Effects of speech babble on transient evoked otoacoustic emissions in normal-hearing adults

The results of transient evoked otoacoustic emissions (TEOAEs) have been found to be adversely affected by noise. However, there are few investigations into the specific effect of background noise on TEOAEs. The purpose of the present study was to determine the effects of increasing levels of speech babble and the recording method on TEOAEs using the ILO88 Otodynamics instrumentation. Subjects were 30 normal-hearing adults (15 males and 15 females), aged between 18 and 32 years. TEOAE recordings were obtained from both ears of each subject under five different levels of speech babble delivered via a loudspeaker in sound field using both the default and Quickscreen methods of data collection. The results indicated that both the whole-wave reproducibility (WWR) and mean signal-to-noise ratio (MSNR), averaged across frequencies from about 2 to 4 kHz, decreased with increasing speech babble levels. The results also showed that the Quickscreen mode was less susceptible to noise than the default mode. The pass percentage, using either WWR > or = 50 percent or an MSNR > or = 3 dB as a pass criterion, also decreased with increasing speech babble levels. Furthermore, the findings indicated that the use of the WWR pass criterion resulted in a high failure rate under high levels of speech babble. In contrast, the MSNR pass criterion was robust to speech babble levels of up to 70 dBA in the Quickscreen mode and 65 dBA in the default setting. The clinical implications of these findings, as applied to non-sound-treated environments, are discussed.     

新生儿自发性耳声发射与瞬态诱发性耳声发射的相关性

目的分析自发性耳声发射（spontaneous otoacoustic emission,SOAE）与瞬态诱发性耳声发射（transient evoked otoacoustic emission,TEOAE）之间的相关性。方法新生儿112例（224耳）,其中女59例,男53例,出生后2～4天内行SOAE及TEOAE检测。结果每耳SOAE信号峰数量与其TEOAE强度相关（r=0.43,P〈0.001）。每耳最大SOAE波幅与其TEOAE强度相关（r=0.49,P〈0.001）。不同耳依据其SOAE信号峰数量将其分为4组：I组无SOAE信号峰;II组为单SOAE信号峰;III组为2～3个SOAE信号峰;IV组为3个以上信号峰。I组TEOAE强度为（10.96±3.77）dBSPL,II组（12.87±3.27）dBSPL,III组（15.61±3.23）dBSPL,IV组（17.100±4.51）dBSPL,各组间的TEOAE强度差异均具有统计学意义。II组SOAE最大强度（-13.54±9.21）dBSPL,III组（-4.56±7.22）dBSPL,IV组（1.00±7.35）dBSPL,各组间最大SOAE波幅差异具有统计学意义。结论SOAE信号峰数量、最大SOAE波幅与TEOAE强度之间存在正相关关系,SOAE信号峰越多,最大SOAE波幅也越强,同时TEOAE强度也越强。     

Contralateral suppression of transient evoked otoacoustic emissions in children with auditory processing disorder

This study concerns contralateral white noise suppression of transient evoked otoacoustic emissions (TEOAEs) in children with auditory processing disorder (APD). Fifty-one children between 7 and 11 years were assigned to 1 of 3 experimental groups: those without auditory complaints (n = 15), those with APD who scored high on a standardized test (n = 20) and those with APD who scored lower on the same test (n = 16). For all groups TEOAE suppression was determined in both linear and nonlinear acquisition mode. The results provide evidence that abnormal TEOAE suppression was significantly more common in the APD groups than in the control group. Contralateral suppression of TEOAE is an additional tool for assessing the efferent pathway in children with APD.     

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.     

