桥小脑角占位病变的前庭诱发肌源性电位检查

图　　近年来,前庭诱发的肌源性电位(vestibularevokedmyogenicpotentials,VEMP)的临床应用进展较快。桥小脑角的病变,磁共振成像是诊断的最好的工具。而听性脑干反应和冷热试验也用于检查诊断,但仍有不足。冷热试验用于检查前庭上神经,而VEMP可用于检查前庭下神经 丘脑通路的功能。本组关注是否VEMPs有助于桥小脑角占位病变的诊治。一、研究对象2003至 2004年 5月在解放军总医院耳鼻咽喉头颈外科就诊的患者。年龄 7~65岁,平均 40 9岁。根据临床表现、听力学检查和前庭功能检查及MRI确诊为桥小脑角占位病变。VEMP的检测与判断采用作…     

前庭诱发肌电位在桥小脑角肿瘤术前术后中的作用

尽管桥小脑角肿瘤 (CPA) 90 %以上为前庭神经鞘瘤 ,但在非手术条件下尚不能确定肿瘤是起源于前庭上神经还是前庭下神经。磁共振成像 (MRI)、听性脑干反应及冷热试验均为检测 CPA的常用手段 ,尤其是MRI,被认为是 CPA的黄金标准检查 ,但这些检测手段对 CPA的诊断及来源等均存在一定程度的漏诊或假阴性结果。二十世纪 90年代 ,前庭诱发肌电位(VEMP)检测技术成功发明 ,为前庭下神经的检测提供了一有效手段。本文作者对 8例 (9侧 ) CPA病例进行 VEMP检测 ,目的在于评估其临床作用。 8例 CPA患者 ,7例为单侧 ,1例为双侧 ,年龄 2 6～ …     

量化的胸锁乳突肌表面肌电对颈部前庭诱发肌源性电位的影响

目的 测试不同头位状态下的胸锁乳突肌肌电和颈部前庭诱发肌源性电位(cervical vestibular evoked myogenic potential,cVEMP),分析胸锁乳突肌表面肌电与cVEMP各参数之间的关系,探讨量化后的胸锁乳突肌表面肌电对cVEMP的影响.方法 选取无耳疾史、听力和前庭功能正常、经cVEMP测试波形分化良好的健康青年人30名(60耳),分别记录在不同向对侧偏向头位(与矢状位呈90°、60°、45°和30°)下的胸锁乳突肌表面肌电和cVEMP,分析量化后的表面肌电与cVEMP振幅和潜伏期之间的关系,并进行统计学分析.结果 cVEMP的P1和N1的总体潜伏期分别为(12.50±2.39)ms和(19.79±3.16)ms,不同头位下的差异无统计学意义(F值分别为0.86和0.52,P值分别为0.46和0.67).不同头位下的胸锁乳突肌表面肌电差异具有统计学意义(F=146.63,P＜0.01),cVEMP的P1-N1振幅随头位及胸锁乳突肌表面肌电的变化而变化,差异亦具有统计学意义(F=55.47,P＜0.01).将多次不同肌电下记录到的cVEMP振幅与胸锁乳突肌表面肌电进行线性拟合模型检验,拟合函数为Y=0.769X(r2 =0.591,校正r2=9.590).结论 cVEMP的潜伏期与胸锁乳突肌肌电大小无关,而cVEMP振幅与胸锁乳突肌表面肌电存在明显的正线性相关.选择合适的头位记录cVEMP,特别是量化肌电与振幅的关系,将有利于增强cVEMP临床应用的敏感性和准确性.     

