Effect of acoustic tumor extension into the internal auditory canal on distortion-product otoacoustic emissions

We studied the effects on distortion-product otoacoustic emissions (DPOAEs) of internal auditory canal (IAC) extension of acoustic neuromas (ANs) with the hypothesis that cochlear patterns of DPOAEs would be more commonly observed when the IAC was completely filled with tumor because of direct tumor involvement of either the inner ear or its blood supply. In a retrospective analysis of 86 patients with surgically proven ANs, DPOAEs were classified as having cochlear or noncochlear patterns on the basis of comparisons with the behavioral pure tone thresholds. The results of behavioral audiometry and DPOAEs were compared with the extension of the tumor into the IAC, which was categorized as full or partial. Of the 86 patients, 58 had tumors with full IAC extension, and 28 had tumors with partial IAC involvement. Cochlear patterns of DPOAEs were found in 55.2% of the tumors in the full IAC group and in 71.4% of those in the partial IAC group (not statistically different). It was concluded that the extent of IAC involvement by ANs was not significantly related to the negative effects of the tumor on cochlear function as represented by DPOAEs.     

Patterns of evoked otoacoustic emissions associated with acoustic neuromas

Evoked otoacoustic emissions (OAEs) are assumed to reflect healthy outer hair cell function. Over the past few years, evoked OAEs have been shown to be useful as indicators of cochlear hearing loss. Because basic studies have shown that OAEs are extremely sensitive to cochlear anoxia and hypoxia, as well as to the adverse effects of many inner ear diseases, it is possible that these objective tests can provide some insight into the fundamental basis of the hearing loss exhibited by patients with acoustic neuromas. The primary aim of the present study was to examine the effects of acoustic neuromas on the amplitudes of evoked OAEs and to compare these findings with tumor-induced hearing levels. To this end, tests of behavioral audiometry, distortion-product otoacoustic emissions and transiently evoked otoacoustic emissions were performed on 44 patients with verified acoustic neuromas. The results demonstrated that the majority of ears with acoustic neuromas displayed one of two distinct patterns of evoked OAEs: a cochlear pattern or a noncochlear pattern. Although behavioral hearing thresholds were higher with larger tumors, OAE levels exhibited no clear relationship to tumor size. The present findings support the notion that acoustic neuromas may cause hearing impairment according to two types of influence that act at different levels of the peripheral auditory system. The tumor's cochlear effect on evoked OAE activity is most likely caused by an indirectly mediated compromise of the organ of Corti's vascular supply. It is probable that the direct pressure of the tumor on the eighth cranial nerve is responsible for the observed noncochlear effects.     

听神经瘤的耳声发射观察

目的 观察和分析听神经瘤的耳声发射特点,为评估听神经瘤患者的耳蜗功能和选择保护听力的术式提供参考依据.方法 对20例（22耳）听神经瘤患者行纯音听阈、阻抗、听性脑干反应（auditory brainstem response,ABR）、诱发性耳声发射（evoked otoacoustic emissions,EOAE）测试及CT和（或）MRI扫描,能引出EOAE的瘤耳检测其自发性耳声发射（spontaneous otoacoustic emissions,SOAE）和传出抑制功能.结果 28.57%听神经瘤耳能引出EOAE,按其畸变产物耳声发射（distortion product otoacoustic emissions,DPOAE）特点分为三型：①“耳蜗型”3耳;②“非耳蜗型”2耳;③“混合型”1耳;“非耳蜗型”耳能引出强大的SOAE;能引出EOAE的6耳均有内侧橄榄耳蜗传出系统功能障碍.结论 EOAE可精确分析听神经瘤患者的耳蜗（外毛细胞）功能,部分听神经瘤病人存在“离断耳”现象.耳声发射（otoacousticemissions,OAE）在诊断重度感音神经性聋（包括听神经瘤病人）方面有一定潜能.     

