The effect of treatment with vincristine on transient evoked and distortion product otoacoustic emissions

OBJECTIVE: Vincristine chemotherapy is mainly associated with neurotoxic effects. The ototoxicity of vincristine has been related to high dosage, while low and moderate doses do not seem to induce significant hearing impairment when measured by pure tone or speech audiometry. Otoacoustic emissions have been reported to be more sensitive in early detection of ototoxicity than conventional pure tone audiometry. The present study was directed at determining whether vincristine treatment interferes with outer hair cell function in the absence of measurable changes in pure tone audiometry. METHODS: We studied prospectively a cohort of ten children suffering from leukemia. All children were subjected to tympanogram, stapedial muscle reflex, pure tone audiometry, transient evoked (TEOAEs) and distortion product (DPOAEs) otoacoustic emissions on day 1 and on day 22 of treatment with vincristine. TEOAEs were analyzed in terms of emission level and reproducibility as a function of frequency. DPOAEs were obtained as DP-grams and were analyzed in terms of amplitude. RESULTS: The analyzed parameters of TEOAEs and DPOAEs revealed a declining tendency, although changes did not reach statistical significance. Pure tone audiometry and stapedial reflex thresholds were not altered. CONCLUSION: For the population of this study, vincristine did not seem to cause significant alterations of otoacoustic emissions' recordings and consequently significant outer hair cell damage.     

The effect of impulse noise on distortion product otoacoustic emissions

The aim of this study was the evaluation of distortion product otoacoustic emissions (DPOAEs) before and after noise exposure from shooting, and the comparison of DPOAEs with pure-tone audiometry. Thirteen young male police officers were exposed to impulse noise from shooting, without using earplugs. Standard pure-tone audiometry, tympanometry, and DPOAEs were performed before exposure and at one hour post- and 24 hour post-exposure. In the one hour post-exposure testing mean pure-tone thresholds were elevated in the 1-8 kHz frequency zone and DPOAE levels were reduced at several frequencies. DPOAEs were more affected at 3 kHz or lower, whereas pure-tone thresholds were more affected at higher frequencies. After the final examination, non-significant partial shifts at high frequencies on both tests remained. Pure-tone audiometry was overall more sensitive, but DPOAEs provided additional information about the cochlear status of certain ears. These data suggest that besides behavioral testing, DPOAEs may play a role as a fast, objective, and easy to perform test for monitoring subjects exposed to impulse noise.     

听性脑干反应与畸变产物耳声发射检测在听神经病诊断中的表现和意义

目的分析听神经病患者的听性脑干反应与畸变产物耳声发射特征,探讨该类听力学检测方法在听神经病诊断中的意义。方法回顾性研究本科确诊为听神经病的患者37例,比较分析其听性脑干反应与畸变产物耳声发射检测结果,探索其诊断意义。结果本组患者中,3例5耳（双耳病变2例,单耳病变1例）可引出V波,阈值70～90dB SPL,其余患耳ABR各波均未引出（刺激声强〉100dB SPL）。无论纯音听阈损失程度轻重如何,所有患者的DPOAE均全部引出。在各个频率点上,DPOAE的DP—gram幅值左、右耳间的差异均无统计学意义（P〉0．10）。结论听神经病的主要病变部位可能位于听神经传入通路,或伴有脑干内侧橄榄耳蜗系统的传出神经通路病变。     

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。     

The effect of impulse noise on distortion product otoacoustic emissions

The aim of this study was the evaluation of distortion product otoacoustic emissions (DPOAEs) before and after noise exposure from shooting, and the comparison of DPOAEs with pure-tone audiometry. Thirteen young male police officers were exposed to impulse noise from shooting, without using earplugs. Standard pure-tone audiometry, tympanometry, and DPOAEs were performed before exposure and at one hour post- and 24 hour post-exposure. In the one hour post-exposure testing mean pure-tone thresholds were elevated in the 1–8 kHz frequency zone and DPOAE levels were reduced at several frequencies. DPOAEs were more affected at 3 kHz or lower, whereas pure-tone thresholds were more affected at higher frequencies. After the final examination, non-significant partial shifts at high frequencies on both tests remained. Pure-tone audiometry was overall more sensitive, but DPOAEs provided additional information about the cochlear status of certain ears. These data suggest that besides behavioral testing, DPOAEs may play a role as a fast, objective, and easy to perform test for monitoring subjects exposed to impulse noise.     