前庭诱发的肌源性电位临床应用

前庭诱发的肌源性电位（Vestibular evoked myogenic potentials，VEMP）可用于评价球囊功能及其对称性。本文总结VEMP在神经耳科学中的应用情况。首先建立VEMP的临床适用的检查方法，这些方法包括：刺激声的选择、刺激强度及给声方式，建立VEMP在振幅、阈值、潜伏期和耳间潜伏期的正常值。临床上常用于：梅尼埃病和迟发性膜迷路积水、前庭神经炎、听神经瘤、前半规管裂综合征和听神经病的诊断定位。VEMP的振幅变化较大．潜伏期的变化较大，而阈值较稳定。梅尼埃病和迟发性膜迷路积水、前庭神经炎、听神经瘤可以出现振幅的异常或引不出；梅尼埃病、迟发性膜迷路积水和听神经瘤可见振幅和潜伏期异常。听神经瘤还可见耳间潜伏期延长。听神经病主要表现为振幅的异常，振幅减低或引不出。VEMP是一种稳定的肌源性电位，双侧声刺激较为适宜。VEMP的阈值检查主要用于压力或声音敏感性眩晕；耳间潜伏期的异常主要见于桥一小脑角占位病变：振幅和潜伏期的异常一般没有特异性．可见于累及前庭下神经的病变。     

小脑脑桥角肿瘤的MRI诊断

目的 通过分析各种小脑脑桥角肿瘤的MRI表现，评价MRI在鉴别诊断方面的价值。方法回顾性分析139例经临床病理确诊的各种小脑脑桥角肿瘤的MRI图像资料，其中听神经瘤81例，三叉神经瘤23例，脑膜瘤15例，胆脂瘤11例，血管母细胞瘤2例，蛛网膜囊肿4例，脉络丛乳头状瘤、髓母细胞瘤和Ⅱ级星形细胞瘤各1例。结果小脑脑桥角肿瘤中，脑外肿瘤占96．4％，脑内肿瘤占3．6％；本组肿瘤中良性肿瘤占98．6％，恶性肿瘤占1．4％。发生于小脑脑桥角的前三位肿瘤分别为听神经瘤(58．2％)、三叉神经瘤(16．5％)和脑膜瘤(10．8％)，该区肿瘤大多具有特征性的MRI表现，术前定位、定性诊断准确率分别为100％和93．7％。结论MRI是小脑脑桥角肿瘤有效的补充检查方法，对该区肿瘤的诊断和鉴别具有重要的价值。     

小型猪肌源性诱发前庭电位的检测

目的探索小型猪肌源性诱发前庭电位(Vestibular-evoked myogenic potential,VEMP)的最佳检测方法。方法选取正常成年的雌性小型巴马香猪,以3%戊巴比妥钠+速眠新Ⅱ进行麻醉之后,用自制装置进行固定,1000Hz强短声诱发颈部伸肌肌源性电位和咬肌肌源性电位,并记录其波形;结果颈部伸肌诱发肌源性电位,第一个正向波P的潜伏期7.65±0.64ms,振幅1.66±0.34uv,80dBSPL的引出率为75%;咬肌诱发肌源性电位,第一个正向波P的潜伏期7.60±0.78ms,振幅1.31±0.28uv,80dBSPL的引出率为66%。结论小型猪颈部伸肌和咬肌在强声下诱发的肌源性电位潜伏期和阈值均一致;颈部伸肌部位所记录到的VEMF波幅稍高于咬肌部位记录到波幅;但相比之下,咬肌位置表浅,便于定位,肌肉组织发达,肌紧张性强,更易于肌源性诱发电位的记录。     

前庭诱发肌源性电位

前庭诱发肌源性电位是起源于球囊的能够反映前庭-丘脑通路完整性的一种客观、无创的电生理检查,可应用于梅尼埃病、前庭神经炎与听神经瘤等前庭疾病的诊断与鉴别诊断,与冷热试验和眼震电图一起可全面评价前庭系统的功能。     

前庭诱发肌源性电位

前庭诱发肌源性电位是起源于球囊的能够反映前庭-丘脑通路完整性的一种客观、无创的电生理检查，可应用于梅尼埃病、前庭神经炎与听神经瘤等前庭疾病的诊断与鉴别诊断，与冷热试验和眼震电图一起可全面评价前庭系统的功能。     

眼震电图在桥小脑角占位病变诊断中的意义

目的：为了深入研究眼震电图（ＥＮＧ）对小脑桥脑角病变的诊断价值。方法;对经手术和病理检查证实的２４例桥小脑角病变的ＥＮＧ资料进行总结分析。所有患者均行ＥＮＧ系列检查,包括：扫视试验,凝视试验,平稳跟踪试验,视动性试验,位置试验,温度试验,固视试验共７项试验。ＥＮＧ检查与手术和病理检查结果进行对照分析。结果：ＥＮＧ网膜－眼反射试验障碍表明为中枢性病变而与周围性病变相鉴别;Ｂｒｕｎ‘ｓ眼震等和一侧管麻     

