Influence of static middle ear pressure on transiently evoked otoacoustic emissions and distortion products

Otoacoustic emissions (OAE) are influenced in their amplitude and frequency spectra by the middle ear. The effects of changes in the middle ear transmission mechanisms on transiently evoked OAE (TEOAE) and distortion product emissions (DPOAE) were investigated as a function of static ear canal pressure in 25 normal-hearing test persons aged 18–35 years. The ear canal pressure was varied stepwise between positive and negative values of 200 daPa. TEOAE and DPOAE amplitudes were attenuated significantly with changes of the static ear canal pressure, with greatest changes at low frequencies (< 2 kHz). The alterations of OAE amplitude were slightly dependent on the polarity of the pressure, with positive pressure producing a greater attenuation (0.6 dB). The results demonstrate that changes in middle ear impedance can cause a misinterpretation of OAE. To avoid this problem, tympanometry should always precede OAE measurements. Alternatively, both methods can be combined using one acoustic probe, so that the emissions can be evoked at the peak of middle ear compliance.     

The relationship between auditory threshold and evoked otoacoustic emissions

The aim of this study was to compare transiently evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE) in normal hearing ears (n = 44) and ears with cochlear hearing loss (HL) to obtain defined data on qualitative and quantitative correlations. In addition, we wanted to determine the reliability with which a clinical examiner could predict a typical, idealized audiometric configuration from TEOAE measurements. In the hearing-impaired subjects (n = 149), a 50% reduction of OAE incidence was caused by a mean HL of 10.5 dB for TEOAE compared to 27 dB SPL for DPOAE. A 90% incidence reduction was found at a mean threshold elevation of 33 dB for TEOAE and 51 dB for DPOAE. Correlation between TEOAE amplitudes and HL was in general rather low (r = –0.1 to –0.5), while DPOAE amplitudes showed a slightly better correlation with HL (r = –0.3 to –0.6). In general, efforts to derive an audiogram from evoked OAE have been more promising for DPOAE than for TEOAE. However, our studies showed that approximately 40% of the ears with HL could be categorized correctly into one of five typical audiometric patterns from TEOAE measurements. Additionally, a cochlear HL in or near the medium frequency range was much more likely to cause a reduction in TEOAE than an isolated low- or high-frequency lesion. Accordingly, TEOAE were often preserved in ears with isolated HL in the high or low frequencies. Received: 7 May 1998 / Accepted: 25 September 1998     

Occupational hearing loss: screening with distortion-product otoacoustic emissions

Hearing assessment of applicants for occupational hearing loss compensation can be a time-consuming process. An accurate screening procedure that is sensitive to occupational hearing loss may have application in many situations. The present study developed distortion-product otoacoustic emission (DPOAE) screening criteria to identify subjects likely to meet the Hong Kong requirements for occupational hearing loss compensation, namely a bilateral sensorineural loss ≥ 40 dB HL (average of 1000, 2000 and 3000 Hz). The screening criteria of 1500 and/ or 2000 Hz, with a signal-to-noise ratio of >0 or 3 dB, yielded high sensitivity and specificity. DPOAE measures therefore have the potential to accurately indicate possible occupational hearing loss. However, DPOAEs should be used as a screening tool only, as conventional pure-tone audiometry remains the more comprehensive measure of hearing sensitivity.     

Effect of smoking on transient evoked otoacoustic emissions and contralateral suppression

Objective

The present study compared the amplitudes of transient evoked otoacoustic emissions (TEOAEs) and efferent suppression in smokers and non-smokers taking age into consideration.

Methods

Fifty smokers and fifty non-smokers who had normal hearing sensitivity with age range of 20–69 years were considered for the present study. TEOAEs were measured in both the groups of subjects across different age groups. The functioning of the efferent auditory system was evaluated in both the groups by recording the TEOAEs in the presence of a contralateral white noise (CWN) of 70 dB SPL.

Results

Age did not have a significant effect on the TEOAEs amplitude in both the groups of subjects. However, the TEOAEs amplitude was significantly reduced in smokers compared to non-smokers. The results found a significant effect of age on the amplitude of efferent suppression in smokers, however, no significant effect was found in the non-smokers group.

