Comparison of auditory steady-state responses and auditory brainstem responses in audiometric assessment of adults with sensorineural hearing loss

Audiological assessment using click auditory brainstem response and chirp auditory steady-state response in pediatric patients with congenital microtia under 36 months: A single-center experience

OBJECTIVE

To investigate the audiological characteristics of congenital microtia (CM), and explores the effectiveness of click auditory brainstem responses (c-ABR) and chirp auditory steady-state responses (chirp-ASSR) in assessing hearing loss in affected children.

METHODS

Audiological assessments were performed using c-ABR and chirp-ASSR in infants and toddlers under 36 months with CM who were unable to cooperate for behavioral testing. We used c-ABR to assess the nature of hearing loss. Spearman coefficients were used to evaluate correlations, and differences were assessed by subtracting c-ABR air conduction (AC) thresholds from chirp-ASSR AC thresholds. Additionally, differences were analyzed based on the external auditory canal status, auricle status, unilateral or bilateral CM.

RESULTS

The findings indicate that most CM patients experience conductive hearing loss (CHL, 90.36 %) and mixed hearing loss (MHL, 8.21 %), with a smaller number exhibiting normal (0.71 %) or sensorineural hearing loss (SNHL, 0.71 %). Across the entire sample, ABR thresholds showed the strongest correlation with ASSR thresholds at an average of 2-4 kHz (r = 0.723). Chirp-ASSR was found to be a complementary test to c-ABR for screening hearing loss in CM patients, particularly when behavioral testing is not feasible. Significant differences were found in patients with external auditory canal atresia and stenosis, as well as in those with different auricle statuses (Grade I + II, and Grade III).

CONCLUSION

The study supports the use of c-ABR and chirp-ASSR as valuable tools in the audiological assessment of congenital microtia, aiding in early diagnosis and appropriate intervention for hearing loss in pediatric patients.

Did You Hear That? Detecting Auditory Events with EEGNet

The behavioural nature of pure-tone audiometry (PTA) limits those who can participate in the test, and therefore those who can access accurate hearing threshold measurements. Event Related Potentials (ERPs) from brain signals has shown limited utility on adult subjects, and a neural response that can consistently be identified as a result of pure-tone auditory stimulus has yet to be identified. The in doing so challenge is worsened by the nature of PTA, where stimulus amplitude decrease to a patient's lower threshold of hearing. We investigate whether EEGNet, a compact Convolutional Neural Network, could help in this domain. We trained EEGNet on a dataset collected whilst patients underwent a test designed to mimic a pure-tone audiogram, then assessed EEGNet performance in the detection task. For comparison, we also trained Support Vector Machines (SVMs) and Common Spatial Patterns + Linear Discriminant Analysis (CSPLDA) on the same task, with the same training paradigms. The results show that EEGNet is capable of detecting hearing events with 81.5% accuracy on unseen participants, outperforming SVMs by just over 5%. Whilst EEGNet outperformed SVMs and CSPLDA, it did not, however, always show a statistically significant improvement. Further analysis of EEGNet predictions revealed that, with sufficient test repetition, EEGNet has the potential to accurately ascertain hearing thresholds. The implication of these results is for a brain-signal based hearing test for those with physical or mental disabilities that limit their participation in a PTA. While this research is promising, future research will be needed to address the complexity of test setup, the duration of testing, and to further improve accuracy.

Impact of Noise on Sound Processing at Lower Auditory System: An Electrophysiological Study

The importance of signal-to-noise ratio (SNR) is well documented in behavioral speech perception experiments and psychophysical measurements. Studies on ABR related to the encoding of signals in ipsilateral noise are very limited. The present study aimed to systematically investigate the effect of various SNRs on the latency and amplitude of ABR to a range of stimuli & to compare the latency and amplitude of ABR recorded in various ipsilateral SNRs in children and adults. We recorded auditory brain stem responses (ABR) in children and young adults for clicks, a speech token /da/ of 40 ms duration, and for a 1000 Hz tone burst in the presence of a broad band noise and quiet. There were four SNR conditions (+ 10 dB SNR, 0 dB SNR and -10 dB SNR), and the level of noise was varied, while the stimulus level was fixed at 60 dB HL. The results showed that SNR affects the latency and amplitude of the wave V peak differentially for the different stimuli. A difference in the performance of children and adults was also observed. SNR measurements using ABR provide an objective index of brainstem ability to process sound in the presence of background noise. This measure is important and can be used to assess the sound-in-noise processing ability in the difficult-to-test population such as infants and children where measures of signal-to-noise tests cannot be administered.

