电诱发听性脑干反应（EABR）的临床应用

电诱发听性脑干反应（electrically evoked auditory brainstem responses,EABR）是一种客观的神经电生理检测方法．在耳科学、听力学和神经科学中占有重要的地位。EABR可以估测耳聋患者残存的听神经末梢螺旋神经节数量．客观评价听觉传导通路的功能状态．指导人工耳蜗植入手术及听性脑干植入手术．并在术后设备调试中起重要作用。本文对EABR的临床应用现状及前景做一综述。     

Effect of stimulation parameters on electrically evoked auditory brainstem responses

It is evident that the conventional technique for cochlear implant adjustment is not suitable for children in their first years of life. In order to find a solution to this problem, the possibility of electrically evoked auditory brainstem response (EABR) recording was investigated. EABRs were recorded in 9 patients with the Nucleus multichannel cochlear implant. The main problems that have to be solved during EABR recording in cochlear implantees are: i) EABR distortion due to the stimulus artefact: and ii) difference in the stimulus presentation rate during EABR registration (low pulse rate) and conventional psychophysical threshold estimation (high pulse rate) in cochlear implant patients. The influence of stimulus artefact on the recording results was minimized by setting the implant to the widest amplifier frequency band and by zeroing the initial segment containing the stimulus artefact with subsequent zero-phase digital filtering. The dependence of the EABR amplitude and latency on the stimulus intensity, width, electrode location and interstimulus interval was investigated. It was concluded that despite the difference revealed between absolute values of EABR thresholds and psychophysical threshold levels, it is possible to calculate implant adjustment parameters based on the EABR data with the proper correction applied.     

Pre-perioperative, transtympanic electrically evoked auditory brainstem response in children

The purpose of this study was to characterize the transtympanically evoked, perioperative electrically evoked auditory brainstem response (EABR) and define its relationship with preoperative hearing, age and hearing loss etiology in 59 children (10-60 months of age) who had received cochlear implants. The results indicate that there was no difference between wave V latency obtained from the younger (10-36 months) and the older (37-60 months) children. There was a statistically significant difference in the preoperative pure-tone average between the higher-EABR threshold group (650 microA and above) and the lower-EABR threshold group (600 microA or less). Patients with post-meningitic deafness exhibited the longest EABR wave V latencies. Perioperative, transtympanic, promontory EABR is an effective clinical procedure which can decrease the likelihood of placing a cochlear implant in a non-stimulable ear, and may provide the clinician with a valuable tool for selecting the most appropriate ear for implantation.     

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.     

Characteristics of electrically evoked potentials in patients with auditory neuropathy/auditory dys-synchrony

The primary goal of this study was to compare the characteristics of the post-implant evoked potentials with preimplant evoked potentials in patients with auditory neuropathy (AN) or dys-synchrony. AN is typically characterized by sensorineural hearing loss, reduced speech perception, abnormal temporal processing, and unusual patterns of results with various objective audiological tests. In some cases, these patients may be appropriate candidates for a cochlear implant. In this article, we highlight evoked potential findings in two children diagnosed with AN who were provided with multichannel cochlear implants. Preoperative, interoperative and postoperative evoked potential measures show that the restoration of neural synchrony may occur at multiple levels of the auditory pathways in patients with AN when appropriate diagnostic tests, cochlear implantation and rehabilitation are provided.     

Multichannel cochlear implant and electrically evoked auditory brainstem responses in a child with labyrinthitis ossificans

Ossification of the cochlea following meningitis presents a surgical challenge. Electrode mapping, especially in the young child, is difficult given the uncertainty of electrode contact with viable neural elements. This paper reviews surgical technique and the use of auditory brainstem responses to map the electrodes. A 4-year-old child deafened by meningitis at age 20 months had bilateral cochlear ossification by computed tomography. At surgery, a canal wall-down mastoidectomy and closure of the ear canal were performed. A trough around the modiolus was drilled, and the electrode array was placed in it. Post-operatively, the patient gave aversive or no responses to electrode stimulation. To assess electrode function, auditory brainstem responses to individual electrode activation were obtained under general anesthesia. Functioning electrodes could thus be selected for mapping. The patient now responds well to sound.     