Conclusions

It was found that the difference in the amplitude of efferent suppression in smokers was significantly greater for each age group between 20 and 49 years compared to each age group from 50 to 69 years. Results have important implication on the damage to the cochlear structures from smoking.     

The effect of impulse noise exposure on distortion product otoacoustic emissions in the awake guinea pig

Distortion product otoacoustic emissions (DPOAE) are a sensitive detector of outer hair cell (OHC) function and were monitored in awake guinea pigs before and after impulse noise damaging the cochlea (peak intensity 153 dB SPL, rise time < 0.1 ms). Animals had stable DPOAE levels before noise exposure. In the first hours after noise exposure DPOAE levels were reduced significantly. Three different patterns of recovery of DPOAE were seen in the post-exposure period: restitution exceeding controls, partial recovery and no recovery. In general, DPOAE levels declined and types of recovery closely corresponded to changes in amplitudes of cochlear microphonics after noise exposure. These data suggest that the monitoring of DPOAE is a suitable method for diagnosing impaired OHC function. Received: 25 February 1999 / Accepted: 1 July 1999     

糖尿病大鼠畸变产物耳声发射的观察

目的观察糖尿病大鼠畸变产物耳声发射（distortion product otoacoustic emissions，DPOAE）的改变，探讨链脲霉素有无内耳毒性作用。方法24只SD大鼠随机分为糖尿病组、胰岛素治疗组和对照组，以链脲霉素诱发糖尿病，造模成功后以鱼精蛋白锌胰岛素控制血糖，分别于造模前、造模后3个月及5个月对3组大鼠进行DPOAE幅值测试，统计分析各组实验数据。结果糖尿病组大鼠发病3个月时DPOAE幅值出现下降，其中在1038、4126及5200Hz差异有统计学意义（P〈0．05）；发病5个月时糖尿病组大鼠DPOAE幅值在所有频率均出现显著下降，差异有统计学意义（P〈0．01）。胰岛素组与对照组DPOAE幅值在各个时期差异均无统计学意义。结论糖尿病早期即可出现DPOAE幅值下降，并会随着时间的延长逐渐加重。推测链脲霉素无明显内耳毒性作用。     

Comparison of transient evoked otoacoustic emissions and distortion product otoacoustic emissions when screening hearing in preschool children in a community setting

OBJECTIVE: The first purpose of this study was to compare transient evoked otoacoustic emissions (TEOAE) with distortion product otoacoustic emissions (DPOAE) to determine if they resulted in equivalent signal-to-noise ratios (SNRs) when used for hearing screening in a preschool population in a community setting. The second purpose was to determine if the OAE methods would result in equivalent pass/refer rates. The third purpose was to determine the agreement between the pass/refer rates from a tympanometric screening and the pass/refer rates from each OAE method. METHODS: Thirty-three preschool children ages 4 months to 4 years, 4 months were tested using DPOAE and TEOAE. The frequencies 800-4000Hz were compared. The tympanometric gradient was obtained from a tympanogram done on each ear. A multivariate statistic was used to compare the emission SNR from both methods. A chi(2) statistic was used to compare the pass/refer rates from both methods. The agreement between the pass/refer rates from the OAE screens and from the tympanometric gradient were compared. RESULTS: TEOAE and DPOAE SNRs were significantly different in the low frequency however, there were no significant differences found in the high frequencies. There were no significant pass/refer differences found between the methods at any frequency. When comparing the agreement between the OAE methods with the tympanometry, both methods produced nearly equivalent agreement with tympanometric gradient. However, the overall correspondence between OAE findings and tympanometry was not perfect. CONCLUSIONS: Both methods are effective and especially equivalent in the high frequencies and can be recommended for use in a preschool population in the field. Tympanometric gradient disagreed with both OAE screening results about 25% of the time. Finally, our study also found that higher refer rates can be expected when young (<3 years) preschool children are included in the screen.     

