Mechanisms in noise-induced permanent hearing loss: an evoked otoacoustic emission and auditory brainstem response study

In this study 22 patients (44 ears) with noise-induced permanent hearing loss were audiologically evaluated using transient-evoked otoacoustic emissions (TEOAE) and auditory brain-stem response (ABR). Twenty-one normal subjects (42 ears) without exposure to occupational noise were used as controls. Based upon the hearing loss at 4, 3, 2 and 1 kHz on the pure-tone audiogram, they were classified into four groups. In group 1 (eight ears), emissions were present in all ears but their TEOAE-noise level and their reproducibility (percentage) proved to be weak. The auditory brain-stem response (ABR) indicated that the I/V amplitude ratio, the latency values of wave V and the I-V intervals fell within the normal range in all ears. In Group 2 (14 ears), 40 per cent had no emissions, whereas the remaining ears showed weak emissions. The ABR revealed that in all ears the I/V amplitude ratio became small while wave V peak latency as well as I-V intervals were within the normal range. In Group 3 (10 ears), emissions were absent in 50 per cent, while in the other ears the emissions were very weak. The ABR revealed that the I/V amplitude ratio, which could be calculated in the 60 per cent in which wave I was present, was smaller than in Group 2. Wave V latency as well as I-V intervals were within the normal range. In Group 4 (12 ears), none of the ears showed emissions. The ABR indicated that the I/V amplitude ratio was much smaller when wave I was present (27 per cent) as well as I-V interval values being within the normal range. Wave V absolute latency value (delta V index) indicated a positive index in 17 per cent of this group (two ears) when wave I was absent. In the present study a dynamic process from cochlear outer hair cells to cochlear neurons was seen, correlating with an increasing hearing loss.     

轻度感音神经性听力损失婴儿骨导ABR检测结果分析

目的探讨骨导听性脑干反应(ABR)检测在婴儿轻度感音神经性听力损失诊断中的价值。方法分别对30例(52耳)轻度感音神经性听力损失婴儿(患儿组)和30例(60耳)听力正常婴儿(正常组)行骨、气导ABR检测,并对两组结果进行分析比较。结果从40 dB nHL刺激强度开始,随着刺激强度下降,患儿组骨导ABR波V引出率逐渐下降;在40 dB nHL刺激强度下,患儿组骨导ABR波Ⅰ、Ⅲ、Ⅴ潜伏期较正常组稍延长,但差异无显著统计学意义(P>0.05)。患儿组骨、气导ABR反应阈均较正常组显著升高(P<0.05),但两组骨气导反应阈差值无明显差异(P>0.05)。结论骨导ABR检测对轻度感音神经性听力损失婴幼儿听力损失性质的鉴别诊断和评估具有重要的临床参考价值。     

The effect of stimulus level on click evoked oto-acoustic emissions and brainstem responses in neonates under intensive care

Click evoked oto-acoustic emissions (EOAE) at a range of stimulus levels and the auditory brainstem response (ABR) threshold have been measured in 40 infants admitted to a neonatal intensive care unit (NICU). The stimulus levels at which the emissions were first observed had a similar mean value and distribution to those found in previous studies on normal newborns and young adult volunteers. The difference was in the proportion who had no detectable emissions, 16.7% as against 3.9% in the normal newborns and 2.6% in young adult volunteers. The distribution of thresholds for the ABR was again similar to those measured on normal newborns but 8.1% of the ears of the NICU infants had a threshold worse than 53 dBnHL compared with 0% for the normal newborns. A combined screening method starting with the click evoked oto-acoustic emission is proposed. A comparison of the mean ABR thresholds for those in whom an EOAE was recorded to those with no EOAE showed a group effect. The stimulus latency relationship of the NV peak showed too much variation between individual results to consider its use to define accurately the degree of conductive hearing loss.     

The value of ABR- and ASSR-based hearing estimation in young children with congenital monaural malformation (atresia)

Abstract

Background: The electrophysiology of auditory nerve mature is particularly important for unilateral hearing loss.

Objectives: To assess the hearing status in young children with congenital monaural malformation and evaluate their potential for practical use in the functional maturation parameters of the auditory pathway.

