Diverse etiologies manifesting auditory neuropathy characteristics from infants with profound hearing loss and clinical implications

ObjectiveAuditory neuropathy spectrum disorder (ANSD) is a hearing disorder with impaired signal transmission from the inner ear to the brain. The electrophysiological characteristics of auditory neuropathy (AN characteristics) are marked with presence of otoacoustic emissions (OAE) or cochlear microphonics (CM) in the absence of auditory brainstem response (ABR). This study aimed to review etiologies related to AN characteristics from infants with profound hearing loss (HL), either unilaterally or bilaterally.Study designProspective cohort study for thirty infants with prelingual profound HL.MethodsABR, OAE, and/or CM were analyzed to identify electrophysiological characteristics. Temporal bone computed tomography and/or internal acoustic canal magnetic resonance imaging were reviewed to identify anatomical abnormalities. The electrophysiological characteristics and cochlear nerve status were analyzed according to the laterality of deafness (unilateral vs bilateral).ResultsAmong the total 41 ears (from 30 infants) with profound HL, 13 ears (7 (36.8%) of 19 ears with unilateral HL and 6 (27.3%) of 22 ears associated with bilateral HL) showed AN characteristics (37.1%), and 21 ears showed cochlear nerve deficiency (CND) (51.2%). AN characteristics was detected about two times more frequently in cases with CND (38.1%) than with anatomically normal cochlear nerve (20.0%), the difference not reaching a statistical significance probably due to a small sample size. Detection of AN characteristics did not differ between unilateral and bilateral profound HL, even though presence of CND was more frequently detected in cases with unilateral profound HL than with bilateral cases. There were at least five types of etiologies related to AN characteristics in 13 ears (from 10 infants) in our series depending on the laterality of deafness and presence of CND.ConclusionsThis study demonstrates that there were diverse etiologies related to AN characteristics from infants with unilateral or bilateral profound HL. Association between CND and AN characteristics is suggestive but not solid at this moment and AN characteristics is not a fully penetrant feature of CND.     

Significance of internal auditory canal diverticula in ears with otosclerosis

Abstract

Background: Diverticula in the internal auditory canal (IAC) have been reported in ears with otosclerosis.

Objective: We evaluated hearing levels and vascular activity in ears with otosclerosis with and without IAC diverticula and clarify the significance of IAC diverticula.

Materials and methods: Sixty-one ears from 54 patients who underwent stapes surgery for otosclerosis [fenestral (48 ears) and retrofenestral (13 ears) groups] were included in the present study. Preoperative hearing levels on pure tone audiometry (PTA) and intraoperative measurements of blood flow were compared between the groups.

Results: A total of 24 of 61 ears (39.3%) showed IAC diverticula, significantly higher than the frequency in ears without otosclerosis (3.7%). No significant differences in air- and bone-conduction thresholds on PTA were evident between ears with and without IAC diverticula in each group. Ears without IAC diverticula tended to show higher blood flow in the area anterior to the oval window than ears with IAC diverticula, but the difference was not significant.

Conclusions: The incidence of the IAC diverticula in otosclerosis was significantly higher than in cases without otosclerosis. The existence of IAC diverticula was not evidently related to the severity of the disease from the perspective of hearing level and vascular activity.     

先天性内耳道狭窄的多层螺旋CT和MRI表现

目的 总结先天性内耳道狭窄的多层螺旋CT(multiple slices CT,MSCT)和MRI影像学特点,提高对该病的认识.方法 回顾性分析13例(15耳)先天性内耳道狭窄患者MSCT和MRI检查的影像资料.结果 先天性内耳道狭窄单侧11例,双侧2例.MSCT显示内耳道管腔不同程度狭窄.孤立性内耳道狭窄3耳,合并其他畸形12耳,其中10耳仅合并内耳畸形,1耳同时合并内、中、外耳畸形,另1耳同时合并内、中、外耳畸形及额骨发育畸形.MRI检查15耳均显示前庭蜗神经发育细小;其中7耳蜗神经未显示,7耳蜗神经发育细小,1耳蜗神经显示不清;其中2耳面神经发育细小.容积再现(volume rendering,VR)图像可立体显示内耳道狭窄程度及伴发的内耳畸形.结论 MSCT 可显示内耳道狭窄的程度及伴发畸形,MRI则可显示其神经发育情况.