EABR辅助31例Mondini畸形人工耳蜗植入及术后效果分析

目的探讨电刺激听觉脑干诱发电位(electrical evoked auditory brainstem responses,EABR)辅助Mondini畸形患者人工耳蜗植入手术的方法及术后效果分析。方法我院自2001年开始为Mondini畸形患者植入人工耳蜗,收集2012年至2015年在我院行人工耳蜗手术的Mondini畸形患者31例,回顾性分析Mondini畸形患者术前听力学特征,术前EABR特点,术中手术特点、术后NRT测试结果及开机调试结果,随访术后听觉言语康复能力CAP(categories of auditory performance)和SIR(speech intelligibility rating)评分。另选择相似耳聋年龄的耳蜗结构正常耳蜗植入患者20例作为正常对照组,测试结果进行对比分析。结果 31例Mondini畸形患者术前听力均为极重度感音神经性聋,其中14例无残余听力,对照组7例无残余听力,术前行EABR测试,引出率100%,有反应者植入不同类型电极的人工耳蜗;术中电极全部植入耳蜗内,其中4例出现脑脊液井喷,颞肌封堵,术后无面瘫、脑脊液漏、脑膜炎等手术并发症;所有Mondini畸形患者术后均获得听觉,开机测试神经反射遥测(neural response telemetry,NRT),引出率41.94%低于对照组95%;开机6月平均T值Mondini组171.37±13.14CL;对照组145.34±17.43CL;动态范围Mondini组33.24±10.73CL,对照组43.55±15.36CL,经统计学分析P<0.05,有显著差异;随访6月~4年,Mondini组CAP平均得分6.13±1.15,SIR平均得分3.05±0.62;对照组CAP平均得分7.12±0.80,SIR平均得分4.03±0.91,经两样本比较t检验,P<0.05有显著性差异。结论 Mondini畸形的双侧极重度感音神经性聋患者可以根据残余听力情况在EABR辅助下行人工耳蜗植入,术后听力言语康复较正常耳蜗结构患者效果稍差,但明显好于术前听觉和言语能力。     

Electrically evoked auditory brainstem responses in cochlear implant patients.

Electrically evoked auditory brainstem responses (EABR) were recorded in completely deaf patients implanted with Ineraid multichannel cochlear implants. Clear and reproducible EABR were obtained from all patients. Parametric differences with auditory brainstem responses (ABR) were demonstrated and can be explained by the different natures of both types of stimulations (electric versus acoustic). Evidence is given that other well-known properties of auditory evoked responses, like 'binaural interaction' or suppression of responses in a forward masking paradigm, can be observed in EABR of implanted patients.     

Delayed brainstem auditory evoked responses in diabetic patients

The incidence of subclinical central diabetic neuropathy is unclear due to difficulty in detecting latent alterations of central neural transmission process. The aim of this study was to evaluate a central neuroconductive mechanism in diabetics by brainstem auditory evoked responses (BAER). We found increased latencies of peaks I, III, V in diabetics as compared to control subjects. These BAER abnormalities were demonstrated in 62 per cent of insulin-controlled diabetics and in 33 per cent o patients treated by diet, or peroral drugs. No alterations in brainstem responses were observed in patients with latent diabetes. We did not find any correlation between the BAER abnormalities and the duration of the disease, the blood glucose level or the level of control of the diabetes.     

Recording of electrically evoked auditory brainstem responses after electrical stimulation with biphasic,triphasic and precision triphasic pulses

Biphasic electrical pulses are the standard stimulation pulses in current cochlear implants. In auditory brainstem recordings biphasic pulses generate a significant artifact that disrupts brainstem responses, which are magnitudes smaller. Triphasic pulses may minimize artifacts by restoring the neural membrane to its resting potential faster than biphasic pulses and make auditory brainstem responses detection easier. We compared biphasic pulses with triphasic and precision triphasic pulses to evoke brainstem responses in human subjects. For this purpose, electrically evoked brainstem response audiometry was performed in 10 (11 ears) cochlear implant patients. Artifacts and brainstem responses evoked by bi- and triphasic stimulation were analyzed. Artifact amplitude and decay time were related to pulse pattern shape, but application of averaging and alternation reduced the deterioration of electrically evoked brainstem responses independent of pulse pattern shape. Contrary to our expectations, biphasic pulses showed a higher detectability in comparison to triphasic pulse stimulation at the same stimulation amplitude.     

Development of brainstem auditory evoked responses in the hamster

The hamster is relatively immature at birth compared with other mammalian species. Because of the amount of maturation that occurs postnatally, the development of the peripheral auditory system of the hamster has generated a great deal of interest. However, indices of the developing functional capabilities of the central auditory system of the hamster are lacking. The following study investigated the ontogeny of brainstem auditory evoked responses (BAERs) to clicks in young hamsters. The general maturational trends noted for other species were found for the hamster. The major peaks of the BAER decrease in latency at the same time relative to birth and at the same rate in the hamster as in the cat and rat. Some maturational events such as the onset of a recordable BAER, appearance of the late peaks and increase in amplitude of the late peaks occur later, relative to birth, in the hamster than in the other species. Development delays in the hamster make it an attractive model for studying postnatal development of the central auditory system.     