Interpreting auditory brainstem evoked responses and distortion product otoacoustic emissions in diabetic patients with normal hearing

ObjectiveHearing impairment is a reported late complication of diabetes mellitus (DM). Previous studies have suggested that microangiopathic complications may cause cochlear nerve function deterioration. We evaluated the auditory brainstem evoked responses (ABRs) and distortion product otoacoustic emission (DPOAE) results according to the presence of DM in subjects with normal hearing.MethodsA cross-sectional comparative study was conducted from January 2016 to January 2018. Auditory function tests including ABR and DPOAE were performed for outpatients complaining of unilateral tinnitus. All of analyses were conducted in ears without tinnitus on contralateral side of tinnitus ears. We included subjects showing hearing thresholds within 25 dB at 0.5, 1k, 2k, and 4k on pure tone audiometry. 45 ears in patients with type 2 diabetes mellitus and 85 ears in non-diabetic patients were finally enrolled in our study.ResultsDiabetic subjects showed significantly more prolonged absolute peak latencies (I, III, V) and inter-peak latencies (I–V, III–V) than non-diabetic subjects. However, there was no significant difference in the inter-peak latency (I–III) between these two groups. Diabetic subjects also showed significantly lower amplitudes at f2 frequencies of 1001, 1200, 1587, 4004, 5042, and 6348 Hz than non-diabetic subjects. Additionally, the prevalence of a DPOAE response, defined as 3 dB above the noise floor, was significantly lower in diabetic subjects than that in non-diabetic subjects.ConclusionDiabetic patients with normal hearing can still have abnormal ABR and DPOAE results due to diabetic neuroangiopathy. ABR and DPOAE assessments can help in detecting subclinical auditory dysfunction, which precedes the manifestation of hearing impairment in diabetic patients.     

Changes in distortion product otoacoustic emissions during prolonged noise exposure

The aim of this study was to evaluate the reduction in 2f₁−f₂ distortion product otoacoustic emission (DPOAE) amplitude resulting from prolonged noise exposures. A group of five chinchillas was exposed continuously to an octave-band noise centered at 4.0 kHz for a total of 42 days, 6 days at each of seven exposure levels. Exposure level increased in 8-dB steps from 48 to 96 dB SPL. DPOAE input-output (I/O) functions were measured at octave intervals over a range of primary tone f₂ frequencies between 1.2 and 9.6 kHz. Measurements were obtained (1) pre-exposure, (2) during days 3–6 of each 6-day exposure, and (3) 4 weeks after the final exposure. Continuous noise exposure caused a reduction in DPOAE amplitude that was greatest at f₂ frequencies within and above (3.4–6.8 kHz) the octave-band noise exposure. For these f₂ frequencies, DPOAE amplitudes decreased as exposure level increased up to approximately 72–80 dB SPL; higher exposure levels failed to cause any further reduction in DPOAE amplitude. The noise level at which DPOAE amplitude began to decrease was approximately 50 dB SPL. Above this critical level, DPOAE amplitude decreased 1.3 dB for every dB increase in noise level up to approximately 75 dB SPL.     

足月新生儿的瞬态诱发性耳声发射与听性脑干反应分析

本研究通过对听功能正常 2 2例 (42耳 )和异常 5 5例 (110耳 )的足月新生儿 TEOAEs和 ABR检测 ,将两种方法的主要参量进行对比分析和验证 ,发现 :1以 ABRs阈值≥ 40 d Bn HL为新生儿听损伤标准 ,TEOAEs四项参量指标和四项参量综合指标均为有效指标 ,其符合率如下 :TEOAEs反应强度为 98.6 8% ;TEOAEs反应波的重复率为96 .71% ;TEOAEs反应波 1～ 4k Hz频率范围 (1.0、1.5、2 .0、3.0、4.0 k Hz)的重复率为 96 .71% ;1～ 4k Hz频率范围(1.0、1.5、2 .0、3.0、4.0 k Hz) TEOAEs反应波的信噪比为 98.6 8% ;四项参量综合指标为 97.37% ;2听觉功能异常的足月新生儿中单侧耳听力受损伤 (5 8.18% )多于双侧耳 (41.82 % ) ;3TEOAEs测试结果存在假阴性率为 1.32 % ,假阳性率为 1.32 %。     

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     

豚鼠噪声暴露后畸变产物耳声发射及神经元特异性烯醇化酶表达的观察

为观察豚鼠暴露于强噪声后畸变产物耳声发射(DPOAE)及神经元特异性烯醇化酶(NSE)的变化,选用13只Preyer's反射正常的健康豚鼠,分为二组,8只噪声暴露组,5只为NSE表达对照组。噪声强度115dB(A),连续暴露4小时,DPOAE幅值于噪声暴露前后进行测试,结果DPOAE幅值噪声暴露前后差异明显(P<0.001),豚鼠内耳内、外毛细胞及螺旋神经细胞胞浆、隧道贯穿纤维NSE免疫组化反应均呈阳性表达,暴震前后无明显变化。结果提示豚鼠接受短时间强噪声刺激后,DPOAE幅值的下降为暂时阈移,而内耳神经元及其末梢未受损伤。     