Handedness effects on transient evoked otoacoustic emissions in schoolchildren

Handedness, as a potentially influencing, nonpathologic factor, has not been investigated in relation to transient evoked otoacoustic emissions (TEOAEs). The present study aimed to examine the effects of handedness on the TEOAE spectrum in entry-level schoolchildren, with attention also to possible ear asymmetry. A total of 228 subjects (114 males, 114 females, mean age = 6.3 years) were tested using the ILO292 Otodynamics Analyzer (Quickscreen mode) in quiet rooms in 22 schools. For statistical analysis, subjects were matched for factors such as handedness, gender, age, and history of recent ear infection. The results from subjects with passing TEOAE, pure-tone screening, and tympanometry revealed no significant handedness effect overall, although a significant ear asymmetry effect on the measurement parameters of AB difference, noise level, response level, whole-wave reproducibility, band reproducibility, and signal-to-noise ratios was found.     

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。     

Aging and contralateral suppression effects on transient evoked otoacoustic emissions

Transient evoked otoacoustic emissions (TEOAEs) were recorded in 30 normal-hearing subjects to nonlinear clicks while continuous contralateral broadband noise (CBBN) was presented at 40, 50, 60, and 70 dB HL. Thirty subjects between 20 and 79 years were divided system-atically into six-decade age groups, five subjects per group. All subjects in each group had hearing thresholds of 20 dB HL or better for the test frequencies from 0.25 to 8.0 kHz and normal acoustic immittance findings. The results provide evidence that contralateral suppression at varying levels of CBBN is interactive with age. Except for subjects in the age ranges between 60 and 69 and 70 and 79 years of age, an increase in CBBN from 40 to 70 dB in 10-dB steps resulted in an average increase in suppression from about 0.5 to 3.5 dB SPL. In addition, the contralateral suppression at 60 and 70 dB HL was significantly greater for subjects between 20 and 59 years of age than for subjects between 60 and 79 years of age.     

Evoked otoacoustic emissions from normal-hearing young Chinese

Evoked otoacoustic emissions (EOAE) were recorded in normal-hearing young Chinese. Incidences and thresholds of EOAE responses, interaural threshold differences and latencies were calculated. The results were compared with other reports in the literature. The average threshold of EOAEs evoked by 1 kHz bone-conducted tone-burst stimuli was found about 4.43 dB below the subjective thresholds for the stimuli. This result is quite different from that reported by Rossi in 1988. The cause of the result is yet not clear.     

Distortion product otoacoustic emissions in normal-hearing children with homozygous sickle cell disease

The purpose of this study was to investigate distortion product otoacoustic emissions (DPOAEs) in young normal-hearing children with sickle cell disease (SCD). It was hypothesized that the prevalence of DPOAEs and response amplitudes would be lower than those in children with normal hemoglobin due to suspected compromised cochlear function as a result of vaso-occlusive events characteristic of SCD. Twenty African-American children with SCD and 15 African-American children with normal hemoglobin participated. Distortion product OAEs were evoked by 13 primary tone pairs with f2 frequencies ranging from 1000 to 4500 Hz. The primary tones were presented at L1 and L2 levels of 70 and 60 dB SPL (high) and 50 and 40 dB SPL (low), respectively. The findings of this study were completely unexpected and contrary to our original hypotheses. The likelihood of detecting a DPOAE response was not related to the clinical status of the children. Distortion product OAE amplitudes were significantly larger for children with SCD (p =.01).     

Evoked otoacoustic emissions in normal-hearing infants and children: emerging data and issues

Evoked otoacoustic emissions (EOAEs) are a promising tool for evaluating cochlear status in children. Preliminary data from normal-hearing subjects ranging from birth to 29.9 years old are discussed. EOAEs are present and robust in infant ears. However, there is a statistically significant decrease in EOAE amplitude for a fixed stimulus level with increasing age even in a carefully screened sample. At the present time it is unclear if these age-associated changes are due to normal developmental changes in the external and/or middle ear acoustics, normal developmental changes in cochlear mechanics and/or everyday cochlear wear and tear. Issues related to further application of evoked emissions to pediatric populations are discussed.     

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.     