Abstract：

Objective To investigate multiple slice computed tomography ( MSCT) and magnetic resonance imaging( MRI) features of congenital stenosis of the internal auditory canal (CSIAC) and improve the ability for diagnosis.Method Thirteen cases with fifteen ears were studied.In all cases a MSCT and MRI was performed.Results Eleven cases were unilateral,and 2 cases were bilateral.MSCT could show the narrowness of IAC.Three cases were isolated,but the others were combined with inner ear malformations.One ear had inner,middle and outer ear malformations.One ear had inner,middle,and outer ear malformations with a frontal bone malformation.MRI demonstrated that all of the vestibulocochlear nerves were hypoplastic.The cochlear nerve in seven ears was not present,in seven ears the nerve was thinner,and in the last case it was poorly visualized.The facial nerve in two ears was hypoplastic.Volume rendering( VR) could present the degree of the narrowed internal auditory canals,combined with other inner ear anomalies.Conclusion MSCT will show the degree of the narrow internal auditory canals and combined anomalies,while the MRI can further demonstrate the nerves' development.     

Central auditory maturation and behavioral outcome in children with auditory neuropathy spectrum disorder who use cochlear implants

Abstract

Objective: We examined cortical auditory development and behavioral outcomes in children with ANSD fitted with cochlear implants (CI). Design: Cortical maturation, measured by P1 cortical auditory evoked potential (CAEP) latency, was regressed against scores on the infant toddler meaningful auditory integration scale (IT-MAIS). Implantation age was also considered in relation to CAEP findings. Study sample: Cross-sectional and longitudinal samples of 24 and 11 children, respectively, with ANSD fitted with CIs. Results: P1 CAEP responses were present in all children after implantation, though previous findings suggest that only 50–75% of ANSD children with hearing aids show CAEP responses. P1 CAEP latency was significantly correlated with participants’ IT-MAIS scores. Furthermore, more children implanted before age two years showed normal P1 latencies, while those implanted later mainly showed delayed latencies. Longitudinal analysis revealed that most children showed normal or improved cortical maturation after implantation. Conclusion: Cochlear implantation resulted in measureable cortical auditory development for all children with ANSD. Children fitted with CIs under age two years were more likely to show age-appropriate CAEP responses within six months after implantation, suggesting a possible sensitive period for cortical auditory development in ANSD. That CAEP responses were correlated with behavioral outcome highlights their clinical decision-making utility.     

内耳道底神经管孔发育不全的CT仿真内镜观察

目的:用多层螺旋CT仿真内镜成像方法显示内耳道底神经管孔的正常解剖及发育异常,并分析各种内耳道底神经管孔发育不全的仿真内镜表现。方法:收集25例(50耳)志愿者高分辨率CT颞骨扫描图像(正常组)和8例(13耳)高分辨率CT和MRI检查示内耳道底发育畸形扫描图像(异常组),用仿真内镜观察内耳道底正常结构及畸形,下限阈值900~1 200 HU,上限阈值3 071 HU。结果:正常组:仿真内镜均显示了50耳各神经管孔的形态和位置。异常组:内耳道底结构紊乱、神经孔缺如9耳,其中内耳道底仅显示单个神经孔1耳;显示2个神经孔4耳,1孔为面神经孔,4个位听神经孔融为1孔;显示3个神经孔2耳,1孔为面神经孔,位听神经孔融为2孔;显示4个神经孔2耳,均为耳蜗神经孔闭锁。单纯神经孔形态异常4耳,均为耳蜗神经孔形态异常,其中非螺旋孔列2耳,蜗轴消失2耳。并发内耳道其他异常3耳。并发内耳畸形8耳。结论:仿真内镜可立体显示各神经孔的形态及位置,显示内耳道底神经管孔发育异常的类型,结合多平面重组(MPR)具有较大的临床应用价值。     

后天性外耳道狭窄的手术治疗

目的探讨后天性外耳道狭窄的手术治疗方法及效果。方法对26例（27耳）外耳道狭窄行外耳道成形术或厢乳突根治鼓室成型术，取大腿内侧自体游离中厚皮片植皮，碘仿纱条压迫并扩张耳道。结果26例病人27耳随访6个月至8年，24耳外耳道宽敞，无再狭窄；3耳出现轻度狭窄，发生率11．1％（3／27），效果满意。结论对后天性外耳道狭窄的治疗可根据狭窄的原因、部位及程度等不同情况采用外耳道成形、游离中厚皮片移植或同时进行乳突根治鼓室成型术等手术治疗，术后局部换药，即能取得较好效果。     

