外耳道压力改变对耳声发射幅值的影响

目的了解外耳道压力改变对耳声发射幅值的影响，进而探讨外耳道压力因素对耳功能状态的影响。方法用ＧＳＩ３３型声导抗仪和ＩＬ０９２型耳声发射仪，对２３例（４６耳）正常人进行不同外耳道压力状态下的ＴＥＯＡＥ和ＤＰＯＡＥ测试。结果外耳道正、负压越大，ＴＥＯＡＥ的平均反应幅值越低，低频区频谱幅值下降明显，高频区无明显改变，Ｆ２在６９６～２００２Ｈｚ之间时，ＤＰＯＡＥ幅值降低明显，Ｆ２为３００３、５００５、６００６Ｈｚ时，ＤＰＯＡＥ幅值无明显改变，Ｆ２为４００４Ｈｚ时，ＤＰＯＡＥ幅值增高。结论正常的耳声发射幅值依赖于正常的耳功能状态。外耳道压力改变可使中耳和内耳的传音功能发生改变，主要表现为低频声的传导被阻滞。     

Otoacoustic emissions at compensated middle ear pressure in children

Middle ear pathology has a negative effect on the detectability of otoacoustic emissions. In this study, we investigated the effect of compensating a deviant static middle ear pressure while measuring transient evoked otoacoustic emissions (TEOAEs). In 59 children (mean age 4 years, 5 months) TEOAEs were measured twice in one session: first at ambient pressure and than at compensated middle ear pressure. On average, TEOAE amplitudes increased by 1.9 dB as a result of middle ear pressure compensation. The amplitude increase was largest in frequency bands centred at 1 and 2 kHz and a statistically significant correlation was found between the amount of compensated pressure and the TEOAE amplitude increase. In the higher frequency bands centred at 3 and 4 kHz, TEOAE amplitudes were almost insensitive to pressure compensation. These results show that measuring OAEs at compensated middle ear pressure enhances the amplitude of TEOAEs, and thus improves the detectability.     

Otoacoustic emissions at compensated middle ear pressure in children

Middle ear pathology has a negative effect on the detectability of otoacoustic emissions.

In this study, we investigated the effect of compensating a deviant static middle ear pressure while measuring transient evoked otoacoustic emissions (TEOAEs). In 59 children (mean age 4 years, 5 months) TEOAEs were measured twice in one session: first at ambient pressure and than at compensated middle ear pressure.

On average, TEOAE amplitudes increased by 1.9 dB as a result of middle ear pressure compensation. The amplitude increase was largest in frequency bands centred at 1 and 2 kHz and a statistically significant correlation was found between the amount of compensated pressure and the TEOAE amplitude increase. In the higher frequency bands centred at 3 and 4 kHz, TEOAE amplitudes were almost insensitive to pressure compensation.

These results show that measuring OAEs at compensated middle ear pressure enhances the amplitude of TEOAEs, and thus improves the detectability.     

基层医院新生儿听力筛查方法与评定标准的建立

目的 :探讨新生儿听力筛查的最佳方法与相关标准。方法 :应用Cepella耳声发射仪对 12 77例(2 5 5 4耳 )新生儿作瞬态诱发耳声发射 (TEOAE)测试。以 4个频带中 3个频带信噪比≥ 3dB为通过标准。结果 :通过率为 89.4%,测试时间以产后 2d以上为佳。结论 :TEOAE是新生儿听力筛查的首选方法 ,频带信噪比≥ 3dB为最适当的筛查标准。     

The hearing system in newborns from the Upper Silesia. Assessment of TEOAE depending on selected parameters of delivery disorders

Transient evoked otoacoustic emission (TEOAE) is an accepted test for screening of the cochlea function in newborns. In this study 300 newborns was tested using TEOAE, as well as analysing such parameters as birth weight, Apgar scale, bilirubinaemia. The study indicated the tendency of TEOAE to decrease in newborns with low birth weight and low Apgar scores. Hyperbilirubinaemia seems to have an influence on cochlea function monitored by TEOAE, especially if there were simultaneously low Apgar scores. A similar tendency, although slightly stronger, was observed in the preterm newborn group. TEOAE seems to be a good method of recording the negative influence on the cochlea activity such factors as low birth weight and asphyxia. Hyperbilirubinaemia with asphyxia acts upon the cochlea similarly. All these tendencies were observed more strongly in the preterm newborn group. It is concluded that TEOAE analysis demonstrated its utility as a screening test assessing the hearing state in newborns, additionally the associations of cochlea activity was found with a few parameters of delivery disorders.     

