The effects of crossed olivocochlear bundle section on transient evoked otoacoustic emissions

The purpose of this study was to investigate the effect of sectioning the crossed olivocochlear bundle (COCB) on transient evoked otoacoustic emissions (TEOAEs) in anesthetized adult chinchillas. Of particular interest is the role of cochlear efferents to the outer haircells (OHCs) and how they control mechanisms responsible for otoacoustic emissions. Specifically the experiment addressed whether a tonic level of inhibitory control is reduced by COCB section. The nonlinear component of TEOAEs was measured before and after COCB section. Analysis was made of the 1, 2, 3, 4, and 5 kHz frequency components and of the total emission, as quantified by fast Fourier transform (FFT) of the raw (time domain) response. After COCB section, the amplitude of the total response and of the 2, 3, 4, and 5 kHz components increased whereas the amplitude of the 1 kHz component decreased. The results indicate that COCB section reduces inhibitory control of the OHC mechanisms responsible for nonlinear TEOAE generation. It is not clear whether the nerve section eliminates a spontaneous level of activity in COCB efferents, or whether it results in the interruption of a stimulus-evoked feedback loop.     

Influence of a 6–8 kHz audiometric notch on transient evoked otoacoustic emissions

Thirty-eight patients with known unilateral cochlear hearing loss at 6 and/or 8 kHz were examined for transient evoked otoacoustic emisssions (TEOAEs). These findings were compared with those of the contralateral “normal hearing” ear. Statistically significant lower values of echo reproducibility and amplitude were recorded in hearing-impaired ears, together with a more narrow TEOAE spectrum. In addition to these findings, a globally reduced amplitude of the cochlear response was found that was unrelated to the frequency impaired in pure-tone audiometry (6, 8, or 6–8 kHz). Since patients’ audiometric thresholds at such frequencies could influence test results, findings could possibly be due to an altered echo travelling wave across the most basal part of the cochlea or to coexisting damage in the rest of Corti’s organ that were undetectable with standard audiometry. A significant overlap was found between the results from hearing-impaired ears and those from normally hearing ones. Although TEOAEs were not helpful in the present study in identifying patients with a unilateral hearing loss at 6 and/ or 8 kHz when compared to normal contralateral ears, they are still considered to play an important role in the follow-up of subjects at risk for hearing damage. Received: 22 December 1997 / Accepted: 14 May 1998     

An implementation study of neonatal hearing screening in the Netherlands

The objective of this study was to investigate whether universal neonatal hearing screening could be integrated in the youth health care program. The screening was performed by nurses of the well baby clinics. A three stage transient evoked otoacoustic emission screening was performed in three different screening settings in order to study the most effective set up regarding participation, refer rates, and costs. In one setting parents visited the well baby clinic, and in two settings babies were screened at home (either in combination with the screening for metabolic diseases or during an intake visit). Screening was performed on 3114 healthy newborns. The setting where universal neonatal hearing screening is integrated with the screening for metabolic diseases, proved to be most efficient and effective. The participation rate of 88.9% was highest in this setting and the overall refer rate (1.4%) was the lowest. The implementation of universal neonatal hearing screening by the well baby clinic nurses was judged to be possible. The results of this study formed the basis for nationwide implementation.     

Transient evoked otoacoustic emissions and contralateral suppressions in children with auditory listening problems

Objectives

Transient evoked otoacoustic emissions (TEOAEs) are reflections of cochlear energy produced during the processing of sound. The suppression effect identified as the decrease with the additional tone stimulator of the otoacoustic emission amplitude is use for assessing efferent auditory system function. The aim of this study is to investigate the contralateral suppression effect (CSE) of transient evoked otoacoustic emissions (TEOAEs) in children with auditory listening problems (ALPs) compared to normal hearing children.

Method

The study group (Group 1) was consisted of 12 ALP children (8 males and 4 females), aged 5–10 years, and associated with receptive and expressive language delay. The control group was consisted of (Group 2) 12 children with normal hearing levels, matched according to gender and age of TEOAEs and CSE of TEOAEs were investigated at 1.0–4.0 kHz in both groups.

Results

For right ear, at 1.0 and 3.0 kHz, TEOAE amplitudes of the ALP group were significantly lower than the control group. At 2.0, 4.0 and 5.0 kHz of the right ear and at 1.0–5.0 kHz of the left ear, TEOAE amplitudes were found as not different between ALP and control groups. Suppression values of the ALP group were significantly lower than the control group at 1.0–2.0 kHz of the right ear and at 2.0 kHz of the left ear. At the other frequencies, there was no significant difference between the suppression values of the ALP and control groups.