Prediction of hearing outcomes by auditory steady-state response in patients with sudden sensorineural hearing loss

BACKGROUND

There has been no report on the predictive value of auditory steady-state response (ASSR) in the hearing prognosis of sudden sensorineural hearing loss (SSNHL).

AIMS/OBJECTIVES

To investigate whether ASSR can be a prognostic indicator of hearing outcome in patients with SSNHL after systemic steroid treatment.

MATERIAL AND METHODS

Fifty-three patients with unilateral mild to severe SSNHL (≤90 dB HL at 0.5k, 1k, 2k, and 4 kHz, 4FA) were included. All patients received systemic high dose steroid therapy within one month after onset. The difference between the threshold levels measured by ASSR and PTA on the same day [ASSR - PTA] was calculated. The hearing recovery (HR) was defined as a < 30 dB HL of final degree of hearing loss and a > 15 dB HL of hearing gain.

RESULTS

The HR (+) group showed significantly worse ASSR predicted threshold than pure-tone threshold in univariate (t(51) = 2.412, p = .020) and multivariate analysis (OR 0.910, p = .012). The [ASSR - PTA] threshold showed significantly moderate correlation with hearing gain (r = -0.303, p = .028).

CONCLUSIONS

Worse ASSR predicted threshold than pure-tone threshold predicted poor hearing outcome after systemic steroid treatment in mild to severe unilateral SSNHL.

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.

Hearing threshold estimation by auditory steady state responses (ASSR) in children

Hearing threshold identification in very young children is always problematic and challenging. Electrophysiological testing such as auditory brainstem responses (ABR) is still considered the most reliable technique for defining the hearing threshold. However, over recent years there has been increasing evidence to support the role of auditory steady-state response (ASSR). Retrospective study. Forty-two children, age range 3-189 months, were evaluated for a total of 83 ears. All patients were affected by sensorineural hearing loss (thresholds ≥ 40 dB HL according to a click-ABR assessment). All patients underwent ABRs, ASSR and pure tone audiometry (PTA), with the latter performed according to the child’s mental and physical development. Subjects were divided into two groups: A and B. The latter performed all hearing investigations at the same time as they were older than subjects in group A, and it was then possible to achieve electrophysiological and PTA tests in close temporal sequence. There was no significant difference between the threshold levels identified at the frequencies tested (0.25, 0.5, 1, 2 and 4 kHz), by PTA, ABR and ASSR between the two groups (Mann Whitney U test, p < 0.05). Moreover, for group A, there was no significant difference between the ASSR and ABR thresholds when the children were very young and the PTA thresholds subsequently identified at a later stage. Our results show that ASSR can be considered an effective procedure and a reliable test, particularly when predicting hearing threshold in very young children at lower frequencies (including 0.5 kHz).

Effects of degree and symmetricity of bilateral spectral smearing, carrier frequency, and subject sex on amplitude of evoked auditory steady-state response signal

The characteristics of an auditory steady-state response (ASSR) signal can be affected by the pathophysiological statuses of the left and right ears, such as a smeared sensation by native spectral smearing owing to sensorineural hearing impairment, because they can affect the perception of the stimulus, the degree of concentration on the stimulus and comfort in concentration. However, to date, few studies have examined the effects of such smeared sensations on the amplitude of the evoked ASSR signal. In this study, we synthesized various auditory stimuli with different degrees of spectral smearing using a hearing loss simulator to match the age of participant groups with different degrees of spectral smearing. We then performed three subjective tests, representing symmetric and asymmetric bilateral spectral smearing, with 16 normal-hearing individuals to observe the effects of the severity and symmetricity of bilateral spectral smearing, the value of the carrier frequency of auditory stimuli, and the sex of the individual on the amplitude in evoked ASSR signals. The experimental results demonstrated the following: (1) the application of spectral smearing to normal sounds may result in amplitude-reduced ASSR signals, (2) the effect of spectral smearing on the amplitude of the ASSR signals is most significant when the degrees of bilateral spectral smearing are asymmetric, (3) the selection of carrier frequency in an auditory stimulus can affect the amplitude of evoked ASSR signals regardless of the degree of spectral smearing, and (4) the sex of the individual can affect the amplitude of the evoked ASSR signal in various test conditions. The results of this study can help estimate the effects of smeared sensation by spectral smearing owing to sensorineural hearing impairment on the amplitude of evoked ASSR signals.

