Auditory brainstem responses in women: influence of Body Mass Index.

Background and ObjectivesThe auditory brainstem response (ABR) represents a critical tool for evaluating auditory pathways. Although absolute and inter-peak latencies (IPLs) are commonly analyzed, the differences between different stimulus types and presentation modes, particularly during binaural processing, remain underexplored. This study compared the absolute latencies, IPLs, and binaural interaction component (BIC) latencies of ABRs elicited by click and LS CE-chirp stimuli under both monaural and binaural conditions. The present study analyzed the clinical features of cochlear function in Ramsay-Hunt syndrome. Subjects and MethodsTwenty-one adults with normal hearing aged 22-25 years underwent ABR testing using click and LS CE-chirp stimuli under binaural, right ear, and left ear conditions. Their absolute latencies, IPLs, and BIC latencies for waves I, III, and V were recorded. BIC latencies were calculated by subtracting each subject’s binaural wave latency from their mean monaural latency. ResultsThe subjects’ LS CE-chirp stimuli elicited significantly longer wave V latencies under binaural vs monaural conditions, although their click-evoked ABRs did not show significant differences across the different presentation modes evaluated. The wave III latencies were significantly longer for the LS CE-chirp stimuli under the binaural and right-ear conditions. The IPLs showed stimulus- and ear-dependent differences, with LS CE-chirps evoking shorter IPLs vs. regular clicks under some conditions. The BIC latencies for waves III and V were significantly longer for the LS CE-chirp stimuli, whereas those for wave I showed no significant differences. ConclusionsLS CE-chirp stimuli enhanced ABR detectability and revealed longer binaural processing times, particularly at higher auditory brainstem levels. These findings support the utility of LS CE-chirp in terms of assessing binaural integration and central auditory processing.

Diagnosis of hearing loss and prescription of amplification for infants and young children require accurate estimates of ear- and frequency-specific behavioral thresholds based on auditory brainstem response (ABR) measurements. Although the overall relationship between ABR and behavioral thresholds has been demonstrated, the agreement is imperfect, and the accuracy of predictions of behavioral threshold based on ABR may depend on degree of hearing loss. Behavioral thresholds are lower than ABR thresholds, at least in part due to differences in calibration interacting with the effects of temporal integration, which are manifest in behavioral measurements but not ABR measurements and depend on behavioral threshold. Listeners with sensory hearing loss exhibit reduced or absent temporal integration, which could impact the relationship between ABR and behavioral thresholds as degree of hearing loss increases. The present study evaluated the relationship between ABR and behavioral thresholds in infants and children over a range of hearing thresholds, and tested an approach for adjusting the correction factor based on degree of hearing loss as estimated by ABR measurements. A retrospective review of clinical records was completed for 309 ears of 177 children with hearing thresholds ranging from normal to profound hearing loss and for whom both ABR and behavioral thresholds were available. Children were required to have the same middle ear status at both evaluations. The relationship between ABR and behavioral thresholds was examined. Factors that potentially could affect the relationship between ABR and behavioral thresholds were analyzed, including degree of hearing loss observed on the ABR, behavioral test method (visual reinforcement, conditioned play, or conventional audiometry), the length of time between ABR and behavioral assessments, and clinician-reported reliability of the behavioral assessment. Predictive accuracy of a correction factor based on the difference between ABR and behavioral thresholds as a function of ABR threshold was compared to the predictive accuracy achieved by two other correction approaches in current clinical use. As expected, ABR threshold was a significant predictor of behavioral threshold. The agreement between ABR and behavioral thresholds varied as a function of degree of hearing loss. The test method, length of time between assessments, and reported reliability of the behavioral test results were not related to the differences between ABR and behavioral thresholds. A correction factor based on the linear relationship between the differences in ABR and behavioral thresholds as a function of ABR threshold resulted in more accurately predicted behavioral thresholds than other correction factors in clinical use. ABR is a valid predictor of behavioral threshold in infants and children. A correction factor that accounts for the effect of degree of hearing loss on the differences between ABR and behavioral thresholds resulted in more accurate predictions of behavioral thresholds than methods that used a constant correction factor regardless of degree of hearing loss. These results are consistent with predictions based on previous research on temporal integration for listeners with hearing loss.