畸变产物耳声发射对侧抑制效应的临床应用价值

目的：为观察畸变产物耳声发射（ＤＰＯＡＥ）对侧抑制效应的临床应用价值。方法：研究以白噪声为对侧声刺激,对１７例正常人（３４耳）,１３例蜗性聋（１３耳）,９例蜗后聋（９耳）进行了ＤＰＯＡＥ及其对偶抑制效应测试。结果：蜗性聋耳的ＤＰＯＡＥ幅值较正常耳显著下降（Ｐ〈０．０１）,对偶抑制效应减弱,但与正常人差异无统计学意义（Ｐ〉０．０５）,蜗后聋耳ＤＰＯＡＥ幅值高于正常耳（Ｐ〉０．０５）,对侧抑制效应显著     

Detection of loudness recruitment in patients with retrocochlear lesions using the "Würzburger Hörfeld" loudness scaling

BACKGROUND: The pathogenesis of hearing loss caused by cerebellopontine angle tumors such as acoustic neuromas is unknown. The lack of loudness recruitment is thought to be one of the features of retrocochlear hearing impairment. In contrast to conventional suprathreshold tests, the categorial loudness scaling using the "Würzburger H?rfeld" is a valuable tool to describe the individual perception of sound. The aim of the present study was to analyze the loudness growth rate in patients with acoustic neuroma. PATIENTS AND METHOD: Pure tone and speech audiometry as well as auditory brainstem response and bilateral categorial loudness scaling were performed preoperatively in 54 patients with acoustic neuroma. Loudness scaling was done in free field switching off the contralateral ear by using an ear-plug. RESULTS: An abnormal rapid loudness growth function was found in 38 of the 54 patients (70.4%) at least at one frequency on the tumor side. The contralateral side was effected only in 57.4% of the patients. The incidence of a recruitment depended on the frequency with a maximum at 4 kHz. The slope of the loudness function showed a tendency to increase with increasing hearing loss. CONCLUSIONS: Loudness recruitment is not a rare phenomenon in patients with acoustic neuroma. The underlying cause (a preexisting hair cell damage, hair cell changes resulting from an obstruction of the cochlear blood supply or a disruption of the cochlear efferents) still remains unclear.     

对侧刺激声影响畸变产物耳声发射临床意义的探讨

观察白噪声对畸变产物耳声发射输入输出函数曲线影响，探讨其临床价值。方法：检测临床患者６１例，包括单纯性耳鸣不伴有听力下降患者３２例；以低频听力下降为主的耳聋患者２７例；蜗后病变２例。     

Distortion product otoacoustic emissions in patients with King-Kopetzky syndrome

In the present study, mild impairment of cochlear function in patients with King-Kopetzky syndrome was investigated using DPOAEs. A significant decrease in DPOAE levels in both ears was found in patients with King-Kopetzky syndrome compared with the controls after considering the thresholds as a co-variable. It is noteworthy that the global mean levels of DPOAEs were still significantly greater in controls than in patients with matched thresholds. Further frequency analyses showed a significant decrease in DPOAE levels over the mid- and high-frequency range in patients with better hearing thresholds when compared with those in the control group. Moreover, significantly smaller DPOAEs were found in the ears of patients with King-Kopetzky syndrome and without SOAEs, than in such ears of control subjects after considering the thresholds as a co-variable. However, when SOAEs were present there was no difference. Decreases in DPOAE level appear to represent evidence of minor cochlear pathology, and provide a pathological basis for the difficulty of hearing speech in the presence of background noise, which characterizes King-Kopetzky syndrome.     

Hearing evaluation with distortion-product otoacoustic emissions in young patients undergoing haemodialysis.

Sensorineural hearing loss is frequently reported in young patients with chronic renal failure having haemodialysis. The effect of a single session of haemodialysis on hearing acuity was assessed prospectively in nine children with end-stage renal disease using pure-tone audiometry (PTA) and distortion-product otoacoustic emissions (DPOAEs). Results were compared with those obtained from nine audiologically normal healthy children also tested with PTA and DPOAEs twice during a 4-h interval. Sensorineural hearing loss of unknown aetiology was found in 55.5% of renal patients, mainly in the higher frequencies. Patients on HD had mean PTA thresholds significantly poorer than those of the control group in the frequency range 1000-12 000Hz (P < 0.05). Their mean DPOAE amplitudes were significantly lower in all frequencies > 1184 Hz (P < 0.05). Furthermore, patients' ears with normal PTA thresholds between 250 and 4000 Hz also had decreased DPOAE amplitudes. No significant changes in PTA thresholds or DPOAE amplitudes were encountered in renal patients before and after a HD session (P > 0.05). Changes in PTA thresholds or DPOAE amplitudes were not significantly different than those in the control group (P > 0.05). In conclusion, sensorineural hearing loss of unknown origin, especially in high frequencies, is frequent in young renal patients under HD and single HD sessions do not seem to alter the hearing acuity of these patients. DPOAEs seem to be more sensitive to incipient cochlear damage than behaviour thresholds in monitoring renal patients.     

