新生儿和正常青年人瞬态诱发耳声发射的频谱分析

选用短声及短音１ｋＨｚ和２ｋＨｚ作为瞬态刺激声，对１８名正常产新生儿及１８名正常青年人进行诱发耳声发射测试，并将所测得的瞬态诱发耳声发射（ＴＥＯＡＥ）波形进行频域分析。结果表明：两年龄组及三种刺激声的ＴＥＯＡＥ检出率比较差异无显著性，但新生儿组短声ＴＥＯＡＥ检出率（９１．７％）低于国外资料报道，提示生后４天内测试ＴＥＯＡＥ会影响检出率。频谱分析表明：两年龄组及三种刺激声的ＴＥＯＡＥ频谱带宽间比较差异无显著性，但ＴＥＯＡＥ的频谱峰值随刺激声的不同而不同，其频谱特征与刺激声频率间有某种依赖关系，考虑与内耳机械、调谐特性，外耳、中耳谐振等多因素相关。     

高频耳蜗性聋诱发耳声发射测试结果分析

对高频耳蜗性聋耳及正常耳进行短声诱发的瞬态耳声发射（ＴＥＯＡＥ）及脑干诱发电位（ＡＢＲ）测试。结果：①正常组ＴＥＯＡＥ的频率主要成分为０．５－５ｋＨｚ之间，最大能量频谱在１－２ｋＨｚ范围内。②ＴＥＯＡＥ频谱与纯音听力图形状之间有密切关系。③正常组ＴＥＯＡＥ的输入输出函数呈非线型特点，在高刺激强度下呈饱和倾向。患者组ＴＥＯＡＥ与ＡＢＲ的增长率均可见在高刺激强度显著高于正常组的特点。提示ＴＥＯＡＥ的异     

中耳病变时瞬态诱发耳声发射的表现

目的 了解中耳病变时ＴＥＯＡＥ的表现。方法 选择经耳镜检查、纯音听阈及声导抗测试确诊为中耳病变，纯音气导听阈不超过３０ｄＢＨＬ的４６只病变耳及对照组正常２８耳进行ＴＥＯＡＥ测试，病安不同听阈水平及不同病变分组，并对其结果进行分析比较。结果ＴＥＯＡＥ反应幅值及反应重复性随听阈提高而降低，听阈〉２０ｄＢ部分耳ＴＥＯＡＥ消失，气骨导间距〉１０ｄＢ时ＴＥＯＡＥ消失者为５０％。在不同中耳病变中，鼓室负压组     

新生儿和正常青年人瞬态诱发耳声发射的频谱分析

选用短声及短音１ｋＨｚ和２ｋＨｚ作为瞬态刺激声，对１８名正常产新儿及１８名正常青年人进行诱发耳声发射测度，并将所测得的瞬态诱发耳声发射（ＴＥＯＡＥ）波形进行频域分析。结果表明：两年龄组及三种刺激声的ＴＥＯＡＥ检出率比较差异无显著性，但新生儿组短声ＴＥＯＡＥ检出率（９１．７％）低于国外资料报道，提示生后４天内测试ＴＥＯＡＥ会影响检出率。频谱分析表明：两年龄组及三种刺激声的ＴＥＯＡＥ频谱带宽间比较差异     

耳声发射技术在围产期听力学中的应用价值

本研究用瞬态诱发耳声发射技术对北京海演妇幼保健院１９９８年４－８月出生的新生儿进行听功能筛查，用听觉脑干反应和４０ＨＺ听觉相关电位技术作为确诊程序，探讨了ＴＥＯＡＥ技术在婴幼儿听功能监测中的作用和可能的应用前景。其结果显示：（１）１４７０例新生儿接受了ＴＥＯＡＥ听功能筛查，经过以阶段的ＴＥＯＡＥ筛查后，总通过率为９４．９０％；９２）双阶段ＴＥＯＡＥ听功能筛查程序的阳性预测值为７３．０８％；（３）接     

对侧白噪声刺激对正常人瞬态诱发耳声发射的影响

近年发现对侧声刺激可引起耳声发射（ＯＡＥｓ）减弱；认为是由于内侧橄榄耳蜗系统对外毛细胞的调控所致。本实验观察了对侧耳给予白噪声对正常人瞬态诱发耳声发射（ＴＥＯＡＥｓ）的影响，结果表明对侧声刺激能抑制ＴＥＯＡＥｓ，抑制作用随对侧刺激声强的增大而增大；讨论了本实验的有关影响因素及ＴＥＯＡＥｓ受抑制的机理，认为通过检测对侧声刺激对ＯＡＥｓ的抑制作用可以了解内侧橄榄耳蜗系统的功能。     