Assessment of transient evoked otoacoustic emission (TEOAE) in preterm newborns with low birth weight

Transient evoked otoacoustic emission (TEOAE) is accepted as a good and universal test for screening of the cochlea function in newborns. This method is particularly useful in the newborn group with risk-factors of hearing losses. Early identification of the cochlear pathology gives possibility of supplying with hearing aid and rehabilitation. In this study 300 newborns were tested with TEOAE, especially patients whose birth weight was below 1500 g and were born preterm--below 33 hbd. The study did not indicate any tendency of changing TEOAE in newborns with hypotrophy. Hypotrophy does not seem to influence the cochlea function monitored by TEOAE analysis.     

Transient evoked otoacoustic emission measurement in infants

Transient evoked otoacoustic emissions (TEOAEs) were measured and evaluated in 194 ears of 101 subjects under 4 years old who were suspected of hearing loss, using a ILO88 Otoacoustic Emission Analyzer, to study the basic characteristics of this measure and its utility for hearing screening. The mean time necessary to record TEOAEs in both ears was short, about 3 minutes. In 58 ears judged as normal hearing within 30 dB in ABR, TEOAE levels in infants aged less than 2 months were significantly higher than in those aged more than 1 year, especially in the high frequency bands (4-kHz and 5-kHz bands). One case which had been judged as bilateral moderate-to-profound hearing impairment in initial ABR testing showed good responses in TEOAEs, indicating normal cochlear function, and obvious wave Vs in follow-up ABRs recorded at 30 dB nHL confirmed normal auditory function. Therefore, in a case like this one, suspected of retardation in brain stem maturation, TEOAE is more useful than ABR as a hearing screening technique. Since external and middle-ear factors caused poor TEOAE responses in some cases which had been judged as normal hearing by ABR. TEOAE seems to be more sensitive in detecting external and middle ear problems than ABR. Moreover, TEOAE measurement of infants was easy and noninvasive. We conclude that TEOAE is an excellent tool for screening auditory function in infants.     

Transient evoked otoacoustic emissions pattern as a prognostic indicator for hearing preservation in acoustic neuroma surgery.

OBJECTIVE: To determine whether pre-operative transient otoacoustic emission (TEOAE) patterns are predictive of successful hearing preservation in acoustic neuroma surgery. STUDY DESIGN: Retrospective observational study. SETTING: Tertiary referral medical center. PATIENTS: A convenience sample was identified in whom pre-operative TEOAE data were available in patients undergoing acoustic neuroma surgery from 1993-2004. Ninety-three patients were identified who met this inclusion criterion. INTERVENTIONS: Subjects underwent attempted hearing preservation surgery via middle cranial fossa or retrosigmoid approaches. Routine audiometry, ABR, and TEOAE. MAIN OUTCOME MEASURES: Pre- and post-operative pure tone and speech results were categorized into hearing classes A, B, C, and D as described in the American Academy of Otolaryngology guidelines (1995). Hearing preservation was defined by maintenance of the pre-operative hearing class or downgrade to within one hearing class post-op. Pre-operative TEOAE results were divided into five frequency bands and described as positive in each band if there was a response above the noise floor with >50% reproducibility. RESULTS: Hearing was preserved in 51 patients (55%). Of these, 11 (22%) had positive TEOAE response in all five frequency bands measured (1, 1.5, 2, 3, 4 kHz), whereas 40 (78%) had TEOAE responses ranging from 0 to 4 frequency bands. 42 patients failed to preserve their hearing. Of these, only three (7%) had positive TEOAE in all five frequency bands, and 39 (93%) had TEOAE responses ranging from 0 to 4 frequency bands (p<0.05). Other variables of prognostic significance to hearing preservation in our series included smaller tumor size, tumor location within the IAC, better pre-operative hearing, and shorter latencies on ABR. Logistic regression was then used to compare the prognostic value of TEOAE against these variables. In our series, ABR latencies and 5 frequency band response on TEOAE showed the highest significant correlation to hearing preservation (p<0.05). CONCLUSION: A robust pre-operative TEOAE frequency band pattern may be used as a favorable prognostic indicator for potential hearing preservation in acoustic neuroma surgery. The prognostic value may be enhanced when combined with other prognostic factors such as tumor size, tumor location, pre-operative ABR and audiometric results.     