The aim of this study was to compare the human auditory brain stem response (ABR) elicited by clicks and chirps with overall behavioral hearing thresholds in participants with normal hearing and with sensory hearing loss. The authors hypothesized that ABRs to chirps would be more robust and that thresholds would be more similar to overall behavioral hearing thresholds compared with ABRs to clicks. Twenty-five adults with normal hearing and 25 adults with sensory hearing loss were recruited. Subjects were without middle ear or neurological pathologies at the time of testing. Subjects with sensory hearing loss were separated into mild to moderate hearing loss and mild to severe hearing loss groups. Behavioral hearing thresholds for pure tones were obtained at nine octave and interoctave frequencies ranging from 250 to 8000 Hz; an average of these nine frequencies was calculated for each participant. Evoked potential thresholds were measured by ABRs to click and chirp stimuli. Analyses included wave V absolute latencies and wave V peak-to-peak amplitudes. Thresholds for ABRs to clicks and chirps were compared with each other and with overall behavioral hearing thresholds. ABR thresholds to chirp and click stimuli did not differ significantly for either the normal-hearing or the hearing loss groups. Wave V peak-to-peak amplitude was higher for chirps than clicks, particularly at lower intensities, for all groups. ABR thresholds to chirps were closer to overall behavioral thresholds than clicks in all groups. Moreover, ABR thresholds to chirps did not differ significantly from behavioral thresholds in the two hearing loss groups. ABRs obtained with chirp stimuli provide an efficient method for estimating hearing thresholds in individuals with normal hearing and sensory hearing loss where broadband signals are selected for testing. ABRs to chirps display higher peak-to-peak amplitudes than those obtained with clicks and may provide responses closer to behavioral thresholds. This information could result in improved accuracy in identifying hearing loss and estimating hearing sensitivity for broadband signals in infants, children, and difficult-to-test older populations.

Contralateral noise masking is an important aspect of auditory brainstem response (ABR) measurements. The primary aim of this study is to determine how contralateral white noise (WN) masking influences the amplitude and the latency of V wave generated during ABR measurements, using tone burst (TB), in adult ears with normal hearing (NH). The secondary aim of this study is to ascertain the need of contralateral masking in ABR measurements with the TB stimuli using a 3A insertion earphone, and to propose the applicability of WN masking in unilateral sensorineural hearing loss (USNHL). It is a cross-sectional observational and descriptive study. Experiment 1: Thirty individuals, without any otologic, psychological, or neurological dysfunction, were selected. Experiment 2: Fifteen individuals with previous audiological diagnoses of severe and profound USNHL were considered. The study involves ABR TB at specific frequencies of 0.5, 1, 2, and 4 kHz. Experiment 1: The evaluation was performed at the fixed intensity of 80 dB nHL (decibel normalized hearing level) on the tested ear, followed by the application of simultaneous masking to the nontested ear, intensity ranged from 0 to 80 dB. Experiment 2: ABR threshold measurements were first performed on the ear with hearing loss (HL) at the frequencies of 1, 2, and 4 kHz. The results were subsequently confirmed using contralateral masking. Experiment 1: At any given frequency, there were no statistically significant differences in the amplitude and latency of V wave with increase in the intensities of WN masking. Experiment 2: Cross-hearing was observed at least once in all frequencies analyzed through the occurrence of V wave. In conclusion, the contralateral WN masking at the maximum intensity of 80 dB does not affect the amplitude and latency of V wave of the ABR TB at 1, 2, and 4 kHz. Contralateral masking for the ABR TB presented using 3A insertion earphones is necessary at 1, 2, and 4 kHz in individuals with severe or profound degrees of USNHL and at intensities of 15, 20, and 10 dB above the ABR threshold of the nontested ear.

