Predictive value of ABR in infants and children with moderate to profound hearing impairment

Click and 500 Hz tone pip ABR thresholds obtained in infancy were compared to pure-tone thresholds in 25 preschool-aged patients with moderate to profound hearing impairments. The electrophysiologic thresholds obtained in infancy were generally lower than the recent audiometric thresholds. Clicks best predicted the lowest pure-tone threshold within the 1 to 8 kHz range. The 500 Hz tone-pip thresholds were closest to the lowest of 250 Hz and 500 Hz pure-tone thresholds. Regression analyses involving audiometric and electrophysiologic thresholds and 95% confidence intervals of the differences between their means provide a basis for behavioral threshold prediction in this patient group.     

Frequency-specific auditory brainstem responses relationship to behavioural thresholds in cochlear-impaired adults

Auditory brainstem response (ABR) thresholds to ipsilaterally masked tone pip stimuli were obtained from three groups of hearing-impaired subjects. Using high-pass (for 500-Hz tone pips) and notched noise (for 1-, 2- and 4-kHz tone pips), ABR thresholds in subjects with low-frequency, high-frequency or flat cochlear hearing losses were compared to conventional pure-tone audiometric thresholds. A strong positive relationship was found between ABR and behavioural threshold elevation. Absolute ABR thresholds at 500 Hz were significantly higher than those at other frequencies. The results of this study indicate that frequency-specific ABR testing can provide an approximation of both degree and configuration of cochlear hearing losses in adults. Further refinements of testing and judging procedures are needed however to reduce the variation evident in our results and thus achieve the accuracy required for most clinical applications.     

ABR thresholds to tonebursts gated with Blackman and linear windows in adults with high-frequency sensorineural hearing loss

OBJECTIVE: The goal of this study was to determine whether tonebursts gated on and off using a nonlinear, exact-Blackman-gating function would be a more frequency-specific stimulus for auditory brain stem response audiometry than the more traditional 2-1-2 cycle linearly gated toneburst. DESIGN: Toneburst ABRs were recorded in 10 adults with normal hearing and in 18 adults with sloping high-frequency sensorineural hearing loss. It was hypothesized that any advantage of the Blackman stimuli for frequency-specific threshold assessment should be evident in hearing-impaired subjects with hearing loss confined to the 2000 to 4000 Hz frequency region since spectral splatter in the toneburst stimuli could lead to an underestimation of hearing loss based on the ABR thresholds. ABR stimuli consisted of 2000- and 4000-Hz 2-1-2 (rise-plateau-fall) cycle linearly gated tonebursts and 1-0-1 msec exact-Blackman-gated tonebursts. An additional 0.5-0-0.5 msec 4000-Hz Blackman-gated toneburst was used to investigate whether the difference in rise/fall characteristics of the linearly and Blackman-gated tonebursts could account for any differences in ABR results at 4000 Hz. The ABR toneburst stimuli were calibrated behaviorally in 15 adults with normal hearing. RESULTS: In the normal-hearing listeners toneburst-ABR thresholds generally exceeded behavioral thresholds by 10 to 13 dB for all stimuli. Correlations of 0.85 to 0.96 were obtained between 2000 and 4000 Hz toneburst ABR thresholds and pure-tone audiometric thresholds in the hearing-impaired listeners. Results were similar for Blackman- and linearly gated stimuli. CONCLUSIONS: There were no clear differences between Blackman- and linearly gated tonebursts in terms of how well ABR thresholds predicted pure-tone thresholds at 2000 and 4000 Hz. In general audiometric thresholds were predicted with good accuracy (+/-15 dB) by the toneburst ABR thresholds. The 4000-Hz audiometric threshold was underestimated in one subject with a very steeply sloping hearing loss by both Blackman- and linearly gated toneburst ABR thresholds, indicating that ipsilateral masking such as notched noise would be needed to ensure frequency specificity in this and similar cases.     