Materials and methods: ABR (auditory brainstem responses) and ASSR (auditory steady-state responses) threshold measurements were performed in 21 young children with congenital monaural atresia.

Results: The average electrophysiologic thresholds for the ABR were 65?dB nHL ± 1.20 in malformed ears and 25?dB nHL ± 0.48 in normal ones. All 21 atretic ears presented with typical conductive hearing loss. There was no statistic positive correlation in hearing-impaired ears between the methods of ABR and ASSR responses (r?=?0.12, 0.20 and 0.17). The IPL (interpeak latency) of I–III, III–V and I–V of atretic ears in ABR test was decreased relative to normal ears. Furthermore, a shortening of the IPLs I–III, III–V, I–V can be observed with increasing age of the children in malformed ears.

Conclusions and significance: The ABR- and ASSR-based hearing evaluation in young children with congenital monaural malformation should be viewed as complementary technologies. Besides, there was no delay of functional maturation at brainstem level although unilateral hearing was deprived during their early years of life.     

Dependence of Auditory Brainstem Response on Click Polarity and High-Frequency Sensorineural Hearing Loss

An investigation is presented on the effect of click polarity upon the auditory brainstem response (ABR) in cases of simulated high-frequency hearing loss. A high-frequency hearing loss was simulated in 12 normal subjects by applying a high-pass noise masker, the noise cutoff frequency being varied in half-octave steps through the range of audiometric frequencies. With this paradigm, the effects of click polarity on the ABR are similar to those reported in patients with high-frequency hearing loss, including changes in waveform morphology and substantial peak latency shifts. To evaluate the role of individual cochlear frequency channels in a more direct way, half-octave narrow-band responses were determined by pair-wise subtraction of the high-pass-noise-masked responses. As far as ABR peak latencies are concerned, stimulus polarity effects tend to increase towards the lower frequency bands. Thus, the selective elimination of the contribution to the ABR of cochlear high-frequency channels can be held responsible for the increased dependence of ABR on click polarity observed in high-frequency hearing loss. However, statistical evaluation of peak I, III and V latencies, both in high-pass-noise-masked and in narrow-band ABRs, reveals that the latency effects are not systematic between subjects. Mechanisms producing the observed rarefaction-condensation differences, possible explanations for the large intersubject variability and the consequences for clinical interpretation of ABR are discussed.     

Dependence of auditory brainstem response on click polarity and high-frequency sensorineural hearing loss.

An investigation is presented on the effect of click polarity upon the auditory brainstem response (ABR) in cases of simulated high-frequency hearing loss. A high-frequency hearing loss was stimulated in 12 normal subjects by applying a high-pass noise masker, the noise cutoff frequency being varied in half-octave steps through the range of audiometric frequencies. With this paradigm, the effects of click polarity on the ABR are similar to those reported in patients with high-frequency hearing loss, including changes in waveform morphology and substantial peak latency shifts. To evaluate the role of individual cochlear frequency channels in a more direct way, half-octave narrow-band responses were determined by pair-wise subtraction of the high-pass-noise-masked responses. As far as ABR peak latencies are concerned, stimulus polarity effects tend to increase towards the lower frequency bands. Thus, the selective elimination of the contribution to the ABR of cochlear high-frequency channels can be held responsible for the increased dependence of ABR on click polarity observed in high-frequency hearing loss. However, statistical evaluation of peak I, III and V latencies, both in high-pass-noise-masked and in narrow-band ABRs, reveals that the latency effects are not systematic between subjects. Mechanisms producing the observed rarefaction-condensation differences, possible explanations for the large intersubject variability and the consequences for clinical interpretation of ABR are discussed.     

Auditory brainstem responses in noise-induced permanent hearing loss

Fifty-four patients (108 ears) with presumed noise-induced hearing loss, were subjected to tonal and speech audiometry, impedance tests and measurements of auditory brainstem responses (ABR), in order to check for possible retrocochlear involvement. ABR data indicated that latency values of waves I, III and V, as well as III-I, V-III and V-I intervals fell within the normal range in all cases (M +/- 2 SD), even for fast repetition rates (51 stim/s). Poor waveform resolution of early components, particularly of wave I, was found in 12 ears (11.1%) and a total absence of evoked potentials not always related to the hearing loss, occurred in 5 ears (4.6%).     