前庭诱发肌源性电位

前庭器官及与之关联的脑内各级中枢组成前庭系统,司体位感觉及平衡,各种平衡失调及表现不一的眩晕病是耳科及神经科的多发病,病因常不易确诊.由于技术上的难度,前庭功能的检查方法一直较为落后.惯用的大幅度旋转方法虽然也不断在改进,但通用的眼震等类指标都较为间接.虽然加速度刺激及电刺激记录前庭诱发电位是一项新技术,可直接提供有关前庭系统各级结构功能状态的信息,但目前尚无可用于临床检查的商品仪器.所以寻找其它的方法反映前庭功能是当前面临的重要任务.短声刺激前庭(球囊)诱发肌源性(颈肌)电位,能间接地反映前庭系统的功能,且操作方法简单易行,反应具有单侧性,是一个很有前景的临床检查方法.本文就其概念、研究概况及实验对象、方法、电位的起源、传导途径、影响因素及临床应     

前庭诱发肌源性电位对眩晕患者的诊断价值

目的通过记录、分析眩晕患者的前庭诱发肌源性电位(VEMP),了解眩晕患者的球囊功能。方法对15例梅尼埃病患者和16例突聋伴眩晕患者行VEMP检查,分析其VEMP的不同表现形式,并将该结果与冷热试验结果比较。结果正常双侧短纯音刺激p13波和n23波出现率为100%,30%梅尼埃病患者、50%突聋伴眩晕患者VEMP不能正常引出,VEMP患侧有3种表现形式：无反应,振幅正常,振幅低。结论VEMP检查有助于客观评价眩晕患者球囊功能。     

Vestibular evoked myogenic potentials in children

OBJECTIVE: The aim of this work is to establish if the vestibular evoked myogenic potentials (VEMPs) could be used as a clinical test of vestibular function in children. MATERIALS AND METHODS: Forty normal hearing children, aged between 3 and 15 years, and classified in preschool and scholar group, have been investigated in order to study normal development of vestibular potentials and to define fundamental parameters of VEMPs, establishing normal data of latencies and amplitude ratio. Electromyographic activity of sternocleidomastoid muscle was recorded while children were laid supine on a bed and asked to raise their head off of the bed in order to activate their neck flexors bilaterally. The saccular receptors were acoustically stimulated with a logon of 500Hz at an intensity of 130dB peSPL presented monaurally through earphones. In each recording, we analysed latencies and amplitudes of the p13 and n23 waves and the amplitude ratio between the two ears. RESULTS: VEMPs were normally detected in all subjects. In preschool group mean p13 and mean n23 latencies were, respectively, 16.13 (+/-2.12)ms and 21.17 (+/-2.77)ms; mean amplitude ratio was 28.49 (+/-18.10). In scholar group mean p13 and n23 were respectively 16.14 (+/-3.48)ms and 21.78 (+/-3.39)ms, while mean amplitude ratio 20.44 (+/-13.24). Comparison of latencies and amplitude ratio between the children groups and control adult group did not showed any significant differences. CONCLUSION: In conclusion, VEMPs could represent a valid and non-invasive technique able to investigate vestibular function in children and, in particular, vestibulo collic reflex.     

Vestibular evoked myogenic potentials of haemodialysed patients with end stage renal disease

End stage renal disease (ESRD) can cause malfunction of multiple organs, including auditory and vestibular systems. During recent years, a significant amount of research has demonstrated the direct involvement of the otolith organs in stabilizing body and gaze which led to the development of specific functional tests. Stable gaze and body are more important in patients with ESRD, as they have an increased risk of bone fracture. The aim of this study was to investigate saccule and related neural pathways in haemodialysed patients with chronic renal failure. Twenty patients (40 ears) with ESRD were tested for vestibular evoked myogenic potentials (VEMP). Results were compared with those of 16 healthy controls (32 ears). VEMP response was significantly different between subjects and patients with ESRD. There was a significant difference between the presence and absence of VEMP waves in ESRD patient when compared with creatinine levels.     