Cochlear schwannoma removed through the external auditory canal by a transcanal exclusive endoscopic technique

Surgical approaches to the inner ear and internal auditory canal (IAC) are widely known and extensively recorded. The most popular can be classified as retrosigmoid, transmastoid‐translabyrinthine, and middle cranial fossa approaches. For the first time, an exclusive endoscopic approach to the IAC is described here, used to remove a cochlear schwannoma involving both the IAC and labyrinth. The operation provided a direct transcochlear intradural approach from lateral to medial and from external to internal auditory canal, without any external incision. The pathology was totally removed, and the postoperative outcome of the facial nerve was grade II (House‐Brackmann grading system) at 3‐month follow‐up. Laryngoscope, 123:2862–2867, 2013     

Prevalence of auditory neuropathy spectrum disorder in an auditory health care service

Auditory neuropathy spectrum disorder (ANSD) is characterized by impairment of the auditory nerve associated with preservation of outer hair cell function.ObjectiveTo establish the prevalence of ANSD in subjects with sensorineural hearing loss (SNHL).MethodThis retrospective study was carried out between 2010 and 2012 and included the charts of 2,292 individuals with SNHL. Data from otolaryngological and audiological examinations based on pure-tone and speech audiometry, impedance tests, otoacoustic emissions (OAEs), and brainstem auditory evoked potentials (BAEPs) were collected. Inclusion criteria: presence of OAEs and/or cochlear microphonic (CM); absent or altered BAEPs, and normal MRI scans of the brain.ResultsTwenty-seven (1.2%) of the 2,292 subjects with SNHL had ANSD (37% males; 63% females). Mild SNHL was seen in 29.6% of the individuals with ANSD; 55.5% had moderate SNHL; 7.4% had severe SNHL; and 7.5% had profound SNHL. In terms of age, 14.8% were aged between zero and 20 years, 44.1% were 41 to 60 years old, and 7.4% were above the age of 60.ConclusionANSD was seen in 1.2% of the individuals with SNHL included in this study.     

Bilateral narrow duplicated internal auditory canal

Internal auditory canal (IAC) anomalies are rare malformations that may include alterations of shape, size or orientation of the IAC. Bilateral duplication of IAC is a very rare malformation and only one case has been described in literature. We report a case of bilateral duplicated IAC together with other inner ear anomalies.     

Usefulness of measuring electrically evoked auditory brainstem responses in children with inner ear malformations during cochlear implantation

Conclusions: EABR is a reliable and effective way of objectively confirming device function and implant-responsiveness of the peripheral auditory neurons up to the level of the brainstem in cases of inner ear malformation. Objective: To investigate the usefulness of measuring the intra-operative electrically evoked compound action potential (ECAP) and electrically evoked auditory brainstem response (EABR) in patients with and without congenital inner ear anomalies during cochlear implantation. Method: Thirty-eight consecutive children (40 ears) aged 5 or younger with congenital profound hearing loss. Twenty-four (25 ears) lacked congenital inner ear anomalies. The 14 patients (15 ears) with a malformation had common cavities (four ears), incomplete partition type I (three ears), cochlea hypoplasia type III (three ears), enlarged vestibular aqueduct (four ears), and cochlear nerve canal stenosis (one ear). Main outcome measures are ECAP and EABR responses. Results: Of the 25 ears lacking any malformation, 21, three, and one showed ‘Good’, ‘Variable’, and ‘No’ ECAP responses, respectively, and 24 and one showed ‘Good’ and ‘Variable’ intra-cochlear responses, respectively. Of the 15 ears with a malformation, two showed ‘Good’ ECAP responses, nine had ‘Variable’ ECAP responses, and four showed ‘No’ ECAP responses. Moreover, five showed ‘Good’ EABR responses and 10 showed ‘Variable’ EABR responses.     

Auditory and speech performance in cochlear implanted ANSD children

Background: Auditory neuropathy spectrum disorder (ANSD) is a distinct type of SNHL that is characterized by the presence of otoacoustic emissions and/or cochlear microphonics. Cochlear implantation was initially not recommended for ANSD children, later studies showed variable outcomes among those subjects.

Objective: To assess the auditory and speech performance of cochlear implanted children with auditory neuropathy spectrum disorder (ANSD) and to compare these results to those obtained from cochlear implanted children with sensorineural hearing loss (SNHL)

Material and methods: 18 cochlear implanted children with ANSD and 40 cochlear implanted children with SNHL were included in this study. Auditory and speech performance results were compared across both subject groups using the Category of Auditory Performance (CAP) and Speech Intelligibility Rate (SIR) tests, with measurements recorded one year post implantation.

