后颅凹肿瘤术中的脑干听觉诱发电位监测分析

目的:探讨脑干听觉诱发电位技术对后颅凹肿瘤术中监护的临床意义。方法:对16例后颅凹肿瘤患者进行术前检查,术中监护,并对BAEP各波波形、潜伏期进行分析。结果:Ⅰ、Ⅲ、Ⅴ波潜伏期延长10例伴Ⅰ—Ⅲ、Ⅲ—Ⅴ或Ⅰ—Ⅴ波波间期延长;波形分化不良或波幅较低6例;手术操作牵拉可引起BAEP不同程度变化。结论:后颅凹占位病变术中的BAEP监护,对保护听觉和脑干功能及术后功能的评估有重要意义。     

Clinical interpretation of brainstem evoked response audiometry abnormalities in cochlear pathology

This investigation involved 45 patients with sensorineural hearing loss (SNHL): 24 with Meniere's disease, 18 with acoustic trauma, and 3 with SNHL due to ototoxic drugs. They all underwent pure tone audiometry and standard brainstem evoked response audiometry (BERA). In patients without wave I in auditory brainstem response, electrocochelography (ECochG) was performed. The findings are presented showing that cochlear lesions (beside threshold elevation) cause latency prolongation of wave I, III and V relative to normal latencies at the actual click hearing level. At high stimulation levels, this effect is almost completely compensated for by the fact that cochlear recruiting ears exhibit steeper latency-intensity curves than do normal ears. But, at the same time this pathology does not cause latency prolongation of central conduction time (CCT). Beside this, cochlear lesions will cause, in some cases, deterioration of replicability (poor waveform resolution) of waves preceding wave V. In such cases, the authors strongly recommend electrocochleography (ECochG) to make wave I visible, because they think that it is the best way to verify the diagnosis of cochlear lesion using BERA.     

Effect of body temperature changes on evoked potentials

Short-latency somatosensory (SSEPs) and brainstem auditory evoked potentials (BAEPs) were recorded in 12 patients with fever due to respiratory infection (age, 44.3 +/- 20.9 years, mean +/- SD) to clarify the effect of body temperature change on conduction in the central somatosensory and brainstem auditory pathways. Subjects were studied during episodes of fever (37.9 +/- 0.8 degrees C) and after their body temperature had decreased (36.6 +/- 0.3 degrees C). The central conduction time (CCT), which is the peak latency between N 13 and N 20, was significantly longer after body temperature had decreased than during fever. Likewise the interpeak latency between waves I and V (I-V IPL) was significantly prolonged following decrease in body temperature. These results suggest that increases in body temperature have an effect upon conduction in the central somatosensory and brainstem auditory pathways.     

Abnormal brainstem evoked potentials in diabetes mellitus. Evoked potential testings and magnetic resonance imaging

Brainstem auditory evoked potentials (BAEPs) and median nerve somatosensory evoked potentials (MN-SEPs) were measured in 53 diabetic patients. Magnetic resonance imaging (MRI) was performed 12 patients with abnormal BAEPs and/or MN-SEPs in order to confirm the existence of lesions in the central nervous system. Twenty-six percent of the diabetic patients had abnormal BAEPs and three had a prolongation of the central conduction time in the MN-SEPs. MRI findings of ten of the 12 patients with abnormal BAEPs or MN-SEPs showed multiple small lesions in the pons, thalamus, and centrum semiovale etc. Two of them showed small lesion in the pontine basis which could induce prolonged interpeak latencies of BAEPs. Our MRI study might suggest that abnormal brainstem evoked potentials in diabetic patients were induced by diabetic macroangiopathy or microangiopathy.     