Use of distortion-product otoacoustic emissions for auditory evaluation in Meniere's disease

Otoacoustic emissions are a relatively new tool for assessment of inner ear function. We studied 65 patients diagnosed as having Meniére's disease. In order to obtain and characterize responses at different frequencies we used distortion-product otoacoustic emissions (DPOAE). In unilateral cases, the difference in response between ears on the diseased and healthy sides was evident at all frequencies. In the former the result was lower than expected for a group of normally hearing subjects, while in the latter it was better than expected according to pure tone averages. Reduction in amplitude and increment in threshold of the DPOAE in the diseased ear was a significant finding and could be correlated to the stage of the disease. In those subjects treated with Betahistine after 1 year's follow-up, DPOAE testing showed the recovery of response at low frequencies and a reduction of its threshold at all frequencies studied.     

The effects of anesthesia on otoacoustic emissions

We have measured transient-evoked and distortion-product otoacoustic emissions (OAEs) in the chinchilla and compared them in the awake and anesthetized animal (using either ketamine or barbiturate agents). We report a significant increase in OAE amplitudes during anesthesia, particularly using ketamine. These effects are most evident for transient-evoked otoacoustic emissions (TEOAEs) as measured in the non-linear mode. Our data support the hypothesis that tonic activity levels in cochlear efferents may be reduced by anesthetic effects, either directly or indirectly (e.g., by general reductions in descending pathway activity), and that reduced cochlear efferent activity will result in the observed increase of OAE amplitudes.     

Newborn hearing screening project using transient evoked otoacoustic emissions: Western Sicily experience

OBJECTIVE: To study the incidence of congenital sensorineural hearing loss in all newborns introducing a screen test with a protocol no expensive, with a good "screen sensitivity" that could let an earlier identification of hearing impairment beginning early intervention by 2 months of age and increasing the probability of having language development within the normal range of development. METHODS: The study was conducted in Sciacca hospital from the beginning of 2003 to our days and was carried out with transient evoked otoacoustic emission using the criteria for PASS or RETEST and considering eventual prenatal and perinatal risk factors. All the newborns were divided into four groups each one with its personal secondary step program. RESULTS: In the years 2003-2004 the number of the newborns in Sciacca hospital was: 538 for 2003, 653 for 2004 with a total of 1191; all these infants were divided in three groups: resident in Sciacca, resident in the Sciacca borderlands and resident out of the district of Sciacca. The coverage (percentage of the target population who undergo the screen) was of 90% in the 2003 (483 newborns) and of 90% in the 2004 (585 newborns) with two cases of congenital sensorineural hearing loss identified. The incidence of sensorineural hearing loss, in the District of Sciacca, was estimated to be 2.07/1000 in 2003 and 1.70/1000 in 2004. CONCLUSIONS: The higher incidence of sensorineural hearing loss in our study is due to a high prevalence of consanguineous marriage in Sicily that was shown to be linked with hearing impairment. The "sensitivity value" was 95% at the first step but became 99% after the second step with a few number of false positive (0.74%). All the infants with a diagnosis of sensorineural hearing loss began a rehabilitation program before the age of 5 months and they have a good speech development and speech intelligibility.     

Neonatal hearing screening in Benin City

Objective

Congenital hearing loss is a major health care problem that tends to retard the developmental milestones of children. It takes early detection and intervention to avoid a permanent loss in acquisition of speech and cognitive functions. Hence, the importance of hearing screening in all newborns especially in the developing world for accurate statistics and early intervention. Therefore, this work was aimed at detecting the crude prevalence of congenital hearing loss among the newborns in Benin City.

Methodology

Consecutive neonates at designated immunization centers in Benin City metropolis were screened for hearing loss via the detection and analysis of distortion product otoacoustic emissions from both ears. The handheld otoacoustic machine model MAICO 8172 was employed and the outcome results presented in tables. Statistical analysis was performed using SPSS 11.

Results

A total of 400 neonates (218 males and 182 females) were screened for the presence of otoacoustic emission in both ears. Ninety neonates (22.5%) p < 0.05 were referred. Bilateral hearing loss was seen in 26 (6.5%) whereas 64 (16%) had unilateral loss.

Conclusions

The screening tests suggest a high crude prevalence (6.5%) of bilateral neonatal hearing impairment in Benin City necessitating confirmation and intervention. The study fortifies the need for hearing screening among all new born in developing countries.     