Brainstem auditory evoked potentials with the use of acoustic clicks and complex verbal sounds in young adults with learning disabilities

Background and ObjectivesNo known studies have investigated the influence of stimulus polarity on the Auditory Brainstem Response (ABR) elicited from level-specific (LS) chirp. This study is important as it provides a better understanding of the stimulus polarity selection for ABR elicited from LS chirp stimulus. We explored the influence of stimulus polarity on the ABR from LS chirp compared to the ABR from click at 80 dBnHL in normal-hearing adults.Subjects and MethodsNineteen adults with normal hearing participated. The ABRs were acquired using click and LS chirp stimuli using three stimulus polarities (rarefaction, condensation, and alternating) at 80 dBnHL. The ABRs were tested only on the right ear at a stimulus rate of 33.33 Hz. The ABR test was stopped when the recording reached the residual noise level of 0.04 µV. The ABRs amplitudes, absolute latencies, inter-peak latencies (IPLs), and the recorded number of averages were statistically compared among ABRs at different stimulus polarities and stimuli combinations.ResultsRarefaction polarity had the largest ABR amplitudes and SNRs compared with other stimulus polarities in both stimuli. There were marginal differences in the absolute latencies and IPLs among stimulus polarities. No significant difference in the number of averages required to reach the stopping criteria was found.ConclusionsStimulus polarities have a significant influence on the ABR to LS chirp. Rarefaction polarity is recommended for clinical use because of its larger ABR peak I, III, and V amplitudes than those of the other stimulus polarities.

Objective To estimate the impact of body mass index (BMI) categories on duration of the nonstress test (NST), and the need for additional tests of fetal wellbeing or interventions. Methods We conducted a retrospective cohort study of women with singleton pregnancies who had an NST for the indications of severe obesity (BMI ≥40 kg/m2), diabetes (pre-gestational or gestational), hypertensive disorders (chronic, gestational, and preeclampsia), and others between 1 January 2015 until 31 December 2016. NST durations (<30 and ≥30 min) were compared between groups first based on BMI (kg/m2) categories (<30, 30–39, 40–49, and ≥50) and then based on BMI and comorbidities: (1) severe obesity alone, (2) severe obesity and comorbidities, and (3) comorbidities alone. We compared the results of the NSTs, any subsequent fetal testing or interventions, and pregnancy outcomes among groups. Demographic information was compared using t-tests for continuous data and χ 2 analyses or Fisher’s exact test, if the cells sizes were small, for categorical data. NST durations based on BMI groups, as well as BMI and comorbidities groups, were compared using linear mixed models and ANOVA. Results Three hundred and fifty-one women underwent 1665 NSTs during the study period. After excluding women <18 and >50 years, gestational age <30 weeks, fetal anomalies, and NSTs lasting longer than 60 min, the study population included 313 women and 1471 NSTs. The mean NST duration in minutes of the BMI ≥50 (32.2 ± 9.6) category was significantly longer than the NST duration of the other BMI categories (BMI <30: 29.4 ± 8.3; BMI 30–39: 29.7 ± 8.9; BMI 40–49: 29.9 ± 8.3) (p=.05). Additionally, there was an increased percentage of NSTs lasting ≥30 min as the BMI category increased (p=.005). Women in the severe obesity and comorbidities group (n = 79) were less likely to have a reactive NST than women with severe obesity alone (n = 56) or comorbidities alone (n = 178) (92% vs. 97% vs. 98%, p<.0001). They were also more likely to need a biophysical profile (BPP) (8% vs. 3% vs. 2%, p<.0001). Of the 25 women that were sent to the labor and delivery unit for evaluation, 20 (80%) were admitted and delivered. The reasons for delivery were hypertension (n = 9, 45%), an abnormal NST (n = 5, 25%), oligohydramnios (n = 4, 20%), and labor (n = 2, 10%). Conclusions We found an increase in NST duration as the BMI increased. Women with severe obesity and a comorbidity were more likely to have a nonreactive NST and require a subsequent BPP. Of the 20 patients delivered due to NST surveillance, the most common indication for delivery was hypertension.

An initial overestimation of sensorineural hearing loss in NICU infants after failure on neonatal hearing screening