Vestibular evoked myogenic potentials in brainstem stroke

OBJECTIVES/HYPOTHESIS: Despite its widespread application in the posterior fossa tumor, the study of vestibular evoked myogenic potential (VEMP) in cases of posterior fossa stroke remains scarce. The purpose of the study was to establish the role of VEMP in patients with brainstem stroke. STUDY DESIGN: Retrospective study. METHODS: Patients with acute vertigo were admitted and underwent a battery of auditory vestibular tests including caloric and VEMP tests; then they were surveyed by magnetic resonance imaging scan. Seven patients (two men and five women) were demonstrated as having brainstem stroke, including infarction in five patients and hemorrhage in two. RESULTS: Clinical manifestations consisted of dizziness/vertigo in all patients, spontaneous nystagmus in five (71%), and ataxia in three. No patients had experienced conscious change or conventional neurological deficits (eg, long tract signs). Electronystagmography revealed abnormal findings on eye tracking test in 100% of patients, on optokinetic nystagmus test in 71% of the patients, and on caloric testing in 10 ears (71%), including absent ice-water caloric test response in 7 ears and canal paresis in 3 ears. Vestibular evoked myogenic potential testing displayed normal response in 3 ears and abnormal response in 11 ears (79%), including absent vestibular evoked myogenic potentials in 8 ears and delayed vestibular evoked myogenic potentials in 3 ears. When results of both caloric testing and VEMP test were combined, the abnormal rate increased to 93% (13 of 14 patients). CONCLUSIONS: Caloric testing assesses the vestibulo-ocular reflex, which passes upward through the upper brainstem, whereas VEMP testing evaluates the sacculocollic reflex, which travels downward through the lower brainstem. Hence, in evaluating the extension of brainstem stroke, both caloric and VEMP testing should be performed.     

Vestibular evoked myogenic potentials of undiagnosed dizziness

OBJECTIVE: Recording of vestibular evoked myogenic potentials (VEMP) can facilitate the evaluation of otolith function. The dizziness caused by otolith lesions is not completely understood. To clarify which symptoms of dizziness originate from the otolith organs, we examined the relationship between symptoms and VEMP results in patients with undiagnosed dizziness. METHODS: The subjects were 18 patients with undiagnosed dizziness aged less than 40 years who underwent VEMP examination. The VEMP results were evaluated using the interaural ratio of p13-n23 amplitude. RESULTS: Abnormal VEMP results were obtained in five of seven patients who experienced a sensation of falling (p=0.013), in none of the three patients who experienced a swaying sensation (p>0.05), and in one of eight patients who experienced a floating sensation (p>0.05). Five of six patients with abnormal VEMP results complained of disequilibrium lasting a few seconds. CONCLUSIONS: Dizziness with a sensation of falling lasting for a few seconds was related to abnormal VEMP results, suggesting that it resulted from saccular dysfunction. VEMP examination may be considered a useful modality in the diagnosis of dizziness of unknown origin.     

Vestibular evoked myogenic potentials in children after cochlear implantation

Objective

The aim of this study was to report the effect of unilateral cochlear implantation to vestibular system using vestibular evoked myogenic potentials (VEMPs) by air-conduction in a sample of children aged less than 5 years.

Materials

This study consisted of 10 children (6 boys and 4 girls), who underwent cochlear implantation surgery at our clinic, and 8 normal hearing children (5 boys and 3 girls) matched for age. The VEMPs were performed before, 10 days, and 6 months after surgery. Both the implanted and unimplanted ears of each child were evaluated, with the cochlear implant both off and on.

Results

Preoperatively, six (60%) children had abnormal VEMPs responses on both ears. In the postoperative sessions, no child showed any VEMPs response on the implanted side. The VEMPs were not recorded on the unimplanted side either, except for one case. At 6 months, the VEMPs response on the unimplanted side of three children became normal when the cochlear implant was on, and in two children with the device off.