Results: Cochlear implanted children with ANSD showed clinically significant improvements that were comparable to those observed from cochlear implanted subjects without ANSD.

Conclusions: Children with ANSD benefit from early cochlear implantation and can reach similar auditory and speech performance results as that achieved by children without ANSD.     

The value of ABR- and ASSR-based hearing estimation in young children with congenital monaural malformation (atresia)

Abstract

Background: The electrophysiology of auditory nerve mature is particularly important for unilateral hearing loss.

Objectives: To assess the hearing status in young children with congenital monaural malformation and evaluate their potential for practical use in the functional maturation parameters of the auditory pathway.

Materials and methods: ABR (auditory brainstem responses) and ASSR (auditory steady-state responses) threshold measurements were performed in 21 young children with congenital monaural atresia.

Results: The average electrophysiologic thresholds for the ABR were 65?dB nHL ± 1.20 in malformed ears and 25?dB nHL ± 0.48 in normal ones. All 21 atretic ears presented with typical conductive hearing loss. There was no statistic positive correlation in hearing-impaired ears between the methods of ABR and ASSR responses (r?=?0.12, 0.20 and 0.17). The IPL (interpeak latency) of I–III, III–V and I–V of atretic ears in ABR test was decreased relative to normal ears. Furthermore, a shortening of the IPLs I–III, III–V, I–V can be observed with increasing age of the children in malformed ears.

Conclusions and significance: The ABR- and ASSR-based hearing evaluation in young children with congenital monaural malformation should be viewed as complementary technologies. Besides, there was no delay of functional maturation at brainstem level although unilateral hearing was deprived during their early years of life.     

婴幼儿单侧听神经瘤

目的：探讨婴幼儿单侧听神经病（AN）神经生理学特点。方法：对3例单侧AN患儿在采集病史和耳科检查的基础上,行系统的听力学检查,包括声阻抗、镫骨肌反射、听性脑干反应（ABR）、耳蜗微音电位（CM）、诱发耳声发射（EOAE）、中潜伏期反应（MLR）和事件相关电位（ERP）以及CT和（或）MRI及周围神经系统检查。结果：3例患儿鼓室图均呈“A”型,健耳的同侧和交叉镫骨肌反射可正常引出,而患耳的同侧和交叉镫骨肌反射未引出。3例患儿双侧EOAE有效引出,健耳的ABR正常引出,思耳的ABR未引出,但CM均正常。3例患儿双耳均记录到MLR及ERP。影像学和周围神经系统未见异常。结论：单侧AN与双侧AN有相似的神经生理学特点。对婴幼儿单侧AN的诊断应着重分析其神经生理学特点,建议联合应用EOAE、ABR、CM和影像学检查。应对AN患儿定期随访。     

Assessment of the efferent auditory system in children with suspected auditory processing disorder: the Middle ear muscle reflex and contralateral inhibition of OAEs

Objective: To determine whether children aged 7 to 12?years with listening difficulties show objective evidence for efferent auditory function based on measurements of medial olivo-cochlear and middle ear muscle reflexes.

Design: Click-evoked otoacoustic emissions recorded with and without contralateral broadband noise and ipsilateral and contralateral tonal (1000, 2000?Hz) middle ear muscle reflex thresholds were examined.

Study sample: 29 children diagnosed with suspected auditory processing disorder (APD) and a control group of 34 typically developing children participated in this study.

Results: Children with suspected APD had poorer performance on auditory processing tests than the control group. Middle ear muscle reflex thresholds were significantly higher at 2000?Hz in the suspected APD group for contralateral stimulation. MOC inhibition effects did not differ between APD and control groups.

Conclusions: This research supports earlier studies showing altered acoustic reflexes in children with APD. No group differences were found for the MOC reflex measures, consistent with some earlier studies in children with APD.     