Transitory evoked otoacoustic emissions in isolated high frequency, low frequency and middle frequency hearing

Transient evoked otoacoustic emissions (TEOAE) of 153 patients of various ages with normal or nearly normal hearing in the low, high or middle frequency ranges (different aetiologies) have been recorded. We found that the rate of detection of otoacoustic emissions depends on the width of the frequency range of preserved hearing. Single cases of narrow bands of hearing in the middle frequency region showed this region's significance for the high detectability of TEOAE. Although the investigated population consists mainly of adults, conclusions for the use of the TEOAE method for infant screening are drawn.     

畸变产物耳声发射与瞬态诱发耳声发射的相关性观察

目的：探讨畸变产物耳声发射（DPOAE)和瞬态诱发耳声发射(TEOAE)的特点和相关性。方法：以20例（40耳）耳科正常青年人观察噪声暴露前后在无对侧抑制（NCS)状态下和有对侧抑制（CS)状态下TEOAE的频带信噪比、频带反应幅值，与DPOAE的2f1-f2幅值、信噪比相互间的相关性。结果：DPOAE与TEOAE虽由不同的刺激声所引出，有各自的图形特征，但在绝大多数相近频率点上，其测量值有较好的相关性，形成一定的数量关系。结论：TEOAE测试较为快捷并有中频优势，而DPOAE则有很好的频率特异性和高频优势。二者幅值及信噪比间有良好的相关性，可得出有统计意义的线性回归方程参数，听觉损害，噪声性。     

新生儿与成人瞬态诱发耳声发射性别差异的比较

目的探讨瞬态诱发耳声发射(TEOAE)的性别差异在新生儿与成人之间的变化。方法以短声刺激分别对120名(女62,男58)通过听力筛查的新生儿及53名(男26,女27)纯音听阈正常的青年成人行TEOAE检测,对两组TEOAE强度及频带信噪比(SNR)的性别差异进行分析。结果①成人组TEOAE强度性别差异(2.41dB)明显高于新生儿(0.99dB)。②新生儿SNR除1kHz男婴高于女婴外,其余频带均为女婴高于男婴,且SNR的性别差异随频率增加而增大,在3、4kHz差异有统计学意义(P<0.05)。成人不同频带SNR均为女性高于男性,除3kHz外也呈现随频率增加而增大的特征,在2、4kHz差异有统计学意义(P<0.05)。结论 TEOAE总强度的性别差异随年龄增加而增大,且新生儿及成人频带SNR的性别差异均随频率增加而增大,成人低频区SNR的性别差异较新生儿更明显。     

Click-evoked otoacoustic emissions recorded from untreated congenital hypothyroid newborns

Thyroid hormone plays an important role in hearing development. Both a genetic or non-genetic hypothyroidism is often associated with congenital hearing loss. The exact incidence of hearing impairment in untreated congenital hypothyroid (CH) patients is unknown. This paper will present the results of measuring of the transient-evoked otoacoustic emissions (TEOAE) in a population of 29 newborns, who tested positive on a screening test for hypothyroidism (CH group) and in 68 well babies (control group) randomly chosen from all the newborns, classified as PASS, included in the Hearing Screening Program of the San Raffaele Hospital in Milan. TEOAE were recorded in all newborns within 1 month after birth and before beginning L-thyroxine treatment with conventional commercial instrumentation. Both temporal and time-frequency analyses of the emitted responses were conducted by means of a wavelet transform. The comparison of the characteristics of the temporal and frequency content of the responses of the two groups (CH and control) showed no statistically significant difference. No correlation was found between outer hair cell dysfunction and hypothyroidism.     

