Comparison between ABR with click and narrow band chirp stimuli in children

Quick Estimation of Minimum Hearing Levels Using a Binaural Multifrequency Stimulus Paradigm: Proof of Concept

OBJECTIVES

Objective estimation of minimum hearing levels using auditory brainstem responses (ABRs) elicited by single frequency tone-bursts presented monaurally is currently considered the gold standard. However, the data acquisition time to estimate thresholds (for both ears across four audiometric frequencies) using this method usually exceeds the sleep time (ranging between 35 and 49 minutes) in infants below 4 months, thus providing incomplete information of hearing status which in turn delays timely clinical intervention. Alternate approaches using faster rate, or tone-burst trains have not been readily accepted due to additional hardware and software requirements. We propose here a novel binaural multifrequency stimulation paradigm wherein several stimuli of different frequencies are presented binaurally in an interleaved manner. The rationale here is that the proposed paradigm will increase acquisition efficiency, significantly reduce test time, and improve accuracy by incorporating an automatic wave V detection algorithm. It is important to note that this paradigm can be easily implemented in most commercial ABR systems currently used by most clinicians.

DESIGN

Using this binaural multifrequency paradigm, ear specific ABRs were recorded in 30 normal-hearing young adults to both tone-bursts, and narrow-band (NB) iChirps at 500, 1000, 2000, and 4000 Hz. Comparison of ABRs elicited by tone-bursts and narrow-band chirps allowed us to determine if NB iChirps elicited a more robust wave V component compared with the tone-bursts. ABR data were characterized by measures of minimum hearing levels; wave V amplitude; and response detectability for two electrode configurations (high forehead-C7; and high forehead-linked mastoids).

RESULTS

Consistent with the research literature, wave V response amplitudes were relatively more robust for NB iChirp stimuli compared with tone-burst stimuli. The easier identification and better detectability of wave V for the NB iChirps at lower stimulus levels contributed to their better thresholds compared with tone-burst elicited responses. It is important to note that binaural multifrequency hearing levels close to minimum hearing levels were determined in approximately 22 minutes using this paradigm-appreciably quicker than the 45 to 60 minutes or longer time required for threshold determination using the conventional single frequency method.

CONCLUSIONS

Our novel and simple paradigm using either NB iChirps or tone-bursts provides a reliable method to rapidly estimate the minimum hearing levels across audiometric frequencies for both ears. Incorporation of an automatic wave V detection algorithm increases objectivity and further reduce test time and facilitate early hearing identification and intervention.

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.

The Effects of Different Reference Methods on Decision-Making Implications of Auditory Brainstem Response

Hearing loss is a common disease affecting public health all around the world. In clinic, auditory brainstem response (ABR) has been widely used for the detection of hearing loss based on its convenience and accuracy. The different reference methods directly influence the quality of the ABR waveform which in turn affects the ABR-based diagnosis. Therefore, in this study, a reference electrode standardization technique (REST) was adopted to systematically investigate and evaluate the effect of different reference methods on the quality of ABR waveform in comparison with the conventional average reference (AR) and mean mastoid (MM) methods. In this study, ABR signals induced by click stimulus were acquired via an EEG electrode cap arrays, and those located on the six channels along the midline were compared systemically. The results showed that, when considering the different channels, the ABR in the Cz channel showed the best morphology. Then, the ABR waveforms acquired via the REST method possessed better morphologies with large amplitude ( $0.06\pm 0.02$  μV for wave I, $0.07\pm 0.02$  μV for wave III, and $0.21\pm 0.04$  μV for wave V) when compared with the traditional method. Summarily, we found that the REST and MM methods improved the quality of ABR on both amplitude and morphology under different stimulation rates and levels without changing the latencies of ABR when compared with the conventional AR method, suggesting that the REST and MM methods have the potential to help physicians with high accurate ABR-based clinical diagnosis. Moreover, this study might also provide a theoretic basis of reference methods on the acquisition of electroencephalogram over public health issues.

