Auditory brainstem responses to CE-Chirp®stimuli for normal ears and those with sensorineural hearing loss

Auditory Electrophysiological Thresholds With Different Chirps and Their Correlation With Behavioral Thresholds in Hearing-Impaired Children

OBJECTIVES

Research focusing on changes in the clinical practice of audiological diagnosis has become increasingly necessary, particularly in pediatric audiology. The pursuit of accurate and reliable examinations has intensified given the importance of early detection and intervention in cases of childhood hearing loss. Thus, this study aims to investigate the correlation between electrophysiological auditory thresholds, as obtained through frequency-specific auditory brainstem responses with two distinct chirp stimuli (narrow-band CE-Chirp Level Specific and narrow-band iChirp), in children with hearing impairments. In addition, this research set out to correlate these thresholds with behavioral responses while simultaneously comparing the examination durations relative to the type of stimuli and the degree of hearing loss.

DESIGN

A cohort of 20 children (aged 6 months to 12 years) with varying degrees of hearing impairment (ranging from mild to profound) were recruited. The participants underwent bilateral measurement of their electrophysiological thresholds via auditory brainstem responses across different frequencies (500, 1000, 2000, and 4000 Hz), and the timeframe for determining these thresholds was carefully recorded. Subsequently, behavioral thresholds were ascertained using pure-tone audiometry or visual reinforcement audiometry based on the child's age. The data collected was subsequently analyzed using Pearson and Spearman correlation coefficients. To compare examination times, the Student t test and the Kruskal-Wallis test were used.

RESULTS

There was a pronounced correlation between the thresholds obtained through both narrow-band chirp stimuli. Moreover, a substantial correlation was found between electrophysiological and behavioral thresholds at 1000, 2000, and 4000 Hz, especially when compared with pure-tone audiometry. The mean differences between the electrophysiological and behavioral thresholds were below 6 dB nHL, and the exam duration was relatively consistent across both devices, averaging 47.63 (±19.41) min for the narrow-band CE-Chirp Level Specific and 52.42 (±26) min for the narrow-band iChirp. Notably, variations in exam duration did not relate to varying degrees of hearing loss when using the narrow-band CE-Chirp Level Specific. Nevertheless, the narrow-band iChirp indicated significantly shorter durations in instances of profound degree measurements, demonstrating a statistically significant difference.

CONCLUSIONS

The narrow-band CE-Chirp Level Specific and narrow-band iChirp stimuli provided similar estimates of electrophysiological auditory thresholds in children with hearing impairments, giving accurate estimations of behavioral thresholds. The time it took to complete the assessment is comparable between both stimuli. For the narrow-band iChirp, the degree of hearing loss was shown to impact the testing time, and children with profound hearing loss underwent faster exams. Ultimately, this study exhibits significant clinical implications as it reveals that the narrow-band CE-Chirp Level Specific and narrow-band iChirp stimuli could be remarkably promising for clinically exploring electrophysiological thresholds in children with hearing impairments.

Investigating the Effects of Level-Specific CE-Chirp on Auditory Brainstem Response Waves in Normal Hearing Infants

Background

Auditory brainstem response (ABR) to the level-specific (LS) CE-Chirp has been reported to provide optimum neural synchrony along cochlear partitions, theoretically improving ABR waveform resolution. Despite this promising finding, limited studies have been conducted to contrast the results between LS CE-Chirp and Click stimuli. The current study aimed to compare the results of ABR between the two stimuli (Click and LS CE-Chirp).

Method

Sixty-seven normal-hearing infants, both with and without risk factors, aged less than 7 months old, participated in this study. The ABR test was conducted at 70 dBnHL using 33.3 stimulus repetition rates with both Click and LS CE-Chirp stimuli. The signal averaging was stopped at a maximum fixed signal average of 2,500 sweeps. Data were statistically compared between the two stimuli using the Wilcoxon signed-rank test.

Results

The waves I and V ABRs elicited by LS CE-Chirp exhibited significantly larger amplitudes than the Click stimulus. However, the amplitude of wave III and absolute latencies were similar in both stimuli at a supra-threshold level.

Conclusion

LS CE-Chirp has the advantage of larger amplitudes than the ABR from Click at the supra-threshold level (70 dBnHL) in normal-hearing infants.

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.

Auditory brainstem response with click and CE-Chirp® Level Specific stimuli in hearing infants

INTRODUCTION

The assessment of the integrity of the neural responses with ABR, aims to assist in the differential diagnosis of retrocochlear alterations. The gold standard stimulus for this assessment is Click. However, the CE-Chirp® Level Specific was developed to optimize the triggering of neural responses.

OBJECTIVE

to compare neural responses obtained with CE-Chirp® LS stimulus to those obtained with Clicks at 70 dB nHL in hearing infants, in order to analyze advantages in using CE-Chirp® LS.

METHODS

Eighteen infants with normal hearing were evaluated with Eclipse EP25 ABR System. Clicks and CE-Chirp® LS stimuli were presented using ER-3A insert earphones at 70 dB nHL, rate 45.1/s, and alternating polarity. A 30 Hz high-pass and 1500 Hz low-pass filter was applied, and ±40 μV artifact rejection level. Absolute latency of waves I, III and V and their interpeak intervals I-III, III-V and I-V were measured, as well as interaural difference for wave V and interpeak I-V, and wave V amplitude.