Conclusion

Lower suppression values in ALP group at all frequencies (significant at 1.0–2.0 and 2.0 kHz in the right and left ears, respectively) showed that cochlear and cranial maturation of the ALP group may lower than the control group. Since the age profile in both group is similar, we thought that age's effect on this results is not important. Our results showed that children with ALP have auditory processing difficulties in noisy environment. For understanding the efferent auditory system, patients with auditory processing disorders may be evaluated by the help of background noise.     

Audiologic evaluation of neonates with severe hyperbilirubinemia using transiently evoked otoacoustic emissions and auditory brainstem responses

OBJECTIVES: To audiologically clarify the lesion site and to test the reliability of transiently evoked otoacoustic emissions (TEOAEs) in hearing screening of hyperbilirubinemic neonates. STUDY DESIGN: Eleven neonates with severe hyperbilirubinemia who had exchange transfusion in the neonatal intensive care unit of an academic hospital over a 3-year period were included in this study. They were tested with auditory brainstem response (ABR) and TEOAEs after exchange transfusion during hospitalization or at an immediate follow-up visit after discharge. Follow-up ABR tests were performed when infants showed significant hearing loss. METHODS: ABR and TEOAE tests were performed on the 11 neonates with severe hyperbilirubinemia after exchange transfusion. Follow-up ABR tests were carried out in 3-month intervals in the four neonates who showed abnormal or no response on initial ABR. RESULTS: Four neonates showed abnormal or no response and the other seven demonstrated normal response in ABR. All 11 neonates passed TEOAEs. Two neonates showed improvement in auditory function at 3- or 6-month follow-up ABR. CONCLUSION: The results of this study indicate that the site of lesion in hearing loss caused by hyperbilirubinemia may be at the retrocochlear location while the cochlea remains intact. TEOAEs may have limitations in evaluation of hearing in the neonates with hyperbilirubinemia.     

TEOAE与AABR在高危新生儿听力筛查中的联合应用

目的探讨联合应用瞬态诱发性耳声发射(TEOAE)和自动听性脑干反应(AABR)在高危新生儿听力筛查中的应用。方法对新生儿科NICU高危新生儿200例（400耳）,运用AccuScreen听力筛查仪,同时进行TEOAE和AABR联合听力筛查,根据TEOAE初次筛查结果通过与否,分为双耳TEOAE初筛均未通过组(A组)和双耳TEOAE初筛均通过组（B组）,共2组,每组100例（200耳）,其中3个月时任何一项检查未通过者均在患儿6个月时进行听性脑干反应、声导抗测试等诊断性检查。结果A组：3个月时TEOAE未通过12例（22耳）,AABR未通过2例（2耳）,联合筛查未通过22例。6月龄时确诊1例（2耳）分泌性中耳炎,该两耳均为3次TEOAE筛查未通过、AABR筛查通过者,本组高危新生儿听力损伤现患率为1.7%（2/120）;B组：3个月时TEOAE未通过2例（2耳）,AABR未通过5例（5耳）,联合筛查未通过5例（5耳）。6月龄时确诊2例（2耳）诊断为蜗后性耳聋,该两耳均为3次AABR筛查未通过、TEOAE筛查通过者,本组高危新生儿听力损伤现患率为1.4%（2/146）,每组在定期复筛时均有部分失诊患儿。结论通过TEOAE和AABR联合筛查,可以检出中耳、蜗性及蜗后听损伤,证实了TEOAE和AABR是听力筛查的有效组合方式,AABR和TEOAE联合筛查应用可以优势互补,降低漏诊、误诊率。     

Effects of interaural intensity and time disparity on transient evoked otoacoustic emissions

Monaural and binaural 11/s, 65 dB pe SPL clicks with interaural time and intensity disparities known to affect central auditory processing were used to study contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) in 10 subjects (20 ears). Psychophysical assessment of sound lateralization induced by the same stimuli was also conducted. TEOAEs were recorded to monaural (ipsilateral to the OAE recording probe) and to binaural clicks when clicks to the contralateral ear were synchronous and symmetrical in intensity, or, in the binaural intensity disparity conditions, synchronous but 10 dB higher or 10 dB lower in the ear contralateral to the OAE recording probe. When interaural time disparities were studied, the clicks to the contralateral ear were of the same intensity throughout, but 400 μs earlier or 400 μs later than to the ear with the probe. The TEOAE components at 13–15.8 ms showed suppression, relative to monaural responses, under all binaural conditions. This contralateral suppression did not correlate with the psychophysical findings. Suppression effects were more pronounced with binaural disparity than with binaurally symmetrical clicks. Thus, although contralateral click intensity was the same with time disparities, suppression was paradoxically enhanced compared to the binaurally symmetrical stimulation. To explain these results we propose that two factors are involved in TEOAE suppression with binaural clicks: (1) contralateral intensity and (2) interaural disparity (time or intensity). The latency of the suppressions observed, the effect of interaural disparity on these suppressions, coupled with the anatomical origin of the crossed efferent fibers and the disparity sensitivity of the superior olivary complex (SOC), all suggest SOC involvement in these TEOAE suppressions.     