Concurrent measurement of distortion product otoacoustic emissions and auditory steady state evoked potentials

Distortion product otoacoustic emissions (DPOAEs) and auditory steady state evoked response potentials (ASSRs) can both be evoked by tone pairs with frequencies f(1) and f(2). The DPOAE is maximal at 2f(1)-f(2) and the ASSR is maximal at f(2)-f(1). Since DPOAE magnitude depends on the ratio f(2)/f(1), but ASSR amplitude depends on the beat frequency f(2)-f(1), compromises are necessary when recording both responses concurrently. Tone pairs with f(2) of 900, 1800 and 3600 Hz were presented simultaneously at either 40 or 50 dB sound pressure level (SPL). The f(1) frequency of each pair was approximately 85 or 180 Hz lower than f(2). Phase measurements were used to calculate apparent latencies at 40 dB SPL. For increasing f(2), DPOAE latencies were 14.5, 9.7 and 6.3 ms for 85 Hz beats, and 11.5, 9.0 and 4.3 ms for 180 Hz beats. ASSR latencies were 22.0, 15.7 and 17.8 ms at 85 Hz, and 17.7, 11.3 and 9.6 ms at 180 Hz. From a model of the mechanical transmission in the cochlea, delays between the basilar membrane and the generator of the ASSR were estimated as 15.4, 12.2 and 15.3 ms at 85 Hz and 8.6, 7.6 and 8.0 ms at 180 Hz.     

Sensitivity of transient evoked and distortion product otoacoustic emissions to the direct effects of noise on the human cochlea

Measurement of otoacoustic emissions (OAEs) has been proposed as a sensitive test to reliably assess the effects of noise exposure. The present study in humans was designed to evaluate the sensitivity and applicability of transient evoked OAEs (TEOAEs) and 2f1-f2 distortion product OAEs (DPOAEs) as quantitative indices of the functional integrity of the outer hair cells (OHC) during growth of and recovery from temporary threshold shift (TTS). This was examined in two different groups of volunteers by measuring the per- and post-stimulatory effects of a one hour BBN and an on-site five hour exposure to loud music from a discotheque. The results of both experiments show consistent growth and recovery patterns for both DPOAEs and TEOAEs. For TEOAEs, both the reproducibility scores and signal to noise ratio values for the 4 kHz frequency band exhibited the greatest sensitivity. The DPOAEs, on the other hand, showed the greatest sensitivity between 2 and 5.5 kHz. Thus, both the TEOAEs and DPOAEs have a great potential in the detection of TTS after noise exposure.     

Transient evoked otoacoustic emissions and auditory brainstem response in infants with perinatal asphyxia

ObjectiveThe objective of this study was to verify the effects of perinatal asphyxia on different parts of the auditory system.MethodsThis was a non-concurrent cohort study conducted on a fixed population in a tertiary public hospital. Participants included 181 infants born at term who underwent the transient evoked otoacoustic emission test as a part of a neonatal hearing screening program, with a “pass” result in both ears, and by auditory brainstem response testing. The infants were divided into 3 groups: G1, 20 infants who had perinatal asphyxia; G2, 111 infants with an Apgar score lower than 4 in the first minute and/or lower than 6 in the fifth minute (called “low Apgar” at birth); and G3, 50 infants with first- and fifth-minute Apgar scores ≥7.ResultsThe signal-to-noise ratio of transient evoked otoacoustic emissions were greater in G3 compared with G1 and G2 at 4 kHz frequency for males. An increased latency of waves I and III in the auditory brainstem response of male infants in G1 was observed.ConclusionThis study demonstrated that alterations occurred in both the cochlear and the neural components in male infants who had perinatal asphyxia.     

谷氨酸对豚鼠畸变产物耳声发射和听性脑干反应的影响

目的 研究外源性谷氨酸对畸变产物耳声发射(distortion product otoacoustlcemission，DPOAE)、听性脑干反应(auditory brainstem response，ABR)及耳蜗形态学的影响。方法应用豚鼠全耳蜗灌流技术，耳蜗灌流10mmol/L谷氨酸2h，分别记录灌流前、后DPOAE和ABR；耳蜗微音电位(cochlear microphonics，CM)和听神经复合动作电位(compound action potential，CAP)；应用透射电镜进行耳蜗形态学观察。结果灌流人工外淋巴液前、后CM及CAP无改变；灌流10mmol／L谷氨酸后DPOAE无改变，ABR潜伏期延长；同样灌流10mmol／L谷氨酸后CM幅度虽有下降、但是其非线性特点无改变；CAP阈值平均升高了35dB；灌流谷氨酸后内毛细胞及其下方神经纤维出现空泡。结论谷氨酸作为耳蜗主要的兴奋性传入神经递质，过度释放可以产生兴奋性毒性，损伤耳蜗内毛细胞及传入神经。同时本实验为建立听神经病的动物模型提供了一个参考方法。     

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.     

