABR was larger than that by click ABR. The results also showed that the swept-tone ABR could measure the visible V waves at lower stimulus levels in the severe sensorineural hearing loss group. Conclusion: Swept-tone improves the ABR waveforms and helps to obtain more accurate threshold to some extent. Therefore, the proposed swept-tone ABR may provide a new solution for better morphology of ABR waveform, which can help to make more accurate diagnosis about the hearing functionality in the clinic.

Auditory brainstem responses in children with autistic spectrum disorder

Background The assessment and management of autism spectrum disorder (ASD) is complex and therefore requires continuous efforts for developing evidence-based guidelines for the screening, diagnosis, and treatment of ASD. This research aims to study auditory brainstem response (ABR) in autistic children as a potential biomarker that could detect autism early during infancy as well as to study its relation to repetitive behavior. Patients and methods It included 60 children diagnosed with ASD according to DSM-5 among those attending the Child and Adolescent Outpatient Clinic at Elhadara University Hospital and Mamoura Psychiatric Hospital. Those with hearing or visual impairment, epileptic syndromes, psychotic illness, or other affective disorder were excluded from the study. In all, 53 (88.3%) boys and seven (11.7%) girls participated in this study. Their mean±SD age was 6.41±1.99 years. Childhood Autism Rating Scale, 2nd ed., Repetitive Behavior Scale–Revised, and audiological studies were performed with emphasis on ABR by a consultant of audiology. Results Statistical analysis was done on the results and the study showed that absolute latency of waves III and V on the right ear and those of waves I and III on the left ear and interpeak latencies I–III and I–V of both the right and left ears were significantly away from norms in the ASD group and latency of wave I from the left side shows a significant positive correlation with total Repetitive Behavior Scale–Revised score. This denotes that a longer duration of wave I corresponds to severity of repetitive and restricted behaviors. Conclusion During initial assessment of a suspected ASD case, click ABR at an intensity of 80 dB (not the usual one at an intensity of 30 dB for screening of hearing impairment) to be requested and examination of the full parameters for assessment of auditory processing and not only for excluding a hearing problem.

Dextromethorphan Attenuates Sensorineural Hearing Loss in an Animal Model and Population-Based Cohort Study.

The effect of dextromethorphan (DXM) use in sensorineural hearing loss (SNHL) has not been fully examined. We conducted an animal model and nationwide retrospective matched-cohort study to explore the association between DXM use and SNHL. Eight-week-old CBA/CaJ hearing loss was induced by a white noise 118 dB sound pressure level for 3 h. DXM (30 mg/kg) was administered intraperitoneally for 5 days and boost once round window DXM socking. In population-based study, we examined the medical records over 40 years old in Taiwan’s National Health Insurance Research Database between 2000 and 2015 to establish retrospective matched-cohort to explore the correlation between DXM use and SNHL. Using click auditory brainstem response (ABR), hearing threshold was measured as 48.6 ± 2.9 dB in control mice compared with 42.6 ± 7.0 dB in DXM mice, which differed significantly (p = 0.002) on day 60 after noise exposure with a larger ABR wave I amplitude in DXM mice. In human study, we used a Cox regression hazard model to indicate that a significantly lower percentage individuals developed SNHL compared with and without DXM use (0.44%, 175/39,895 vs. 1.05%, 1675/159,580, p < 0.001). After adjustment for age and other variables [adjusted hazard ratio: 0.725 (95% confidence interval: 0.624–0.803, p < 0.001)], this study also demonstrated that DXM use appeared to reduce the risk of developing SNHL. This animal study demonstrated that DXM significantly attenuated noise-induced hearing loss. In human study, DXM use may have a protective effect against SNHL.