0～6岁听力损失儿童短纯音诱发的听性脑干反应研究

目的比较听力损失儿童短纯音听性脑干反应（auditory brainstem response，ABR）反应阈与40Hz听觉事件相关电位（auditory event-related potentials，AERP）及短声ABR反应阈的相关性，评价短纯音ABR在儿童听力评估中的应用。方法应用SmartEP听觉诱发电位仪在0～6岁听力损失儿童中记录短声、短纯音ABR及40 Hz AERP的反应阈，共43例85耳（男／女=27／16）。结果0．5、1、2kHz短纯音ABR反应阈与40 Hz AERP反应阈的线性相关系数分别为0．84、0．80、0．80，反应闯之差分别为3．6±12．2、5．9±14．8、1．7±13.7dB。0．5、1、2、4kHz短纯音ABR反应阈与短声ABR反应阈的线性相关系数分别为0．81、0．89、0．94、0．91，反应阈之差分别为6．6±13．4、0．2±10．7、1．5±8．1、4．2±10．2dB。2kHz、4kHz短纯音反应阈的平均值与短声ABR反应阈的线性相关系数为0．93，反应阈之差为2．8±8．3dB。结论短纯音ABR的反应阈可作为一种儿童听力评估的方法。     

Low-frequency specificity of the auditory brainstem response threshold elicited by clicks masked with 1590-Hz high-pass noise in subjects with sloping cochlear hearing losses.

In this study, the frequency specificity of the ABR threshold to stimulation with a click masked with 1590-Hz high-pass noise was determined in subjects with sloping cochlear hearing losses both high- and low-frequency in character. The results show that the ABR threshold elicited by this stimulus is low-frequency specific. The standard error in estimating the 1,000-Hz pure-tone threshold from the high-pass-noise-masked click-evoked ABR threshold is 10.2 dB which equals that for estimating the 3,000-Hz pure-tone threshold from the routinely used unmasked click ABR threshold. The ABR threshold elicited by a click masked with 1590-Hz high-pass noise can therefore be regarded as an accurate tool to predict the pure-tone hearing loss at 1,000 Hz. However, this method is less suitable for routine clinical testing because of the masking noise needed: the occasional high loudness level adversely affects the response quality and reduces the dynamic range of pure-tone hearing losses to be assessed. A third disadvantage is that determining the masking level electrophysiologically for each ear is time consuming. The search for a method with no or less masking noise should therefore continue.     

Long-term audiometric follow-up of click-evoked auditory brainstem response in hearing-impaired infants

Conventional pure-tone thresholds were collected as determined at ages between 4 and 8 years from a group of 163 infants, tested by auditory brainstem response (ABR) in the age range between 1 and 3 years old for objective hearing assessment. The subjects suffered from a variety of degrees and types of sensorineural hearing impairment. The prognostic value of the ABR peak V thresholds in response to 0.1 ms clicks with respect to the behavioural thresholds at octave frequencies from 125 to 8,000 Hz obtained later is evaluated. Correlation between ABR and behavioural thresholds is largest in the 1,000- to 8,000-Hz frequency range. Predicted pure-tone audiograms (mean and SD) were determined for each 10-dB class of ABR thresholds. SDs are in the order of 15 to 18 dB in the 500- to 4,000-Hz range and slightly higher at adjacent frequencies (i.e., somewhat larger than in comparable adult studies). Mean pure-tone thresholds in the 1,000- to 8,000-Hz frequency range are up to 20 dB worse than ABR thresholds, which is opposite to findings in normally-hearing subjects. Thus, with an increasing degree of sensorineural hearing impairment, pure-tone thresholds increase at a significantly higher rate than ABR thresholds. The observation is explained in terms of reduced temporal integration in cochlear hearing loss. ABR thresholds worse than 80 dB nHL are demonstrated to have very limited predictive value with respect to the amount of residual hearing, not only in the low- but also in the high-frequency range. The presence of otitis media during ABR testing is shown to make estimation errors increase to more than 25 dB (SD).     

Simultaneous Acquisition of 80 Hz ASSRs and ABRs From Quasi ASSRs for Threshold Estimation

OBJECTIVES:: 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. DESIGN:: 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 ?MP 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. RESULTS:: 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 ?MP or visual ABR threshold detection in the time domain. CONCLUSIONS:: 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.     