同步多频听觉稳态诱发反应与听性脑干诱发电位相关性研究

目的探讨同步多频听觉稳态诱发反应(auditory steady-state responses to multiple simultaneous stimuli,MSS-ASSR)与听性脑干诱发电位(auditory brainstem response audiometry,ABR)的关系。方法受试者为不同程度听力损失的儿童70名(140耳),年龄范围为3月龄～6岁。测试状态为水合氯醛镇静睡眠。仪器采用美国INTELLEGENT HEARING的诱发电位仪,MSS-ASSR及ABR测试的软件分别为SMART ASSR和SMART EP,刺激声信号的载波频率为0．5kHz、1kHz、2kHz及4kHz。左耳上述各个载波频率的调制频率分别为77Hz、85Hz、93Hz、101Hz,右耳为79Hz、87Hz、95Hz、103Hz。测试时,双耳八个调幅调制声信号经ER-3A标准插入式耳机同时给出。ABR的刺激声为短声,极性为交替波,刺激速率为19．3次／分,耳机也是ER-3A插入式耳机。受试儿先进行ABR测试、然后进行MSS-ASSR的测试,分别以降10升5法得出二者的反应阈。将MSS-ASSR 0．5kHz、1kHz、2kHz和4kHz的反应阈与ABR反应阈比较,以SPSS 10．0软件进行相关性分析。结果除去58耳ABR无反应外,剩余82耳ABR反应阈与MSS-ASSR 0．5kHz、1kHz、2kHz、4kHz的反应阈相关性具有显著性意义(P=0．000)。Pearson相关系数分别为0．757,0．854,0．906,0．912。结论MSS-ASSR作为儿童听力定量诊断的客观方法有很大的临床应用价值。     

Auditory neuropathy characteristics in children with cochlear nerve deficiency

OBJECTIVE: To describe a group of children exhibiting electrophysiologic responses characteristic of auditory neuropathy (AN) who were subsequently identified as having absent or small cochlear nerves (i.e., cochlear nerve deficiency). DESIGN: A retrospective review of the clinical records, audiological testing results, and magnetic resonance imaging (MRI) studies. Fifty-one of 65 children with AN characteristics on auditory brain stem response (ABR) testing had MRI available for review. Nine (18%) of these 51 children with ABR characteristic of AN have been identified as having small (N = 2; 4%) or absent (N = 7; 14%) cochlear nerves on MRI. RESULTS: Of the nine children with cochlear nerve deficiency, five (56%) were affected unilaterally and four (44%) bilaterally. Eight of nine presented after failing a newborn infant hearing screening, whereas one presented at 3 yr of age. On diagnostic ABR testing, all 9 children (9 of 13 affected ears; 69%) had evidence of a cochlear microphonic (CM) and absent neural responses in at least one ear. In the unilateral cases, AN characteristics were detected in all affected ears. In bilateral cases, at least one of the ears in each child demonstrated the AN phenotype, whereas the contralateral ear had no CM identified. Only one ear with cochlear nerve deficiency had present otoacoustic emissions as measured by distortion-product otoacoustic emissions. In children with appropriate available behavioral testing results, all ears without cochlear nerves were identified as having a profound hearing loss. Only 4 (31%) of the 13 ears with cochlear nerve deficiency had a small internal auditory canal on MRI. CONCLUSIONS: Children with cochlear nerve deficiency can present with electrophysiologic evidence of AN. These children frequently refer on newborn screening examinations that use ABR-based testing methods. Similar to other causes of AN, diagnostic ABR testing will show a CM with absent neural responses. Given that 9 (18%) of 51 children with available MRI and electrophysiologic characteristics of AN in our program have been identified as having cochlear nerve deficiency makes this a relatively common diagnosis. These findings suggest that MRI is indicated for all children diagnosed with AN. Moreover, electrophysiologic evidence of unilateral AN in association with a profound hearing loss should make the clinician highly suspicious for this problem. Although children with cochlear nerve deficiency who have a small nerve may benefit from cochlear implantation or amplification, these interventions are obviously contraindicated in children with completely absent cochlear nerves.     

气导和骨导ABR在先天性外耳道闭锁小儿听力评估中的应用

目的研究先天性外耳道闭锁小儿气导和骨导短声诱发的听性脑干反应（auditory brain stem response,ABR）的特点,评价骨导ABR的应用价值。方法将受试者分为两组。组1（闭锁组）为16例（21耳）先天性外耳道闭锁患者,年龄在1～13岁之间,平均为5．62岁;组2（对照组）为正常听力小儿15例（25耳）。年龄在1～13岁之间,平均为6．1岁。比较两组气、骨导ABR的特点。结果闭锁组气、骨导ABR反应阈值分别为（73．81±7．4）dBnHL和（6．19±4．98）dBnHL,正常组分别为（23．20±4．76）dBnHL和（5．60±5．07）dBnHL。30dBnHL刺激强度下闭锁组骨导ABR潜伏期与对照组相比差异无显著性。闭锁组气、骨导ABR阈值差值与正常组相比差异有显著性。结论骨导ABR可以用于评估先天性外耳道闭锁患者的耳蜗功能。     

Internal auditory canal morphology in children with cochlear nerve deficiency.