Brain stem auditory-evoked potentials in different strains of rodents

This study was conducted to evaluate variations in brain stem auditory-evoked potentials (BAEPs) among different strains of rodents. BAEPs were recorded by routine procedures from rodents of different strains or species. These included 22 Long-Evans, 28 Wistar and 28 Sprague-Dawley rats, and six hamsters. Within the first 10 ms, there were five consistent and reproducible positive waves of BAEPs in each rodent, named I, II, III, IV and V in correspondence with the nomenclature of waves I-VII in human BAEPs. These BAEPs were also similar to those observed in other vertebrates and in human controls. However, there were variations in waveforms and peak latencies among rodents, even in the rats of the same strain that came from different laboratory centres. At optimal stimulation intensity, usually around 90 dB, the mean latencies of the waves varied as follows: I, 1.23-1.53 ms; II, 1.88-2.28 ms; III, 2.62-2.94 ms; IV, 3.49-3.97 ms; and V, 4.47-5.14 ms. They were significantly different between species, but not in different strains of rats if they came from the same animal centre. The conduction time in the central portion illustrated by interpeak latencies between I and III, III and V, and I and V was dependent on the species (P less than 0.05). When recorded in a soundproof incubator, the minimal hearing threshold showed a significant species difference. The animal BAEP model can be employed for evaluating the physiological function or the pathological conditions of the brain stem. The confirmation of BAEP variations among different species or strains will be helpful in deciding which kind of rodents will be appropriate to serve as animal models for the various purposes of BAEP studies.     

孤独症患者脑干听觉通路功能的评估与研究

目的：研究孤独症患者脑干听觉通路的功能状态,并探讨其可能的构建模式。方法：采用脑干听觉诱发电位（BAEP）技术对36例孤独症患者（孤独症组）与27例对照者（对照组）进行测试,分析比较BAEP成分的组问差异。结果：孤独症组BAEP中双侧Ⅲ、V波的潜伏期（PL）和各峰间期（IPL）均较对照组延长,其中右侧Ⅲ波PL和双侧V波PL延长之组间差异显著（P〈O．05）,左侧Ⅲ-V波和双侧I—V波IPL延长组间差异显著（P〈0．05）。结论：孤独症患者存在脑干听觉通路功能异常或脑干功能发育不成熟。脑干传导时间延长产生的听觉信息传递失真与中枢性听觉紊乱可能是孤独症形成的构建模式之一。     

The usefulness of the brainstem auditory evoked potential in the early diagnosis of cranial nerve neuropathy associated with diabetes mellitus

BACKGROUND: An evaluation of the extent and mechanism of damage of the central nervous system in diabetes mellitus is of high value in current neurological research. Electrophysiological abnormalities are frequently present is completely asymatomatic diabetes mellitus (DM) patients. Limited data is available in the use of brainstem auditory evoked potential (BAEP) in DM. AIM: Is to evaluate the efficacy of BAEP as a method useful in the diagnosis of subclinical damage of the central nervous system in DM. MATERIAL AND METHOD: 67 diabetes and 32 healthy controls - age and sex matched - were chosen. The diabetes were of type I and II and more than or less than 10 years duration. The BAEP was elicited by using auditory stimulus by using Dantec Evomatic 4000 evoked potential machine. The latency of component response recored as waves I, III and V, interpeak latency (IPLs) I - III, I - V, III - V and amplitude of waves V. RESULTS: The difference was highly significant in the increased latency of waves I, III and V, interpeak latency (IPLs) I - III, I - V, III - V and amplitude of waves V of each type of diabetes as compared to control. Comparison of the type and duration of diabetes between each other showed no significant difference. CONCLUSION: BAEP recording can represent an objective, clinically useful and non invasive procedure to stress the early impairment both of the auditory nerve and of brainstem function.     

Effects of low pass filtering on the brainstem auditory evoked potential in the rat

Summary The effects of low pass filtering on the brainstem auditory evoked potential (BAEP) were studied in the adult male rat. The bandpass of the recording system was progressively widened while the cut-off frequency of the high pass filter remained constant at 3.2 Hz. When the high frequency cut-off was 320 Hz or less, the principal waveform recorded in response to a click stimulus was a slow positive-negative complex. As the high frequency setting was raised from 800 Hz to 3.2 kHz, the slow components of the brainstem were replaced by four fast BAEP waves (I, II, III and IV). As the bandpass widened there was an increase in amplitude and a decrease in the absolute latency of all four fast waves in the order of 0.1 ms although the wave I–IV interpeak latency remained unaffected. The results confirm that the high frequency components of the BAEP are underlain by a slow positivity of uncertain origin followed by a slow negativity which probably arises within the inferior colliculus.This study was supported by the Medical Research Council of New Zealand     