Comparison of click auditory brainstem response and chirp auditory steady-state response thresholds in children

OBJECTIVES

During the last twenty years, auditory steady-state responses (ASSRs) are being used as an alternative and adjunct to the auditory brainstem response (ABR) for threshold estimation. This study aims at comparing and finding correlations between air-conduction thresholds using the traditional click ABR and the relatively recently used chirp ASSR test methods, for a large pediatric population.

METHODS

One hundred and thirty children referred to our Clinic from Hospitals and Clinics of Western Greece ranging in age from 5 to 79 months (mean age = 32.7 ± 14.0 months) participated prospectively.

RESULTS

Strong and statistically significant correlations were found between the average of the 1000, 2000 and 4000 Hz chirp ASSR thresholds and click ABR thresholds (r_s = .826, p < .001), and the average of the 2000 and 4000 Hz chirp ASSR and click ABR thresholds (r_s = .824, p < .001). Additionally, there have been measurements for some children with hearing loss in the severe-to-profound range during the ASSR test, but no ABR at the upper limits of the equipment. Click ABR and chirp ASSR thresholds averaged at 2000 and 4000 Hz were within 20 dB in 90% of the ears tested.

CONCLUSIONS

The results of this study support the inclusion of chirp ASSRs into the pediatric test battery and indicate that they may provide an essential adjunct to the click ABR, especially in the management of very young children with severe-to-profound hearing loss.

The maxillary nerve block for in-office hybrid balloon sinus dilation procedures: A preliminary study

Transitioning of rhinologic procedures from the operating room to the office setting in selected patients is a rising trend. An effective pain-control, patient-preparation protocol is essential, especially with advanced in-office rhinologic procedures such as hybrid balloon sinus dilation (BSD), in which other procedures such as ethmoidectomy, turbinate reduction, and other procedures are concomitantly performed. A regimen using oral sedation, topical tetracaine gel, topical tetracaine/epinephrine-soaked cottonoid packs, and intranasal local infiltrative anesthesia can vary significantly in effectiveness and be suboptimal at times (as determined by using treated patients as historical controls). A modification of this regimen was subsequently used, incorporating the maxillary nerve block, and qualitative differences were then assessed retrospectively between the two regimens. Twenty-five consecutive patients were retrospectively studied who underwent hybrid BSD procedures in the office setting using the maxillary nerve-block regimen modification. All patients underwent BSD of the sphenoid, frontal, and maxillary sinuses with anterior and partial posterior ethmoidectomies. Five patients also underwent septoplasty, and 18 patients underwent inferior turbinate reduction procedures. Twenty-four patients received oral sedation, and all patients received topical tetracaine/epinephrine-soaked cottonoid packs. The topical tetracaine gel was dropped after 5 patients because it was not felt to be needed anymore. No intranasal local infiltrative anesthesia was used. Several qualitative differences were observed after modifying the patient-preparation regimen incorporating the maxillary nerve block. The most important observation seen with this modification was a consistently reproducible, dense anesthesia coverage over the entire nasal cavity with good paranasal sinus coverage. This modification eliminated intranasal bleeding and swelling associated with intranasal local anesthetic injections. No complications were encountered. This preliminary study provides support for use and further evaluation of the maxillary nerve block for in-office rhinologic procedures. If the trend continues to rise in performing advanced in-office rhinologic procedures in selected patients, the maxillary nerve block may find a place in the patient-preparation protocol.

Threshold monitoring of intraoperative auditory steady-state responses for ossiculoplasty surgery

OBJECTIVE

The objective of this study is to establish a reliable intraoperative auditory threshold monitoring system for ossiculoplasty surgery.