RESULTS

Although 18 infants were included in the study, it was possible to collect data only in 30 ears for Click stimulus, and 33 ears for CE-Chirp® LS, according to exclusion criteria. It was possible to record waves I, III, and V for both stimuli at 70 dB nHL in all normal-hearing infants. CE-Chirp® LS stimulus evoked a higher wave V amplitude than Click (p < 0.001). Wave I absolute latency was statistically different between stimuli (p < 0.001), being delayed for CE-Chirp® LS. Wave III absolute latency was statistically different between stimuli only for the right ear (p = 0.021), and wave V absolute latency was similar in both stimuli (p = 0.210). Interpeak intervals I-III and I-V were statistically different between stimuli (p < 0.001), being reduced for CE-Chirp® LS. Interpeak interval III-V was different between the stimuli only for right ears (p = 0.006). There was no difference between stimuli for interaural difference wave V (p = 1.33) and interaural difference interpeak I-V (p = 0.409).

CONCLUSION

It is possible to use CE-Chirp® LS stimulus in order to analyze neural synchrony in infants at 70 dB nHL, since better morphology waveforms were observed, and higher wave V amplitudes could be recorded. We suggest that new studies with infants with neurological disabilities and various hearing status, to observe how CE-Chirp® LS stimulus evokes neural responses in these conditions.

Effects of Stimulus Repetition Rates on the Auditory Brainstem Response to Level-Specific CE-Chirp in Normal-Hearing Adults

Purpose The purpose of this study is to investigate the influence of stimulus repetition rates on the auditory brainstem response (ABR) to Level-Specific (LS) CE-Chirp and click stimuli at multiple intensity levels in normal-hearing adults. Method A repeated-measure study design was used on 13 normal-hearing adults. ABRs were acquired from the study participants using LS CE-Chirp and click stimuli at four stimulus repetition rates (19.1, 33.3, 61.1, and 81.1 Hz) and four intensity levels (80, 60, 40, and 20 dB nHL). The ABR test was stopped at 40-nV residual noise level. Results High-stimulus repetition rates caused the ABR latencies to be longer and have reduced amplitudes in both ABR to LS CE-Chirp and click stimuli. The ABR to LS CE-Chirp Wave I, III, and V amplitudes were larger than ABR to click in almost all the stimulus repetition rates. However, there were no differences in the number of averages required to reach the stopping criterion between ABR to LS CE-Chirp and click stimulus, and between high-stimulus repetition rates and low-stimulus repetition rates. Conclusion The LS CE-Chirp at standard low-stimulus repetition rates can be used to elicit ABR for both neurodiagnostic and threshold seeking procedure.

Intraoperative quantification of floating mass transducer coupling quality in active middle ear implants: a multicenter study

Purpose

Evaluating the effectiveness of intraoperative auditory brainstem responses (ABRs) to stimulation by the Vibrant Soundbridge (VSB) active middle ear implant for quantifying the implant’s floating mass transducer (FMT) coupling quality.

Methods

In a diagnostic multicentric study, patients (> 18 years) who received a VSB with different coupling modalities were included. Pre- and postoperative bone conduction thresholds, intraoperative VSB-evoked ABR thresholds (VSB-ABR) using a modified audio processor programmed to preoperative bone conduction thresholds, postoperative vibrogram thresholds, and postoperative VSB-ABR thresholds were measured. Coupling quality was calculated from the difference between the pure tone average at 1000, 2000, and 4000 Hz (3PTA) vibrogram and postoperative 3PTA bone conduction thresholds.

Results

Twenty-three patients (13 males, 10 females, mean age 56.6 (± 12.5) years) were included in the study. Intraoperative VSB-ABR response thresholds could be obtained in all except one patient where the threshold was > 30 dB nHL. Postoperatively, an insufficient coupling of 36.7 dB was confirmed in this patient. In a Bland–Altman analysis of the intraoperative VSB-ABRs and coupling quality, the limits of agreement exceeded ± 10 dB, i.e., the maximum allowed difference considered as not clinically important but the variation was within the general precision of auditory brainstem responses to predict behavioral thresholds. Five outliers were identified. In two patients, the postoperative VSB-ABR thresholds were in agreement with the coupling quality, indicating a change of coupling before the postoperative testing.

Conclusion

The response thresholds recorded in this set-up have the potential to predict the VSB coupling quality and optimize postoperative audiological results.

Diagnostic accuracy of CE Chirp

OBJECTIVE

There has been an increase in the use of the CE-Chirp stimulus in automated auditory brainstem response (AABR) equipment for neonatal hearing screening. The purpose of this study is to evaluate the diagnostic accuracy of the LS CE-Chirp-evoked auditory brainstem response (ABR) compared to the click-evoked ABR for the identification of different degrees and configurations of sensorineural (SNHL) hearing loss.