瞬态诱发耳声发射对梅尼埃病的诊断意义

目的：确定瞬态诱发耳声发射（ＴＥＯＡＥ）甘油试验对梅尼埃病的诊断意义。方法：对梅尼埃病患者的患耳及健耳（共６０耳），以及非梅尼埃病耳（对照耳共８耳）作ＴＥＯＡＥ测试。结果：甘油摄入后，患耳ＴＥＯＡＥ的波重复性、反应幅值、频带重复性及信噪比值皆比摄入前增加，且甘油试验阳性者纯间听阈高，阴性耳也有显著增加；健耳各参数值也有增加，主频也出现变化。结论：甘油试验ＴＥＯＡＥ测试是比纯间听阈测试更为敏感更简便     

缺氧缺血性脑病新生儿瞬态诱发耳声发射测试

目的了解应用瞬态诱发性耳声发射（ｔｒａｎｓｉｅｎｔｅｖｏｋｅｄｏｔｏａｃｏｕｓｔｉｃｅｍｉｓｉｏｎｓ,ＴＥＯＡＥ）对正常新生儿高危新生儿行听力筛查的可行性。方法采用ＳＦ－Ⅰ型耳声发射接受器与ＣｏｍｐａｃｔＡｕｄｉｔｏｒｙＴＩＰ－３００电反应测听仪联合记录,对２０名正常新生儿及３６名缺氧缺血性脑病（ｈｙｐｏｘｉａ－ｉｓｃｈｅｍｉｃｅｎｃｅｐｈａｌｏｐａｔｈｙ,ＨＩＥ）新生儿进行ＴＥＯＡＥ和ＡＢＲ测试。结果ＨＩＥ患儿ＴＥＯＡＥ多表现为阈值升高或波缺失,ＴＥＡＯＥ能否出现与ＡＢＲ之Ｖ波阈值密切相关,重度ＨＩＥ的ＴＥＯＡＥ出波率较轻度者明显减低。结论ＴＥＯＡＥ可早期发现缺氧等高危因素所致听力损伤,因此有可能成为早期监测新生儿及高危儿听力的一种方法。     

瞬态诱发耳声发射频域分析的临床意义

目的：确定瞬态诱发耳声发射（ＴＥＯＡＥ）频域分析的应用价值。方法：对正常耳，噪声暴露耳，梅尼埃病耳，中耳病变耳及对侧抑制耳，进行ＴＥＯＡＥ频域测试。结果（１）噪声暴露耳，一些频率带的频信噪比降低，主频出现移动变化；（２）梅尼埃病一些甘油摄入后，频带信噪比增高，未引出ＴＥＯＡＥ的部分耳出现ＴＥＯＡＥ，主频也有移动变化；（３）中耳病变耳，不同的鼓室病变耳的频带信噪比降低，程度各异，其变化与声导纳改变有     

耳声发射在耳蜗病变早期诊断中的应用

人的内耳是一个精细的流体动力学的频率分析器，人对声音感受主要取决于耳蜗的功能状态，而耳蜗的损伤一般来讲是不可逆的，所以对感音神经性耳聋做到早期发现提早防治就显得非常重要。耳声发射（ＯＡＥ）被认为是一个理想的客观检测方法。ＴＥＯＡＥ（瞬态诱发性耳声发射）在正常青年人的检出率为１００％。本文就５７耳（５０～６９岁）听力正常者（纯音测听各频率均≤２５ｄＢＨＬ），用短声进行了ＴＥＯＡＥ检测。结果发现：８．４７％的正常耳未记出ＴＥＯＡＥ，其中５０～５９岁年龄组６．９８％未记出ＴＥＯＡＥ；６０～６９岁年龄组１４．２９％未记出ＴＥＯＡＥ。说明受试者纯音测听虽然正常，但其耳蜗已有损伤，且似乎随年龄的增长，损伤的机率增加，其原因一般认为是耳蜗外毛细胞损失和耳蜗功能状态改变有关。提示ＴＥＯＡＥ可以早期预测耳蜗外毛细胞的功能状态，其敏感性优于主观纯音测听，可弥补纯音测听之不足，为早期诊断提供了有利手段。     

Personal long-term reproducibility of the TEOAE time-frequency distributions

The TEOAE signal is relatively short and content changes in time. Due to the fact that signal is very short (20 ms) a special approach must be applied for the analysis of this nonstationarity. Usually the spectral estimation in TEOAE is based on procedures directly employing the fast Fourier transform (FFT). Because TEOAE signal is non stationary the classical Fourier analysis is not adequate for this signal. The aim of our study was the personal comparison of the TEOAE spectograms by using Wigner-Ville distribution (WVD) before and after one year period. Material consisted of 152 men (304 ears) in the age between 18-19 year with good quality OAE. After one year period the comparison of WVD spectrograms showed the highest similarity in the 274 ears (90%), less in the 24 (8%) and in 6 (2%) similarity was not noticed. Personal similarity of the spectrum TEOAE and differences between individual people's ears despite a long time, give a proof about individual architecture of outer hearing cell and maybe useful in the biometrics as a ear-print.     