To determine the auditory brainstem response (ABR) patterns in infants with prenatal cocaine exposure as detected by meconium analysis. Meconium drug analysis was done on term infants who were at risk for antenatal illicit drug exposure. Infants who tested positive for cocaine served as the exposed group; those who tested negative served as control subjects. An ABR was done on the infants within 6 days of life. Absolute latencies at 40 and 70 decibels (dB) of waves I, III, and V and interpeak latencies between I and III, III and V, and I and V were measured. Among 58 infants in the study, 21 (35.6%) were positive, by meconium analysis, for cocaine and 5 (8.5%) were positive for cannabinoids. Four infants tested positive for cocaine, although their mothers denied illicit drug use. There was a significant difference in mean maternal age, gravidity, parity, birth weight, and head circumference among cocaine-exposed versus nonexposed infants. The ABR from cocaine-positive infants showed significantly prolonged mean absolute latencies in both ears as compared with nonexposed infants: right ear at 40 dB III (4.823 vs 4.447 milliseconds), 40 dB V (7.400 vs 6.968 milliseconds), 70 dB I (2.111 vs 1.631 milliseconds), and 70 dB III (4.122 vs 3.821 milliseconds); left ear at 40 dB III (4.820 vs 4.444 milliseconds), 40 dB V (7.460 vs 6.860 milliseconds), 70 dB I (2.063 vs 1.741 milliseconds), 70 dB III (4.026 vs 3.656 milliseconds), and 70 dB V (6.568 vs 6.258 milliseconds). The interpeak latency was not significantly different except in 1 cocaine-positive infant: left ear at 40 dB III to V (2.667 vs 2.417 milliseconds). The ABR in neonates who are exposed prenatally to cocaine shows prolonged absolute peak latencies compared with nonexposed neonates and may indicate compromise of the auditory system from gestational exposure to cocaine that will need additional audiologic follow-up. Meconium analysis can more accurately detect the infants who are at risk.

Background: Hormone receptor-positive (HR+) breast cancer patients derive only modest benefit from extended endocrine therapy (EET) while facing an increased risk of late distant recurrence (DR). The Breast Cancer Index (BCI) is a validated genomic assay for providing individualized risk of overall (0-10y) and late (5-10y) DR and predicts the likelihood of benefit from EET. The predictive component of BCI, the HOXB13/IL17BR ratio [BCI (H/I)] with a high status predicting EET benefit, has been validated in several randomized controlled trials including MA.17, Trans-aTTom, IDEAL, and NSABP B-42. Previous studies suggest that breast cancer survivors who are overweight or obese based on Body Mass Index (BMI) are at an increased risk of cancer recurrence, and higher all-cause mortality. This analysis aims to investigate the correlation between BCI and BMI in patients enrolled in the BCI Registry study. Methods: The BCI Registry study is a prospective study to evaluate the long-term clinical outcome, decision impact and medication adherence in early-stage, HR+ breast cancer patients. BMI scores were categorized as underweight/normal (BMI &amp;lt; 25), overweight (25 ≤ BMI &amp;lt; 30), obese (30 ≤ BMI &amp;lt; 40), and severely obese (BMI ≥ 40). BCI score, BCI (H/I) and categorical groups based on default cut-points were calculated as previously described. Spearman’s correlation coefficient (R) was used to estimate the correlation between BCI (H/I), BCI risk score, and BMI as continuous variables. Kruskal-Wallis test was used to assess pairwise comparisons between BMI groups and BCI categories. Results: BCI and BMI results were included from 1664 breast cancer patients (74.8% T1; 53.5% grade II; 79.5% N0). BCI (H/I) classified 1025 patients (61.6%) as BCI (H/I)-Low and 639 (38.4%) as BCI (H/I)-High. BCI scores classified 771 patients (46.3%) as low-risk and 893 (53.7%) as high-risk for late DR. BMI classified 417 patients (25.0%) as underweight/normal, 552 (33.2%) as overweight, 584 (35.1%) as obese and 111 (6.7%) as severely obese. When analyzed as continuous variables, no correlation with BMI was observed for BCI (H/I) (R=-0.04) nor BCI score (R=0.007). In addition, no significant relationship was observed between BMI and BCI (H/I) categories (p = 0.16) as well as between BMI and BCI prognostic groups (p =0.51). Conclusions: BCI (H/I) and BCI risk scores exhibited no correlation with BMI categories. BCI (H/I) consistently stratified patients into low- and high-likelihood for extended endocrine benefit independent of BMI categories, suggesting that BMI is not a reliable indicator for predicting recurrence risk or benefit from EET. Citation Format: Natalia Siuliukina, Brandon O’Neal, Amanda K.L. Anderson, Yi Zhang, Kai Treuner, Joyce O'Shaughnessy. Correlative analysis of Breast Cancer Index with Body Mass Index for prediction of extended endocrine therapy benefit in the BCI Registry study [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P4-11-04.

