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.     

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.     

Evaluation of residual hearing in cochlear implants candidates using auditory steady-state response

Conclusion: The correlations between behavioral and auditory steady-state response (ASSR) thresholds were significant at 500, 1000, 2000, and 4000 Hz. ASSR presented high sensitivity and specificity in the detection of residual hearing in cochlear implant candidates when compared with warble-tone audiometry. Objectives: To assess residual hearing in cochlear implant candidates by comparing the electrophysiological thresholds obtained in dichotic single-frequency ASSR with behavioral thresholds at 500, 1000, 2000, and 4000 Hz. Methods: This was a comparative study between ASSR and warble-tone audiometry thresholds in 40 cochlear implant candidates (80 ears) before cochlear implantation with bilateral severe-to-profound sensorineural hearing loss. Results: Thresholds were obtained in 62.5% of all frequencies evaluated in warble-tone audiometry and in 63.1% in the ASSR. ASSR sensitivity was 96% and specificity was 91.6%. Mean differences between behavioral and ASSR thresholds did not reach significance at any frequencies. Strong correlations between behavioral and ASSR thresholds were observed in 500, 1000, and 2000 Hz and moderate in 4000 Hz, with correlation coefficients varying from 0.65 to 0.81. On 90% of occasions, ASSR thresholds were acquired within 10 dB of behavioral thresholds.     

Vestibular evoked myogenic potentials in acute acoustic trauma.

OBJECTIVES: Anatomical proximity of the saccule to the stapedial footplate points to the possibility of acoustic trauma associated with saccular dysfunction. Therefore, it was the authors' premise that abnormal vestibular evoked myogenic potential (VEMP) after acute acoustic trauma may be caused by saccular damage from very high intensity noise; consequently, irreversible hearing loss ensued. The aim of this study was to investigate the VEMP responses in those with acute acoustic trauma. STUDY DESIGN: A prospective study. SETTING: University hospital. PATIENTS: Twenty patients (29 ears) without previous ear disorders diagnosed as acute acoustic trauma were enrolled in this study. MAIN OUTCOME MEASURES: Before treatment, each patient underwent pure tone audiometry and caloric and VEMP tests. Correlations between the hearing outcome and mean hearing level, sources of noise, caloric responses, or VEMP results were investigated. RESULTS: After 3 months of medication, complete recovery was achieved in 4 ears and hearing improvement in 4 ears, whereas hearing in 21 ears (72%) remained unchanged. Eighteen ears presenting normal VEMPs revealed hearing improvement in eight ears (44%) and unchanged hearing in ten ears (56%). However, hearing loss remained unchanged in all 11 ears (100%) with absent or delayed VEMPs, exhibiting a significant relationship between VEMP results and hearing outcome. Thus, VEMP test can predict the hearing outcome after acute acoustic trauma with a sensitivity of 44% and a specificity of 100%. CONCLUSION: The greater the noise intensity, the severer damage on the cochlea and saccule is shown. Absent or delayed VEMPs in ears after acute acoustic trauma may indicate poor prognosis with respect to hearing improvement, whereas normal VEMP is not a powerful indicator for expectation of hearing improvement.     

Prediction of the nerves of origin of vestibular schwannomas with vestibular evoked myogenic potentials

OBJECTIVE: To determine whether the nerves of origin of vestibular schwannomas can be predicted using vestibular evoked myogenic potentials (VEMPs). STUDY DESIGN: The study was a retrospective analysis. SETTING: The ear, nose, and throat department of Tokyo Medical and Dental University. PATIENTS: Twenty-eight patients undergoing removal of vestibular schwannomas were included in the study. INTERVENTIONS: Patients underwent pure tone audiometry, VEMP testing, caloric testing, and magnetic resonance imaging preoperatively. Hearing level, caloric weakness, maximum tumor size, and the nerves of origin of tumors were compared with VEMP testing. MAIN OUTCOME MEASURE: Results of VEMP testing. RESULTS: Comparisons between VEMPs and results of the other three examinations revealed no correlations. Complete disappearance of VEMPs was observed only in patients with tumors arising from inferior vestibular nerves. Patients in whom hearing was preserved tended to have preserved VEMPs. Some patients showed damaged hearing and normal VEMP results, although with inferior vestibular schwannomas. A patient with a tumor arising from a cochlear nerve exhibited preservation of VEMP, preserved caloric response, and moderate hearing loss. CONCLUSIONS: Inferior vestibular nerve function and hearing level were reflected in VEMP results. Prediction of the nerve of origin of a tumor was possible only in certain restricted cases.     