The influence of body temperature on transient evoked otoacoustic emissions

Thirty patients undergoing open heart surgery under induced hypothermia had transient evoked otoacoustic emissions (TEOAE) recorded during cooling to 26.07 degrees C (standard deviation (SD) 4.25 degrees C) vesically measured temperature and 24.86 degrees C (SD 4.7 degrees C) nasopharyngeally measured temperature respectively. Subsequently tè patients were rewarmed until normal body temperature was reached again. There was a clear influence of body temperature on the amplitudes and reproducibilities of the TEOAE. The relationship of temperature and amplitude or reproducibility during the cooling phase was significantly different from that during rewarming. No TEOAE were measurable during cooling at a mean temperature lower than 33.41 degrees C (SD 2.04 degrees C) vesical temperature and 30.16 degrees C (SD 3.0 degrees C) nasopharyngeal temperature respectively. During rewarming the echoes became recognizable again at a mean temperature of 28.75 degrees C (SD 3.38 degrees C) vesical temperature and 27.49 degrees C (SD 2.99 degrees C) nasopharyngeal temperature. These results suggest a hysteresis in the relationship between the amplitude of TEOAE and temperature, similar to the well-established relationship between evoked potentials and temperature.     

TEOAE monitoring of Cisplatin induced ototoxicity in guinea pigs: the protective effect of vitamin B treatment

OBJECTIVE: To evaluate Cisplatin (CP) induced ototoxicity and the effects of vitamin B treatment on ototoxicity in guinea pigs by using the Transient Evoked Otoacoustic Emission (TEOAE) technique. METHODS: Eleven guinea pigs were divided into two groups and they were tested by TEOAE before and after the experiment. A TEOAE response was regarded as positive when all of the following criteria were met: 1. The mean amplitude of the cochlear response in dB pe SPL should be greater than that of the noise in the external auditory canal; 2. The reproducibility rate of the response should be greater than 50%; 3. The stimulus stability rate should be greater than 65%; 4. The signal to noise ratio of the response in 1, 2, 3, 4 and 5 kHz band frequencies should be greater than 3 dB pe SPL in at least two bands. The first group included five animals that had only CP injections. Six animals in the second group received additional 0.2 ml/kg combined vitamin B preparations for 7 consecutive days. Thereafter, the right and left ears of all animals in both groups were tested by TEOAE. RESULTS: TEOAE responses recorded from 22 ears of 11 guinea pigs before drug administrations showed that the responses with maximum amplitude were originated from the mid-frequency region. Positive TEOAE responses were significantly reduced after CP administrations in both groups when compared with their respective pretreatment results (P<0.01). However, vitamin B injections, in addition to a single large dose of CP, resulted in significantly better TEOAE responses than those obtained after only CP injections (P<0.05). CONCLUSIONS: The routine use of TEOAE monitoring is recommended in clinical CP treatment protocols for the early detection and follow up of ototoxicity. Also, prospective clinical trials are needed in order to validate the protective effects of vitamin B treatment against ototoxicity.     

Comparison of transient evoked otoacoustic emission thresholds recorded conventionally and using maximum length sequences

Presenting clicks according to maximum length sequences (MLSs) enables transient evoked otoacoustic emissions (TEOAEs) to be recorded at very high stimulation rates. Despite a decrease in TEOAE amplitude, the very large number of responses obtainable at high rates means that both signal to noise ratio (SNR) and detection sensitivity increase as the click rate increases. This study characterises conventional and MLS TEOAEs near threshold for a group of normally hearing adults. Stimulus presentation rates of 40 clicks/s (conventional) and 5000 clicks/s (MLS) were used. Compared to conventional recordings, the MLS technique enabled smaller responses to be detected, when averaged for the same time and to the same SNR. TEOAE amplitude recorded at detection threshold for MLS responses was 13 dB lower than that recorded conventionally. For each individual, MLS recording also produced clear, repeatable responses at stimulus levels below the detection threshold for conventional TEOAEs. The click level at TEOAE threshold was 12 dB lower for MLS compared to conventional emissions. These results suggest that TEOAE thresholds are not absolute but strongly related to the detection sensitivity of the recording system and physiological noise. The initial growth rates and the shape of input/output functions were found to be similar for the two recording techniques.     