Influence of age and hearing loss on the latency shifts of the auditory brainstem response as a result of increased stimulus rate

Latency shifts of auditory brainstem response waves, I, III and V were studied as a function of increasing the stimulus repetition rate from 9 to 21, 42 and 63/s. There appears to be an accumulative retardation of the successive waves when faster click rates are administered that yield a prolongation of the interpeak intervals I-III and III-V. The effect on wave V and on the interpeak interval III-V seems to intensify with age (especially over 55 years). In ears with a flat sensorineural hearing loss, the adaptation of waves III and V is found to be somewhat smaller than in normal ears at the same intensity in dB SPL.     

尿毒症患者听力状况及其影响因素研究

目的观察尿毒症患者的听力状况,探讨引起尿毒症患者听力下降的原因。方法采用纯音测听和高刺激率ABR对30例（60耳）尿毒症患者及31例（62耳）非尿毒症者进行测试,用SPSS19．0软件进行统计分析。结果30例尿毒症患者中有26例伴有不同程度的听力下降,其中19例听力曲线为下降型,5例为平坦型,2例为单侧全聋和另侧下降型。尿毒症组内纯音测听结果与肌酐水平无相关（P〉0．05）。与尿素氨水平为负相关（P=0．011）,高刺激率ABR与纯音测听结果无相关（P〉0．05）。尿毒症组和对照组间高刺激率ABR波I～V潜伏期的差值有统计学意义（P〈0．05）。结论尿毒症患者的听力下降是以高频为主的下降型曲线,内耳血供不足是导致尿毒症患者听力障碍的一个主要因素。     

Relationship between the auditory brainstem response and auditory nerve thresholds in cats with hearing loss

This study explored the relationship between the auditory brainstem response (ABR) and auditory nerve sensitivity in cats with normal hearing and with noise-induced permanent threshold shifts. A statistically significant linear correlation was found between each cat's ABR thresholds and the most sensitive single neuron thresholds at the same frequency. ABR thresholds were approximately 25 dB higher than the thresholds of the most sensitive neural responses in cats with normal hearing. The two measures produced equivalent thresholds at impaired frequencies in subjects with sensorineural hearing loss. Two factors may have contributed to this convergence of ABR and neural thresholds. First, our results suggest that the elevation of the most sensitive neural responses led to a compressed threshold distribution. Consequently, only a narrow range of sound levels separated stimulus conditions that activated relatively few fibers from those that were sufficient to evoke a robust population response. In addition, the threshold responses of impaired auditory nerve fibers may have been augmented by activity in the more sensitive 'off-frequency' regions that surrounded a discrete cochlear lesion. Across varying degrees of hearing loss, the ABR maintained a systematic relationship to auditory nerve fiber thresholds, and therefore has the potential to be used as a functional assay of cochlear pathology.     

儿童chirp听性脑干反应与行为测听的相关性

目的 采用chirp信号作为声刺激进行听性脑干反应(ABR)测试,观察chirp ABR阈值与行为测听的相关性,探讨chirp ABR作为儿童临床客观听力评估的可行性.方法 选择2007年8月至9月佛山市听觉语言康复中心的听力障碍儿童和广州市儿童医院听力门诊的正常听力儿童共22例(共35耳)作为研究对象,分别进行行为测听和chirp ABR测试,并对chirp ABR反应阈和行为测听阈值进行Pearson相关性分析.结果 22例接受测试儿童中男14例,女8例,年龄3.3～6.5岁,平均年龄4.8岁.纳入研究的35耳中,正常听力6耳,听力损失轻度2耳、中度4耳、重度10耳、极重度13耳.行为测听0.5、1、2、4 kHz平均听阈与chirp ABR阈值,0.5 kHz听阈与L-chirp ABR阈值,1～4kHz平均听阈与U-chirp ABR阈值之间的相关系数分别为0.939,0.900及0.930,P值均<0.05.结论 chirp ABR作为一种客观测听技术,能够较好地反映儿童的听力水平,有希望应用到临床工作中.     