Changes in Ribbon Synapses and Rough Endoplasmic Reticulum of Rat Utricular Macular Hair Cells in Weightlessness

Although still the subject of discussion, vestibular-evoked myogenic potentials (VEMPs) have been considered to reflect the function of the saccular and, more recently, the cochlear tracts. To accurately determine the precise afferent pathway carrying VEMPs, we studied the outcomes of VEMPs and other examinations in patients with unilateral vestibular schwannomas. Eleven patients with unilateral vestibular schwannomas resected using a middle cranial fossa approach were included in the study. Patients underwent pure-tone threshold audiometry, caloric tests and analysis of auditory brainstem responses (ABRs) and VEMPs pre- and postoperatively. The results were compared with those obtained in patients with intact superior or inferior vestibular and cochlear nerves. Among the 11 patients studied, 4 retained their VEMPs postoperatively. Three of the 10 patients with inferior vestibular schwannomas exhibited normal VEMPs, preserved hearing levels (20 dB HL) and anatomically intact superior vestibular nerves. In all of these cases, ABRs more closely correlated with VEMPs than with caloric responses. In one of the cases with inferior vestibular schwannomas, VEMPs were preserved postoperatively and VEMP latencies were shortened, which indicates the preoperative presence of a conduction block in either the cochlear or superior vestibular nerve. VEMPs may be conducted in both the superior vestibular and cochlear nerves, as well as in the inferior vestibular nerve. Thus, evaluation of saccular nerve function should be performed carefully, especially in cases where hearing is preserved. It appears that cochlear conduction may proceed along two pathways, one direct and the other via the brainstem, but this remains to be verified.     

Postoperative vestibular-evoked myogenic potentials in cases with vestibular schwannomas

Although still the subject of discussion, vestibular-evoked myogenic potentials (VEMPs) have been considered to reflect the function of the saccular and, more recently, the cochlear tracts. To accurately determine the precise afferent pathway carrying VEMPs, we studied the outcomes of VEMPs and other examinations in patients with unilateral vestibular schwannomas. Eleven patients with unilateral vestibular schwannomas resected using a middle cranial fossa approach were included in the study. Patients underwent pure-tone threshold audiometry, caloric tests and analysis of auditory brainstem responses (ABRs) and VEMPs pre- and postoperatively. The results were compared with those obtained in patients with intact superior or inferior vestibular and cochlear nerves. Among the 11 patients studied, 4 retained their VEMPs postoperatively. Three of the 10 patients with inferior vestibular schwannomas exhibited normal VEMPs, preserved hearing levels (20 dB HL) and anatomically intact superior vestibular nerves. In all of these cases, ABRs more closely correlated with VEMPs than with caloric responses. In one of the cases with inferior vestibular schwannomas, VEMPs were preserved postoperatively and VEMP latencies were shortened, which indicates the preoperative presence of a conduction block in either the cochlear or superior vestibular nerve. VEMPs may be conducted in both the superior vestibular and cochlear nerves, as well as in the inferior vestibular nerve. Thus, evaluation of saccular nerve function should be performed carefully, especially in cases where hearing is preserved. It appears that cochlear conduction may proceed along two pathways, one direct and the other via the brainstem, but this remains to be verified.     

Effects of stimulus conditions on vestibular evoked myogenic potentials in healthy subjects

Background: Characteristics of vestibular evoked myogenic potentials (VEMPs) depend on stimulus conditions.