Auditory Brainstem Response with the iChirp stimuli in the infant's audiological diagnosis

OBJECTIVE

to investigate the use of the iChirp stimulus in the infant's audiological diagnosis compared to stimuli typically used in the ABR in infants, in addition to suggesting reference values for the assessment of this population.

METHODS

62 infants participated in the study, 29 females and 33 males. The subjects underwent the recording of the Auditory Brainstem Response in the Smart Ep equipment, with the stimuli click, iChirp-broadband, tone burst and iChirp-narrowband, which were presented at three levels of intensity (20 dB, 40 dB and 60 dB) and, for tone burst and iChirp-narrowband stimuli, at different frequencies (0.5, 1 k, 2 k and 4 KHz). The data were later analyzed using Student's t-test.

RESULTS

In general, the iChirp-broadband and iChirp-narrowband stimuli showed higher latency values and greater amplitudes when compared to click and tone burst stimuli. Furthermore, better signal-to-noise ratios were observed when contrasting iChirp-narrowband with tone burst. Additionally, reference values were established for the assessment of ABR in infants with the iChirp-broadband and iChirp-narrowband in the Smart-Ep equipment.

CONCLUSION

The iChirp stimulus appears to be promising in the infant's audiological diagnosis, as its use promoted greater amplitudes and better wave morphology, which facilitates to mark the waveforms and provides greater efficiency in the investigation of the auditory thresholds. The indication of normative data also enables the clinical use of these stimuli in the infant's audiological diagnosis.

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.

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.

Using ASSR with narrow-band chirps to evaluate hearing in children and adults

PURPOSE

All studies concerning the reliability and threshold prediction of auditory steady-state responses (ASSR) focused on a particular group of patients. The present article evaluates the use of narrow-band, chirp-evoked ASSR for testing hearing in adults and children of all ages and with different types of hearing loss, as well as normal hearing. The aims are: to determine whether there are possible influencing factors, mainly the degree of hearing loss; and to validate the clinical value of using ASSR with chirp-stimuli.

METHODS

This is a retrospective study of 667 patients who had been diagnosed with and treated for hearing loss at our tertiary referral center. The following results were compared: ASSR to pure tone audiometry (PTA); click-ABRs to PTA; and click-ABRs to ASSR. We then calculated mean, median and standard deviation. A regression analysis was used to examine the correlation between: ASSR and click-ABRs; "estimated" audiogram and PTA; click-ABRs and PTA; and ASSR and PTA.

RESULTS

We found significant correlations at all frequencies when comparing ASSR to click-ABRs, click-ABRs to PTA, and ASSR to PTA. Concerning the degree of hearing loss, there were significant differences between the patients with normal hearing and those with moderate-to-profound hearing loss.

CONCLUSION

ASSR with narrow-band chirps are a reliable tool for estimating hearing thresholds in children and adults with all kinds of hearing loss. We have demonstrated that threshold differences between PTA and ASSR are negligible in the clinical routine. The "estimated" ASSR audiogram is a good approach for communicating ASSR results to the average user.

Comparing Auditory Brainstem Responses evoked by Click and Sweep-Tone in Normal-Hearing Adults

Auditory brainstem response (ABR) is an objective method via which hearing loss could be detected. ABR induced by click, a broadband signal, is generally considered as the gold standard. However, due to the inherent delay of the cochlear traveling wave, click cannot excite the entire cochlear basement membrane at the same time, leading to the attenuation of the induced ABR waveform. In order to resolve this limitation, a sweep-tone-based stimulus that reconstructs the arrival time of different frequency components with respect to the delay characteristics of cochlear basement membrane was designed and used to induce ABR in this study. Subsequently, we compared the performance of the proposed sweep-tone-induced ABR method and the commonly adopted click induced ABR at different test levels and different stimulus rates. And the obtained results showed that the waveform morphology of sweep-tone-induced ABR was significantly better than that of click induced ABR across different test levels and stimulus rates. Moreover, compared to the click induced ABR at different sweeps, we found that the proposed sweep-tone-induced ABR effectively induced the ABR waveform at a relatively faster rate. Hence, the proposed sweep-tone-induced ABR approach provides a new method to improve the sensitivity of ABR detection in hearing loss.