短纯音及切迹噪声掩蔽的短纯音ABR用于儿童听力评估的研究

目的研究儿童短纯音（tone burst）及同侧切迹噪声（notched noise）掩蔽短纯音诱发的ABR反应阈,与短声诱发的听性脑干反应（click-evoked auditory brainstem response,c-ABR）以及40Hz听觉事件相关电位（40Hz Auditory Event Related Potentials,40Hz AERP）反应阈的关系,以评价这些测试方法在儿童听力评估中的应用价值。方法应用SmartEP听觉诱发电位仪在29例（53耳）儿童（男18例,女11例,年龄2月-8岁）中测试短声ABR、短纯音ABR、两种不同强度切迹噪声掩蔽短纯音诱发的ABR（分别定义为c-ABR、tb-ABR、amtb-ABR和bmtb-ABR）及40Hz AERP。结果（1）fb-ABR、amtb-ABR、bmtb-ABR在2kHz、4kHz两个频率的反应阈与c-ABR的反应阈接近,反应阈之间有较好的相关性;（2）tb-ABR、amtb-ABR、bmtb-ABR的反应阈与40Hz AERP的反应阈在0.5、1、2、4kHz各个频率均接近并有较好的相关性。结论使用短纯音及同侧切迹噪声掩蔽短纯音诱发的ABR的反应阈预测儿童的纯音行为听阈是可行的。     

Threshold prediction using the auditory steady-state response and the tone burst auditory brain stem response: a within-subject comparison

OBJECTIVE: 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. DESIGN: 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. RESULTS: 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. CONCLUSIONS: 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.     

Comparison between the frequency specificities of auditory brainstem response thresholds to clicks with and without high-pass masking noise.

In this study, the frequency specificity of the auditory brainstem response (ABR) threshold to a click masked with 1590-Hz high-pass masking noise is compared with the frequency specificity of the unmasked click-evoked ABR threshold. The ABR threshold to the high-pass-noise-masked click stimulus is low frequency specific and corresponds with the 1,000-Hz pure-tone threshold. Although the ABR threshold to the unmasked click stimulus corresponds with the '3,000'-Hz pure-tone threshold, the frequency specificity seems much less pronounced than that of the low-frequency-specific stimulus. This study shows, however, that this apparent lack of frequency specificity can be attributed to the selection of pure-tone hearing losses. The ABR threshold evoked by an unmasked click stimulus is, therefore, preeminently useful as a high-frequency point of a two-point audiogram. The possible reasons why the ABR threshold evoked by a broad-band stimulus as the unmasked click corresponds with the higher frequencies of the pure-tone audiogram are discussed.     

浅睡眠状态下的行为观察测听

目的 分别测试低龄儿双耳的听力状况.方法 对327名婴幼儿进行浅睡眠状态下的行为观察测听,并与click声刺激ABR结果进行比较;其中有58名婴幼儿一段时间后再进行游戏测听和纯音测听.结果 浅睡眠状态下的行为观察测听在2 kHz和4 kHz的平均反应阈与ABR的反应阈相当,但比跟踪测得的同频率纯音听阈值高约5～10 dB HL.结论 浅睡眠状态下的行为观察测听可分别测得低龄儿的双耳听反应阈.     

Predicting pure-tone thresholds with dichotic multiple frequency auditory steady state responses

The accuracy of dichotic multiple frequency auditory steady state in predicting pure-tone thresholds at 0.5, 1, 2, and 4.0 kHz compared to an ABR protocol (click and tone burst at 0.5 kHz) were explored in a group of 25 hearing-impaired subjects across the degree and configuration spectrum. Mean steady state thresholds were within 14, 18, 15, and 14 dB of the pure tones at 0.5, 1, 2, and 4 kHz, compared to the tone-burst ABR at 0.5 kHz pure-tone difference of 24 dB, and a click-evoked pure-tone (2-4 kHz) difference of 9 dB. Recording time for the steady state protocol was 28 minutes (+/- 11) compared to 24 minutes (+/- 9) of the ABR protocol. Degree of loss had a significant effect on steady state; configuration of hearing loss had a limited effect. Mf ASSR predicted thresholds with relative accuracy although some configurations showed discrepancies for low-frequency estimates.     

