两种刺激方式引发面神经诱发电位的比较

神经电生理是目前检测面神经功能最有价值的手段 ,国外的研究显示 ,面神经逆行诱发电位能直接反映面神经本身的功能状态及病变 ,有可能成为一种新的电生理检测方法〔1〕。本研究旨在比较经皮刺激与直接刺激面神经所记录的面神经诱发电位有无差异 ,现报告如下。1　对象与方法1 .1 　 实验对象选体重 2 .0～ 2 .5 kg的健康成年家兔 1 5只 (由我校实验动物中心提供 ) ,雌雄兼有。随机选取一侧面神经进行实验。1 .2 　 记录方法与观察指标采用头皮圆盘电极记录 ,项部接地 ,前额作为参考点 ;面神经刺激采用双极电极。所用测试仪为Nicolet公司产…     

损伤面神经分支引起不全面瘫的临床恢复情况

本研究是通过实验损伤家兔面神经的口轮匝肌支致成此肌麻痹以观察其恢复情况。试验共分两部分: 面神经部分切断后肌肉神经系统的功能观察动物麻醉后,暴露面神经的右侧口轮匝肌支,先在睑裂中线的近侧刺激并记录诱发波和肌肉收缩,其后在手术显微镜下用剪刀剪断口轮匝肌神经直径的1/4;再刺激损伤神经的近端,对产生的诱发波和口轮匝肌收缩进行测定,继而分别切断神经的约1/2、3/4及7/8,作相同的观察。电生理学测量的结果与神经切断前记录的结果作比较。 [结果] 面神经被切断1/4的家兔,摄取食物时口轮匝肌的运动消失,表明面神经麻痹,然而切断神经直径的1/4及1/2所引起的诱发波和肌肉收缩,在振幅和时间方面与神经切断前无区别。当神经切断的程度增至3/4及7/8时,诱发波     

正常青年人失匹配负波检查

目的探讨失匹配负波(mismatch negativity,MMN)检查在正常青年人中的特点,并分析阅读状态和集中注意力时MMN检查的结果有无差异。方法对12例青年女性(年龄29-31y,平均30.08y)和18例青年男性(年龄27-34y,平均30.22y)行MMN检查,所有受试者均行听性脑干反应(ABR)阈值检查,确定ABR阈值,MMN检查在受试者在阅读状态和集中注意力状态时分别检测,采用oddball刺激方式,给予短纯音刺激,偏差刺激声为2000Hz,概率为20%,标准刺激为1000 Hz,概率为80%,刺激频率为1.1次/s,刺激声强度为ABR阈上50dB nHL;观察MMN潜伏期及波幅的特点。结果所有受试者ABR阈值均≤25 dB nHL。每例受试者均可引出MMN波形,女性在阅读状态下MMN潜伏期为159.57±20.64 ms,波幅为3.82±1.38 uV,在集中注意力状态下MMN潜伏期为155.96±17.51 ms,波幅为4.28±1.89 uV,经配对t检验潜伏期和波幅在两种状态下无显著差异;男性在阅读状态下MMN潜伏期为150.48±19.57 ms,波幅为3.75±1.27 uV,在集中注意力状态下MMN潜伏期为144.81±15.42 ms,波幅为3.99±1.34 uV,经配对t检验潜伏期和波幅在两种状态下无显著差异;经独立样本t检验,男女在上述两种状态下MMN波幅和潜伏期均无显著差异。结论正常青年男女均能引出MMN波形,男女之间MMN检查的波幅和潜伏期无差异,阅读状态和集中注意力状态对MMN检查的波幅和潜伏期无影响。     

听性脑干反应各波幅度的测量方法-动物实验研究

目的研究高刺激声强(90dB SPL)下豚鼠听性脑干反应(ABR)波Ⅰ、波Ⅲ、波Ⅴ的波幅测量方法。方法11只(22耳)2-3月龄白毛雌豚鼠,初测听力正常,测量短声(Click)、短纯音(4k、8k、12k、16k、24k、32kHz)下的听性脑干反应,记录反应阈及90dB SPL刺激声强下的基线高度、波Ⅰ、波Ⅲ、波Ⅴ的潜伏期、波间期、波峰高度、波谷高度,比较波幅的两种测量方法,即波峰-基线和波峰-波谷在90dB SPL刺激声强下,波Ⅰ、Ⅲ、Ⅴ两种测量方法的稳定性,并比较两种测量方法下波Ⅰ波幅与Ⅰ/Ⅴ波幅比的稳定性。结果 90dB SPL声强下ABR波Ⅰ、波Ⅲ、波Ⅴ的波幅两种测量方法,波峰至基线比波峰至波谷所得的数据更集中,离散程度更小;两种方法的波Ⅰ波幅的变异系数均小于Ⅰ/Ⅴ波幅比。结论在豚鼠中,使用波峰-基线的幅度测量方法得到的最高刺激声强下的ABR波Ⅰ、波Ⅲ、波Ⅴ波幅更稳定;在正常豚鼠中判断波Ⅰ波幅有无下降,直接通过比较波Ⅰ波幅,比通过Ⅰ/Ⅴ波幅比的变异度更小。     