DESIGN

The chirp signal of self-designed sound field earphone (SFE) was calibrated physically and psychophysically. The interaural attenuation of the SFE was tested in patients with unilateral complete deafness and contralateral normal hearing (10 patients). Self-designed SFEs were used to measure the chirp-evoked auditory steady-state responses (Chirp-ASSR) threshold of patients (14 cases and 15 ears) with conductive hearing loss after anesthesia but before surgery.

RESULTS

The response threshold of Chirp-ASSR under anesthesia displayed a strong correlation with the hearing threshold for pure tones: the Pearson coefficients at various frequencies (1, 2, and 4 kHz) were 0.56 (p = .03), 0.82 (p < .001), and 0.90 (p < .001), respectively, and the intragroup correlation coefficients were 0.70 (p = 0.02), 0.90 (p < 0.001), and 0.95 (p < 0.001), respectively. The average test time was 7.0 ± 0.7 min.

CONCLUSIONS

By combining Chirp-ASSR with self-designed SFE, we obtained objective multi-frequency intraoperative auditory thresholds that correlate well with the pure tone audiometry threshold. This reliable system can be applied to future intraoperative auditory threshold monitoring for ossiculoplasty surgery.

Effects of spectral smearing of stimuli on the performance of auditory steady-state response-based brain-computer interface

There have been few reports that investigated the effects of the degree and pattern of a spectral smearing of stimuli due to deteriorated hearing ability on the performance of auditory brain-computer interface (BCI) systems. In this study, we assumed that such spectral smearing of stimuli may affect the performance of an auditory steady-state response (ASSR)-based BCI system and performed subjective experiments using 10 normal-hearing subjects to verify this assumption. We constructed smearing-reflected stimuli using an 8-channel vocoder with moderate and severe hearing loss setups and, using these stimuli, performed subjective concentration tests with three symmetric and six asymmetric smearing patterns while recording electroencephalogram signals. Then, 56 ratio features were calculated from the recorded signals, and the accuracies of the BCI selections were calculated and compared. Experimental results demonstrated that (1) applying smearing-reflected stimuli decreases the performance of an ASSR-based auditory BCI system, and (2) such negative effects can be reduced by adjusting the feature settings of the BCI algorithm on the basis of results acquired a posteriori. These results imply that by fine-tuning the feature settings of the BCI algorithm according to the degree and pattern of hearing ability deterioration of the recipient, the clinical benefits of a BCI system can be improved.

Electrophysiological exploration of hearing

Electrophysiologic hearing tests have been developed since the 1960s to determine hearing thresholds objectively. They are now implemented in newborn hearing screening. While they determine thresholds, interpretation requires subjective pure-tone and speech audiometry to determine the type of hearing loss. Each examination tests a different anatomic region, enabling the auditory system to be explored from the organ of Corti to the auditory cortex. Thus, the various objective audiometric examinations are complementary.

Intra-operative hearing monitoring methods in middle ear surgeries

Hearing loss is a condition affecting millions of people worldwide. Conductive hearing loss (CHL) is mainly caused by middle ear diseases. The low frequency area is the pivotal part of speech frequencies and most frequently impaired in patients with CHL. Among various treatments of CHL, middle ear surgery is efficient to improve hearing. However, variable success rates and possible needs for prolonged revision surgery still frustrate both surgeons and patients. Nowadays, increasing numbers of researchers explore various methods to monitor the efficacy of ossicular reconstruction intraoperatively, including electrocochleography (ECochG), auditory brainstem response (ABR), auditory steady state response (ASSR), distortion product otoacoustic emissions (DPOAE), subjective whisper test, and optical coherence tomography (OCT). Here, we illustrate several methods used clinically by reviewing the literature.

Evaluation of noise-induced hearing loss by auditory steady-state and auditory brainstem-evoked responses

OBJECTIVES

Noise-induced hearing loss (NIHL) may result from occupational noise exposures and is considered as an 'Occupational Disease'; therefore, it is compensable. To verify the existence and severity of the work-related hearing loss, there is a need of an objective, reliable auditory measure in cases of arbitration of financial disputes to resolve any medicolegal aspects. The objective of the study was to compare between the ABR and ASSR for predicting the behavioural threshold in subjects with normal hearing or NIHL.