听力筛查转诊婴幼儿不同滤波条件短纯音诱发听性脑干反应的比较

目的 短纯音诱发听性脑干反应(ABR)是听力筛查转诊婴幼儿听力评估的重要方法,本研究比较滤波分别为30～1500 Hz与30～3000 Hz时不同频率短纯音ABR阈值之间的差异,总结两种滤波条件下ABR波形特点及对阈值判断的影响,以选择更优化的频率特异性ABR测试参数.方法 应用美国IHS公司SmartEP听觉诱发电位仪记录18例(22耳)2～33月龄婴幼儿短声、滤波为30～1500 Hz与30～3000 Hz短纯音ABR各频率反应阈.结果 0.5 kHz、1 kHz、2 kHz、4 kHz滤波为30～3000 Hz短纯音ABR反应阈比滤波为30～1500 Hz短纯音ABR反应阈高.0.5 kHz及2.0 kHz两种滤波条件下短纯音ABR反应阈之间差异具有统计学意义(t值分别为2.238及2.217,P值均＜0.05),其他频率两种滤波条件下反应阈之间差异无统计学意义(P值均＞0.05).同等刺激强度下,滤波为30～3000 Hz的ABR波形与30～1500 Hz相比不平滑,反应波曲线上会出现锯齿状细小的干扰波.结论 在用短纯音ABR反应阈评估婴幼儿听力时,30～1500 Hz可以作为更优化的滤波设置参数.

Abstract：

Objective Auditory brainstem responses (ABR) evoked by tone burst is an important method of hearing assessment in referral infants after hearing screening. The present study was to compare the thresholds of tone burst ABR with filter settings of 30 - 1500 Hz and 30 - 3000 Hz at each frequency,figure out the characteristics of ABR thresholds with the two filter settings and the effect of the waveform judgement, so as to select a more optimal frequency specific ABR test parameter. Methods Thresholds with filter settings of 30 - 1500 Hz and 30 -3000 Hz in children aged 2 -33 months were recorded by click,tone burst ABR. A total of 18 patients ( 8 male / 10 female), 22 ears were included. Results The thresholds of tone burst ABR with filter settings of 30 - 3000 Hz were higher than that with filter settings of 30 - 1500 Hz. Significant difference was detected for that at 0. 5 kHz and 2.0 kHz ( t values were 2.238 and 2. 217, P ＜ 0. 05 ), no significant difference between the two filter settings was detected at the rest frequencies tone evoked ABR thresholds. The waveform of ABR with filter settings of 30 - 1500 Hz was smoother than that with filter settings of 30 - 3000 Hz at the same stimulus intensity. Response curve of the latter appeared jagged small interfering wave. Conclusions The filter setting of 30 - 1500 Hz may be a more optimal parameter of frequency specific ABR to improve the accuracy of frequency specificity ABR for infants' hearing assessment.     

Cochlear Initiation Site of the Frequency-Following Response: a Study of Patients with Sensorineural Hearing Loss

The cochlear initiation of the frequency-following response (FFR) was assessed by comparing the FFR thresholds to the pure-tone thresholds in four groups of patients suffering from different forms of sensorineural hearing loss. The groups consisted of patients suffering from (1) pure high-frequency hearing losses; (2) high-frequency hearing losses mixed with moderate low-frequency losses; (3) flat hearing losses, and (4) low-frequency hearing losses. Across groups, the pattern of thresholds of the FFR evoked by 500-Hz tone bursts paralleled the pattern of pure-tone thresholds only for the low frequencies - not the high frequencies. In order to clarify the interpretation of this result, a high-pass masking experiment was performed on patients with low-frequency hearing losses. High-pass masking noise did not affect the FFR thresholds to 500-Hz tone burst, but it produced a phase shift of the FFR at stronger intensity levels. The data are interpreted as strongly supporting the view that the FFR at low levels is initiated primarily by activity in the apical portion of the cochlea.     