Comparison of hearing screening programs between one step with transient evoked otoacoustic emissions (TEOAE) and two steps with TEOAE and automated auditory brainstem response

OBJECTIVE: To compare the efficacy between one step with transient evoked otoacoustic emissions (TEOAE) and two steps with TEOAE and automated auditory brainstem response (AABR) in a newborn hearing screening program. We investigated their differences in referral rate, the accurate identification rate of congenital hearing loss (HL), and cost effectiveness. METHOD: From November 1998 to December 2004, a total of 21,273 healthy newborns were screened for HL in Mackay Memorial Hospital, Taipei. In the periods from November 1998 to January 2004 and from February 2004 to December 2004, the screening tools used were TEOAE alone (n = 18,260) and TEOAE plus AABR (n = 3,013), respectively. RESULTS: A statistically significant decrease of referral rate was achieved in the group using TEOAE and AABR as screening tools when compared with TEOAE alone (1.8% vs. 5.8%). The accurate identification rate of congenital HL was 0.45% in TEOAE protocol and 0.3% in TEOAE and AABR protocol, which was not statistically significant. The total direct costs per screening were 10.1 U.S. dollars for the program using TEOAE alone and 8.9 U.S. dollars for the TEOAE plus AABR program. The intangible cost, however, was much higher in the earlier program because of the higher referral rate. CONCLUSION: In terms of the efficacy of a hearing screening program using the one step TEOAE and two step TEOAE and AABR programs, the later significantly decreased the referral rate from 5.8% to 1.8%. No significant difference was noted between the accurate identification rates of congenital HL. The total costs, including expenditures and intangible cost, were lower in the protocol with TEOAE plus AABR.     

Evaluation of anesthesia effects in a rat animal model using otoacoustic emission protocols

Anesthesia effects on otoacoustic emission (OAE) recordings were evaluated in a group of 72 Sprague–Dawley rats (mean weight 225±20 gr). Two anesthesia dosages (high and normal) and two anesthetic protocols (ketamine–xylazine, ketamine–xylazine–atropine) were tested. Transient evoked OAE (TEOAE) and distortion product OAE (DPOAE) responses were recorded in 10 min intervals, for a total period of 60 min. Analyses of the data with repeated measure models indicated the following: (1) The animals receiving a high dose of anesthesia (cumulative dose 66.6 mg of ketamine and 13.2 mg of xylazine/kg of body weight) presented significant alterations of the TEOAE response level and the signal to noise ratio at 3.0 kHz; (2) the animals receiving a normal dose of ketamine–xylazine anesthesia (cumulative dose 50 mg of ketamine and 10 mg of xylazine/kg of body weight) presented TEOAE and DPOAE responses invariant in terms of time; (3) significant differences were observed in the DPOAE responses from animals anesthetized with ketamine–xylazine and ketamine–xylazine–atropine. The data support the hypothesis that the ketamine anesthesia OAE suppressing mechanism is related to middle-ear mechanics.     

Distortion product otoacoustic emissions in patients with King-Kopetzky syndrome

In the present study, mild impairment of cochlear function in patients with King-Kopetzky syndrome was investigated using DPOAEs. A significant decrease in DPOAE levels in both ears was found in patients with King-Kopetzky syndrome compared with the controls after considering the thresholds as a co-variable. It is noteworthy that the global mean levels of DPOAEs were still significantly greater in controls than in patients with matched thresholds. Further frequency analyses showed a significant decrease in DPOAE levels over the mid- and high-frequency range in patients with better hearing thresholds when compared with those in the control group. Moreover, significantly smaller DPOAEs were found in the ears of patients with King-Kopetzky syndrome and without SOAEs, than in such ears of control subjects after considering the thresholds as a co-variable. However, when SOAEs were present there was no difference. Decreases in DPOAE level appear to represent evidence of minor cochlear pathology, and provide a pathological basis for the difficulty of hearing speech in the presence of background noise, which characterizes King-Kopetzky syndrome.