短纯音诱发的听性脑干反应测试中声诱发短潜伏期负反应研究

目的 总结在有听力损失儿童中行短纯音诱发的听性脑干反应(tbABR)测试时记录到的声诱发短潜伏期负反应(acoustically short latency negative response,ASNR)的特点.方法 在有听力损失的0～6岁儿童中应用SmartEP听觉诱发电位仪记录短声和短纯音ABR的反应阈,在记录到ASNR的受试者中分析其反应阈和潜伏期.结果 在所有80受试耳中共7耳(8.75%)在cABR测试中引出ASNR,40耳(50%)在tbABR测试中引出ASNR,其中1 kHz引出率最高(37耳,46.25%),2 kHz次之(25耳,31.25%).引出ASNR者ABR波V反应阈最低65 dB nHL,ASNR反应阈最低80 dB nHL.0.5、1、2和4 kHz短纯音诱发的ASNR潜伏期分别为6～8、5～7、3～5、3～4 ms.随刺激强度的增加,其潜伏期缩短.结论 有听力损失的儿童tbABR测试中可以记录到AS-NR,但不影响以波V反应阈评估听力.     

Relationships between selected auditory and phonatory latency measures in normal speakers

Interaction between auditory and phonatory systems was explored in normal speakers by comparing laryngeal reaction time (LRT) with interpeak intervals from the auditory brainstem response (ABR) obtained using high and low stimulus presentation rates. Thirty-four subjects with no history of neurological or speech-language disorders and normal hearing sensitivity participated. Interpeak intervals were derived from ABR's recorded for each ear at rates of 21.1 and 91.1 clicks/s. LRT responses were obtained by instructing subjects to sustain an /s/ and then phonate an /a/ as fast as possible following visual cues. Two measures of reaction time performance were derived, Mean Laryngeal Reaction Time (MLRT) and Best Laryngeal Reaction Time (BLRT). Linear regression analyses were completed between each measure of reaction time performance and each ABR interpeak interval. Using either LRT measure, two significant (p less than .05) positive linear relationships were found. One involved the interpeak interval between Waves III and V and the other involved the interpeak interval between Waves I and V. Both were recorded at high stimulus presentation rates. These results support the small body of literature from normal speakers, stutterers, and spasmodic dysphonics suggesting interaction between the auditory and phonatory systems at the brainstem level.     

Comparison of ABR amplitudes with TIPtrode and mastoid electrodes

ABR evaluations were completed for 36 adults (18 males, 18 females) having normal hearing sensitivity and for 91 adult patients having various degrees of sensorineural hearing loss. Amplitudes of waves I and V were compared for ear canal (TIPtrode) electrode and mastoid electrode recordings. Interpeak intervals (I-III, III-V, and I-V) were determined and upper 95% confidence limits defined for normative data. In general, amplitude of wave I was larger when TIPtrodes were used. Wave V amplitude was nearly identical for the two electrodes. Wave I was identified more frequently for TIPtrode than for mastoid recordings of ABR waveforms for the sensorineural hearing loss subjects.     

The normative basis for click and frequency-specific BERA in high-risk infants

The use of brainstem electric response audiometry (BERA) for early detection of hearing loss is predicated upon large-sample normative data. Auditory brainstem response (ABR) thresholds for click and notch-masked tonepip stimuli were examined in 230 normal infants with no risk factors for hearing loss, tested under audiometrically ideal conditions at between 48 and 56 weeks post-conception. The ABR threshold distributions for clicks and tonepips differed considerably. Almost all infants had click thresholds consistent with normal hearing on adult criteria, whereas many appeared to have hearing loss at 500 Hz. ABR latencies for 70 dBnHL clicks were more variable than expected, even in infants with click thresholds of 30 dB or better. In males, wave V latency was about 0.2 ms larger than in females, but there was no such difference for wave I. For both sexes, there was a linear decrease in wave V latency with age at approximately 0.1 ms per month, but wave I latency was constant.     

