40-Hz multiple auditory steady-state responses to narrow-band chirps in sedated and anaesthetized infants

The purpose of this study was to evaluate the accuracy with which auditory steady-state response (ASSR) and tone burst auditory brain stem response (ABR) thresholds predict behavioral thresholds, using a within-subjects design. Because the spectra of the stimuli used to evoke the ABR and the ASSR differ, it was hypothesized that the predictive accuracy also would differ, particularly in subjects with steeply sloping hearing losses. ASSR and ABR thresholds were recorded in a group of 14 adults with normal hearing, 10 adults with flat, sensorineural hearing losses, and 10 adults with steeply sloping, high-frequency, sensorineural hearing losses. Evoked-potential thresholds were recorded at 1, 1.5, and 2 kHz and were compared with behavioral, pure-tone thresholds. The predictive accuracy of two ABR protocols was evaluated: Blackman-gated tone bursts and linear-gated tone bursts presented in a background of notched noise. Two ASSR stimulation protocols also were evaluated: 100% amplitude-modulated (AM) sinusoids and 100% AM plus 25% frequency-modulated (FM) sinusoids. The results suggested there was no difference in the accuracy with which either ABR protocol predicted behavioral threshold, nor was there any difference in the predictive accuracy of the two ASSR protocols. On average, ABR thresholds were recorded 3 dB closer to behavioral threshold than ASSR thresholds. However, in the subjects with the most steeply sloping hearing losses, ABR thresholds were recorded as much as 25 dB below behavioral threshold, whereas ASSR thresholds were never recorded more than 5 dB below behavioral threshold, which may reflect more spread of excitation for the ABR than for the ASSR. In contrast, the ASSR overestimated behavioral threshold in two subjects with normal hearing, where the ABR provided a more accurate prediction of behavioral threshold. Both the ABR and the ASSR provided reasonably accurate predictions of behavioral threshold across the three subject groups. There was no evidence that the predictive accuracy of the ABR evoked using Blackman-gated tone bursts differed from the predictive accuracy observed when linear-gated tone bursts were presented in conjunction with notched noise. Similarly, there was no evidence that the predictive accuracy of the AM ASSR differed from the AM/FM ASSR. In general, ABR thresholds were recorded at levels closer to behavioral threshold than the ASSR. For certain individuals with steeply sloping hearing losses, the ASSR may be a more accurate predictor of behavioral thresholds; however, the ABR may be a more appropriate choice when predicting behavioral thresholds in a population where the incidence of normal hearing is expected to be high.

Background Verification of the hearing level in the malinger workers is a long-standing problem. Otolaryngologists and audiologists are often called upon to evaluate the auditory thresholds of workers who file claims for compensation as a result of noise-induced hearing loss. Although objective diagnostic methods tend to dominate modern medical science, behavioral pure-tone audiometry (PTA) remains the golden standard for identifying hearing threshold levels. A number of auditory-evoked potential techniques have been implemented for this purpose over the past three decades. The most widely used of these techniques has been the auditory brainstem response (ABR) and more recently another auditory-evoked potential, the auditory steady-state response (ASSR). We also used old techniques such as postauricular myogenic potential and late cortical-evoked potential P100 as an alternative technique for objective audiometry. Rationale Integration of different objective hearing tests is deficient in the literature on high-risk adult population. Objectives To implement an objective protocol for assessing hearing in adult patients and for those difficult to test by routine PTA in Suez Canal Authority. Materials and methods This study was designed as a case–control study to collect and analyze data from September 2012 to be finished on June 2014. Sixty adult patients divided into two groups: those suffering from normal hearing and those suffering from sensorineural hearing loss. All patients in this research were submitted to the following: full history taking and otologic examination; basic audiological evaluations (PTA, speech audiometry and immittacemetry); tone burst ABR recorded using 500, 1000, 2000, and 4000 Hz stimulus; and ASSR stimulus using carrier frequencies 500, 1000, 2000, and 4000 Hz; postauricular myogenic potential response using 1000 and 4000 Hz; and late cortical-evoked potential P100 using 1000, 2000, and 4000 Hz. Results In the normal hearing group, ASSR and ABR thresholds are closer to PTA thresholds than posterior auricular muscle (PAM) thresholds, the difference decrease with increasing frequency being closer at 4000 Hz than 500 Hz results. In the study group ASSR and ABR thresholds are approximated to PTA thresholds but still the ASSR thresholds are closer to PTA thresholds than ABR thresholds and PAM threshold but much higher in the case of P100. In the study group, ABR and ASSR thresholds show the best level of prediction of PTA thresholds. We found that the mean difference between all test and pure-tone thresholds had a tendency to be smaller with increasing frequency in both groups. However, the mean difference in the study group was statistically significantly lower than the control group. There are statistically significant positive correlation between PTA threshold and both ABR and ASSR threshold at all frequencies. A statistically significant correlation was found only at 1000 Hz in PAM test and a statistically significant correlation was found only at 1000 and 2000 Hz in P100 test. Conclusion ASSR is more accurate at higher frequencies, making ASSR more suitable in accessing auditory thresholds in patients with noise-induced hearing loss.