Objective: To determine the optimal stimulus conditions for cervical and ocular VEMPs.

Methods: Participants were 23 healthy subjects. We compared air-conducted cervical and ocular VEMPs elicited by various tone-burst conditions (frequencies 500–1,000?Hz, rise/fall times 1–2?ms, and plateau times 0–6?ms) with an intensity of 105?dB normal hearing level. Effects of simultaneous contralateral masking noise on VEMPs were also evaluated.

Results: The largest cervical VEMP amplitudes were elicited by 500–750?Hz and 2–6?ms plateau time-tone-bursts, and the largest ocular VEMP amplitudes by 750?Hz and 2–4?ms plateau time-tone-bursts. Repeatability of the latency was better at 1?ms than at 2?ms rise/fall time in both VEMPs. In both VEMPs, masking noise reduced amplitude, and in ocular VEMP, amplitudes were significantly larger at the left ear stimulation than the right.

Conclusion: Optimal tone-burst stimulation for both VEMPs seemed to be 500–750?Hz frequency and 1/2/1?ms rise/plateau/fall time without contralateral masking noise. Ocular VEMP amplitudes from left ear stimulation were originally larger than those from right ear stimulation.     

Acoustic and psychoacoustic analysis of the noise produced by the police force firearms

Police officers are exposed to impact noise coming from firearms, which may cause irreversible injuries to the hearing system.AimTo evaluate the noise exposure in shooting stands during gunfire exercises, to analyze the acoustic impact of the noise produced by the firearms and to associate it with tonal audiometry results.Study designCross-sectional.Materials and methodsTo measure noise intensity we used a digital sound level meter, and the acoustic analysis was carried out by means of the oscillations and cochlear response curves provided by the Praat software. 30 police officers were selected (27 males and 3 females).ResultsThe peak level measured was 113.1 dB(C) from a .40 pistol and 116.8 dB(C) for a .38 revolver. The values obtained for oscillation and Praat was 17.9±0.3 Barks, corresponding to the rate of 4,120 and 4,580 Hz. Audiometry indicated greater hearing loss at 4,000Hz in 86.7% of the cases.ConclusionWith the acoustic analysis it was possible to show cause and effect between the main areas of energy excitation of the cochlea (Praat cochlear response curve) and the frequencies of low hearing acuity.     

人类声诱发短潜伏期负电位的研究

目的在极重度感音性聋耳的ABR检测中发现一个位于3～4ms潜伏期的"V"字形负向波形,称声诱发短潜伏期负电位(Acoustically Evoked Short Latency Negative Response,ASNR)。本研究通过大宗病例调查和临床实验来探讨ASNR的特点和起源。方法回顾性调查并分析3104例ABR检测结果,以详尽了解ASNR的出现率和特性。对20名双耳极重度感音性耳聋患者(6～62岁)和12名健康人(23～30岁)进行了ABR和前庭诱发肌源性电位(VEMP)测试。患者组包括了16名人工耳蜗植入术后的患者,植入耳在裸耳状态时可提供无功能耳蜗模型。结果判读侧重于:人工耳蜗植入耳能否诱发ASNR,以及对比在极重度感音性聋耳中ASNR组和非ASNR组的VEMP出现率及反应阈值。结果ASNR仅出现于极重度感音性聋耳,并且对强声刺激(80～120dBnHL)有依赖性。在653例极重度感音性聋患者(981耳)的ABR波形中,有80例(12.3%)117耳(11.9%)出现了ASNR。ASNR有良好的重复性,可排除伪迹干扰的可能性。ASNR具有神经电位的特征,表现在随着声刺激的增强,其潜伏期缩短而振幅增大。ASNR与ABR的波形完全不一样,无法将其解释为传统听觉神经通路产生的电位。临床实验中,3个人工耳蜗植入耳能诱发出ASNR,说明ASNR的发生与耳蜗无关。所有9个ASNR耳都诱发出VEMP,且阈值与正常对照组无统计学差异(P>0.05),提示ASNR耳具有正常的球囊功能。在非ASNR组中,三分之二没有引出VEMP,而另外三分之一虽然可以诱发出VEMP,但阈值明显较正常对照组高(P<0.01),分别提示球囊功能丧失或低下。此外,有一外半规管麻痹耳诱发出了ASNR和VEMP。结论ASNR并非伪迹,而是一种依赖强声刺激,且只出现于极重度感音性聋耳的神经电位。ASNR的出现完全依赖于正常的球囊功能,而不依赖于残余听力或者半规管功能。据此认为ASNR起源感觉器官为球囊,根据其潜伏期推测电位源自前庭神经核。     