OBJECTIVE: To describe the internal auditory canal (IAC) and inner ear morphologic characteristics of children with cochlear nerve (CN) deficiency. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Fourteen children with small or absent (deficient) CNs have been identified by means of high-resolution magnetic resonance imaging (MRI). INTERVENTIONS: MRI of the brain. Clinical evaluation. MAIN OUTCOME MEASURES: Review of medical records, audiological testing results, and imaging studies. Images were evaluated for the structure of the cochlear, vestibular and facial nerves, IACs and inner ears. Audiometric thresholds were evaluated in all subjects. METHODS: Fourteen children with small or absent (deficient) CNs have been identified by means of high-resolution MRI. A review of the medical records, audiologic testing results, and imaging studies was undertaken. The images were evaluated for the structure of the cochlear, vestibular and facial nerves, IACs, and inner ears. The audiometric thresholds were evaluated in all subjects. RESULTS: Among the 14 patients, 5 had known syndromes. MRI allowed an exact specification of the nervous structures within all ears with normal-size IACs. Precise characterization of the nerves in ears with small IACs was more difficult, requiring a consideration of both imaging findings and functional parameters. Five children had bilateral deficient CNs, whereas the remaining 9 subjects were affected unilaterally. Thus, 19 ears had CN deficiency (absent CN, 16; small CN, 3). Eleven ears had normal-size IACs and deficient CNs. Of the 9 ears with small IACs, 8 had deficient CNs (absent, 7; small, 1) on the basis of both MRI and functional assessments. Two ears with small IACs had clear morphologic and/or functional evidence for the presence of a CN: one had a small-size CN on MRI, whereas another had a single nerve in a small IAC with present facial and auditory functions. CONCLUSION: The findings of this study suggest that CN deficiency is not an uncommon cause of congenital hearing loss. The findings that most ears with CN deficiency had normal IAC morphology and that two ears with small IACs had CNs present indicate that IAC morphology is an unreliable surrogate marker of CN integrity. On the basis of these findings, we think that high-resolution MRI, rather than CT imaging, should be performed in all cases of pediatric hearing loss, especially in those cases where profound hearing loss has been documented. For ears with small IACs, the resolution of MRI currently remains limiting. In these cases, the determination of CN status frequently requires a variety of anatomic (CT and MRI) and functional tests (auditory brainstem response, otoacoustic emissions, behavioral audiometry, and physical examination).     

周围神经脱髓鞘豚鼠模型听神经病变及听功能研究

目的:通过建立实验性变态反应性神经炎这一周围神经脱髓鞘动物模型,观察其听神经病变,初步探讨其听性脑干反应(ABR)和听神经复合动作电位(CAP)的改变。方法:以粗提的牛外周神经髓鞘碱性蛋白(MBP)作为抗原,免疫实验组豚鼠;对照组以生理盐水代替MBP。检测动物血清抗MBPIgG水平、坐骨神经传导速度,观察坐骨神经、听神经病理改变;检测ABR、CAP阈值及潜伏期;观察内耳病理损伤。结果:实验组血清抗MBPIgG水平升高,与对照组相比P<0.01;实验组坐骨神经传导速度减慢,与对照组相比P<0.05;透射电镜发现坐骨神经、听神经脱髓鞘改变;免疫前后实验组14只(26耳)出现ABR反应阈升高,伴Ⅰ、Ⅲ、Ⅴ波潜伏期明显延长,与对照组比较P<0.01,而Ⅰ～Ⅲ、Ⅲ～Ⅴ波间期与对照组比较P>0.05;CAPN1、N1波潜伏期延长,与对照组比较P<0.01;另有4只(8耳)仅出现潜伏期延长而无阈值升高;免疫组织化学显示内耳免疫损伤部位主要在蜗神经、内耳神经纤维、螺旋神经节;扫描电镜显示内毛细胞纤毛紊乱、胞质溢出。结论:实验性变态反应性神经炎动物模型作为一种可靠的周围神经脱髓鞘动物模型,其病变可累及听神经出现听神经脱髓鞘改变,ABR和CAP阈值升高、潜伏期明显延长,该模型可望成为探讨听神经脱髓鞘的听力学表现的一种有用的动物模型。