言语信号诱发听力正常老年人听觉皮层诱发电位P1-N1-P2特征值研究

目的　获得听力正常老年人P1-N1-P2各波在不同言语刺激参数下的参考值并分析其特征。方法　使用澳大利亚HEARLab辅助皮层测试模块，对61例听力正常老年人在3种言语刺激声下进行测试，每种言语刺激声测试4个强度，获取各反应波潜伏期幅值的参考值。采用方差分析评估刺激声特性对波形特征值的影响。结果　①61例受试 者P1、N1、P2波均引出的引出率为91.8%；②刺激声为/g/时，听力正常老年人较青年人潜伏期延长幅值增大；③刺激声频率一定时，信噪比为10 dB诱发的反应波幅值最小，潜伏期最长；④刺激声强度一定时，较低频率语音/m/和/g/产生的振幅大于高频语音/t/。结论　听力正常老年人P1-N1-P2波引出率低于青年人，波形特征值亦有明显不同。刺激声特性对听力正常老年人P1-N1-P2特征值有显著影响。     

耳科手术中面神经监测仪的应用

目的探讨面神经监测仪在耳科手术中的应用价值.方法在22例耳科手术时,用面神经监测仪监测面神经,并比较手术时面神经水平段的暴露情况与面神经电流刺激阈值的关系.结果6例面神经骨管完整患者的电流刺激阈值为0.41～0.97mA;12例面神经骨管缺损但表面有黏膜及软组织覆盖者的电流刺激阈值为0.08～0.26mA;4例面神经直接暴露者的电流刺激阈值为0.06～0.16mA.经统计学分析,3组差异有显著性(P＜0.05).结论耳科手术时应用面神经监测仪可判断面神经骨管状况及探测面神经走行,是耳科手术时防止面神经损伤的有效辅助设备.     

“计数”和“不计数”状态下300ms处电位研究

文中观察了１０名健康飞行员在“计数”和“不计数”状态下３００ｍｓ的电位情况。采用新异的声刺激模式，小概率靶刺激信号为２ｋＨｚ短音（占２０％），大概率非靶刺激信号为１ｋＨ２短音（占８０％）。测试方式分为“计数”、“不计数”两种，分别测定靶与非靶刺激所诱发的３００ｍｓ处电位，并计算二者相减所得差异负波各参数。结果显示：“计数”状态下，比“不计数”状态下Ｐ３００的潜伏期为短，波幅为大，Ｐ３００反映了选择性注意时脑控制性加工过程。而“不计数”状态下的差异负波的基线上面积，虽较“计数”状态时为小，但仍清晰可辨。差异负波包括失匹配负电位（ＭＭＮ）和／或Ｎ２ａ，属外源性电位，反映了被动注意时脑自动加工过程。作者认为Ｐ３００及差异负波可分别作为“计数”与“不计数”测试指标，有可能客观而无创性地对中枢听觉脑认知功能作出评估，具有一定的临床应用价值。     

中耳手术中面神经监测的应用

目的 评价术中面神经监测在中耳手术中的作用并系统化其监测方法,探讨全身麻醉对神经监测的影响.方法 40例鼓室成形术中应用面神经实时监测,静脉输注罗库溴铵维持50%的肌松程度.根据术中直视下面神经暴露程度,分为面神经暴露组(A组,n=16)和面神经非暴露组(B组,n=24),测定面神经诱发肌电位的电刺激阈值.结果 所有病例均成功诱发面神经肌电位反应,且术后面神经功能均未见异常.50%肌松程度下面神经暴露组电刺激阈值为0.15 mA±0.07mA(0.07～0.25 mA),面神经非暴露组电刺激阈值为0.53 mA±0.21mA(0.20～1.00mA).两者比较,差异有统计学意义(P<0.001).结论 中耳手术中面神经监测有助于定位面神经,预警手术操作,避免医源性面神经损伤.定位未暴露的面神经时,可先用0.5mA刺激,再用1.0mA探寻;面神经暴露时,用0.1mA开始刺激.部分神经肌肉阻滞技术可以满足面神经监测的需要.     