DESIGN

The study included 82 subjects regularly exposed to high levels of occupational noise, with normal hearing and NIHL. ABR to clicks and to tone bursts were recorded followed by multiple-frequency ASSR. Physiological and behavioural thresholds were compared for specific frequencies (1000, 2000 Hz) and average of high-frequency range (2000 and 4000 Hz). In addition, Pearson correlations and the specificity and sensitivity of each measure were also calculated using receiver operating characteristic (ROC) curves.

RESULTS

In the NIHL group, there was a significantly smaller difference between the behavioural threshold and click-ABR than the ASSR in high-frequency range. Pearson correlations were significantly higher for click-ABR. Analysis of specific frequencies yielded a smaller difference between behavioural and ASSR than tone-burst-ABR thresholds, with a slightly better correlation for ASSR than tone-burst-ABR. Higher sensitivity but lower specificity was suggested for ASSR than ABR.

CONCLUSIONS

ASSR is associated with high-frequency specificity, shorter test sessions and good correlations with behavioural thresholds, making it a potentially better measure than ABR for predicting audiograms in subjects with NIHL. These findings have diagnostic implications, especially in cases of workers' compensation when subjects may be uncooperative.

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.

Age-related changes in the relationship between auditory brainstem responses and envelope-following responses

Hearing thresholds and wave amplitudes measured using auditory brainstem responses (ABRs) to brief sounds are the predominantly used clinical measures to objectively assess auditory function. However, frequency-following responses (FFRs) to tonal carriers and to the modulation envelope (envelope-following responses or EFRs) to longer and spectro-temporally modulated stimuli are rapidly gaining prominence as a measure of complex sound processing in the brainstem and midbrain. In spite of numerous studies reporting changes in hearing thresholds, ABR wave amplitudes, and the FFRs and EFRs under neurodegenerative conditions, including aging, the relationships between these metrics are not clearly understood. In this study, the relationships between ABR thresholds, ABR wave amplitudes, and EFRs are explored in a rodent model of aging. ABRs to broadband click stimuli and EFRs to sinusoidally amplitude-modulated noise carriers were measured in young (3-6 months) and aged (22-25 months) Fischer-344 rats. ABR thresholds and amplitudes of the different waves as well as phase-locking amplitudes of EFRs were calculated. Age-related differences were observed in all these measures, primarily as increases in ABR thresholds and decreases in ABR wave amplitudes and EFR phase-locking capacity. There were no observed correlations between the ABR thresholds and the ABR wave amplitudes. Significant correlations between the EFR amplitudes and ABR wave amplitudes were observed across a range of modulation frequencies in the young. However, no such significant correlations were found in the aged. The aged click ABR amplitudes were found to be lower than would be predicted using a linear regression model of the young, suggesting altered gain mechanisms in the relationship between ABRs and FFRs with age. These results suggest that ABR thresholds, ABR wave amplitudes, and EFRs measure complementary aspects of overlapping neurophysiological processes and the relationships between these measurements changes asymmetrically with age. Hence, measuring all three metrics provides a more complete assessment of auditory function, especially under pathological conditions like aging.

Refining the audiological assessment in children using narrow-band CE-Chirp-evoked auditory steady state responses

OBJECTIVE

To demonstrate the feasibility and reliability of simultaneous binaural recording of auditory steady-state responses (ASSR) in young children using narrow-band CE-Chirps as stimuli.

DESIGN

Prospective cohort study comparing ASSR thresholds to four frequency stimuli (0.5, 1, 2, and 4 kHz), with click-evoked auditory brainstem responses (ABR) and behavioral response audiometry.

STUDY SAMPLE

Thirty-two young children (mean age 7.4 ± 5.2 months) referred for auditory assessment were evaluated.

RESULTS

The mean duration for ABR recordings was 13.3 ± 7.2 min versus 22.9 ± 15.8 min for ASSR (p < 0.01). ASSR (means of 2 and 4 kHz thresholds) were highly correlated with ABR thresholds (R2 = 0.935, p < 0.001), though significantly different (3 ± 10.7 dB, p = 0.02). ASSR (means of 0.5, 1, 2, and 4 kHz thresholds) were highly correlated with mean behavioral response audiometry thresholds (R2 = 0.968, p < 0.001). ASSRs were highly and significantly correlated with behavioral response audiometry at 0.5, 1, 2, and 4 kHz (R2 = 0.845, 0.907, 0.929, and 0.859 respectively, p < 0.001). 87.5% and 90.7% ASSR thresholds were within a ± 10 dB range around their corresponding ABR and mean behavioral response audiometry thresholds.

