Mean Auditory Steady-state Responses Thresholds Research Articles

Measurement of Thresholds Using Auditory Steady-State Response and Cochlear Microphonics in Children with Auditory Neuropathy.

The detection of precise hearing thresholds in infants and children with auditory neuropathy (AN) is challenging with current objective methods, especially in those younger than six months of age. The aim of this study was to compare the thresholds using auditory steady-state response (ASSR) and cochlear microphonics (CM) in children with AN and children with normal hearing. The thresholds of CM, ASSR, and visual reinforcement audiometry (VRA) tests were recorded; the ASSR and VRA frequencies used were 250, 500, 1000, 2000, and 4000 Hz. The participants in this study were 15 children with AN (27 ears) (1-7.6 years, median age 4.1 years) and ten children with normal hearing (20 ears) (1-8 years, median age four years). The thresholds of the three methods were compared, and histograms were used to represent frequency distributions of threshold differences obtained from the three methods. In children with normal hearing, the average CM thresholds (84.5 dB) were significantly higher than the VRA thresholds (10.0-10.8 dB); in children with AN, both CM and VRA responses were seen at high signal levels (88.9 dB and 70.6-103.4 dB, respectively). In normal children, the difference between mean VRA and ASSR thresholds ranged from 17.5 to 30.3 dB, which was significantly smaller than the difference seen between the mean CM and VRA thresholds (71.5-72.3 dB). The correlation between VRA and ASSR in children with normal hearing ranged from 0.38 to 0.48, whereas no such correlation was seen in children with AN at any frequency (0.03-0.19). Our results indicated that ASSR and CM were poor predictors of the conventional behavioral threshold in children with AN.

Comparison of frequency-Specific hearing thresholds between pure-tone audiometry and auditory steady-state response

Introduction: Hearing assessment in difficult to assess persons gives inconsistent response in free field hearing and pure-tone audiometry (PTA). We have been performing brainstem evoked response audiometry (BERA) as an objective assessment in such cases. BERA has limitations that it is not frequency specific, measures thresholds in higher frequencies only, signal intensity levels cannot be higher than 90 dB and presents the data in waveform which needs to be interpreted by experienced audiologist to deduce correct information. All these limitations can be negated with use of auditory steady-state response (ASSR) which can present intensity levels till 120 dB, is frequency specific, even for lower frequencies and has automated response and deduction analysis. The aim of our study was to compare pure-tone thresholds with ASSR thresholds in normal hearing and hearing loss subjects with an objective to validate the ASSR as a tool for objective hearing assessment. Materials and Methods: In this prospective cross-sectional study of 70 adults (n = 140 ears) of both genders, with and without hearing complaints, Group 1 consisted of 24 individuals of normal hearing, Group 2 consisted of 25 individuals of sensorineural hearing loss, and 21 individuals with conductive hearing loss in Group 3. The patients were evaluated with PTA and ASSR test. The mean pure tone and ASSR thresholds for each frequency were calculated and analyzed using the SPSS IBM software. Results: The mean difference of ASSR with PTA was noted at 9.92 dB in the right ear and 10 dB in the left ear. A high significant correlation was noted between ASSR and PTA with P(0.0005) across all the three groups. The relationship between the PTA and ASSR measurement for measuring average hearing threshold levels is described by the equation: PTA = ASSR mean × 0.99–9.92. Conclusion: ASSR is an excellent tool to predict accurate level of frequency-specific hearing threshold. It has constant relationship with pure tone thresholds. ASSR can predict true hearing thresholds in “difficult to assess” patients such as children and malingerers. This can also be used in the prediction of disability assessment objectively.