面神经F波研究

F波是周围神经在阈上超强刺激条件下,由逆行冲动引起的运动神经纤维的非突触性反应.F波最显著的特点是能够反映神经全程的功能状态.目前国内外各项神经F波相关研究在周围神经病中巳逐渐成为常规检查手段,尤其对整个神经特别是近端神经的运动传导功能可做出早期估价.面神经是人体在骨管内走形最长的脑神经,应用F波可全程,早期的检测其功能状态.     

面神经F波研究

F波是周围神经在阈上超强刺激条件下,由逆行冲动引起的运动神经纤维的非突触性反应.F波最显著的特点是能够反映神经全程的功能状态.目前国内外各项神经F波相关研究在周围神经病中巳逐渐成为常规检查手段,尤其对整个神经特别是近端神经的运动传导功能可做出早期估价.面神经是人体在骨管内走形最长的脑神经,应用F波可全程,早期的检测其功能状态.     

A novel method in predicting immediate postoperative facial nerve function post acoustic neuroma excision.

To determine whether the percentage calculated by dividing the amplitude of postexcision direct facial nerve stimulus responses (at pontomedullary junction) by the amplitude of distal ipsilateral transcutaneous (stylomastoid region) maximal stimulus responses and response amplitude progression by increasing stimulus intensities have predictive value for determining normal or near-normal (House-Brackmann Grade 1 or 2) immediate postoperative facial nerve function. STUDY DESIGN: Intraoperative recordings of three muscle groups: 1) frontalis, 2) orbicularis oculi, and 3) orbicularis oris. Postexcision direct facial nerve stimulation at the pontomedullary junction and transcutaneous maximal facial nerve stimulation at the ipsilateral stylomastoid region and their associated response amplitudes were recorded. SETTING: Tertiary referral center. PATIENTS AND METHODS: Patients who underwent acoustic neuroma surgery from January 2004 to March 2006 with intraoperative facial nerve monitoring and an intact facial nerve after tumor excision were included. Recordings were available for 38 patients. RESULTS: With a stimulus intensity of 0.3 mA at the root exit zone, there was an 81% positive predictive value in patients that exhibited a compound action potential of greater than 20% of maximum (sensitivity, 81%). This increased to 93% when the compound action potential was greater than 50% of maximum. When the amplitude increase was greater than 5 microV, there was a 77% positive predictive value (sensitivity, 87%). CONCLUSION: The percentage of the response amplitude of direct facial nerve stimulation at the pontomedullary junction when compared with the maximum response amplitude of ipsilateral transcutaneous stimulation at the stylomastoid foramen is a good predictor of normal to near-normal immediate postoperative facial nerve function. Progression of amplitude response also seems to be a good predictor of normal to near-normal immediate postoperative facial nerve function.     

Effects of hyperbaric oxygen therapy on facial nerve regeneration

Conclusion. Hyperbaric oxygen treatment (HBOT) promoted an increase of the mean axonal diameter in the group evaluated 2 weeks after lesion induction, which suggests a more advanced regeneration process. However, the number of myelin nerve fibers of the facial nerve of the rabbits was similar when compared to the control and treatment groups, in both evaluation periods. Objective. To evaluate the effect of HBOT on the histological pattern of the facial nerve in rabbits exposed to a nerve crush injury. Materials and methods. Twenty rabbits were exposed to facial nerve crush injury. Ten rabbits received HBOT, 10 rabbits comprised the control group. The rabbits were sacrificed 2 and 4 weeks after the trauma. Qualitative morphological analysis, measurement of the external axonal diameters and myelin fiber count were carried out in an area of 185 000 µm². Results. There was an increase in the area of the axons and thicker myelin in the 2 weeks treatment group in comparison with the control group. The mean diameter of the axons was of 2.34 µm in the control group and of 2.81 µm in the HBOT group, with statistically significant differences. The 2 week control group had a mean number of myelin fibers of 1865.2±664, and the HBOT group had a mean number of 2026.3±302; this was not statistically significant. The 4 week control group presented a mean of 2495.1±479 fibers and the HBOT group presented a mean of 2359.9±473; this was not statistically significant.     