结扎双侧椎动脉对家兔BAEPs的影响

本实验通过对１０只家兔双侧推动脉结扎，观察手术前后脑干听觉诱发电位（ＢＡＥＰｓ）的变化［１］。结果发现：动物在推动脉结扎后，随时间延长ＢＡＥＰｓ各波的波幅逐渐减压，潜伏期逐渐延长；上述变化持续进行４０分钟，以后无大变化。提示：ＢＡＥＰｓ可以客观地反映椎基底动脉的供血情况。本项研究为临床用ＢＡＥＰｓ诊断椎基底动脉供血不足，提供了一项理论依据。     

Comparative study of evoked potentials in multiple sclerosis and neuro-Beh?et's syndrome

We studied somatosensory evoked potentials (SEPs) and brainstem auditory evoked potentials (BAEPs) in Japanese patients with multiple sclerosis (MS) and those with neuro-Behcet's disease (NB). Abnormal cortical P37 of posterior tibial nerve SEPs or cervical N13 of median nerve SEPs were more frequently found in the MS patients than in the NB patients. On the other hand, prolongation of the central conduction time of median nerve SEPs or abnormal BAEPs were more common in NB than in MS. The present data showed that lesions were mainly present in the spinal cord in MS and in the brainstem in NB. SEPs and BAEPs were considered of great value for detecting the involvement of the central nervous system in MS and NB and distinguishing between these diseases.     

Abnormal B.A.E.P. in a family with Moebius syndrome: evidence for supranuclear lesion

A family with Moebius syndrome is presented. Neurological lesions in the affected members are various: complete VI and VII cranial nerves palsy associated with mental retardation in the proband; left convergent strabismus and mental retardation in a brother of the proband and only mental retardation in a sister of the proband. The brainstem auditory evoked potentials (B. A.E.P.), investigated in the proband and his affected sister, are abnormal. The presence of the anomaly after the 3rd wave is consistent with a disfunction of the auditory tract at a supranuclear level. The mental deficiency and the supranuclear site of the acoustic lesion are an indication for a more general involvement of C.N.S. than cranial nerve nuclei alone.
Karyotype and dermatoglyphics of the three affected subjects were normal. The authors hypothesized the same disorganogenetic factor acting very early (4th-6th week of gestational age) on the metamerization process of limb buds mesoderm and brainstem gray matter.     

Normal variations in the morphology of auditory brainstem response (ABR) waveforms: a study in Wistar rats

Auditory brainstem evoked responses (ABR) have been used for decades to assess auditory function. Surprisingly, despite the fact that rats are one of the most widely used experimental models in hearing, there have been no studies that have characterized in detail the normal morphological variations that occur in ABR waves. Therefore, the goal of this study was to characterize the patterns of ABR waves in rats to establish baseline criteria that could be used to identify abnormalities. Rats were stimulated with pure tone sounds at different frequencies and ABR waves were classified based on morphology. The most definitive finding was that, unlike what is observed in human ABRs, wave II of the rat ABR was the most prominent. Additionally, wave III was the smallest and, in many cases, was not apparent at low frequencies. Wave III was frequently involved in the formation of complexes, often appearing as a small wave or adjoining primarily wave IV. Complexes were common at low and medium frequencies and rare at high frequencies. These results indicate that knowledge of the different wave patterns in normal rats is fundamental to understanding how the wave morphology changes in pathological conditions that could lead to hearing impairment.     

Brainstem Auditory Evoked Potentials (BAEPS) and Selective Attention Revisited

Evidence of peripheral filtering of auditory information at the cochlear and brainstem levels was sought using brainstem auditory evoked potentials (BAEPs) recorded during auditory and visual tasks. It can be argued that the discrimination tasks used in the past to investigate peripheral filtering of sensory information in humans involve two levels of discrimination, the consequences of which result in two independent types of inhibition: crossmodal inhibition as a result of between-modality discrimination, and intramodal inhibition as a result of within-modality discrimination. Therefore, the observed effects on the BAEPs may reflect the extent to which these two types of inhibition are engaged. In this investigation a paradigm that included two non-discrimination (passive) tasks and two discrimination (active) tasks was employed. BAEPs recorded during listening (a passive auditory task) provided a baseline measure, against which comparisons of BAEPs recorded during auditory and visual discrimination could be made for independent evidence of crossmodal and intramodal inhibition. The data in this study did not support the presence of two types of inhibition proposed above, or show evidence of peripheral filtering of auditory information at the cochlear and brainstem levels. However, the sensitivity of BAEPs to efferent system activation at the cochlea and hence their value as a tool in investigations of peripheral filtering in humans was questioned.     