单侧人工耳蜗植入术前后双耳残余听力变化的初步研究

目的 通过观察单侧人工耳蜗植入术后儿童双耳残余听力情况,分析其变化趋势,探讨各种可能的影响因素。 方法 将29例单侧人工耳蜗植入的重度极重度感音神经性耳聋儿童纳入研究,根据术前颞骨CT分为A组(有大前庭导水管综合征)和B组(非大前庭导水管综合征),分别于术前、术后1周、开机时、术后半年定期进行裸耳纯音测听,比较植入耳残余听力保存情况及非植入耳残余听力的变化。 结果 患儿术前双耳均不同程度存在残余听力,术后均定期行纯音测听或行为测听,各频率仍部分存有残余听力,主要分布在低频区,且随频率升高其残余听力保留率逐渐下降,各频率残余听力保留率之间差异有统计学意义(Wald χ2=16.980, P=0.001);植入耳与非植入耳各频率残余听力保留率之间差异有统计学意义(Wald χ2=10.031, P=0.002);术前后各时间节点残余听力保留率之间差异无统计学意义(Wald χ2=3.384, P=0.336); AB两组之间残余听力保留率之间差异无统计学意义(Wald χ2=0.906, P=0.341)。 结论 人工耳蜗植入对植入耳残余听力的保留主要分布在低频区;随着植入时间的延长,残余听力可以基本保持;少部分患儿行单侧植入后对非植入耳残余听力有影响;前庭导水管扩大症患儿行单侧耳蜗植入术后,非植入耳残余听力在短期内可有波动。     

The effects of click and tone-burst stimulus parameters on the vestibular evoked myogenic potential (VEMP)

Vestibular evoked myogenic potentials (VEMP) are short latency electromyograms (EMG) evoked by high-level acoustic stimuli and recorded from surface electrodes over the tonically contracted sternocleidomastoid (SCM) muscle and are presumed to originate in the saccule. The present experiments examined the effects of click and tone-burst level and stimulus frequency on the latency, amplitude, and threshold of the VEMP in subjects with normal hearing sensitivity and no history of vestibular disease. VEMPs were recorded in all subjects using 100 dB nHL click stimuli. Most subjects had VEMPs present at 500, 750, and 1000 Hz, and few subjects had VEMPs present at 2000 Hz. The response amplitude of the VEMP increased with click and tone-burst level, whereas VEMP latency was not influenced by the stimulus level. The largest tone-burst-evoked VEMPs and lowest thresholds were obtained at 500 and 750 Hz. VEMP latency was independent of stimulus frequency when tone-burst duration was held constant.     

Low- and high-frequency hearing in patients with Menière's disease

Summary We determined the pure-tone hearing thresholds of 25 patients with unilateral active Menière's disease using standard clinical audiometry, high-frequency audiometry (10–18 kHz), and low-frequency audiometry (20–80 Hz). In addition to hearing loss at the conventional frequencies, all of the affected ears showed deterioration of the thresholds at both low- and high-frequency areas as compared with the reference ears. The degree of hearing loss at these frequencies correlated to the degree of the hearing loss at the conventional frequencies, where it was greatest at 0.5–1 kHz. Our findings suggest that in Menière's disease the whole cochlear sensory area is affected, and that the damage caused by Menière's disease advances simultaneously in all parts of the cochlea. Offprint requests to: T. Rahko     