The effect of noise bandwidth on the contralateral suppression of transient evoked otoacoustic emissions

The purpose of this study was to determine whether the bandwidth or loudness of a contralateral stimulus is the most important factor in evoking suppression of transient evoked otoacoustic emissions (TEOAEs). TEOAEs were measured in both ears of 10 women in quiet and in the presence of one of three contralateral noise bands; narrow band (NB), wide band (WB) and equalized (EQ), all centered at 2000 Hz. The NB (100 Hz bandwidth) and WB (2200 Hz bandwidth) noises were presented at 60 dB SPL. The SPL of the EQ (100 Hz bandwidth) noise was adjusted such that it was equal in loudness to the WB noise as determined using a psychoacoustic procedure. Only the WB noise was associated with a significant reduction of TEOAE levels. It is believed that this effect occurred because the WB noise has greater effective energy representation across frequency on the basilar membrane as it may receive more gain from the action of the cochlear amplifier. Results of the present study indicate that noise bandwidth is the most important factor in the contralateral suppression of TEOAEs.     

噪声暴露工人畸变产物耳声发射和扩展高频测听的研究

目的 :分析畸变产物耳声发射 (DPOAE)和常频纯音测听、扩展高频测听的关系 ,借以探讨DPOAE的产生机制以及在噪声性听力损伤的监测和早期诊断中的应用价值。方法 :对 4 2例耳科正常人 (对照组 )和 2 0例噪声暴露工人 (实验组 )进行 0 .5～ 16 .0kHzDPOAE、常频纯音测听及扩展高频测听的检测 ,比较对照组和实验组DPOAE和常频纯音测听、扩展高频测听的结果。结果 :实验组纯音听阈在 6 .0kHz处和扩展高频区下降明显 ,与对照组比较 ,差异有显著性意义 (P <0 .0 5 ) ;DPOAE幅值在 4 .0、6 .0和 11.2kHz处下降明显 ,与对照组比较 ,差异均有显著性意义 (P <0 .0 5 ) ;而在 12 .5、14 .0、16 .0kHz 3个频率处两组差异无显著性意义 (P >0 .0 5 )。结论 :常频DPOAE检查可用于噪声性聋的早期诊断和监测。DPOAE可能来源于对应频率区及较高频率区耳蜗外毛细胞 ,其产生部位和机制尚待深入研究     

Correlations among evoked potential thresholds, distortion product otoacoustic emissions and hair cell loss following various noise exposures in the chinchilla

Changes in cubic distortion product otoacoustic emissions (ΔDPOAEs), evoked potential threshold shifts (TSs) and outer hair cell (OHC) losses were measured in a population of 95 noise-exposed chinchillas. Each animal was exposed to one of 23 different noises in an asymptotic threshold shift (ATS) producing paradigm or an interrupted noise paradigm which typically produced a toughening effect. Noises were narrow band (400 Hz) impacts with center frequencies of 0.5, 1.0, 2.0, 4.0 or 8.0 kHz presented 1 impact/s at peak SPLs of 109, 115, 121 or 127 dB. The duration of the exposures was 24 h/day for 5 days (ATS paradigm) or 6 h/day for 20 days (toughening paradigm). Based on a linear regression analysis of individual subject and group mean data, correlations among the following dependent variables were made: ΔDPOAEs, ATS, toughening or TS recovery (TS_r), permanent threshold shift (PTS) and OHC loss. Correlations among these metrics were generally highest for DPOAE primary frequency levels, L₁=L₂=70 dB. Correlation between ΔDPOAE and TS_r was typically low, while a considerably higher correlation was found between ΔDPOAE and ATS. Correlations among the permanent measures of noise-induced effects, i.e. for ΔDPOAE/PTS and ΔDPOAE/OHC loss were typically poor when there was only a small or a moderate noise-induced effect (PTS<25 dB and ΔDPOAE<20 dB). However, for PTS<25 dB the correlation between PTS and OHC loss was considerably better than the correlation between ΔDPOAE and OHC loss. For more severe noise-induced changes there was generally a good correspondence between OHC loss, PTS and ΔDPOAE metrics.