The aim of this study was to characterize the auditory brainstem responses (ABRs) of young children with suspected autism spectrum disorders (ASDs) and compare them with the ABRs of children with language delay and with clinical norms. The ABRs of 26 children with suspected ASDs (21 males, five females; mean age 32.5 mo) and an age- and sex-matched group of 26 children with language delay (22 males, four females) were analysed. All children had normal hearing. The absolute latencies of waves I, III, and V, and interpeak latencies (IPLs) I to III, I to V, and III to V of the group with ASDs and the group with language delay were compared. Data from both groups were further compared with clinical norms. All absolute latencies and IPLs were significantly prolonged in the group with suspected ASDs compared with the group with language delay, excluding IPL III-V (all p-values <0.05) and with clinical norms (all p-values <0.001; IPL III-V, p<0.05). Significant prolongation of absolute and IPLs was also evident in the group with language delay compared with clinical norms, excluding IPL III to V (all p-values <0.001). The prevalence of abnormal findings in two or more absolute latencies was found to be significantly higher in the group with ASDs (50%) than in the group with language delay (8%; p=0.002). The results provide first-time evidence for a neurodevelopmental brainstem abnormality that is already apparent in young children with suspected ASD and language delay. The overlap in ABR findings supports the assertion that an auditory processing deficit may be at the core of these two disorders.

The Claus Elberling Chirp (CE-Chirp) stimulus used in the auditory brainstem responses (ABRs) 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. The aim of this study was to compare click ABRs with LS CE-Chirp ABR thresholds in adults with sensorineural hearing loss. The research is a cross-sectional, analytical research. Twenty-two adult patients (n = 44 ears) with bilateral sensorineural hearing loss were included in the study. Pure-tone audiometry, click ABR, and LS CE-Chirp ABR tests were performed on adult (13 males and 9 females; 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 to 4 kHz averages. Both types of ABR stimuli were able to identify with total hearing loss (n = 6). A significant difference was found between LS CE-Chirp ABR thresholds (53.81 ± 20.28 decibel normal hearing level [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 hearing thresholds (p = 0.66, 0.80, and 0.69, respectively). In adults with hearing loss, the LS CE-Chirp provides ABR thresholds closer to the behavioral hearing thresholds at 2 and 4 kHz compared with 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 can be used effectively in the estimation of behavioral hearing thresholds in adults with hearing loss.

In Preliminary Data, Cell Phone Users Have Longer ABR Latencies

If the interpeak intervals in the auditory brain stem response (ABR) are assumed to be statistically independent variables that represent the neural transmission time between loci, then the absolute latency of an ABR wave is the sum of the transmission times between successive loci. Consequently, the correlations between the absolute latencies of the ABR waves would be part-whole correlations whose expected values are appreciably different from r = 0. We derived the expected values of the correlations between the latencies of the ABR waves on the assumption that their latencies are the sum of independent elements (transmission times) and found them to be 0.707, 0.577, and 0.816 for I.III, I.V, and III.V, respectively. In addition, the expected values of the correlations between the latencies of the ABR waves assuming that the absolute wave latencies themselves are independent variables (e.g., rI.III = 0) were derived. Several of the correlations among interpeak and between the interpeak and absolute latencies were demonstrated to be appreciably different from r = 0. It would appear that it is more reasonable to assume that the elements (transmission times) rather than the component latencies are the variables of choice for statistical analysis of ABR data.

The mixture of ketamine and xylazine is widely used for the auditory brainstem response (ABR) measurement. Esketamine is twice as potent as ketamine. Our objective was to assess the influence of esketamine in mice undergoing cochlear function measurement including ABR and distortion product otoacoustic emission (DPOAE) measurement. C57Bl/6J mice were treated with an equivalent dose of analgesia and received either a single intraperitoneal (ip) injection of 100 mg/kg ketamine and 25 mg/kg xylazine or 50 mg/kg esketamine and 25 mg/kg xylazine. Hearing thresholds, peak latencies of waves I and V, and DPOAE thresholds were recorded. Time to loss of righting and time to regain righting were also assessed. We found that hearing thresholds, the peak latencies of waves I and V, and DPOAE thresholds were similar between the two groups (all P>0.05). Time to regain righting was significantly shorter in the esketamine group (P<0.001) than in the ketamine group. We concluded that when using equivalent doses of analgesia, esketamine may be an ideal substitute for ketamine during cochlear function test.