Vestibular evoked myogenic potentials in delayed endolymphatic hydrops

OBJECTIVE/HYPOTHESIS: Vestibular evoked myogenic potential (VEMP) has become an established test to explore the sacculo-collic reflex. The study aims to investigate the VEMPs in cases of delayed endolymphatic hydrops because greatly dilated saccule was observed in histopathological specimens of delayed endolymphatic hydrops. STUDY DESIGN: Prospective study. METHODS: Twenty patients with delayed endolymphatic hydrops were subjected to pure-tone audiometry, caloric testing, and VEMP test. Delayed VEMP was defined as the latency of peak I exceeding 22.6 milliseconds or of peak II exceeding 33.1 milliseconds. Interaural amplitude difference over the sum of amplitudes of both ears was measured, and when the ratio exceeded 0.36, it was identified as augmented VEMP or depressed VEMP depending on whether the amplitude of the lesioned side was greater or less than the opposite side. RESULTS: The VEMP test revealed that 9 patients (45%) were normal, 6 (30%) exhibited absent VEMPs, and 5 (25%) displayed abnormal VEMPs, including delayed VEMPs in 2, depressed VEMPs in 2, and augmented VEMPs in 1. The caloric test indicated that 9 (47%) of the 19 ears exhibited normal caloric response, whereas 10 ears displayed abnormal caloric responses including canal paresis in 8 and absent caloric response in 2. Six ears had preserved both the caloric response and the VEMPs, whereas no ear demonstrated both absent caloric response and absent VEMPs. CONCLUSIONS: The residual caloric as well as saccular functions after ear insult may determine whether delayed endolymphatic hydrops will occur. These findings suggest that patients with sudden deafness or juvenile unilateral total deafness should undergo caloric testing and VEMP test to predict the occurrence of delayed endolymphatic hydrops in the future.     

Cytoarchitecture of the Mammalian Organ of Corti

The objectives of the present study were to evaluate both the respective and combined effects of occupational noise exposure and smoking on hearing, taking age into consideration. The evaluation was conducted using 1478 subjects without a history of ear disease out of a population-based sample of 2267 adults, aged 40–79 years. Pure-tone audiometry and a questionnaire were administered. A deleterious effect of noise exposure on hearing was significantly observed in both genders at many frequencies after adjustment for age, income, and education. The smoking habit alone significantly affected hearing deterioration at 4000 Hz in noise-unexposed males. The combined effect of noise and smoking was not interactive but additive. A dose-response effect of smoking on hearing loss was observed in middle-aged males without noise exposure. Smoking and noise exposure were associated with hearing loss respectively.This result is noteworthy for the preservation of good hearing especially at the beginning of aging.     

Characterization of age-related changes in vestibular evoked myogenic potentials.

A tone-burst stimulation of 500 Hz seems to be clinically most appropriate to elicit vestibular evoked myogenic potentials (VEMPs) because those VEMPs can be recorded at the lowest stimulus intensity possible. However, little is known about gender and age-related changes of the amplitude in tone-burst (500 Hz) evoked VEMPs. The aim of the present paper was therefore to investigate the influence of gender and age on VEMP amplitude in relation to the tonic muscle activity. VEMPs of 64 healthy subjects were recorded ipsilaterally during air- or bone-conducted tone burst stimulation. The EMG of the tonically activated sternocleidomastoid muscle was recorded ipsilaterally with surface electrodes. Averages were taken for P1/N1 amplitudes of male and female volunteers within 3 different age groups. Although the amplitude decreased with increasing age the tonic activity was not significant different between the age groups. Consequently the relation between VEMP amplitude and tonic muscle activity decreased with increasing age. The normative values of the age-dependent relation between VEMP amplitude and tonic muscle activity were described by the 90% confidence interval of the individual values. Normative thresholds were calculated. Normal saccular receptor function could be diagnosed if the VEMP amplitude is above (or equal to) the normative value at a given tonic muscle activity and age. Normative data as described above are required to diagnose isolated saccular defects, which are indicative of a vestibular disorder.     