A TEOAE screening protocol based on linear click stimuli: performance and scoring criteria.

In order to improve the quality of current TEOAE recording methodologies, we have conducted a comparison of TEOAE neonatal recordings acquired with linear protocols using click stimuli of 68 dB SPL and non-linear protocols using the ILO default stimulus values. From a theoretical standpoint it was expected that the linear recordings would generate responses characterized by higher S/N ratios due to the fact that the stimulus sequence contains four clicks of the same intensity and polarity. The project included recordings from 1,416 neonatal ears (age 48 h). The TEOAE data were compared in terms of correlation, response amplitude, noise, corrected response and S/N ratio in the 1.0-, 2.0-, 3.0-, 4.0- and 5.0-kHz bands, using a paired t-test criterion. We found that windowed (4-14 ms) responses evoked by a linear TEOAE protocol generated superior S/N estimates in the 2.0-, 3.0-, 4.0- and 5.0-kHz TEOAE bands, in addition to superior correlation estimates, and demonstrated lower levels of noise. Clear-cut scoring criteria were established for the S/N ratios at 2.0, 3.0 and 4.0 kHz, by constructing one-sided distribution-free tolerance boundaries.     

Effects of ear canal static pressure on the dynamic behaviour of outer and middle ear in newborns

ObjectiveThe present study investigated the effect of ear canal pressure on the dynamic behaviour of the outer and middle ear in newborns with and without a conductive condition using the sweep frequency impedance (SFI) technology.MethodsA test battery consisting of automated auditory brainstem response (AABR), transient evoked otoacoustic emission (TEOAE) and 1000-Hz tympanometry (HFT) was performed on 122 ears of 86 healthy newborns and 10 ears of 10 newborns with a conductive condition (failed TEOAE and HFT). The dynamic behaviour of the outer and middle ear, when the pressure applied to the ear canal was varied from 200 to −200 daPa, was evaluated in terms of the sound pressure level (SPL) in the ear canal, resonance frequency (RF) and displacement (ΔSPL).ResultsApplication of either a positive or negative static pressure to the ear canal of healthy newborns increased the resonance frequency of the outer (RF1) and middle ear (RF2), but decreased the displacements of the outer (ΔSPL1) and middle ear (ΔSPL2). Positive static pressures resulted in lower SPL while negative static pressures resulted in higher SPL than that at ambient pressure (0 daPa). At −200 daPa, more than 90% of ears showed signs of collapsed ear canal. The dynamic behaviour under various positive and negative static pressures for newborn ears with a conductive condition indicated similar pattern of SPL, RF1 and ΔSPL1 responses for the outer ear as per healthy ears, but abnormal responses for the middle ear.ConclusionsWhile both positive and negative pressures applied to the ear canal have the same effect of stiffening the outer and middle ear, negative pressure of up to −200 daPa resulted in more than 90% of ears with a collapsed ear canal. The results of the present study do not only offer useful clinical information for differentiating healthy ears from ears with a conductive condition, but also provide information on the maturation aspects of the outer and middle ear in newborns.     

Synchronized Spontaneous Otoacoustic Emissions Provide a Signal-to-Noise Ratio Advantage in Medial-Olivocochlear Reflex Assays