Speech evoked auditory brainstem response findings in children with epilepsy

Objectives

Children with epilepsy are at a considerable risk of cognitive impairment and school failure. Previous studies have typically documented abnormal responses in children with epilepsy at cortical level using speech stimuli. Recent studies reported that abnormal neural encoding of a speech syllable could be detected at the level of the brainstem using speech-evoked auditory brainstem response (ABR). The aim of this study is to investigate speech-evoked (ABR) results in children with epilepsy.

Methods

The study group consisted of 38 recently diagnosed epileptic children; none of them has received antiepileptic therapy. They were 22 males and 16 females with age 9.1 ± 3.1 years. The control group consisted of 38 healthy normal hearing children with matched age and gender distribution. All subjects underwent full history taking, basic audiologic evaluation including pure-tone, speech audiometry and immittance testing. Click ABR response was recorded monaurally from both ears at 90 dB nHL then speech ABR was recorded monaurally from each ear at 80 dB SPL.

Results

Though the study group disclosed normal click ABR compared to age matched normative values, speech-evoked ABR revealed a delayed waves V and A latencies in both ears. These findings reflect abnormal neural encoding of speech at the level of brainstem. The younger the age of epileptic child the more prolonged wave A latency and increased V/A inter-latency values.

Conclusions

Speech-evoked ABR results denote abnormal timing in the brainstem; such brainstem abnormality could be detected by speech evoked ABR rather than conventional click evoked ABR.     

Receptive language and speech production in children with auditory neuropathy/dyssynchrony type hearing loss

OBJECTIVE: The purpose of this study was to characterize the receptive language and speech production abilities of school-aged children with auditory neuropathy/dyssynchrony (AN/AD) and to compare those abilities to children with sensorineural (SN) hearing loss of similar age and degree of hearing loss. DESIGN: Standardized speech and language tests were carried out on 12 AN/AD children, aged between 57 and 167 mo. Each of these subjects was a full-time hearing aid user or had been just before testing. Receptive language skills were assessed using the Peabody Picture Vocabulary Test (PPVT) and speech production ability was measured using the Diagnostic Evaluation of Articulation and Phonology (DEAP) and a Speech Intelligibility Rating Scale. Data from a matched cohort of children with sensorineural hearing loss were also obtained. RESULTS: Receptive vocabulary and speech production were delayed (to varying degrees) in each of the AN/AD subjects (relative to normally hearing children). The group PPVT Language Quotient score was 0.65 +/- 0.19 and the average number of pronunciation errors was 11 +/- 8.4% higher than expected for age. Results for the AN/AD group were however similar to those obtained for a matched group of children with sensorineural hearing loss on both language and speech production measures. CONCLUSIONS: The findings of this study indicate that while AN/AD type hearing loss can pose a significant developmental risk, at least some children fit with conventional amplification can develop reasonable speech and language abilities.     

Abnormal timing delays in auditory brainstem responses evoked by bilateral cochlear implant use in children.

HYPOTHESIS: A period of unilateral implant use before bilateral implantation affects timing of brainstem processes measured by the electrically evoked auditory brainstem response (EABR). BACKGROUND: EABR latencies decrease with unilateral implant use potentially disrupting binaural timing cues important in auditory brainstem processing of bilateral input. METHODS: EABRs were evoked by electrical pulses from the left, right, and both implants simultaneously in 3 groups of children. All were initially implanted at ages younger than 3 years and had the following: 1) a long delay (>2 yr [n = 16]), 2) a short delay (<1 yr [n = 15]), or 3) no delay (n = 15) between left and right ear implantation. Responses were recorded on the first day of bilateral implant use and 3 and 9 months thereafter. RESULTS: Relative to responses evoked in the experienced ear, the naive ear showed prolonged latency in both the EABR peaks and the binaural difference response. After 3 and 9 months of bilateral implant use, the relative prolongation decreased in the long and short delay groups, but significant differences persisted in the former. No clear differences in latencies evoked by the left versus right implant were found at any time point in children receiving bilateral implants simultaneously. CONCLUSION: Results suggest potential disruptions to binaural brainstem processing based on timing cues in children receiving a second cochlear implant after more than 2 years of unilateral implant use that persist through at least the first 9 months of bilateral implant use.     

Averaged evoked auditory responses in the chronically implanted cat

Averaged evoked auditory responses from chronically implanted dural electrodes over the midectosylvian gyrus were evaluated in eight cats. The effects of the distribution of electrodes and levels of alertness were observed for each animal and the entire group. Changes in duration, rise and decay times, and repetition rates were also analyzed. Data from these experiments suggested a large variability in the amplitude and latency of the response. On the other hand, they also suggested a stable reproducible threshold of detectability — a point where the response disappeared upon further reduction in sound pressure levels. This characteristic of the evoked system served as a reliable measurement of an evoked auditory threshold and appeared as a potential means for evaluating relative changes of auditory function within the same animal.