A longitudinal study of changes in evoked otoacoustic emissions and pure-tone thresholds as measured in a hearing conservation program

Non-linear transient-evoked otoacoustic emissions (TEOAEs) at 74 dB pSPL, distortion-product otoacoustic emissions (DPOAEs) at 65/45 dB SPL and pure-tone audiometry were used to detect noise-induced, inner ear changes in a longitudinal study. Repeated-measures ANOVAs were made on the Noise (n=69) and Quiet (n=42) groups. The Noise group's hearing thresholds increased by 1.2 dB and DPOAE amplitude decreased by ?0.9 dB. For both groups, TEOAE amplitude decreased by approximately ?0.6 dB. Eight of 12 ears with permanent threshold shift (PTS) and 10 of 13 ears with temporary threshold shift (TTS) showed TEOAE decrements or low baseline TEOAE amplitudes. Fewer TTS and PTS ears also showed DPOAE decrements, and there was never a DPOAE decrement without a corresponding TEOAE decrement or low TEOAE baseline. Some TTS ears showed permanent emission decrements. Although otoacoustic emissions show promise in detecting noise-induced inner ear changes, it is premature to use them in hearing conservation programs.     

A comparison of audiometric and objective methods in hearing screening of school children. A preliminary study

Objective

In newborn hearing screening, one exclusively applies objective hearing testing methods - based on evoked potentials and/or on otoacoustic emissions. However, when testing school children, one can consider both audiometric and electrophysiological methods. The choice of methods is determined by the aims of the program. If one wants to detect conductive hearing losses, impedance audiometry seems to be the method of choice.

Methods

The aim of this study was to compare test performance measures from audiometric and objective methods (OAEs and impedance audiometry), in the hearing screening of school children. Screening protocols were applied on a group of 190 children of about 12 years of age (6th grade of primary school).

Results

For a single application of a screening procedure, the best performance was observed in the automated four-tone audiometry, followed by the tympanometry and the TEOAE-based procedures. Screening performance was enhanced using a combination of automated and impedance audiometry. A four-tone audiometry test combined with tympanometry gives a sensitivity of 65%, and the PPV of 46%, which are reasonable values, acceptable for practical use. The use of a TEOAE protocol degrades the overall performance of screening.

Conclusions

Screening of school children is feasible with a combination of automated audiometry and tympanometry with time requirements equal to 3 min per subject.     

Diplacusis,hearing threshold and otoacoustic emissions in an episode of sudden,unilateral cochlear hearing loss

Limited data are available on the relationship between diplacusis and otoacoustic emissions and sudden hearing threshold changes, and the detail of the mechanism underlying diplacusis is not well understood. Data are presented here from an intensively studied single episode of sudden, non-conductive, mild hearing loss with associated binaural diplacusis, probably due to a viral infection. Treatment with steroids was administered for 1 week. This paper examines the relationships between the hearing loss, diplacusis and oto-acoustic emissions during recovery on a day-by-day basis. The hearing thresholds were elevated by up to 20 dB at 4 kHz and upwards, and there was an interaural pitch difference up to 12% at 4 and 8 kHz. There was also a frequency-specific change in transient evoked otoacoustic emission ( TEOAE) and distortion-product otoacoustic emission (DPOAE) level. DPOAE level was reduced by up to 20 dB, with the greatest change seen when a stimulus with a wide stimulus frequency ratio was used. Frequency shifts in the 2f2 – f1 DPOAE fine structure corresponded to changes in the diplacusis. Complete recovery to previous levels was observed for TEOAE, DPOAE and hearing threshold. The diplacusis recovered to within normal limits after 4 weeks. The frequency shift seen in the DPOAE fine structure did not quite resolve, suggesting a very slight permanent change. The timecourses of TEOAE, diplacusis and hearing threshold were significantly different; most notably, the hearing threshold was stable over a period when the diplacusis deteriorated. This suggests that the cochlear mechanisms involved in diplacusis, hearing threshold and OAE may not be identical.     

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.     