397例听神经瘤听力特征分析

目的 分析听神经瘤患者听力学特征,为筛查听神经瘤提供参考依据。方法 回顾性分析2019年8月—2022年4月诊治的397例单侧听神经瘤患者临床资料,所有患者均行纯音测听、声导抗测试、言语识别率(SDS)、畸变产物耳声发射(DPOAE)、听性脑干诱发电位(ABR)和颅脑增强MRI。结果 以典型症状就诊者312例,非典型症状就诊者85例。以突发性聋就诊者25例;患耳听力正常者54例,包含大型甚至特大型肿瘤,99例全聋者亦包含内听道和中型肿瘤。5例全聋者言语识别能力未完全消失。DPOAE一致型245例,耳蜗型72例,蜗后型79例。ABR阳性率98.0%(389/397),8例ABR波形正常者中3例为双侧非对称听力损失。结论 非典型症状就诊者占比21.4%,以突发性聋就诊、听力正常或ABR正常者不能排除听神经瘤;DPOAE和ABR可作为筛查听神经瘤的重要检查方法。     

Hearing evaluation with distortion-product otoacoustic emissions in young patients undergoing haemodialysis

Sensorineural hearing loss is frequently reported in young patients with chronic renal failure having haemodialysis. The effect of a single session of haemodialysis on hearing acuity was assessed prospectively in nine children with end-stage renal disease using pure-tone audiometry (PTA) and distortion-product otoacoustic emissions (DPOAEs). Results were compared with those obtained from nine audiologically normal healthy children also tested with PTA and DPOAEs twice during a 4-h interval. Sensorineural hearing loss of unknown aetiology was found in 55.5% of renal patients, mainly in the higher frequencies. Patients on HD had mean PTA thresholds significantly poorer than those of the control group in the frequency range 1000–12 000Hz (P < 0.05). Their mean DPOAE amplitudes were significantly lower in all frequencies > 1184 Hz (P < 0.05). Furthermore, patients' ears with normal PTA thresholds between 250 and 4000 Hz also had decreased DPOAE amplitudes. No significant changes in PTA thresholds or DPOAE amplitudes were encountered in renal patients before and after a HD session (P > 0.05). Changes in PTA thresholds or DPOAE amplitudes were not significantly different than those in the control group (P > 0.05). In conclusion, sensorineural hearing loss of unknown origin, especially in high frequencies, is frequent in young renal patients under HD and single HD sessions do not seem to alter the hearing acuity of these patients. DPOAEs seem to be more sensitive to incipient cochlear damage than behaviour thresholds in monitoring renal patients.     

Diagnostics of the cochlear amplifier by means of distortion product otoacoustic emissions

Distortion product otoacoustic emission (DPOAE) growth functions reflect the active nonlinear cochlear sound processing when using a primary-tone setting which accounts for the different compressions of the two primaries at the DPOAE generation site and hence provide a measure for objectively assessing cochlear sensitivity and compression. DPOAE thresholds can be derived from extrapolated DPOAE input/output (I/O) functions independently of the noise floor and consequently can serve as a unique measure for reading DPOAE measurements. The thus-estimated DPOAE thresholds exhibit a close correspondence to behavior audiometric thresholds and thus can be used for reconstructing an audiogram, i.e., a DPOAE audiogram. The DPOAE I/O functions' slope increases with cochlear hearing loss and thus provides a measure for assessing recruitment. Hence, DPOAE I/O functions can give more information for diagnostic purposes than those of DP grams, transiently evoked OAEs (TEOAEs), or auditory brain stem responses (ABRs). DPOAE audiograms can be applied in pediatric audiology to assess cochlear dysfunction in a couple of minutes. In newborn hearing screening, they are able to detect transitory sound-conductive hearing loss and thus can help to reduce the rate of false-positive TEOAE responses in the early postnatal period. Since DPOAE I/O functions are correlated with loudness functions, DPOAEs offer the possibility of basic hearing aid adjustments, especially in infants and children. Extrapolated DPOAE I/O functions provide a tool for a fast automated frequency-specific and quantitative evaluation of hearing loss.     