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.

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.

Auditory Steady-State Responses (ASSR) and transient auditory brainstem responses: evaluation and comparison of hearing thresholds based on mouse models of sensorineural hearing loss. The present study compares two objective hearing tests in normal hearing and hearing impaired mice to differentiate the underlying pathomechanisms of sensorineural hearing loss (SNHL). SNHL is caused by diverse pathologies of the inner ear or the auditory nerve. Up to date a clear correlation between the different phenotypes of hearing loss and specific defects has not been established. Based on two defined mouse models of SNHL (Bassoon and KCNQ4) we evaluated the practicability of Auditory Steady-State Responses (ASSR). Initially ASSR recordings were for the first time established and described in normal hearing animals. Within three ranges of modulation frequencies (below 200 Hz, between 200-600 Hz and beyond 600 Hz) ASSR in mice could be generated with steady results. ASSR thresholds were compared to the thresholds of the Auditory Brainstem Response (ABR). The subjective-visually and objective-statistically acquired ASSR thresholds did both not differ from the corresponding ABR thresholds. In the following part of the study ASSR- and ABR recordings were recorded in the SNHL mouse model. Animals bearing defects of the outer hair cells amplifier system (KCNQ4 KO) and animals with a defect of the inner hair cell synaptic transmission (Bassoon mutant) were investigated. The ASSR thresholds were comparable to the ABR thresholds in both groups. Both mutants showed an increase of ASSR- and ABR threshold of approximately 40 dB SPL compared to normal hearing animals of the same age. Animals with a defect of the amplifier system displayed a steep rise of the ASSR- and ABR amplitudes (with increasing sound intensity) near the auditory threshold. This recruitment phenomenon reflects probably a strong activation of synchronized neuronal activity beyond the auditory threshold. In contrast the amplitudes of the ASSR and ABR responses of mice with impaired synaptic transmission augmented very little with increasing sound intensity, which reflects the disturbed signal transmission at the ribbon deficient synapses. In summary ASSR, as an established electrophysiological method, allow a rapid, frequency-specific and objective assessment of the hearing threshold in mice. Together with the ABR and otoacustic emissions it was possible to create an audiological profile of SNHL, which can contribute to the differential diagnosis of SNHL.

The auditory steady state response (ASSR) is an oscillatory brain response, which is phase locked to the rhythm of an auditory stimulus. ASSRs have been recorded in response to a wide frequency range of modulation and/or repetition, but the physiological features of the ASSRs are somewhat different depending on the modulation frequency. Recently, the 20-Hz ASSR has been emphasized in clinical examinations, especially in the area of psychiatry. However, little is known about the physiological properties of the 20-Hz ASSR, compared to those of the 40-Hz and 80-Hz ASSRs. The effects of contralateral noise on the ASSR are known to depend on the modulation frequency to evoke ASSR. However, the effects of contralateral noise on the 20-Hz ASSR are not known. Here we assessed the effects of contralateral white noise at a level of 70 dB SPL on the 20-Hz and 40-Hz ASSRs using a helmet-shaped magnetoencephalography system in 9 healthy volunteers (8 males and 1 female, mean age 31.2 years). The ASSRs were elicited by monaural 1000-Hz 5-s tone bursts amplitude-modulated at 20 and 39 Hz and presented at 80 dB SPL. Contralateral noise caused significant suppression of both the 20-Hz and 40-Hz ASSRs, although suppression was significantly smaller for the 20-Hz ASSRs than the 40-Hz ASSRs. Moreover, the greatest suppression of both 20-Hz and 40-Hz ASSRs occurred in the right hemisphere when stimuli were presented to the right ear with contralateral noise. The present study newly showed that 20-Hz ASSRs are suppressed by contralateral noise, which may be important both for characterization of the 20-Hz ASSR and for interpretation in clinical situations. Physicians must be aware that the 20-Hz ASSR is significantly suppressed by sound (e.g. masking noise or binaural stimulation) applied to the contralateral ear.