Auditory sensitivity in children using the auditory steady-state response

OBJECTIVE: To determine the effectiveness of auditory steady-state response (ASSR) as a measure of hearing sensitivity in young children suspect for significant hearing loss. DESIGN: Within-subject comparisons of click auditory brainstem response (ABR) thresholds and ASSR thresholds. SUBJECTS: The study population comprised 42 children suspect for hearing loss and subsequently referred for hearing assessment using electrophysiologic techniques. MAIN OUTCOME MEASURES: Electrophysiologic threshold responses for click ABR and ASSR stimuli (0.5, 1, 2, and 4 kHz) for right and left ears. RESULTS: Based on ABR and ASSR thresholds, 50% of the subjects demonstrated significant hearing loss in the severe to profound range. In some subjects, ASSRs were present at higher stimulus levels when click ABRs were absent. Significant correlations (P<.05) were found between high-frequency ASSR and click ABR thresholds for this study sample. For some subjects, ASSR findings suggested differences between ears that were not observable from the no-response click ABR results. CONCLUSIONS: Auditory steady-state response testing may provide additional information for children who demonstrate hearing levels in the severe to profound range. This information may be helpful when selecting the ear for cochlear implantation for a young hearing-impaired child. Multiple objective methods, such as ABR and ASSR testing, may be needed to determine accurate hearing sensitivity for young children being considered for sensory devices, and in particular, cochlear implants.     

2062例婴儿的听力检查结果分析

目的探讨3～6月龄婴儿听力障碍的诊断方法。方法对2005年1月～2007年6月在上海交通大学医学院附属上海儿童医学中心就诊的2062例(4124耳)3～6月龄婴儿有选择地进行客观听力测试,包括听性脑干反应(ABR)、畸变产物耳声发射(DPOAE)、声导抗等检查,3月龄时诊断为听力异常者6月龄时复查,收集、分析两次听力测试的资料。结果3月龄时13例(20耳)ABR异常、DPOAE正常,504例(825耳)ABR、DPOAE均异常;ABR异常的845耳中,482例(808耳)(37耳失访)6月龄时复查示:13例(20耳)ABR异常、DPOAE正常,406例(702耳)ABR、DPOAE均异常,47例(64耳)ABR、DPOAR均正常,16例(22耳)ABR正常,DPOAR异常;比较两次检查结果显示:698耳(86.4%)听力无变化,90耳(11.1%)听力改善,20耳(2.5%)听力下降;在ABR反应阈正常、DPOAE未通过者中有438耳同时行226Hz及1000Hz探测音声导抗测试,1000Hz探测音声导抗异常183耳(41.8%),226Hz探测音声导抗异常6耳(1.37%)。结论3～6月龄婴儿的听力诊断必须结合ABR、OAE检查结果综合分析判断,必要时进一步行高频声导抗检查;0～6月龄婴儿中耳功能的检查,运用1000Hz探测音声导抗比226Hz的更敏感;对确诊听力障碍者,尤其是有听力障碍高危因素者,必须密切随访,警惕听力波动及进行性的听力下降。     

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.     

Evaluation of auditory brainstem responses for hearing screening of high-risk infants

Auditory brainstem responses (ABR) were recorded in 30 normal and 60 high-risk neonates with gestational age between 30 and 45 weeks. The normative data of normal group as regard to age, sex and various parameters of ABR were compared with high-risk group. ABR parameters especially wave V and interwave V-I intervals were significantly prolonged in high-risk infants. An infant was considered to “pass” the ABR test if an identifiable and replicable wave V response was present at 30 dB HL in both ears. All the normal neonates had click thresholds consistent with normal hearing. 12 of the highrisk neonates showed mild to moderate hearing impairment (absent replicable wave V at 30–60 dB HL) and 2 of them showed severe to profound hearing impairment (absent replicable wave V at 70 dB HL). 9 of the “failed” group were reevaluated within 3 months and several times thereafter if the abnormal responses persisted. 2 (3.3%) infants showed persistent hearing loss, which was confirmed later by behavioral audiometry.     