Increased amplitudes of distortion product otoacoustic emissions in patients with unilateral acoustic neuroma

We present a case series of 4 patients with a unilateral acoustic neuroma and increased amplitudes of the distortion products of otoacoustic emissions (DPOAEs) at the low- and middle- frequency bandwidth on the involved side compared to the uninvolved side despite a 28-dB hearing level (HL) worse (compared to the uninvolved side) pure-tone hearing threshold average for standard audiometric frequencies between 1 and 6 kHz at the involved side. In 3 of these patients, 2 with an inferior vestibular nerve origin of the acoustic neuroma and one in whom the nerve of origin could not be unequivocally defined, the tumor was extending extrameatally. One patient had a purely intrameatal acoustic neuroma of superior vestibular nerve origin. Moreover, notable was the presence of the DPOAEs in all of the involved ears despite elevated pure-tone hearing thresholds (pure- tone averages for the standard audiometric frequencies between 1 and 6 kHz ranging between 36 and 62 dB HL).     

Acoustic neuroma presenting as sudden hearing loss

Sudden hearing loss occurs as the initial symptom in 1 to 9 per cent of all acoustic neuromas. A case of an acoustic neuroma presenting with sudden hearing loss is described. In this case, the hearing thresholds returned to normal. To the authors' knowledge, this is the first case in which an acoustic neuroma presenting with sudden hearing loss exhibited a return to normal thresholds. This suggests that such tumors may have an initial reversible effect on hearing thresholds.     

Impaired cochlear function correlates with the presence of tinnitus and its estimated spectral profile

The presence of tinnitus often coincides with hearing loss. It has been argued that reduced peripheral input leads to frequency-specific increase in neuronal gains resulting in tinnitus-related hyper-activity. Following this gain-adaptation hypothesis, impaired cochlear function should be predictive of the presence and spectral characteristics of tinnitus. To assess cochlear function, perceptual thresholds and distortion product otoacoustic emissions (DPOAEs) were measured with high frequency resolution for subjects with tinnitus and non-tinnitus control subjects (N?=?29 and N?=?18) with and without hearing loss. Subjects with tinnitus also provided a 'tinnitus likeness spectrum' by rating the similarity of their tinnitus to tones at various frequencies. On average, subjects with tinnitus had elevated thresholds, reduced DPOAE, and increased slope of the DPOAE input-output function in the range from 4 to 10?kHz. These measures were strongly correlated and were equally predictive of the presence of tinnitus. Subjects with a pronounced edge to their hearing loss profile were very likely to have tinnitus. In the group average, the tinnitus likeness spectrum was correlated with perceptual thresholds (r?=?0.98, p?相似文献   

Cochlear implants in the management of bilateral acoustic neuromas.

Multichannel cochlear implants currently provide the only modality for successful auditory rehabilitation of patients with bilateral profound sensorineural hearing loss who derive no benefit from amplification. We have developed a protocol for patients with neurofibromatosis and bilateral acoustic neuromas in which every effort is made to preserve hearing in at least one ear. Failing that, the cochlear nerve is spared, potentially allowing for the insertion of a cochlear implant. We present our data on one such patient whose auditory function was restored with a Nucleus mini 22-channel cochlear implant following removal of his acoustic neuroma.     

Is hyperventilation-induced nystagmus more common in retrocochlear vestibular disease than in end-organ vestibular disease?

Hyperventilation-induced nystagmus (HVIN) has previously been shown by the senior author to be common in patients with both acoustic neuromas and following resection. The recurrent study's aim was to examine if HVIN was specific for retrocochlear pathology. To test this, the incidence of HVIN in 24 patients with confirmed acoustic neuroma was compared with its incidence in 38 patients with end-organ vestibular disease (defined as a greater than 25% reduction in caloric testing). Hyperventilation was carried out for 90 seconds. The results showed that 58% of the acoustic neuroma group were positive for HVIN versus 18% of the end-organ group. This difference was very significant on chi-square testing (p < .002). Hyperventilation-induced nystagmus appears to be much more prevalent in retrocochlear pathology than in end-organ pathology.     

Vertex response: influence of lesions in the auditory system

The principal value of specialized audiologic techniques lies in early diagnosis of retrocochlear lesions, which in turn minimizes technical difficulties in the surgical removal of acoustic neuromas; however, despite a wide battery of audiometric tests, the otolaryngologist too often has difficulty in distinguishing between cochlear and retrocochlear lesions. Johnson¹ observed deviations in one or more respects from the classic audiometric findings in almost half of the cases of acoustic neuroma that he studied. Other audiologists² have encountered similar problems.     