豚鼠畸变产物耳声发射潜伏期的对侧抑制效应现象

目的通过观察对侧抑制效应中畸变产物耳声发射(distortion product otoacoustic     

自发性耳声发射与耳蜗传出调控的关系探讨

目的探讨自发性耳声发射(spontaneous otoacoustic emissions, SOAE)与内侧橄榄耳蜗传出系统 (medial olivocochlear system, MOCS)对耳蜗调控之间的关系及其临床意义.方法检测可疑蜗后病变和(或)内侧橄榄耳蜗传出系统功能障碍患者及正常中青年人的SOAE、瞬态诱发性耳声发射(transient evoked otoacoustic emissions, TEOAE)、畸变产物耳声发射(distortion product otoacoustic emissions, DPOAE)及后二者的对侧声抑制效应.结果发现①听神经病65例(130耳)中126耳、听神经瘤2例(2耳)、听觉过敏2例(4耳)、听力正常耳鸣26例(48耳)中共146耳伴有MOCS功能障碍;② MOCS功能障碍146耳无论其纯音听阈如何,均能引出较强的诱发性耳声发射(EOAE),其中86.3%(126耳)能引出增强的SOAE,明显高于健康青年人正常耳的SOAE引出率34.3%;③ MOCS功能障碍耳SOAE的主要频率范围0.693～3.055 kHz明显大于正常耳SOAE的频率范围1.135～2.746 kHz,低频端前移有显著统计差异(P<0.01);④ MOCS功能障碍耳SOAE的平均最高幅值(-3.4±6.4)dB SPL明显大于正常耳(-6.8±7.8) dB SPL(P<0.01);⑤正常耳传出抑制的频率范围主要在0.7～3k Hz,与MOCS功能障碍耳SOAE的平均频率范围0.693～3.055kHz基本一致.结论 MOCS对耳蜗主动机制的调控以低、中频为主; SOAE信号频率与耳蜗传出调控频率范围基本一致;SOAE增强具有病理性临床意义.SOAE与耳蜗传出调控具有明显的临床相关性.     

Hearing screening and middle ear measures in American Indian infants and toddlers

American Indian children have three times the rate of otitis media compared to the general population, yet prospective cohort studies of OME and hearing loss have not been previously reported in American Indian infants. Between 1997 and 2003, a cohort of 421 infants was enrolled at birth from Minnesota American Indian reservations and an urban clinic and followed to age 2 years. This study reports OAE hearing screening results related to OME diagnoses, as well as risk for recurrent hearing screening failure and OME in American Indian infants and children. METHODS: Infants were prospectively assessed at regular intervals with pneumatic otoscopy, distortion product otoacoustic emissions, and tympanometry by nurses who were trained in all procedures and validated on pneumatic otoscopy. RESULTS: In the newborn period, 23.5% of infants failed hearing screening in at least one ear. Hearing screening failures increased to 29.9% from 2 to 5 months of age. Technical fail results due to excessive noise occurred frequently in infants 6-24 months of age, making interpretation of true pass and fail rates questionable in older infants. OAE test result was associated with OM diagnosis, and this relationship strengthened with age, with the strongest association above 6 months of age. CONCLUSIONS: A high rate of hearing screening failures occurred among American Indian infants in the first 5 months of age, and was significantly associated with a correspondingly high rate of otitis media. Only one infant out of 366 was identified with sensorineural hearing loss, thus essentially all of the hearing screening failures reflected either a middle ear origin or other temporary problems. OAE screening provided a valuable hearing screening measure in this population at high risk for recurrent otitis media, but due to excessive noise in infants 6 months and older, practical use of OAE screening is limited. Use of behavioral assessment is needed after 6 months of age, when high rates of OME persist in this population. Increased efforts to develop public and medical education, as well as screening, diagnosis and treatment programs are needed to detect and decrease recurrent OME in American Indian infants and children.     

畸变产物耳声发射影响因素研究进展

畸变产物耳声发射 (DPOAE)是由外毛细胞主动运动产生并从一定程度上反映外毛细胞的功能。由于DPOAE测量容易、客观、无损伤 ,可作为评价耳蜗功能的有效手段。但 DPOAE的测试结果受多种因素影响。本文对近年来报道的有关影响因素从参数、仪器以及各种病理因素等诸方面进行了综述 ,并对其可能的影响机制及临床意义进行了初步探讨