Mode of recording and modulation frequency effects of auditory steady state response thresholds

IntroductionThe performance of auditory steady state response (ASSR) in threshold testing when recorded ipsilaterally and contralaterally, as well as at low and high modulation frequencies (MFs), has not been systematically studied. ObjectiveTo verify the influences of mode of recording (ipsilateral vs. contralateral) and modulation frequency (40Hz vs. 90Hz) on ASSR thresholds. MethodsFifteen female and 14 male subjects (aged 18–30 years) with normal hearing bilaterally were studied. Narrow-band CE-chirp® stimuli (centerd at 500, 1000, 2000, and 4000Hz) modulated at 40 and 90Hz MFs were presented to the participants’ right ear. The ASSR thresholds were then recorded at each test frequency in both ipsilateral and contralateral channels. ResultsDue to pronounced interaction effects between mode of recording and MF (p<0.05 by two-way repeated measures ANOVA), mean ASSR thresholds were then compared among four conditions (ipsi-40Hz, ipsi-90Hz, contra-40Hz, and contra-90Hz) using one-way repeated measures ANOVA. At the 500 and 1000Hz test frequencies, contra-40Hz condition produced the lowest mean ASSR thresholds. In contrast, at high frequencies (2000 and 4000Hz), ipsi-90Hz condition revealed the lowest mean ASSR thresholds. At most test frequencies, contra-90Hz produced the highest mean ASSR thresholds. ConclusionsBased on the findings, the present study recommends two different protocols for an optimum threshold testing with ASSR, at least when testing young adults. This includes the use of contra-40Hz recording mode due to its promising performance in hearing threshold estimation.

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.

Relationship between behavioral hearing thresholds and estimated auditory steady-state response thresholds in children with a history of neonatal hyperbilirubinemia

Increased serum bilirubin levels during infancy increase the risk of hearing loss in infants. This study aimed to investigate the relationship between pure-tone audiometry hearing thresholds and thresholds estimated using auditory steady-state responses (ASSRs) in children with a history of neonatal hyperbilirubinemia, and to evaluate the usefulness of 90-Hz ASSR in estimating hearing thresholds in children. This study was conducted on 26 children (13 girls and 13 boys) who were aged 2.4-11 years and had a history of neonatal hyperbilirubinemia (bilirubin level >17 mg/dL). ASSR thresholds were compared with behavioral thresholds and were interpreted after considering the amount and type of hearing loss. Of the 26 children, 12 had normal hearing thresholds, and 14 had varying degrees of sensorineural hearing loss. In general, a high correlation (r ≥ 0.81, p < 0.01) was found between the ASSR and behavioral thresholds. The highest correlation was observed at 2,000 Hz (r = 0.88, p < 0.01). No significant difference was observed (p > 0.13) between mean behavioral and ASSR thresholds at 52 studied ears. The results of this study showed that 90-Hz ASSR assessments provide reliable estimates of behavioral hearing thresholds in children who have a history of neonatal hyperbilirubinemia and sensorineural hearing loss or normal hearing.

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.

California sea lion (Zalophus californianus) aerial hearing sensitivity measured using auditory steady-state response and psychophysical methods

Although electrophysiological methods of measuring the hearing sensitivity of pinnipeds are not yet as refined as those for dolphins and porpoises, they appear to be a promising supplement to traditional psychophysical procedures. In order to further standardize electrophysiological methods with pinnipeds, a within-subject comparison of psychophysical and auditory steady-state response (ASSR) measures of aerial hearing sensitivity was conducted with a 1.5-yr-old California sea lion. The psychophysical audiogram was similar to those previously reported for otariids, with a U-shape, and thresholds near 10 dB re 20 μPa at 8 and 16 kHz. ASSR thresholds measured using both single and multiple simultaneous amplitude-modulated tones closely reproduced the psychophysical audiogram, although the mean ASSR thresholds were elevated relative to psychophysical thresholds. Differences between psychophysical and ASSR thresholds were greatest at the low- and high-frequency ends of the audiogram. Thresholds measured using the multiple ASSR method were not different from those measured using the single ASSR method. The multiple ASSR method was more rapid than the single ASSR method, and allowed for threshold measurements at seven frequencies in less than 20 min. The multiple ASSR method may be especially advantageous for hearing sensitivity measurements with otariid subjects that are untrained for psychophysical procedures.