Comparison of ABR and ASSR using NB-chirp-stimuli in children with severe and profound hearing loss

INTRODUCTION

Objective techniques for hearing threshold estimation in infants and children with profound or severe hearing loss play a key role in pediatric audiology to prevent speech acquisition disorders by choosing the adequate therapy. Auditory brainstem responses and auditory steady-state responses are available for frequency-dependent hearing threshold estimations and both techniques show strong correlations. However, various systems and stimuli are available, which is one reason why comparison is challenging, and, so far, no single "gold standard" could be established for hearing threshold estimation in children suffering from profound or severe hearing loss. The aim of the study was to compare hearing threshold estimations in children with profound or severe hearing loss derived with narrow-band CE-chirps evoked auditory brainstem responses and auditory steady-state response.

SUBJECTS

and Methods: 71 children (121 ears) with an age from 3 month to 15 years were measured with the Interacoustics Eclipse EP25 ABR system® (Denmark) with narrow-band CE-chirps® at 500, 1000, 2000 and 4000 Hz under identical conditions.

RESULTS

Auditory brainstem responses and auditory steady-state responses highly correlate (r = 0.694, p < 0.001). Correlation coefficients differ depending on the center frequency and patient age. Generally, auditory steady-state responses show a better hearing threshold than auditory brainstem responses or a remaining hearing threshold when auditory brainstem responses could not be obtained. In approximately 15% of cases this would have affected the therapeutic strategy when only taking one technique into account.

CONCLUSION

Auditory brainstem responses and auditory steady-state responses should be jointly used in the diagnostic approach in children with suspected profound or severe hearing loss.

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.

Neonate Auditory Brainstem Responses to CE-Chirp and CE-Chirp Octave Band Stimuli II: Versus Adult Auditory Brainstem Responses

OBJECTIVES

The purpose of the study was to examine the differences in auditory brainstem response (ABR) latency and amplitude indices to the CE-Chirp stimuli in neonates versus young adults as a function of stimulus level, rate, polarity, frequency and gender.

DESIGN

Participants were 168 healthy neonates and 20 normal-hearing young adults. ABRs were obtained to air- and bone-conducted CE-Chirps and air-conducted CE-Chirp octave band stimuli. The effects of stimulus level, rate, and polarity were examined with air-conducted CE-Chirps. The effect of stimulus level was also examined with bone-conducted CE-Chirps and CE-Chirp octave band stimuli. The effect of gender was examined across all stimulus manipulations.

RESULTS

In general, ABR wave V amplitudes were significantly larger (p < 0.0001) and latencies were significantly shorter (p < 0.0001) for adults versus neonates for all air-conducted CE-Chirp stimuli with all stimulus manipulations. For bone-conducted CE-Chirps, infants had significantly shorter wave V latencies than adults at 15 dB nHL and 45 dB nHL (p = 0.02). Adult wave V amplitude was significantly larger for bone-conducted CE-Chirps only at 30 dB nHL (p = 0.02). The effect of gender was not statistically significant across all measures (p > 0.05).

CONCLUSIONS

Significant differences in ABR latencies and amplitudes exist between newborns and young adults using CE-Chirp stimuli. These differences are consistent with differences to traditional click and tone burst stimuli and reflect maturational differences as a function of age. These findings continue to emphasize the importance of interpreting ABR results using age-based normative data.

Auditory Brainstem Response Thresholds to Air- and Bone-Conducted CE-Chirps in Neonates and Adults

PURPOSE

The purpose of this study was to compare auditory brainstem response (ABR) thresholds to air- and bone-conducted CE-Chirps in neonates and adults.

METHOD

Thirty-two neonates with no physical or neurologic challenges and 20 adults with normal hearing participated. ABRs were acquired with a starting intensity of 30 dB normal hearing level (nHL). The lowest stimulus intensity level at which a wave V was identifiable and replicable was considered the ABR threshold.