CONCLUSIONS

Narrow-band CE-Chirps allow a fast and reliable assessment of auditory thresholds in children, especially in the low-frequency range, by comparison with other stimuli.

The auditory brainstem responses in patients with unilateral cochlear hearing loss

The aim of our study is to analyze changes occurring in the auditory brainstem response (ABR) according to stimulus parameters in unilateral cochlear hearing loss cases. Twenty-nine cases (14 male, 15 female) with unilateral sensorineural hearing loss (SNHL) were investigated. All cases had cochlear SNHL on one side whereas normal hearing on the other side. All cases underwent ABR testing with varying stimulus intensity levels and stimulus repetition rates (SRRs). Results were compared and their correlation with audiogram shapes investigated. As stimulus intensity levels decreased on both ears, latencies expanded and amplitudes decreased in all traces of ABR. Latencies of ears with cochlear hearing loss were observed to be longer than those in normal ears. Responses to SRR increases were similar on both ears. Audiogram shapes should be taken into consideration while performing ABR in order to address asymmetric SNHL. The interpretation of ABR changes with various stimulus levels may provide a better understanding of cochlear pathologies associated with hearing loss in the future.

Hearing threshold estimation by auditory steady-state responses with narrow-band chirps and adaptive stimulus patterns: implementation in clinical routine

Objective hearing threshold estimation by auditory steady-state responses (ASSR) can be accelerated by the use of narrow-band chirps and adaptive stimulus patterns. This modification has been examined in only a few clinical studies. In this study, clinical data is validated and extended, and the applicability of the method in audiological diagnostics routine is examined. In 60 patients (normal hearing and hearing impaired), ASSR and pure tone audiometry (PTA) thresholds were compared. ASSR were evoked by binaural multi-frequent narrow-band chirps with adaptive stimulus patterns. The precision and required testing time for hearing threshold estimation were determined. The average differences between ASSR and PTA thresholds were 18, 12, 17 and 19 dB for normal hearing (PTA ≤ 20 dB) and 5, 9, 9 and 11 dB for hearing impaired (PTA > 20 dB) at the frequencies of 500, 1,000, 2,000 and 4,000 Hz, respectively, and the differences were significant in all frequencies with the exception of 1 kHz. Correlation coefficients between ASSR and PTA thresholds were 0.36, 0.47, 0.54 and 0.51 for normal hearing and 0.73, 0.74, 0.72 and 0.71 for hearing impaired at 500, 1,000, 2,000 and 4,000 Hz, respectively. Mean ASSR testing time was 33 ± 8 min. In conclusion, auditory steady-state responses with narrow-band-chirps and adaptive stimulus patterns is an efficient method for objective frequency-specific hearing threshold estimation. Precision of threshold estimation is most limited for slighter hearing loss at 500 Hz. The required testing time is acceptable for the application in everyday clinical routine.

Prognostic validity of dichotic multiple frequencies auditory steady-state responses versus distortion product otoacoustic emissions in hearing screening of high risk neonates

OBJECTIVE

To determine the validity of dichotic multiple frequencies auditory steady-state responses (ASSR) as a hearing screening technique versus using distortion product otoacoustic emissions (DPOAEs) among high-risk neonates.

METHODS

A cross sectional study was performed on 118 high-risk neonates by means of dichotic multiple frequencies ASSR and DPOAE for hearing screening. DPOAE results were used as the standard for hearing screening in parallel with ASSR. Dichotic multiple frequencies ASSR results were analyzed by means of F-value of less or greater than 0.05 criteria as a pass-fail for the responses. Dichotic multiple ASSR hearing screening technique was considered in two intensity levels at 40 and 70 dB HL. The ASSRs thresholds were measured in high risk neonates with and without hearing deficits as determined by DPOAES. The results of ASSR and DPOAE were compared to be gathered by contingency table in order to obtain sensitivity, specificity and other different statistical values. Average performing times for the tests were analyzed.