Auditory steady-state responses in babies with normal hearing and with temporary conductive hearing loss

AbstractObjectives: To investigate whether test age and middle ear dysfunction had a significant effect on the variability of Auditory Steady-State Response (ASSR) thresholds when this test was undertaken on referrals from the newborn hearing screen. Methods: ASSR thresholds were measured at octave intervals from 500 Hz to 4000 Hz. They were recorded in 389 ears with normal hearing and middle ear function, and in a further 189 ears with temporary middle ear dysfunction. The modal corrected age at which the tests were undertaken was four weeks, with a minimum of one week and maximum corrected age of 26 weeks. Results: The mean ASSR thresholds of those with normal hearing were 47dB HL at 500 Hz, 36dB HL at 1000 Hz, and 34dB HL at both 2000 Hz and 4000 Hz. Standard deviations (SDs) from the mean ranged from 7.7 to 9.9dB. For those with middle ear dysfunction the mean ASSR thresholds were significantly greater at each frequency, with thresholds of 65dB HL at 500 Hz, 55dB HL at 1000 Hz, 53dB HL at 2000 Hz and ...

Auditory steady-state response and auditory brainstem response thresholds in children

The inclusion of the auditory steady-state response (ASSR) into test-batteries for objective audiometry has allowed for clinical comparisons with the most widely used procedure, the auditory brainstem response (ABR). The current study describes ASSR and ABR thresholds for a group of infants and young children with various types and degrees of hearing loss. A sample of 48 subjects (23 female) with a mean age of 2.8+/-1.9 years SD were assessed with a comprehensive test-battery and classified according to type and degree of hearing loss. Thresholds were determined with a broadband click-evoked ABR and single frequency ASSR evoked with continuous tones (0.25-4 kHz) amplitude modulated (67-95 Hz). Mean difference scores (+/-SD) between the ABR and high frequency ASSR thresholds were 9.8 (+/-11), 3.6 (+/-12) and 10.5 (+/-12) dB at 1, 2 and 4 kHz, respectively. An ASSR mean threshold for 2-4 and 1-4 kHz compared to the ABR threshold revealed an average difference of 7 (+/-9) and 7.9 (+/-8) dB, respectively. The overall correlation between the ABR and ASSR thresholds was highest for the mean ASSR thresholds of 2-4 and 1-4 kHz (r=0.92 for both conditions). Correlations between the ABR and individual ASSR frequencies were slightly less (0.82-0.86). The average of the 2-4 kHz ASSR thresholds correlated best with the click-evoked ABR for all categories of hearing loss except for the sensorineural hearing loss category for which the 1-4 kHz ASSR average was better correlated to ABR thresholds. Findings demonstrate the reliability of verifying high frequency ASSR thresholds with a click-evoked ABR as an important cross-check in infants for whom behavioural audiometry may not be possible.

Clinical Comparison of the Auditory Steady-State Response with the Click Auditory Brainstem Response in Infants

ObjectivesOur goal was to determine the effectiveness of using the auditory steady state response (ASSR) as a measure of hearing thresholds in infants who are suspected of having significant hearing loss, as compared with using the click-auditory brainstem response (C-ABR).MethodsWe retrospectively analyzed the audiologic profiles of 76 infants (46 boys and 30 girls, a total of 151 ears) who ranged in age from 1 to 12 months (average age: 5.7 months). The auditory evaluations in 76 infants who were suspected of having hearing loss were done via the C-ABR and ASSR. In addition, for reference, the mean ASSR thresholds were compared to those of 39 ears of infants and 39 ears of adults with normal hearing at 0.5, 1, 2, and 4 kHz.ResultsThe highest correlation between the C-ABR and ASSR thresholds was observed at an average of 2-4 kHz (r=0.94). On comparison between the hearing of infants and adults at 0.5, 1, 2, and 4 kHz, the mean ASSR threshold in infants was 12, 7, 8, and 7 dB higher, respectively, than that in adults.ConclusionASSR testing may provide additional audiometric information for accurately predicting the hearing sensitivity, and this is essential for the management of infants with severe to profound hearing loss.