Comparison of ASSR and frequency specificity ABR induced by NB CE-Chirp for prediction of behavioral hearing thresholds in children with conductive hearing loss

Both 80 Hz auditory steady state responses (ASSRs) and tone burst auditory brainstem responses (ABRs) have been shown to provide reasonable estimates of the behavioral thresholds. Although ASSRs provide statistically objective estimates that can be easily automated by computers, they present no information for the neurophysiological interpretation of the results. ABRs, on the other hand, do not provide easily automated information and usually need expert interpretation of the recorded waveforms. A recently developed continuous loop averaging deconvolution algorithm offers an alternative solution by acquiring slightly jittered 80 Hz quasi auditory steady state responses (QASSRs), thus enabling the acquisition of both recordings simultaneously. The purpose of this study is to investigate a specially developed 80 Hz QASSR paradigm for simultaneous acquisition for both responses for threshold detection purposes. Sixteen ears from eight adults with normal hearing were tested. Amplitude modulated QASSRs were obtained using slightly jittered temporal sequences of tone bursts presented at a mean rate of 78.125 Hz. Four carrier frequencies (500, 1000, 2000, and 4000 Hz) at several stimulus intensity levels were monaurally presented and QASSRs to 128 sweeps blocks were recorded. The ABRs were extracted using the CLAD algorithm. Wave V was visually identified and analyzed in the time domain as in everyday clinical practice. In addition, statistically objective ƒMP computation method was used to automatically detect ABR threshold as well. The QASSRs were analyzed in the frequency domain and magnitudes, phase delays, and thresholds were obtained. Phasor (polar plot) diagrams were constructed. QASSR and ABR hearing thresholds were obtained and compared with behavioral thresholds. Study reveals that the QASSR method provides accurate objective estimation of the audiometric thresholds from extracted ASSRs and latency/amplitude information from extracted ABRs. The largest mean threshold difference for QASSR was within 5 dB for all carrier frequencies including 500 Hz. For auditory threshold estimation in adults with normal hearing, the Hotelling's T-Square test in four dimensions in the frequency domain was more accurate than the ƒMP or visual ABR threshold detection in the time domain. Simultaneously recorded ASSR and ABR from QASSRs provide accurate and effective method for frequency-specific hearing threshold estimation with neurophysiological information in adults with normal hearing. Further research is required for hearing-impaired adults, newborns, and infants.

Auditory steady state responses (ASSRs) to multiple air conduction (AC) stimuli modulated at ∼80 Hz have been shown to provide reasonable estimates of the behavioral audiogram. To distinguish the type of hearing loss (i.e., conductive, sensorineural, or mixed), bone conduction (BC) results are necessary. There are few BC-ASSR data, especially for individuals with hearing loss. The present studies aimed to (1) determine multiple ASSR thresholds to BC stimuli in adults with normal hearing, masker-simulated hearing loss, and sensorineural hearing loss (SNHL) and (2) determine how well BC-ASSR distinguishes normal versus elevated thresholds to BC stimuli in adults with normal hearing or SNHL. Multiple ASSR and behavioral thresholds for BC stimuli were determined in two studies. Study A assessed 16 normal-hearing adults with relatively flat threshold elevations produced by 50, 60, and 70 dB SPL AC masking noise, as well as no masking. Study B assessed 10 adults with normal hearing and 40 adults with SNHL. In both studies, the multiple (500 to 4000 Hz) ASSR stimuli were modulated between 77 and 101 Hz and varied in intensity from 0 to 50 dB HL in 10-dB steps. Stimuli were presented using a B71 bone oscillator held on the temporal bone by an elastic band while participants relaxed or slept. Study A: Correlations (r) between behavioral and ASSR thresholds for all conditions combined were 0.77, 0.87, 0.90, and 0.87 for 500, 1000, 2000, and 4000 Hz, respectively. ASSR minus behavioral threshold difference scores for all frequencies combined for the no-masker, 50, 60, and 70 dB SPL masker conditions were 14.3 ± 9.2, 12.1 ± 10.4, 12.7 ± 7.7, and 11.4 ± 8.1 dB, respectively. Study B: The difference scores for 500, 1000, 2000, and 4000 Hz were, on average, 15.7 ± 12.3, 10.3 ± 10.7, 9.7 ± 10.3, and 5.7 ± 7.9 dB, respectively, with correlations of 0.73, 0.84, 0.87, and 0.94 for the normal-hearing and SNHL groups combined. The ASSR minus behavioral difference scores were significantly larger for 500 Hz and significantly smaller for 4000 Hz compared with 1000 and 2000 Hz. Across all frequencies, the BC-ASSR correctly classified 89% of thresholds as "normal" or "elevated" (92% correct for 1000, 2000, and 4000 Hz). The threshold difference scores and correlations in individuals with SNHL are similar to those in normal listeners with simulated SNHL. These difference scores are also similar to those shown by previous studies for the AC-ASSR in individuals with SNHL, at least for 1000 to 4000 Hz. The BC-ASSR provides a reasonably good estimate of BC behavioral threshold in adults, especially between 1000 and 4000 Hz. Further research is required in infants with hearing loss.