Sumario

En el presente estudio, se investigó una leve alteración en la función coclear en pacientes con el síndrome de King-Kopetzky usando DPOAE. Se encontró una disminución significativa en los niveles de intensidad de las DPOAE en ambos oídos en pacientes con este síndrome, al compararlos con los controles, luego de considerar el umbral como una co-variable. Es digno de resaltar que los niveles globales medios de las DPOAE fueron aún significativamente mayores en los controles que en los pacientes con umbrales correspondientes. Un análisis de frecuencia ulterior mostró una disminución significativa en los niveles de las DPOAE, en el rango de frecuencias medias y altas, en pacientes con los mejores umbrales auditivos, al compararlos con aquellos del grupo control. Más aún, se encontraron DPOAE significativamente menores en la audición de pacientes con el síndrome de King-Kopetzky y ausencia de SOAE, comparados con los oídos de sujetos control, luego de considerar el umbral como una co-variable. Sin embargo, cuando las SOAE estuvieron presentes, no hubo diferencia. La disminución en el nivel de intensidad de las DPOAE parece representar evidencia de patología coclear menor, y aporta una base patológica para explicar la dificultad para entender el lenguaje en presencia de ruido de fondo, que caracteriza al síndrome de King-Kopetzky.     

瞬态诱发耳声发射在农村学龄儿童听力筛查中的应用

目的探讨瞬态诱发耳声发射(transient evoked otoacoustic emission,TEOAE)应用于中国农村学龄儿童听力筛查的意义和可行性。方法用Madsen Celesta503耳声发射仪对317例(634耳)正常农村小学1~6年级学生进行听力筛查,并用耳镜、纯音测听和鼓室导抗图系列检查作为“金标准”,验证其结果。结果317例(634耳)儿童TEOAE的通过率为94.64%(600/634),金标准的通过率为94.48%(599/634)。TEOAE测试中,一致百分率为96.69%±0.71%,灵敏度为0.69±0.078(69%±7.8%),特异度为0.98±0.0052(98%±0.52%),漏诊率β=0.31,误诊率α=0.02,Youden指数J=0.67±0.078,阳性似然比LR =34.5,阴性似然比LR-=0.32,阳性预报值PV =0.71(71%),阴性预报值PV-=0.98(98.%),AZ=0.8。结论TEOAE测试具有方便、快速、无创、灵敏、客观等优点,是较好的中国农村学龄儿童听力筛查的方法。     

Comparison of two-step transient evoked otoacoustic emissions (TEOAE) and automated auditory brainstem response (AABR) for universal newborn hearing screening programs

OBJECTIVE: Both transitory auditory otoemissions (TEOAE) and automated auditory brainstem responses (AABR) are considered adequate methods for universal hearing screening. The goal of this study was to compare the results obtained with each device, applying the same screening procedure. MATERIALS AND METHODS: From 2001 to 2003, all the newborns in our health area (2454 infants) were evaluated with TEOAE (ILO92, otodynamics) and all those born from 2004 to 2006 (3117) were evaluated with AABR (AccuScreen, Fischer-Zoth). The population studied included all well newborns and those admitted to neonatal intensive care units (NICU). The first screening was normally undertaken with well babies during the first 48h of life, before hospital discharge. Infants referred from this first step underwent a second screening after hospital discharge, before they were a month old. RESULTS: The results from each study group were compared and analyzed for significant differences. TEOAE screening yielded 10.2% fail results from the first screening step; AABR gave 2.6%. In the second screening step, 2% of the newborns screened with TEOAE were referred, whereas 0.32% of those screened with AABR were referred. These differences are statistically significant. CONCLUSIONS: Although AABR screening tests involve a slightly higher cost in time and money than TEOAE, the results obtained compensate this difference. AABR gives fewer false positives and a lower referral rate; the percent of infants lost during follow-up is consequently smaller. Therefore, in our environment, universal newborn auditory screening with AABR is more effective than that with TEOAE.     

TEOAE suppression in adults with learning disabilities

The presentation of contralateral noise during the recording of transient evoked otoacoustic emissions (TEOAEs) reduces the amplitude of the TEOAE in normally-hearing adults. This is known as TEOAE suppression. The present study investigated TEOAE suppression in 18 adults with learning disabilities (LDs) compared to 18 adults without LDs. TEOAEs were elicited by 60 dB p.e. SPL clicks and were suppressed by the presentation of 60 dB SPL contralateral broadband noise. Suppression was measured as a change in the overall TEOAE response amplitude, and also analysed in 2-ms epochs representing different TEOAE frequency-response bands. A significant interaction was evident between group type and ear tested. Participants in the control group had right ear dominance for the suppression effect, whereas the left ear was found to be dominant for the LD group. These findings suggest a mechanism of the medial olivary cochlear bundle and efferent auditory pathway that differs in those with LD compared to those with typical learning abilities.     