Effects of Ambient Acoustic Noise on the Auditory Steady-State Response Thresholds in Normally Hearing Adults

The effect of noise on auditory steady-state response (ASSR) has not been systematically studied, despite the fact that ASSR thresholds are sometimes measured in noisy environments. This study examined the effects of noise (speech babble) on the ASSR thresholds obtained from 31 normal hearing adults aged from 17 to 36 years (mean = 25 years). The ASSR thresholds at 0.5, 1, 2 and 4 kHz were measured in the right ear only using the Biologic MASTER system twice in quiet and in the presence of 55 dB A and 75 dB A of speech babble. The results showed no change in mean ASSR thresholds across the test-retest conditions in quiet. The mean ASSR thresholds obtained in the quiet conditions were 23.8, 22.5, 18.2 and 20.4 dB HL at 0.5, 1, 2 and 4 kHz, respectively. No significant shift in ASSR thresholds across all test frequencies was found when 55 dB A of speech babble was presented. However, when 75 dB A of noise was applied, the mean ASSR thresholds were significantly shifted by 9.5, 3.8, 4.2 and 5.8 dB at 0.5, 1, 2 and 4 kHz, respectively.

Clinical Application of Dichotic Multiple-Stimulus Auditory Steady-State Responses in High-Risk Newborns and Young Children

Experience with dichotic multiple-stimulus auditory steady-state responses (ASSRs) in clinical practice is described. ASSR thresholds were assessed in a sample of 60 high-risk newborns and young children between birth and 4 years of age. Amplitudes and signal-to-noise ratios (SNRs) of the ASSR were compared between normal-hearing infants and adults. Age-related changes within a group of infants younger than 3 months of age were investigated. A comparison was made between ASSR, the click-evoked auditory brainstem response and behavioral hearing thresholds in infants with a wide range of hearing threshold levels. Mean ASSR thresholds for normal-hearing infants at an average corrected age of 12 days were 42 ± 10, 35 ± 10, 32 ± 10 and 36 ± 9 dB SPL for 0.5, 1, 2 and 4 kHz, respectively. Compared to adults, these thresholds were elevated by on average 11 dB and SNRs were 1.7 times smaller. However, based on ASSRs, reasonably accurate estimations could be made of behavioral hearing thresholds obtained at a later age (median delay of 7 months). The predicted thresholds were in 61% of the cases within 10 dB of the corresponding behavioral thresholds, and in 83% of the cases within 15 dB. In less than 1 h, thresholds at four frequencies per ear could be obtained. The optimal age of testing is between 1 week and 3 months corrected age. The dichotic multiple-stimulus ASSR technique is a valuable extension of the clinical test battery for hearing-impaired children, as a follow-up diagnostic after the neonatal hearing screening.

Multiple auditory steady-state response (ASSR) thresholds to bone-conduction stimuli in young infants with normal hearing

Bone-conduction ASSR thresholds (carrier frequencies: 500–4000 Hz; 77–101-Hz modulation rates; amplitude/frequency modulated; single-polarity stimulus) were obtained in two infant groups (N=29 pre-term, tested in NICU; N=14 0-to-8 months of age, tested in soundbooth). Mean (1SD) ASSR thresholds were 16 (11), 16 (10), 37 (10), and 33 (13) dBHL in pre-term infants and 14 (13), 2 (7), 26 (6), and 22 (8) dBHL in older infants at 500, 1000, 2000, and 4000 Hz, respectively. Both infant groups had significantly better thresholds for 500 and 1000 Hz compared to 2000 and 4000 Hz, in contrast to adults who have similar thresholds across frequency (22, 26, 18, and 18 dBHL) [Small and Stapells, J. Am. Acad. Audiol (in press)]. When 500- and 1000-Hz thresholds were pooled, NICU infants and 0–8-month-old infants tended to have better low-frequency thresholds than adults. When 2000- and 4000-Hz thresholds were pooled, NICU and 0–8 month-old infants tended to have poorer thresholds than adults. Overall, these results suggest that low-frequency bone-conduction thresholds worsen and high-frequency bone-conduction thresholds improve with maturation. [Work supported by CIHR and NSERC Canada.]