最大长度序列诱发听性脑干反应的线性与非线性成分引出率和稳定性分析

在记录常规的听性脑干反应(cABR)时,听觉系统被视为一个线性系统,无法获取反映听觉系统非线性特性的成分。而采用最大长度序列(MLS)刺激,对记录的反应建立Volterra级数展开模型,能够同时获取反映听觉系统线性与非线性特性的不同成分,所获取的ABR被称为MLS-ABR。由于这种方法在实验和计算方面的困难,现阶段对MLS-ABR的特性了解尚少,所以通过实验研究对其引出率及稳定性进行分析。利用MLS方法提取非线性成分,选择一个9阶MLS,提取11例正常青年人的MLS-ABR及cABR,其中MLS-ABR的一阶和一个二阶核切片（VS1和VS21）的波形清晰完整,分别表达ABR的线性和非线性成分。以cABR、VS1、VS21中各特征波出现率、潜伏期及峰峰值变异系数为考察指标,对照分析cABR与MLS ABR的线性、非线性成分引出率和稳定性。结果发现,MLS-ABR中线性成分各特征波引出率都较高（>90%）,且其潜伏期（1、3、5潜伏期波变异系数分别为5.17、3.70、2.00）比cABR（Ⅰ、Ⅲ、Ⅴ波潜伏期变异系数分别为6.54、3.70、2.87）更加稳定;非线性成分也可稳定引出1、3、5波（>80%）,并且非线性成分的在5波的表达更加强烈。进一步证实MLS在获取ABR非线性成分的可靠性,加深对MLR-ABR的认识,为后续相关研究提供重要依据。     

A possible collicular component of the auditory evoked potential and its relationship to brainstem and cerebellar auditory potentials.

Auditory evoked potentials were recorded from the rat using skull screw electrodes inserted over the inferior colliculus and the cerebellum. In addition, brainstem auditory evoked potentials (BAEPs) were also recorded. The response recorded from over the inferior colliculus consisted of a slow positive potential with one of two possible peak latencies. The mean latency of the earlier potential was 5.6 ms and that of the later potential was 6.4 ms. A hypothetical generator for the first collicular potential is the termination of the lateral lemniscus in the ventrolateral inferior colliculus, while the later collicular potential could have its origins within the brachium of the inferior colliculus. None of the principal nor minor BAEP waves corresponded to either of the collicular responses. Nor did the trough of negativity between BAEP waves IV and V which is often thought to reflect activity generated within the midbrain. The potential recorded over the cerebellum also consisted of a slow positivity but with a slightly sharper contour than that of the collicular response. The mean latency of the cerebellar potential was 4.9 ms. As there was no temporal relationship between collicular and cerebellar potentials, the present study provided no support for the theory that cerebellar auditory potentials are artefactual and simply far field reflections of activity generated in the inferior colliculus. Judging by the timing of the BAEP waves, it is also concluded that the afferent volley most likely projects to the cerebellum via a collateral pathway branching off the caudal part of the lateral lemniscus.     

Antioxidant Treatments Recover the Alteration of Auditory‐Evoked Potentials and Reduce Morphological Damage in the Inferior Colliculus after Perinatal Asphyxia in Rat

Maturation of the auditory pathway is dependent on the central nervous system myelination and it can be affected by pathologies such as neonatal hypoxic ischemic (HI) encephalopathy. Our aim was to evaluate the functional integrity of the auditory pathway and to visualize, by histological and cellular methods, the damage to the brainstem using a neonatal rat model of HI brain injury. To carry out this morphofunctional evaluation, we studied the effects of the administration of the antioxidants nicotine, melatonin, resveratrol and docosahexaenoic acid after hypoxia‐ischemia on the inferior colliculus and the auditory pathway. We found that the integrity of the auditory pathway in the brainstem was altered as a consequence of the HI insult. Thus, the auditory brainstem response (ABR) showed increased I–V and III–V wave latencies. At a histological level, HI altered the morphology of the inferior colliculus neurons, astrocytes and oligodendricytes, and at a molecular level, the mitochondria membrane potential and integrity was altered during the first hours after the HI and reactive oxygen species (ROS) activity is increased 12 h after the injury in the brainstem. Following antioxidant treatment, ABR interpeak latency intervals were restored and the body and brain weight was recovered as well as the morphology of the inferior colliculus that was similar to the control group. Our results support the hypothesis that antioxidant treatments have a protective effect on the functional changes of the auditory pathway and on the morphological damage which occurs after HI insult.     