Contralateral suppression of otoacoustic emissions in a clinical sample of children with auditory processing disorder

Objective: The suppression of evoked otoacoustic emissions (EOAE) may serve as a clinical tool to evaluate the medial olivocochlear (MOC) reflex, which is thought to aid speech discrimination (particularly in noise) by selectively inhibiting cochlear amplification. The present study aimed to determine if contralateral transient evoked otoacoustic emission (TEOAE) suppression was present in a clinical sample of children with listening difficulties with and without auditory processing disorder (APD).

Design: A three-group, repeated measure design was used.

Study sample: Forty three children aged 8–14?years underwent an auditory processing assessment and were divided into three groups: children with reported listening difficulties with APD, children with reported listening difficulties without APD, and children with normal hearing. APD was defined as per British Society of Audiology.

Results: TEOAE suppression was present in all three participant groups. No significant group, age or ear effects were observed for TEOAE suppression in dB or as a normalised index.

Conclusion: Contralateral TEOAE suppression method could not be used as a clinical tool to identify APD in this study’s participating children and did not support the hypothesised link between reduced MOC function and general listening difficulties in background noise in children with or without APD.     

外周性脑积水致听力障碍小儿的DPOAE检查

目的综合评估外周性脑积水伴感音神经性聋小儿临床听力学特点及选择适宜的听力评估参数.方法选取我院神经康复科住院患儿,年龄不超过2岁,听觉脑干诱发电位(ABR)波V阈值≥50dBHL且排除中耳功能异常,并经神经康复科医师综合评估确诊为外周性脑积水者57例95耳,平均年龄7.21个月.入选的小儿,根据ABR波V阈值的不同分为二组:波V阈值＜80dBHL组和波V阈值≥80dBHL组.另设同年龄段正常对照组.各组受试者均进行畸变产物耳声发射(DPOAE)的测试.结果外周性脑积水患儿ABR波V阈值＜80dBHL耳所占比例高达78.95%;各组间的DPOAE检出率无显著性差异;波V阈值＜80dBHL组和≥80dBHL组的DPOAE异常率分别为21.33%和35%,二者的差异有显著性意义;波V阈值＜80 dBHL组和≥80dBHL组与正常对照组的DPOAE幅值存在显著性差异;但前二者间的DPOAE幅值则无显著性差异.结论外周性脑积水主要表现为轻中度的听力损害;听觉系统受损部位主要表现在蜗后,但也有一小部分的耳蜗功能受损;在评估外周性脑积水患儿听力的参数中,ABR波V阈值与DPOAE异常率更能准确反映外周性脑积水听力损失的听力学特点.     

Alport综合征畸变产物耳声发射测试

目的 分析遗传性血尿肾病耳聋综合征(Alport syndrome,As)病人的听功能改变特点,畸变产物耳声发射(DPOAEs)测试的意义。方法 对10例As病人进行了纯音测听、声导抗、DPOAEs和听性脑干反应(ABR)测试。结果 As病人全部DPOAEs反应缺失或高频、中频振幅下降,声导抗测试10例病人鼓室压图均为A型曲线,除2例重度感音性耳聋病人声反射阈与听阈之差<60dB,提示Metz重振试验阳性外,其余病人各波潜伏期和波间期均在正常范围。结论 10例As病人DPOAEs均不正常,声导抗、ABR均能引出,验证了As病人耳部病变定位为耳蜗基底膜,与肾脏基底膜病变为共同靶器官,DPOAEs能反映耳蜗外毛细胞的功能微病理改变,对As的早期诊断、鉴别诊断及对遗传咨询有指导意义。     

Ototoxic effects of cisplatin in a Sprague-Dawley rat animal model as revealed by ABR and transiently evoked otoacoustic emission measurements

The ototoxic effects of cisplatin in a Sprague–Dawley rat model were evaluated by recordings of auditory brainstem responses (ABR) and transiently evoked otoacoustic emissions (TEOAEs). The ABR responses were evoked from alternating clicks and 8, 10, 12, 16, 20 and 30 kHz tone pips in a range from 40 to 100 dB SPL range. The TEOAEs were recorded with a non-linear protocol, and were evoked by a 63.5 dB SPL click stimulus. Twenty five male Sprague–Dawley rats were used in the study, 20 animals were treated with cisplatin (16 mg/kg, body weight) and five animals served as controls. The data showed that 72 h after the cisplatin administration, the TEOAE and ABR variables were significantly altered. The relationship between the ABR and TEOAE variables was shown to be non-linear. The most significant relationships were observed between the TEOAE correlation and the ABR threshold values at 10, 12, and 16 kHz.