Detection of medial olivocochlear-induced (MOC) changes to transient-evoked otoacoustic emissions (TEOAE) requires high signal-to-noise ratios (SNR). TEOAEs associated with synchronized spontaneous (SS) OAEs exhibit higher SNRs than TEOAEs in the absence of SSOAEs, potentially making the former well suited for MOC assays. Although SSOAEs may complicate interpretation of MOC-induced changes to TEOAE latency, recent work suggests SSOAEs are not a problem in non-latency-dependent MOC assays. The current work examined the potential benefit of SSOAEs in TEOAE-based assays of the MOC efferents. It was hypothesized that the higher SNR afforded by SSOAEs would permit detection of smaller changes to the TEOAE upon activation of the MOC reflex. TEOAEs were measured in 24 female subjects in the presence and absence of contralateral broadband noise. Frequency bands with and without SSOAEs were identified for each subject. The prevalence of TEOAEs and statistically significant MOC effects were highest in frequency bands that also contained SSOAEs. The median TEOAE SNR in frequency bands with SSOAEs was approximately 8 dB higher than the SNR in frequency bands lacking SSOAEs. After normalizing by TEOAE amplitude, MOC-induced changes to the TEOAE were similar between frequency bands with and without SSOAEs. Smaller MOC effects were detectable across a subset of the frequency bands with SSOAEs, presumably due to a higher TEOAE SNR. These findings demonstrate that SSOAEs are advantageous in assays of the MOC reflex.     

Assessment of the medial olivocochlear efferent system in children. pure tone 1.0 kHz and 2.0 kHz suppressive effects on transient evoked otoacoustic emission

The role of medial efferent system in regulating outer hair cell function has been studied by many investigators. Usually narrow band noise or white noise as contralateral stimulation (CS) suppressors have been used and changes in OAE amplitudes estimated. Thirty children aged 6-15 years (mean 12.5 +/- 4.7), without any changes in tonal and impedance audiometry and with negative history regarding otiatric diseases were examined. Transient evoked otoacoustic emissions (TEOAE) were recorded using ILO 92 Otodynamics Analyser. CS was performed using 1.0 kHz and 2.0 kHz continuous pure tones of 30 dB SL or 50 dB SL. Effects of CS on TEOAE evoked by click of 80, 70 and 60 dB SPL were investigated. TEOAE analysis included assessment of TEOAE amplitude of half octave frequency bandwidth (HOFBW-1.0; HOFBW-1.5; HOFBW-2.0; HOFBW-3.0 and HOFBW-4.0 kHz) and 0.8 kHz frequency bandwidth (0.8-FBW) amplitudes centred at 1.0; 2.0; 3.0; 4.0 and 5.0 kHz. TEOAE amplitude recorded for stimuli 80, 70 and 60 dB SPL without CS decreased: mean values respectively 6.1 +/- 4.2; 5.4 +/- 4.5 and 3.3 dB SPL +/- 4.3. CS effect on TEOAE was observed for all CS options, however, larger suppressive effect was recorded on TEOAE elicited by 70 dB SPL stimulus using 1 kHz/50 dB SL tone as a suppressor and on TEOAE elicited by 60 dB SPL stimulus using 2 kHz/50 dB SL tone as a suppressor. HOFBW and 0.8-FBW analyses showed the association between the frequency/intensity of the suppressors and decreasing of amplitudes of adequate frequency bands. It is concluded that the described method of investigating of the medial olivocochlear efferent system seems to be sensitive and confirms frequency-dependent suppressive effect on OAE.     

Reference data for DPOAE in healthy newborns

Distortion Product Otoacoustic Emissions (DPOAE) can be used as an alternative to Transient Evoked Otoacoustic Emissions (TEOAE). This study aims to establish normal values for DPOAE in healthy newborns. DPOAE were determined with the Madsen Celesta 503 at 0.5, 1, 2, 4 and 8 kHz with an unequal stimulus level of the primaries (L1 = 65 dB SPL, L2 = 50 dB SPL). DPOAE were present in 92.4% of the ears of the 185 babies tested at 4 days after birth. The 5% quantile and the median of the DPOAE of the right and left ears were calculated for the five frequencies tested. At 4 kHz there was a significant sex effect (mean amplitude of DPOAE was higher in female than in male babies) and at 2 kHz a significant interaction effect was found between sex and side. The calculated reference limits are open to comparison with data obtained using other commercial equipment.     