RESULTS

The specificity of dichotic multiple ASSR was 92.6%, 93.8% and the sensitivity was 71.6%, 62.2% at the 70 and 40 dB hearing levels, respectively. Mean ASSR thresholds for normal-hearing infants at an average corrected age of 6 days were 32.2 ± 12.2, 29.8 ± 10.2, 26.2 ± 11.4 and 30.4 ± 10.8 dB HL for 0.5, 1, 2 and 4 kHz, respectively. The average times for performing the tests were 18.7 and 32.9 min respectively.

CONCLUSIONS

ASSR with this special paradigm is a fairly desirable method for hearing screening of high-risk neonates. There is good concordance between ASSRs and DOPAEs results among high risk neonates referred for hearing screening. The sensitivity and specificity of this test is sufficient for hearing screening in high risk neonates. This test could be valuable for rapid confirmation of normal thresholds. As long as further research have not been conducted on ASSR, great caution should be made to interpret the results of ASSR as a hearing screening technique in young infants and also additional techniques such as the tone-evoked ABRs should be used to cross-check results. It's still too soon to recommend ASSRs as a standalone electrophysiologic measure of hearing thresholds in infants.

Using multi-stimulus auditory steady state response to predict hearing thresholds in high-risk infants

The purpose of this study was to investigate whether multi-stimulus auditory steady-state responses were capable of estimating hearing thresholds in high-risk infants. A retrospective chart review study. Three tertiary referral centers. Infants born between January 2004 and December 2006 who met the criteria for risk factors of congenital hearing loss were enrolled in the study. While under sedation, the multi-stimulus auditory steady-state response was used to determine multi-channel auditory steady-state response thresholds for high-risk infants younger than 13 months. Conditioned play audiometry was then applied to these children at 23-48 months of age to obtain pure tone audiograms. Auditory steady-state response thresholds and pure tone thresholds were then compared. A total of 249 high-risk infants were enrolled in the study. 39 infants were lost during follow-up. The remaining 216 infants completed both examinations. The Pearson correlation coefficients (r) between the ASSR levels and pure tone thresholds were 0.88, 0.94, 0.94 and 0.97 at 500, 1,000, 2,000 and 4,000 Hz, respectively. The strength of the relationship between the auditory steady-state responses and pure tone thresholds increased with more severe degrees of hearing loss and higher frequencies. We conclude that initial multichannel ASSR thresholds measured under sedation are highly correlated with pure tone thresholds obtained 2 or 3 years later. ASSR can be used to predict the frequency-specific hearing thresholds of high-risk infants and can provide information for early hearing intervention.

Comparison between auditory steady-state responses and pure-tone audiometry

BACKGROUND/AIM

A more recent method, the auditory steady-state response (ASSR), has become more and more important test method due to difference that was found in previous investigations between hearing thresholds determined by the ASSR and the pure-tone audiometry (PTA). The aim of this study was to evaluate the reliability of the ASSR in determining the frequency specific hearing thresholds by establishing a correlation between the thresholds determined by PTA, as well as to evaluate the reliability of ASSR in determining the hearing threshold with respect to the level of hearing loss and the configuration of the PTA findings.

METHODS

The prospective study included 46 subjects (92 ears) which were assigned to groups based on their level of hearing loss and audiometric configuration. All the subjects underwent determination of hearing thresholds by PTA and ASSR without insight into their previously obtained PTA results.

RESULTS

The overall sample differences between the ASSR and PTA thresholds were 4.1, 2.5, 4.4, and 4.2 dB at 0.5, 1, 2, and 4 kHz, respectively. A high level of correlation was achieved in groups with different configurations of PTA findings. The correlation coefficients between the hearing thresholds determined by ASSR and PTA were significant in subjects with all levels of hearing loss. The differences between hearing thresholds determined by ASSR and PTA were less than 10 dB in 85% of subjects (ranging from 4 dB for moderately severe hearing loss to 7.2 dB for normal hearing).

CONCLUSION

The ASSR is an excellent complementary method for the determination of hearing thresholds at the 4 carrier frequencies, as well as determination of the level of hearing loss and the audiometric configuration.