RESULTS

ABR thresholds to air-conducted CE-Chirps were 9.8 dB nHL for neonates and adults. ABR thresholds to bone-conducted CE-Chirps were 3.8 and 13.8 dB nHL for neonates and adults, respectively. The difference in ABR thresholds to bone-conducted CE-Chirps was significantly different (p < .0001, ηp2 = .45). Adults had significantly larger wave V amplitudes to air- (p < .0001, ηp2 = .50) and bone-conducted (p = .013, ηp2 = .15) CE-Chirps at a stimulus intensity of 30 dB nHL. At the same intensity, adults evidenced significantly shorter wave V latencies (p < .0001, ηp2 = .49) only with air-conducted CE-chirps.

CONCLUSION

The difference in ABR thresholds and wave V latencies to air- and bone-conducted CE-Chirps between neonates and adults may be attributed to a disparity in effective signal delivery to the cochlea.

Threshold changes of ABR results in toddlers and children

INTRODUCTION

Auditory brainstem response (ABR) is a clinically established method to identify the hearing threshold in young children and is regularly performed after hearing screening has failed. Some studies have shown that, after the first diagnosis of hearing impairment in ABR, further development takes place in a spectrum between progression of hearing loss and, surprisingly, hearing improvement.

OBJECTIVE

The aim of this study is to evaluate changes over time of auditory thresholds measured by ABR among young children.

MATERIAL AND METHODS

For this retrospective study, 459 auditory brainstem measurements were performed and analyzed between 2010 and 2014. Hearing loss was detected and assessed according to national guidelines. 104 right ears and 101 left ears of 116 children aged between 0 and 3 years with multiple ABR measurements were included. The auditory threshold was identified using click and/or NB-chirp-stimuli in natural sleep or in general anesthesia. The frequency of differences of at least more than 10dB between the measurements was identified.

RESULTS

In 37 (35%) measurements of right ears and 38 (38%) of left ears there was an improvement of the auditory threshold of more than 10dB; in 27 of those measurements more than 20dB improvement was found. Deterioration was seen in 12% of the right ears and 10% of the left ears. Only half of the children had stable hearing thresholds in repeated measurements. The time between the measurements was on average 5 months (0 to 31 months).

CONCLUSION

Hearing threshold changes are often seen in repeated ABR measurements. Therefore multiple measurements are necessary when ABR yields abnormal. Hearing threshold changes should be taken into account for hearing aid provision.

Gender and modulation frequency effects on auditory steady state response (ASSR) thresholds

For estimating behavioral hearing thresholds, auditory steady state response (ASSR) can be reliably evoked by stimuli at low and high modulation frequencies (MFs). In this regard, little is known regarding ASSR thresholds evoked by stimuli at different MFs in female and male participants. In fact, recent data suggest that 40-Hz ASSR is influenced by estrogen level in females. Hence, the aim of the present study was to determine the effect of gender and MF on ASSR thresholds in young adults. Twenty-eight normally hearing participants (14 males and 14 females) were enrolled in this study. For each subject, ASSR thresholds were recorded with narrow-band chirps at 500, 1,000, 2,000, and 4,000 Hz carrier frequencies (CFs) and at 40 and 90 Hz MFs. Two-way mixed ANOVA (with gender and MF as the factors) revealed no significant interaction effect between factors at all CFs (p > 0.05). The gender effect was only significant at 500 Hz CF (p < 0.05). At 500 and 1,000 Hz CFs, mean ASSR thresholds were significantly lower at 40 Hz MF than at 90 Hz MF (p < 0.05). Interestingly, at 2,000 and 4,000 Hz CFs, mean ASSR thresholds were significantly lower at 90 Hz MF than at 40 Hz MF (p < 0.05). The lower ASSR thresholds in females might be due to hormonal influence. When recording ASSR thresholds at low MF, we suggest the use of gender-specific normative data so that more valid comparisons can be made, particularly at 500 Hz CF.