糖尿病患者瞬态诱发耳声发射对侧抑制现象的临床研究

目的:研究听力正常的糖尿病患者瞬态诱发耳声发射(TEOAE)对侧抑制现象.方法:分别对30例听力正常的糖尿病患者(糖尿病组)及30例健康对照者(对照组)行纯音听阈、声导抗、TEOAE检测,并通过在其对侧耳中加入60 dB SPL的宽带噪声后TEOAE对侧抑制效应测试以评估其传出神经功能.结果:糖尿病组受试者的纯音听阈及TEOAE的幅值稍低于对照组,但两者间差异无统计学意义;其TEOAE的对侧抑制效应低于对照组,其中在2000 Hz及4 000 Hz处差异有统计学意义(P<0.05).结论:糖尿病患者在其外周听力尚处于正常状态时,其听觉传出神经的功能即已发生了改变.     

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.     

Optimal band pass filtering of transient evoked otoacoustic emissions in neonates

This paper investigated the performance of an optimal bandpass filtering technique to effectively identify click evoked otoacoustic emissions in neonates. The frequency response of the filter was optimized by maximizing the correlation coefficient between two replicate recordings (reproducibility). The optimal cut-off frequencies were also set by controlling the maximum energy loss after filtering to stop the crucial response contents being filtered along with the noise. As an additional constraint, the cut-off frequencies were forced to be outside the range of 1.6 to 4.2 kHz to avoid (in a response identification task) the spontaneous otoacoustic emissions from polarizing the cut-offs and thereby filtering fundamental frequency components, thus leading to an erroneous response classification. The best performance of the optimal filter in terms of increasing the post-filtering reproducibility was obtained when the procedure was applied to recordings whose reproducibility before filtering ranged between 60 and 80 per cent, i.e. for responses classified in most cases as partial pass.     

Linear and nonlinear transient evoked otoacoustic emissions in humans exposed to noise

Transient evoked otoacoustic emissions (TEOAEs) have been analyzed in a population of 134 ears, divided into three classes: (1) nonexposed ears in bilaterally normal hearing subjects, (2) audiometrically normal ears of subjects exposed to noise and affected by unilateral high-frequency (f>3 kHz) hearing loss in the contralateral ear, and (3) the contralateral impaired ears of the exposed subjects. The statistical distributions of global and spectral signal-to-noise ratio (SNR) were analyzed. TEOAEs were recorded both in the linear and nonlinear acquisition mode to evaluate the effectiveness of two standard averaging techniques with respect to their sensitivity to the early effects of noise exposure. Good discrimination between nonexposed and exposed ears was obtained using either the linear or the nonlinear mode. Despite its intrinsically higher SNR, the linear mode is not more sensitive than the nonlinear mode for this purpose because it is not possible to find a window for effectively cancelling the linear artifact while keeping a suitable sensitivity to the short-latency high-frequency aspect of the response. Moreover, with respect to another measurable parameter, the TEOAE latency, good discrimination is obtained only by using the nonlinear mode because, again, the linear artifact masks the high-frequency TEOAE response.     

Development of auditory asymmetry in transient evoked otoacoustic emissions in pre-term infants

We previously reported that transient evoked otoacoustic emissions (TEOAEs) continue to develop after the onset of cochlear function in pre-term infants from 34 to 39 weeks of conceptional age (Morlet et al., 1996). The time-course of development differed between genders. Reported here are findings of further analysis of data from the study cohort, comprising 1020 ears of 510 pre-term neonates (conceptional age ranging from 34 to 39 weeks), demonstrating developmental differences between right and left ears. The left ear of female pre-term infants showed enhancement of TEOAE amplitude at low and medium frequencies with age, whereas differences were less dramatic in the right ear. In male infants, TEOAE amplitude decreased in several frequency bands at high frequencies, above 4 kHz, between 34 and 39 weeks conceptional age; most developmental differences were found to be more dramatic in the right than in the left ear. It is tempting to speculate that these developmental features underlie well-known inter-aural asymmetries that have been demonstrated in the adult human.