Estimating audiometric thresholds using simultaneous acquisition of ASSR and ABR from QASSR in patients with sensorineural hearing loss

Objectives: To evaluate the accuracy with which the innovative QASSR method predicts behavioral thresholds in adult patients with sensorineural hearing loss. Design: Subjects were tested at four carrier frequencies (500, 1000, 2000, and 4000?Hz).The resulting QASSR recordings were analyzed for thresholds and magnitude/phase characteristics. Tone-burst ABR was recovered from QASSR signal using CLAD method and analyzed in the time domain. The electrophysiological estimates were compared to hearing thresholds determined behaviorally. Study sample: Sixteen ears of nine volunteer subjects recruited from a clinical population. Results: All mean threshold estimates differed less than 3?dB for QASSR and less than 5?dB for ABR at 1000, 2000 and 4000Hz (carrier or pure-tone test frequencies). The largest differences were observed for both at 500?Hz (5.63 and 11.56?dB respectively).The audiometric configurations of QASSR and ABR estimates followed those of the respective behaviorally determined configurations across ears tested. Conclusions: QASSR method merges two dissimilar stimulation techniques, transient and steady-state, to create a hybrid stimulation-and-analysis paradigm that seems to improve the overall performance of the electrophysiological threshold estimation. The unique feature of the QASSR technique is the additional information afforded by the transient ABR, recovered from the same recording. The QASSR thus holds promise to be a very useful tool for practical clinical applications.     

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

Objective

Many of the medico-legal patients who claimed compensation may exaggerate hearing loss that varies in degree, nature, and laterality. The purpose of this study was to investigate whether Auditory Steady-State Response (ASSR) could be used to predict the hearing level of adults, and whether ASSR could become a better testing method than Auditory brainstem response (ABR) in audiometric assessment of adults with sensorineural hearing loss.

Methods

This was a prospective study, which was conducted in a tertiary referral hospital. From January to June 2007, 142 subjects (284 ears) with varying degrees of sensori-neural hearing impairment were included in this study. Four commonly used frequencies (500, 1000, 2000, 4000 Hz) were evaluated. All subjects received pure-tone audiometry, multi-channel ASSR, and ABR tests for threshold measurement. The correlation of pure tone thresholds with ASSR and ABR thresholds were assessed.

Results

Between multi-channel ASSR and pure tone thresholds, a difference of less than 15 dB was found in 71% while a difference of less than 25 dB was found in 89% of patients. The correlation coefficient (r) of multi-channel ASSR and pure tone thresholds were 0.89, 0.95, 0.96, and 0.97 at 500, 1000, 2000, and 4000 Hz, respectively. The strength of the relationship increased with increasing frequency. On the other hand, between ABR and pure-tone thresholds, a difference of less than 15 dB was found in 31%; a difference of less than 25 dB was found in 62% of patients. The r correlation value for ABR and pure tone thresholds was 0.83.

Conclusion

ASSR is a more reliable test for the accurate prediction of auditory thresholds than ABR. It can be a powerful and convenient electro-physiologic examination tool for clinically assessing of adults with sensorineural hearing loss.     

Establishing normal hearing with the dichotic multiple-frequency auditory steady-state response compared to an auditory brainstem response protocol