Transient evoked otoacoustic emissions in young children with otitis media with effusion before and after surgery

Objective

Otitis media with effusion (OME) is one of the commonest causes of acquired hearing loss in children with increasing incidence. In young children the diagnosis is restricted to clinical trials and tympanometry whereas evaluation of the auditory function is impossible due to noncompliance during pure tone audiometry. For this purpose, measurement of otoacoustic emissions, especially transient evoked ones (TEOAE), can be applied. The aim of this study is to evaluate the parameters of TEOAE in young children with OME prior and after surgery.

Methods

Prospective study included 50 children with OME, both sexes, aged 2–5 years. Preoperatively tympanometric examination was performed and TEOAE were recorded. Surgery was performed under general anesthesia and included myringotomy with/without ventilation tube insertion. Measurements of TEOAEs (correlation percentage, signal to noise ratio and amplitude) were repeated on the first and six day postoperatively as well as 6 weeks and 6 months postoperatively.

Results

The preoperative TEOAEs were not recorded in 93.5%, with values of all TEOAE parameters being the most affected on highest frequencies. Significant changes of all TEOAE parameters were found 6 weeks postoperatively with further improvement 6 months postoperatively. Statistically highly significant difference of TEOAE between examinees with and without inserted ventilation tubes was established only in regard to preoperative results.

Conclusion

In small children with OME, application of TEOAEs in follow-up of surgical effects is a method of choice for hearing screening due to its objectivity, simplicity and ease of use even after insertion of ventilation tubes. Follow-ups of TEOAE correlation percentage and signal to noise ratio reflect the condition earlier than follow-ups of TEOAE amplitude.     

Otoacoustic emissions and tympanometry screening among 0-5 year olds

OBJECTIVES: To determine the rate of otitis media (OM)-associated transient evoked otoacoustic emissions (TEOAE) screening failure in a sample of preschool children, to evaluate concordance between TEOAE and tympanometry, to investigate risk factors for TEOAE failure, and to determine agreement between TEOAE failure and physician findings at referral. STUDY DESIGN: Cross-sectional. METHODS: Children from birth to 5 years underwent screening by TEOAE and tympanometry, and those with one or more abnormal test result(s) were referred to their physician for further evaluation. Univariate associations between risk factors and TEOAE failure were determined using chi-square analysis. Multiple logistic regression analysis was done to examine the relationship between specific risk factors and TEOAE failure. RESULTS: A total of 664 children aged 2 weeks to 71 months were screened between September 1997 and May 1999. TEOAE and tympanometry failure was found in 25% and 35% of all subjects, respectively. The overall prevalence of OM-associated hearing loss was 20%. Agreement between tympanometry and TEOAE was better for the youngest (<6 mo) and oldest > or =36 mo) age groups. Of those who failed TEOAE, a physician saw 81% within 3 months, and 80% of these had a diagnosis consistent with hearing loss but only 18% had audiometric testing. Sibling history of OM was the only significant predictor for TEOAE failure. CONCLUSIONS: TEOAE screening failure was highly consistent with physician diagnosis at follow-up. Failure of TEOAE in a screening program should be followed with diagnostic audiology testing to determine whether conductive or sensorineural hearing loss is present.     

Applying signal statistical analysis to TEOAE measurements

Automated detection of TEOAE gains increasing importance in screening applications. Conventional signal statistical analysis methods (buffer correlation and +/- difference) of TEOAE waveforms are compared with one another and with a method based on binomial statistics. It turns out that binomial statistics are more reliable and valid than conventional methods with common criteria. In particular, under narrowband noise conditions they are also faster. A frequency specific evaluation is hardly possible by means of conventional methods because of the high random correlation of narrow band signals.     

Combination of derived non-linear and linear methods to increase the reproducibility of transiently evoked otoacoustic emissions

This paper proposes a segmented average method that combines the derived non-linear response (DNLR) and linear-averaging methods to increase the reproducibility of transiently evoked otoacoustic emissions (TEOAEs). In this method, the DNLR method is used at the 2.5-P-ms segment of each TEOAE signal, and the linear-averaging method is used from P to 20 ms. This exploits the reduced-artefact advantage of the DNLR method and the high-reproducibility advantage of the linear-averaging method. To evaluate the performance of the proposed method, 26 normal ears were tested, with P selected as 8 ms. Each TEOAE signal obtained was decomposed into three scales using the discrete wavelet transform. Then the similarities and differences between the signals obtained with this method and with the DNLR method were assessed. The results show that the average reproducibility of the TEOAE signals increases from 78.1%, to 88.7% when applying the proposed method.