89例瞬态声诱发耳声发射筛查未通过婴幼儿听力学特点分析

目的 探讨听力筛查未通过而短声(click)诱发听性脑干反应阈值正常婴幼儿的听力学特点,进一步分析畸变产物耳声发射(DPOAE)不同频率异常与其他客观听力检查异常之间的关系.方法 瞬态声诱发耳声发射(TEOAE)听力筛查未通过而接受包括DPOAE、短声ABR、40 Hz听觉相关电位、226 Hz声导抗、1000 Hz声导抗和声反射等诊断性听力学检查的患儿共695例,以其中诊断性短声诱发ABR阈值正常的新生儿及婴幼儿89例(123耳)作为研究对象,根据DPOAE频率异常的不同分为A组(全频正常)、B组(低频异常)、C组(高频异常)和D组(全频异常).对比各项听力检查结果,分析DPOAE频率异常各组与其他5项客观听力检查(ABR Ⅰ波潜伏期、40 Hz听觉相关电位、226 Hz鼓室声导抗、1000 Hz鼓室声导抗及声反射)之间的相互关系.结果 123耳中所有6项听力检查均正常者7耳(5.7%);6项听力检查中有一项或一项以上异常者116耳(94.3%).男婴的异常率为93.9%(77/82),女婴的异常率为95.1%(39/41),二者差异无统计学意义(P＞0.05);左耳异常率为93.1%(54/58),右耳异常率为95.4%(62/65),二者差异无统计学意义(P＞0.05).各组耳数所占比例由高到低分别是D组48.0%(59/123)、B组27.6%(34/123)、A组16.3%(20/123)和C组8.2%(10/123).A组、B组和D组中异常率最高的检查项目均为声反射,异常率分别为40.0%,55.9%和66.1%;而C组中异常率最高的项目为ABR Ⅰ波潜伏期(50.0%).各组低频听力损失均以轻度为主,在B组中有1耳为中度听力损失,D组中有6耳为中度听力损失,1耳为重度听力损失.结论 听力筛查未通过而短声ABR反应阈值正常的婴幼儿,如果DPOAE全频异常,需要及时进行全面的听力学评估,而DPOAE全频正常、低频异常或高频异常者,需要进行跟踪随访.

Abstract：

Objective The presnt study was to evaluate the audiological characteristics of infants with normal auditory brainstem response thresholds in click and abnormal transiently evoked otoacoustic emissions. Relationships between test results of distortion product otoacoustic emissions(DPOAE) and other hearing testing methods were also evaluated. Methods The participants consisted of eighty-nine infants,with a total of 123 ears. All participants' TEOAE screening results were abnormal but diagnostic click ABR results were normal. The participants were classified into the following goups based on the test results from distortion product otoacoustic emissions: group A (normal all-frequency ), group B (abnormal lowfrequency), group C (abnormal high-frequency ), and group D (abnormal all-frequency ). Results Obtained from these groups were compared to results of other hearing tests including the latency of ABR wave Ⅰ, 40 Hz auditory event related potential (40 Hz AERP), 226 Hz and 1000 Hz tympanometry, and acoustic reflex. Results In six hearing tests in the 123 ears, seven ears (5.7%) were normal, while 116ears (94. 3% ) were abnormal. No significantly differences were detected between boys (93.9%) and girls (95. 1% ), as well as between left (93. 1% ) and right ears (95.4%). The proportion of abnormal test results ranked as follows: 59 ears in group D (48.0%), 34 ears in group B (27.6%), 20 ears in group A (16. 3% ), and 10 ears in group C (8.2%). The highest abnormal rates in groups A, B and D were acoustic reflex, which were 40. 0% for group A, 55.9% for group B and 66. 1% for group D respectively.The highest abnormal rate in group C was the latency of ABR wave Ⅰ ( 50. 0% ). Distribution of lowfrequency hearing loss in each group was mainly mild. However, one ear in group B was moderate hearing loss, six ears in group D were moderate hearing loss, and one ear in group D was severe hearing loss.Conclusions The present study showed that, of which infants with normal thresholds of ABR failed the hearing screening, comprehensively audiology assessment is needed. And of which infants with normal DPOAE in full frequency or abnormal in high frequency region or low frequency region need to be followed up.