METHOD

49 ears with mild to moderate SNHL were assessed: 16 ears with rising SNHL and 33 ears with sloping high frequency SNHL. Behavioural pure tone thresholds were obtained at 125-8000 Hz and ABR thresholds were measured using the click and LS CE-Chirp stimuli respectively. Click- and LS CE-Chirp-evoked thresholds were compared with each other and with behavioural pure tone average at 500, 1000, 2000 Hz (PTA), high frequency average at 2000, 4000, 8000 Hz (HFA) and low frequency average at 250, 500, 1000 Hz (LFA). Diagnostic accuracy of the two ABR stimuli was also compared by using ROC curves.

RESULTS

Differences between click- and LS CE Chirp-evoked ABR, and behavioural thresholds were not statistically significant (p > 0.05). The highest significant correlations for ABR using clicks to behavioural thresholds was found at 2000 and 4000 Hz, whereas, the highest correlation for LS CE-Chirp ABRs to behavioural thresholds was found at 1000, 2000 and 4000 Hz (r > 0.7, p < 0.001). A very strong, positive correlation was found between both click (r = 0.805, p < 0.001) and LS CE-Chirp (r = 0.825, p < 0.001) and the behavioural PTA. LS CE-Chirp ABR thresholds were closer to mid and low frequency thresholds than the click ABR while the click-evoked thresholds were in closer proximity to HFA. Sensitivity and specificity and false negative rates were identical. Diagnostic accuracy of the LS CE-Chirp ABR was equal to or better than click for low (area under the curve (AUC) = 0.83), mid (AUC = 0.89) and high frequency hearing losses (AUC = 0.73). However, scatterplots indicated more frequent underestimation of behavioural pure tone thresholds at mid and high frequencies with the LS CE-Chirp than for the click ABR.

CONCLUSION

The diagnostic accuracy of the LS CE Chirp-evoked ABR is equivalent or better than the click-evoked ABR. The importance of ongoing surveillance and consideration of ABR screening protocols is consequently emphasized.

Test-Retest Reliability of Level-Specific CE-Chirp Auditory Brainstem Response in Normal-Hearing Adults

Background and Objectives

There is growing interest in the use of the Level-specific (LS) CE-Chirp^® stimulus in auditory brainstem response (ABR) due to its ability to produce prominent ABR waves with robust amplitudes. There are no known studies that investigate the test-retest reliability of the ABR to the LS CE-Chirp^® stimulus. The present study aims to investigate the test-retest reliability of the ABR to the LS CE-Chirp^® stimulus and compare its reliability with the ABR to standard click stimulus at multiple intensity levels in normal-hearing adults.

Subjects and Methods

Eleven normal-hearing adults participated. The ABR test was repeated twice in the same clinical session and conducted again in another session. The ABR was acquired using both the click and LS CE-Chirp^® stimuli at 4 presentation levels (80, 60, 40, and 20 dBnHL). Only the right ear was tested using the ipsilateral electrode montage. The reliability of the ABR findings (amplitudes and latencies) to the click and LS CE-Chirp^® stimuli within the same clinical session and between the two clinical sessions was calculated using an intra-class correlation coefficient analysis (ICC).

Results

The results showed a significant correlation of the ABR findings (amplitude and latencies) to both stimuli within the same session and between the clinical sessions. The ICC values ranged from moderate to excellent.

Conclusions

The ABR results from both the LS CE-Chirp^® and click stimuli were consistent and reliable over the two clinical sessions suggesting that both stimuli can be used for neurological diagnoses with the same reliability.

Effects of Different Electrode Configurations on the Narrow Band Level-Specific CE-Chirp and Tone-Burst Auditory Brainstem Response at Multiple Intensity Levels and Frequencies in Subjects With Normal Hearing

PURPOSE

The purpose of this study was to investigate the influence of 2 different electrode montages (ipsilateral and vertical) on the auditory brainstem response (ABR) findings elicited from narrow band (NB) level-specific (LS) CE-Chirp and tone-burst in subjects with normal hearing at several intensity levels and frequency combinations.

METHOD

Quasi-experimental and repeated-measures study designs were used in this study. Twenty-six adults with normal hearing (17 females, 9 males) participated. ABRs were acquired from the study participants at 3 intensity levels (80, 60, and 40 dB nHL), 3 frequencies (500, 1000, and 2000 Hz), 2 electrode montages (ipsilateral and vertical), and 2 stimuli (NB LS CE-Chirp and tone-burst) using 2 stopping criteria (fixed averages at 4,000 sweeps and F test at multiple points = 3.1).

RESULTS

Wave V amplitudes were only 19%-26% larger for the vertical recordings than the ipsilateral recordings in both the ABRs obtained from the NB LS CE-Chirp and tone-burst stimuli. The mean differences in the F test at multiple points values and the residual noise levels between the ABRs obtained from the vertical and ipsilateral montages were statistically not significant. In addition, the ABR elicited from the NB LS CE-Chirp was significantly larger (up to 69%) than those from the tone-burst, except at the lower intensity level.

CONCLUSION

Both the ipsilateral and vertical montages can be used to record ABR to the NB LS CE-Chirp because of the small enhancement in the wave V amplitude provided by the vertical montage.