Evoked otoacoustic emission in conduction of dehydration tests in patients with Meniere's disease

We studied potentiality of the test of evoked otoacoustic emission (EOAE) for monitoring of dynamic changes in the internal ear in conduction of dehydration tests. In parallel to registration of tonal hearing thresholds and speech intelligibility in conduction of dehydration tests we registered two classes of EOAE: delayed EOAE (DEOAE) and distortion product otoacoustic emission (DPOAE). Of 36 examinees, we registered DEOAE prior to dehydration in 22 patients. By audiometry, these patients had hearing under 40 dB lower the hearing threshold at frequencies 250-4000 Hz. In registration of DEOAE in dynamics a maximal amplitude increase was seen 2 hours after intake of glycerin. A mean amplitude increase was 7.0+/-2.3 dB. Before dehydration DEOAE was recorded in 26 of 36 patients. Two hours laser otoacoustic response was registered in 29 patients. Hearing loss was not more than 60 dB at frequencies 250-4000 Hz. A maximal amplitude increase was seen in 2 hours. A mean amplitude increase in dehydration was 7.3+/-3.7 dB.     

Is there a relevant effect of noise and smoking on hearing? A population-based aging study

The objectives of the present study were to evaluate both the respective and combined effects of occupational noise exposure and smoking on hearing, taking age into consideration. The evaluation was conducted using 1478 subjects without a history of ear disease out of a population-based sample of 2267 adults, aged 40 79 years. Pure-tone audiometry and a questionnaire were administered. A deleterious effect of noise exposure on hearing was significantly observed in both genders at many frequencies after adjustment for age, income, and education. The smoking habit alone significantly affected hearing deterioration at 4000 Hz in noise-unexposed males. The combined effect of noise and smoking was not interactive but additive. A dose-response effect of smoking on hearing loss was observed in middle-aged males without noise exposure. Smoking and noise exposure were associated with hearing loss respectively..This result is noteworthy for the preservation of good hearing especially at the beginning of aging.     

Our auditory results using the Vibrant Soundbridge on the long process of the incus: 20 years of data

Objective

After 20 years of experience with different types of middle ear implants, we analyzed our database about the Vibrant Soundbridge (VSB) to know the rate of complications, the effect on the residual hearing and the audiometric gain in our center.

REZ-Ⅰ型人工耳蜗植入对成人残余听力的影响

目的 评估REZ-Ⅰ型国产人工耳蜗植入对成人残余听力的影响,探讨该人工耳蜗植入的听力学安全性及其损伤的特点.方法 回顾性分析复旦大学附属眼耳鼻喉科医院2009年9月至2009年11月间16例单侧REZ-Ⅰ型(22通道)人工耳蜗植入者在手术前后的纯音测听、听觉稳态反应(auditory steady-state response,ASSR)、畸变产物耳声发射(DPOAE)及听觉脑干反应(ABR)的资料,比较手术前后残余听力的变化情况.结果 纯音测听植入侧术后残余听力保留率为41.67%;术后植人侧250、500、1000、2000及4000 Hz的残余听力较术前下降,差异具有统计学意义,其中500 Hz下降较明显,平均下降15.3 dB HL,P<0.01;通过与非植入侧对比发现500和1000 Hz的听力损失有统计学意义(P值均<0.05).植入侧术后ASSR阈值在250和500 Hz处较术前升高,差异具有统计学意义(P值均<0.05)),经与非植入侧对比发现500 Hz处ASSR阈值升高有统计学意义(P值<0.05).DPOAE及ABR植入前后差异均无统计学意义(P值均>0.05).结论 REZ-Ⅰ型人工耳蜗植入会对植入侧残余听力造成一定程度的损伤.