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 goal of this study was to assess the effectiveness of auditory steady-state response (ASSR), determine the cut-off values for each frequency, and detect the best correlated frequencies when compared with the auditory brainstem response (ABR) thresholds in term babies under the age of 12 months. In total, 88 term babies with a mean age of 2.98 (1-11) months (174 ears) underwent ASSR and ABR tests. The ASSR thresholds for the frequencies of 500, 1000, 2000, and 4000 Hz were compared with the hearing level of the ABR thresholds. In the ABR test, a cut-off value of 30 dB nHL was selected for normal hearing. In addition, the best correlation between the ABR and ASSR thresholds and the estimated cut-off thresholds of ASSR for each of the abovementioned frequencies were obtained. In total, 135 ears had values indicating normal hearing ability and 39 ears had hearing loss according to the ABR thresholds. Although statistically significant correlations were found between the ABR and ASSR thresholds at all frequencies in all groups, these correlations were not strong. On the other hand, a strong correlation was found between the responses of the ABR and ASSR thresholds at 4000 Hz in the hearing-impaired subjects. Our findings suggest that ASSR may not be beneficial or reliable as a screening test. Thus, it is likely to be considered as a complementary test rather than an alternative to the ABR test.

Background: The auditory brainstem response (ABR) test is used to estimate hearing thresholds and for neurodiagnostic purposes. ABRs can be recorded for traditional stimuli such as broadband clicks and frequency-specific tone bursts (0.5, 1, 2, and 4 kHz). Recently, chirp stimuli (broadband and narrowband chirps [0.5, 1, 2, and 4 kHz]) have been recommended to be used to record ABRs.Purpose: There is a lack of comparative studies of ABR latency, amplitude, and thresholds obtained from these systems for both traditional and chirp stimuli.Research Design: Repeated measure design.Study Sample: Fifteen adults whose hearing thresholds were ≤25 dB HL participated in this study.Data Collection and Analysis: The Interacoustics Eclipse-25 (EP-25), the Intelligent Hearing System (IHS), and the Vivosonic Integrity V500 systems were used. Peak-to-peak voltage was examined for traditional and chirp stimuli across all three systems. Behavioral and ABR thresholds were obtained for all stimuli. Also, peak V latencies and peak-to-peak amplitudes for all stimuli recorded at 80 dBnHL were examined.Results: Peak-to-peak voltage differed between systems, especially for chirp stimuli. The EP-25 and the IHS systems showed significantly lower behavioral thresholds for some chirp stimuli compared with traditional, comparable stimuli, whereas the Integrity V500 system showed significantly lower behavioral thresholds for broadband click and 4-kHz tone burst stimuli compared with comparable chirp stimuli. Significant differences in behavioral thresholds between systems were observed. The EP-25 (broadband chirp, 1-, 2-, and 4-kHz narrowband chirp) and the IHS (2-kHz narrowband chirp) showed significantly lower ABR thresholds for comparable stimuli, whereas the Integrity V500 system showed lower ABR thresholds for broadband click and 0.5-kHz tone burst stimuli compared with comparable chirp stimuli. ABR thresholds for 2-kHz tone burst and 0.5- and 2-kHz narrowband chirp stimuli were significantly different between systems. The peak V latencies of the IHS system were significantly longer for most of the stimuli compared with other systems. The Integrity V500 system showed significantly lower peak-to-peak amplitudes of peak V for most of the stimuli when compared with other systems.Conclusions: The ABR latencies, amplitudes, and thresholds may differ between ABR recording systems, and clinicians should be aware of these differences to avoid misdiagnosis.Clinical Relevance Statement: The differences in ABR latencies, amplitudes, and thresholds between systems may lead to inconsistencies in diagnostic accuracy. Audiologists should use system-specific normative data.

Recently, auditory steady-state responses (ASSRs) have been proposed as an alternative to the auditory brainstem response (ABR) for threshold estimation. The goal of this study was to investigate the degree to which ASSR thresholds correlate with ABR thresholds for a group of sedated children with a range of hearing losses. Thirty-two children from the University of Iowa Hospitals and Clinics ranging in age from 2 months to 3 years and presenting with a range of ABR thresholds participated. Strong correlations were found between the 2000-Hz ASSR thresholds and click ABR thresholds (r = .96), the average of the 2000- and 4000-Hz ASSR thresholds and click ABR thresholds (r = .97), and the 500-Hz ASSR and 500-Hz toneburst ABR thresholds (r = .86). Additionally, it was possible to measure ASSR thresholds for several children with hearing loss that was great enough to result in no ABR at the limits of the equipment. The results of this study indicate that the ASSR may provide a reasonable alternative to the ABR for estimating audiometric thresholds in very young children.