Unilateral hearing loss in children with shunt-treated hydrocephalus

This study investigated the characteristics of hearing loss in children with ventriculoperitoneal (VP) shunted hydrocephalus. Twelve hydrocephalic children with patent VP shunts participated. The etiology of the hydrocephalus was either intraventricular hemorrhage or spina bifida. Audiometric examination included pure-tone air conduction thresholds, tympanometry, contralateral and ipsilateral acoustic reflex thresholds (ARTs), and distortion product otoacoustic emissions (DPOAEs). A unilateral, high-frequency, cochlear hearing loss was found in the ear ipsilateral to the shunt placement in 10 (83%) of the 12 shunt-treated hydrocephalic children. No hearing loss was observed in the ear contralateral to shunt placement. Based on the pure-tone audiometric findings, coupled with the decrease in DPOAE amplitude in the shunt ear, the hearing loss appears to be cochlear in nature. We suggest that cochlear hydrodynamics are disrupted as the result of reduced perilymph pressure, a consequence of cerebrospinal fluid (CSF) reduction due to the combined effects of a patent shunt and a patent cochlear aqueduct. In addition, a concomitant brain stem involvement is evidenced in the ART pattern, possibly produced by the patent shunt draining the CSF from the subdural space, resulting in cranial base hypoplasia.     

Development of distortion product otoacoustic emissions in C57BL/6J mice

Distortion product otoacoustic emissions (DPOAEs) have been used to examine the development of hearing in the rat and gerbil. However, no reports of DPOAE measurement from the onset of hearing in mice are available. Commercially-available components were assembled and adapted to provide a suitable probe microphone and sound delivery system for measuring DPOAE in developing C57BL/6J mice. Furthermore, DPOAE data were compared with the findings of the auditory brainstem response (ABR). DPOAEs were obtained at 8 kHz from 11 days after birth, 20 kHz from 12 days, and 30 kHz from 13 days. Adult-like patterns of DPOAE were obtained 21 days at 8 and 20 kHz, and 28 days at 30 kHz. On the other hand, the ABR thresholds at 12 to 36 kHz appeared between 11 and 12 days and were saturated at 14 days. Based on these data, the onset of measureable DPOAEs in the mouse were earlier than in the rat and gerbil. The maturation of DPOAE in the mouse begins at a lower frequency in the high frequency range. In addition, the ABR threshold reached maturation earlier than DPOAE.     

High-frequency hearing influences lower-frequency distortion-product otoacoustic emissions

OBJECTIVES: The primary goal of this study was to test the ability of 2f1-f2 distortion-product otoacoustic emissions (DPOAEs) to detect reduced cochlear function in the presence of normal behavioral sensitivity. DESIGN: A prospective study was performed in normal-hearing young adults using simple and complex regression analyses to clarify the relationship between ultra-high frequency (UHF) hearing and DPOAE levels at lower frequencies, as well as the influence of hearing levels for frequencies within the conventional test range and subject age on this association. METHODS: Average DPOAE levels between 4 to 8 kHz, which were elicited by equilevel primary tones of low to moderate levels, were measured as level-frequency functions, or distortion-product (DP) grams, and related to the mean UHF hearing levels from 11.2 to 20 kHz. The median hearing level for the UHF hearing was used to separate subjects into good and poor UHF hearers. This distinction was then used to compare DPOAE levels from 4 to 8 kHz for the 2 groups to determine if UHF hearing status influenced DPOAE levels at lower frequencies. RESULTS: Simple regression analysis revealed that the 4-to 8-kHz DPOAE levels were significantly correlated with the pure-tone average (PTA) from 11.2 to 20 kHz. However, the PTA for 4 and 8 kHz was also significantly correlated with the PTA for UHF hearing. Further multiple regression analyses revealed that UHF hearing significantly and uniquely accounted for approximately 14% of the variance in DPOAE levels from 4 to 8 kHz for most of the primary-tone level combinations. In contrast, neither the PTA for the conventional hearing range nor subject age contributed significantly to the DPOAE variance. CONCLUSIONS: The findings suggest that UHF hearing influences DPOAEs at significantly lower frequencies because emissions are sensitive to subtle changes in outer hair cells not yet detected by pure-tone thresholds in this region or because alterations in the basal cochlea affect the generation of lower-frequency DPOAEs originating from more apical cochlear regions.