OBJECTIVE: To determine the clinical usefulness of the dichotic multiple-frequency (MF) auditory steady-state response (ASSR) technique for estimating normal hearing compared to a 0.5-kHz tone burst and broadband click auditory brainstem response (ABR) protocol in a sample of adults. MATERIAL AND METHODS: A comparative experimental research design was selected in order to compare estimations of normal hearing obtained with the dichotic ASSR technique at 0.5, 1, 2 and 4 kHz with a 0.5-kHz tone burst and broadband click ABR protocol. The recording times required for each procedure were also compared. Normal-hearing subjects (n = 28) were selected according to immittance values within normal limits and pure-tone behavioural thresholds of < 25 dB HL across frequencies. RESULTS: The dichotic MF ASSR estimated normal hearing to be, on average, 30-34 dB HL across the range 0.5-4 kHz. The mean estimate of normal hearing for 0.5 kHz using tone burst ABRs was 30 dB nHL and the mean click ABR threshold was 16 dB nHL, i.e. 14-18 dB better than the ASSR thresholds. The dichotic MFASSR technique recorded 8 thresholds (4 in each ear) in a mean time of 23 min. The ABR protocol recorded 4 thresholds (2 in each ear) in a mean time of 25 min. CONCLUSION: Both the dichotic MF ASSR and ABR protocols provided a time-efficient estimation of normal hearing. There was no significant difference between the tone burst ABR and MF ASSR techniques in terms of estimation of normal hearing at 0.5 kHz. The dichotic MF ASSR technique proved more time-efficient by determining more thresholds in a shorter time compared to the ABR protocol.     

Some comparisons between auditory brain stem response thresholds, latencies, and the pure-tone audiogram

Aspects of auditory brain stem responses (ABR) and pure-tone behavioral audiograms were compared in patients with cochlear hearing loss. Click-evoked ABR thresholds appeared to be related most closely to the audiometric thresholds at 2000 and 4000 Hz, with relatively poor agreement at either 1000 or 8000 Hz. These results were related to the amplitude spectrum of the eliciting stimulus. The slope of the wave V latency-intensity function appeared to be related to the configuration of the hearing loss. Patients with high-frequency sensorineural losses had steeper slopes than normal subjects, whereas patients with flat sensorineural losses had shallower slopes. These results were related to the principle that response latency is determined by the cochlear region that predominates the ABR for different stimulus intensities.     

Tone-evoked brainstem responses and auditory steady state responses to 40hz and 80hz amplitude modulated stimuli with different frequencies — a comparative study

Abstract  Tone burst evoked auditory brainstem responses and auditory steady state responses with 40 or > 80 Hz modulation can be used to determine frequency specific threshold. Aim  The present study was taken up to check for the efficacy of estimating hearing thresholds by tone burst ABR and ASSR. The frequency effect (low, mid and high) on estimating the threshold was also focused upon. Methods  20 normal hearing adults (40 ears) in the age range of 16 to 30 years participated in the study. The pure tone audiometry and immittance was initially done. Subsequently, tone-burst ABR, 80Hz ASSR and 40Hz ASSR to estimate the threshold with three frequencies 500Hz (low), 2000Hz (mid) and 4000Hz (high) was done. The data was analyzed statistically using pair sample t-test. Results  ASSR threshold for 80Hz and 40Hz was almost comparable. ASSR was superior to estimate the threshold than tone-burst ABR. For the low frequency the discrepancy between the behavioral threshold and frequency-specific evoked audiometry was more when compared to mid and high frequency. Conclusion  Present study showed that steady-state responses were efficient means of threshold detection than visual detection of ABR wave-V. In awake adult subjects, 40Hz and 80Hz amplitude modulated produced similar results. For the threshold estimation ASSR was better than tone-burst ABR.     

ASSR、Tb-ABR和c-ABR在正常听力人群客观听阈评估中的相关性分析

目的：研究多频听觉稳态反应（ASSR）、短纯音听觉脑千诱发电位（Tb-ABR）和短声听觉脑干诱发电位（c-ABR）反应阈与纯音听阈（PTA）在正常听力人群中的差别和相关性。方法：对正常听力的受试者（共58耳）进行ASSR、Tb-ABR和c-ABR以及纯音测听检查,分别得出前三者测试的反应阂并与PTA进行相关性分析。结果：ASSR和Tb-ABR的反应阈均与同频率的PTA具有良好的相关性;Tb-ABR的反应阈与PTA的值接近,ASSR反应阈与PTA间的差值较大;c-ABR与PTA2、4kHz听阈的均值呈线性相关。结论：ASSR和Tb-ABR都是较好的评估行为听阚的频率特异性客观测听方法,Tb-ABR结合c-ABR能较好地反映PTA。