Conclusion

In the postoperative 6-month-period, the disappearance of VEMPs suggests that the saccule of children can be extensively damaged following cochlear implantation. A recovery of VEMPs can take place on the unimplanted side, with the cochlear implant both on and off. Despite this saccular injury, the absence of clinical signs in children could be explained by their ability to effectively compensate for such vestibular deficits.     

Vestibular evoked myogenic potentials in basilar artery migraine

OBJECTIVES/HYPOTHESIS: Because the sacculocollic reflex is a descending pathway passing through the territory of basilar artery, the aim of the study was to investigate whether hypoperfusion affects this pathway by applying vestibular evoked myogenic potential (VEMP) testing in patients with basilar artery migraine. STUDY DESIGN: A prospective study from May 2000 to April 2002. METHODS: Twenty patients were diagnosed as having basilar artery migraine according to the criteria of the International Headache Society and literature. Eight were male and 12 were female patients, and their ages ranged from 9 to 48 years (mean age, 40 y). Each patient underwent a battery of audio-vestibular tests. RESULTS: Electronystagmography disclosed abnormal eye tracking test in six patients (30%), and there were abnormal optokinetic nystagmus test results in nine patients (45%). Caloric test revealed canal paresis in seven patients, directional preponderance in four patients, and normal responses in nine patients (45%). Vestibular evoked myogenic potential testing disclosed absent vestibular evoked myogenic potentials in seven patients and delayed vestibular evoked myogenic potentials in two patients, with one patient showing absent vestibular evoked myogenic potentials on one side and delayed vestibular evoked myogenic potentials on the other side. The remaining 10 patients (50%) had bilateral normal vestibular evoked myogenic potentials. Five patients had preserved both caloric and VEMP test responses, six patients displayed absent caloric and VEMP test responses, and the remaining nine patients had either abnormal caloric test responses or abnormal vestibular evoked myogenic potentials, exhibiting a nonsignificant relationship between caloric test responses and vestibular evoked myogenic potentials. Relief of headache and vertigo was achieved after 3 months of medication. Ten asymptomatic patients with either absent or delayed vestibular evoked myogenic potentials before treatment underwent follow-up VEMP test, and nine patients (90%) displayed normal vestibular evoked myogenic potentials bilaterally. CONCLUSION: Vestibular evoked myogenic potential testing evaluates the sacculocollic reflex, which descends through the lower brainstem. Some patients with basilar artery migraine have absent or delayed vestibular evoked myogenic potentials, presumably because the descending pathway from the saccule through the brainstem to cranial nerve XI is interrupted, which is attributed to hypoperfusion in the territory of the basilar artery. After 3 months of medication, recovery of normal vestibular evoked myogenic potentials in an asymptomatic patient indicates reversible ischemia in the territory of the basilar artery.     

前庭诱发肌源性电位的正常人群观察

目的:观察我国正常青年人群中前庭诱发肌源性电位(VEMP)出现的阳性率及各项参数指标。方法:选取52例(男31例,女21例)21~22岁正常健康人群,以短声为刺激声,单耳给声,同侧胸锁乳突肌(SCM)记录。结果:47例2耳均可引出VEMP,5例2耳均不能引出。总104耳中,94耳阳性,10耳阴性,阳性率90%。统计阳性耳各参数:p1潜伏期(15.97±3.22)ms、n2潜伏期(24.41±2.46)ms、p1n2间期(8.41±2.06)ms,幅值(33.27±14.37)μV,阈值(93.67±5.20)dB nHL。统计47例正常人同一个体耳内差异的各参数为p1潜伏期(0.97±1.31)ms,n2潜伏期(1.23±1.30)ms,p1n2间期(0.95±1.21)ms,幅值(10.04±11.88)μV,阈值(2.29±2.56)dB nHL。男女各参数比较差异无统计学意义。结论:绝大部分正常人可引出VEMP。VEMP的引出体现该侧耳球囊→前庭下神经→脑干前庭神经核→前庭脊髓通路→颈肌运动神经元这条反射途径的完整性。VEMP可能成为一种检测前庭终器及其传导通路完整性的方法。