葛根素对豚鼠卡那霉素耳中毒听觉诱发电位的影响

观察葛根素在豚鼠卡那霉素耳中毒中的作用。将豚鼠 30只随机分两组 :对照组 15只 ,肌注卡那霉素 40 0mg/kg/d ,共 12天 ;葛根素组 15只 ,除肌注卡那霉素 40 0mg/kg/d外 ,腹腔注射葛根素 10mg/kg/d ,共 12天。以听觉诱发电位为指标进行组间比较 ,听觉诱发电位阈值对照组明显高于葛根素组 (P <0 0 5 ) ;对照组诱发电位各波幅值则明显低于葛根素组 (P <0 0 1)。葛根素能减轻卡那霉素耳毒性 ,对卡那霉素耳中毒具有一定的保护作用 ,为耳毒性抗生素致聋的防治提供了一条新的研究途径     

Localization of Brainstem Auditory Evoked Potentials in Primates: A Comparison of Localization Techniques Applied to Deep Brain Sources

Summary The objective of this study was to evaluate the performance of source localization techniques through localization of deep brain sources. To accomplish this, two replications of a brainstem auditory evoked potential (BAEP, left ear 60 dB nHL clicks) were recorded from five normal rhesus monkeys. We analyzed waves III and IV, as this portion of the BAEP corresponds to the deepest signal. Data were analyzed using five different source localization techniques: Moving Dipoles, Fixed Dipoles, MUSIC (Multiple Signal Classification) dipole scan, LORETA (Low Resolution Tomography), and LCMV (Linearly Constrained Minimum Variance) spatial filtering. The moving dipole, fixed dipole and MUSIC solutions were found to be, on average, 25.1 mm from the brainstem generators. LORETA detected sources within the brainstem 65 of the time. However, 90 of these localization results also included false detections defined as regions of the brain that were more than 2 cm away from the auditory pathway. LCMV included the brainstem in 90 of the trials and false detections in 40 of the cases. These findings indicate that evoked electrical activity from deep brain sources can be localized with cm accuracy. The dipole methods performed better than LORETA and LCMV. Given the depth and amplitude of the sources analyzed in this study, these results can be interpreted as an upper bound on the accuracy of each technique.     

Brain-stem auditory evoked potentials in supratentorial brain tumors.

A group of 42 adult patients with supratentorial brain tumors were studied with computed tomography (CT or/and NMR) and brain-stem evoked potentials (BAEPs). 12 patients had meningiomas and 30 had malignant tumors (gliomas and metastases). The latencies of wave V and of the interpeak latency I-III, III-V and I-V were evaluated both on the lesion side and the opposite side. In meningiomas mean latencies did not show significant differences from normal, while mean latencies in malignant tumors were significantly prolonged, except for the I-III interpeak latency. The results of this study demonstrate that BAEPs may be altered by supratentorial brain tumors. This examination appears to be useful in the monitoring of these lesions after treatment.     

Objective detection of brainstem auditory evoked potentials with a priori information from higher presentation levels

This paper describes a brainstem auditory evoked potentials (BAEPs) detection method based on supervised pattern recognition. A previously used pattern recognition technique relying on cross-correlation with a template was modified in order to include a priori information allowing detection accuracy. Reference is made to the patient's audiogram and to the latency-intensity (LI) curve with respect to physiological mechanisms. Flexible and adaptive constraints are introduced in the optimization procedure by means of eight rules. Several data samples were used in this study. The determination of parameters was performed through 270 BAEPs from 20 subjects with normal and high audiometric thresholds and through additional BAEPs from 123 normal ears and 14 ears showing prominent wave VI BAEPs. The evaluation of the detection performance was performed in two steps: first, the sensitivity, specificity and accuracy were estimated using 283 BAEPs from 20 subjects showing normal and high audiometric thresholds and secondly, the sensitivity, specificity and accuracy of the detection and the accuracy of the response threshold were estimated using 213 BAEPs from 18 patients in clinic.Taking into account some a priori information, the accuracy in BAEPs detection was enhanced from 76 to 90%. The patient response thresholds were determined with a mean error of 5 dB and a standard deviation error of 8.3 dB. Results were obtained using experimental data; therefore, they are promising for routine use in clinic.