Characteristics of normal newborn transient-evoked otoacoustic emissions: ear asymmetries and sex effects

Transient-evoked otoacoustic emissions (TEOAEs) were recorded from more than 30000 newborns over a six year period. Analysis was performed on all the TEOAEs that passed the bedside universal hearing screen (n=60431), in order to characterize the normal properties of neonatal TEOAEs and to study ear and sex effects. Short recording times (median=33 s) were observed in combination with high entire TEOAE level (median=18.8 dB SPL for an 81.8 dB SPL peak stimulus), and high reproducibility (median=86%). Signal-to-noise ratio (S/N) of the TEOAE was highly frequency-dependent, being poorer at low frequencies. Prolonged averaging increased median reproducibility to 97%, but the minor S/N-improvement at low frequencies did not justify the longer test time. Highly significant mean lateral asymmetries (right >left) and sex differences (female >male) existed in entire TEOAE level, S/N TEOAE, and in half-octave frequency bands (700-4000 Hz). Mean lateral and sex entire TEOAE level differences were 1.1 dB and 1.3 dB, respectively. Stimulus levels were not affected by ear or sex. Hence, physiological differences at the level of organ of Corti were demonstrated in newborns.     

Characteristics of normal newborn transient-evoked otoacoustic emissions: Ear asymmetries and sex effects

Transient-evoked otoacoustic emissions (TEOAEs) were recorded from more than 30000 newborns over a six year period. Analysis was performed on all the TEOAEs that passed the bedside universal hearing screen (n=60431), in order to characterize the normal properties of neonatal TEOAEs and to study ear and sex effects. Short recording times (median=33 s) were observed in combination with high entire TEOAE level (median=18.8 dB SPL for an 81.8 dB SPL peak stimulus), and high reproducibility (median=86%). Signal-to-noise ratio (S/N) of the TEOAE was highly frequency-dependent, being poorer at low frequencies. Prolonged averaging increased median reproducibility to 97%, but the minor S/N-improvement at low frequencies did not justify the longer test time. Highly significant mean lateral asymmetries (right >left) and sex differences (female >male) existed in entire TEOAE level, S/N TEOAE, and in half-octave frequency bands (700–4000 Hz). Mean lateral and sex entire TEOAE level differences were 1.1 dB and 1.3 dB, respectively. Stimulus levels were not affected by ear or sex. Hence, physiological differences at the level of organ of Corti were demonstrated in newborns.     

新生儿与成人瞬态诱发耳声发射差异的频谱特性分析

目的 比较新生儿与成人瞬态诱发耳声发射(TEOAE)的差异,并分析其频谱特性.方法 以短声刺激分别对120名通过听力筛查的新生儿(男58,女62)和32名平均纯音听阈(听力级)在20 dB以内的成年人(男15,女17)行TEOAE检测,对于测试结果 行频谱分析和半倍频程分析.结果 ①新生儿组TEOAE总强度(声压级,下同)为(15.18±4.39)dB,高于成人组的(9.51±4.12)dB,差异具有统计学意义(t=9.303,P<0.05).②新生儿的频带重复率、频带重复率非0比例、频带信噪比检出率及频带信噪比在第1频带(0.8 kHz)最低,在3.2 kHz最大;而成人在第5频带(4.0 kHz)处最低,在1.5 kHz最大.③新生儿与成人最大频带信噪比强度差为7.09 dB,二者出现的频率位置相差约1.7 kHz.④半倍频程分析显示新生儿TEOAE最大能量为(10.50±5.09)dB,在2828 Hz处,而成人为(2.84±5.33)dB,在1414 Hz处;二者最大反应在强度上相差7.66 dB,出现的频率位置相差1414 Hz.⑤成人1.5 kHz区的TEOAE信号最强,之后其信噪比随频带增高而降低,而新生儿信噪比却呈现随频带增高而增强的特征;从第1频带到第5频带,新生儿与成人TEOAE强度的差值随频带增高也逐渐增大.结论 成人TEOAE总强度低于新生儿.新生儿频带信噪比及半倍频程能量反应峰的分布频率及反应强度均高于成人.