Prospective data analysis. The intraoperative measurement of auditory brainstem responses (ABR) enables the assessment of the coupling efficiency in active middle ear implant surgeries. Furthermore, auditory steady-state response (ASSR) measurements can offer additional frequency-specific evaluations. This study aims to examine the efficacy of intraoperative ASSR and ABR measurements and optimize implant placement during surgery. Tertiary referral center with an extensive active middle ear implant program. Main outcome measures: Intraoperative ABR and ASSR measurements were conducted using a standard ABR system and the AcoustiAP adapter. After the surgical procedure, vibrogram thresholds were measured. The statistical analysis determined correlations between intraoperative ASSR and ABR thresholds, preoperative bone conduction, and postoperative vibrogram thresholds. All patients underwent successful intraoperative recording of ABR and ASSR measurements. The ASSR thresholds exhibited a high correlation with bone conduction thresholds at 1000 Hz, 2000 Hz, and 4000 Hz. Furthermore, ASSR thresholds demonstrated robust correlations with postoperative vibrogram thresholds. Intraoperative ASSR measurements can provide valuable real-time feedback for ensuring optimal placement during implantation due to their good correlation with bone conduction. The high correlation between intraoperative ASSR and postoperative vibrogram thresholds indicates that ASSR can also assess postoperative hearing outcomes. Further development and implementation of these measurements in the clinical routine might improve surgical outcomes by enabling more precise frequency-specific assessments, improving both coupling efficiency and postoperative hearing results.

Objective: To compare the results of auditory steady-state response (ASSR) and click auditory brainstem response (click ABR) among infants and young children tested at the Ear Unit of a Tertiary General Hospital.&#x0D; &#x0D; Methods:&#x0D; Design: Cross-sectional Study&#x0D; Setting: Tertiary General Hospital&#x0D; Population: Within-subject comparisons of click auditory brainstem response (click ABR) thresholds and auditory steady-state response (ASSR) thresholds among 55 infants and young children, 2 months to 35 months of age referred to the Ear Unit for electrophysiologic hearing assessment.&#x0D; Results: Click ABR showed strong positive correlation to all frequencies and averages of ASSR. Highest correlation was noted with the average of 1-4 kHz ASSR results with Pearson r = 0.89 (Spearman r=0.80), the average of 2-4 kHz had strong positive correlation r = 0.88 (0.79). Correlation was consistently strong through all ASSR frequencies (0.5 kHz at r=0.86 (0.74), 1 kHz at r=0.88 (0.78), 2 kHz at r=0. 87 (0.79), 4 kHz at r=0.85 (0.76)). Average differences of click ABR and ASSR thresholds were 8.2±12.9dB at 0.5 kHz, 8.6±12.6dB at 1 kHz, 5.3±11.8dB at 2 kHz and 7.8±13.4dB at 4 kHz. Among patients with no demonstrable waveforms by click ABR with maximal click stimulus, a large percentage presented with ASSR thresholds. Of these, 80.5% (33 of 41) had measurable results at 0.5 kHz with an average of 107.3±11.1dB, 85.4% (35 of 41) at 1 kHz with an average of 110.5±11.8dB, 73.2% (30 of 41) at 2 kHz with an average of 111.2±11.1dB and 63.4% (26 of 41) at 4 kHz with and average of 112.2±8.21dB. Auditory steady-state response results were comparable to auditory brainstem response results in normal to severe hearing loss, and provided additional information necessary for complete audiologic assessment especially among patients with severe to profound hearing loss wherein click ABR showed no responses. Up to 85.4% of patients that would have been noted to have no waveforms by click ABR still demonstrated measurable thresholds by ASSR&#x0D; &#x0D; Conclusion: Our study suggests that ASSR may be the best available tool for assessing children with severe to profound hearing loss, and is a comparably effective tool in overall hearing assessment for patients requiring electrophysiological testing. The advantages of ASSR over click ABR include: 1) detection of frequency-specific thresholds and; 2) the detection of hearing loss thresholds beyond the limits of click ABR.&#x0D; &#x0D; &#x0D; Key words: Auditory Steady-State Response, ASSR, Auditory Brainstem-Evoked Response, ABR, Hearing Thresholds, Electrophysiologic Testing&#x0D;