Application of an Intraoperative Neuromonitoring System Using a Surface Pressure Sensor in Parotid Surgery: A Rabbit Model Study

ObjectivesFacial nerve monitoring (FNM) can be used to identify the facial nerve, to obtain information regarding its course, and to evaluate its status during parotidectomy. However, there has been disagreement regarding the efficacy of FNM in reducing the incidence of facial nerve palsy during parotid surgery. Therefore, instead of using electromyography (EMG) to identify the location and state of the facial nerve, we applied an intraoperative neuromonitoring (IONM) system using a surface pressure sensor to detect facial muscle twitching. The objective of this study was to investigate the feasibility of using the IONM system with a surface pressure sensor to detect facial muscle twitching during parotidectomy.MethodsWe evaluated the stimulus thresholds for the detection of muscle twitching in the orbicularis oris and orbicularis oculi, as well as the amplitude and latency of EMG and the surface pressure sensor in 13 facial nerves of seven rabbits, using the same stimulus intensity.ResultsThe surface pressure sensor detected muscle twitching in the orbicularis oris and orbicularis oculi in response to a stimulation of 0.1 mA in all 13 facial nerves. The stimulus threshold did not differ between the surface pressure sensor and EMG.ConclusionThe application of IONM using a surface pressure sensor during parotidectomy is noninvasive, reliable, and feasible. Therefore, the IONM system with a surface pressure sensor to measure facial muscle twitching may be an alternative to EMG for verifying the status of the facial nerve.     

Experimental study on facial nerve regeneration with or without geniculate ganglionectomy

OBJECTIVE: To investigate regeneration of the distal facial nerve following nerve grafting within the tympanic segment with geniculate ganglion preservation or dissection. DESIGN: Randomized controlled trial. SUBJECTS: Twenty-three adult New Zealand albino rabbits were used in this study. INTERVENTIONS: A 2-mm tympanic segment of the facial nerve was removed, and the greater auricular nerve was harvested for grafting in all animals. In group 1 (10 rabbits), the geniculate ganglion was preserved. In group 2 (13 rabbits), the geniculate ganglion was dissected. Mastoidal and extratemporal segments of the facial nerve were harvested 3 months postoperatively for histological examination by electron microscopy. RESULTS: The number of myelinated axons in normal facial nerves was 1819.6 +/- 535.6. In group 1, the number of myelinated axons was 123.6 +/- 31.1, and, compared with normal facial nerves, the diameter of the regenerative axons was decreased and the sheath thickness in the regenerative fiber was diminished. In group 2, the number of myelinated axons was 515.1 +/- 103.1, while the myelin sheath thickness was proportionate to axon diameter. (Data are given as mean +/- SD.) CONCLUSION: Geniculate ganglionectomy may improve motor axon regeneration.     

术中面神经监测的动物实验与临床研究

目的：探讨术中面神经监测的参数与面神经减压术后面瘫的预后之间的关系。方法：对15只健康新西兰家兔30侧面神经及21例周围性面瘫患者进行术中面神经监测，术后随访6个月以上，使用χ^2检验评估术中监测的情况与减压术后面瘫的预后之间的关系。结果：15只家兔30侧面神经监测中不同个体的面神经阈值几乎均为0．05mA，在面神经的水平段、垂直段、颞骨外段其阈值也几乎均为0．05mA。21例面瘫患者，术中肌电图(EMG)引出者14例，其中13例减压术后面瘫的预后好，1例测舌差；EMG未引出者7例，其中1例减压术后面瘫的预后好，6例预后差。结论：术中面肌EMG的阈值能够较客观、稳定地评估面神经的功能。术中面肌EMG能否引出可以辅助预测面神经减压术后面瘫的预后情况，EMG能引出者预后好，反之则差。     

Facial nerve monitoring parameters as a predictor of postoperative facial nerve outcomes after vestibular schwannoma resection.

OBJECTIVE: To evaluate whether the intraoperative stimulus threshold and response amplitude measurements from facial electromyography can predict facial nerve function at 1 year after vestibular schwannoma resection. STUDY DESIGN: Prospective study. SETTING: Tertiary academic center. PATIENTS: Seventy-four consecutive vestibular schwannoma patients. INTERVENTION: The minimal stimulus intensity (in milliamperes) and electromyographic response amplitude (in microvolts) were recorded during stimulation applied to the proximal facial nerve after vestibular schwannoma removal. MAIN OUTCOME MEASURE: Facial nerve outcomes at 1 year were evaluated using the House-Brackmann scale. Analysis was then performed to evaluate whether these electrophysiologic recordings and tumor size could predict facial nerve functional outcomes. RESULTS: Of the 74 patients, 66 of 74 (89%) had House-Brackmann Grade I or II facial nerve function and 8 of 74 (11%) had House-Brackmann Grade III-VI function at 1 year after surgery. If standards were set for intraoperative minimal stimulus intensity of 0.05 mA or less and response amplitude of 240 microV or greater, the authors were able to predict a House-Brackmann Grade I or II outcome in 56 of 66 (85%) patients at 1 year after surgery. With these same electrophysiologic parameters, only 1 of 8 (12%) House-Brackmann Grade III-VI patients also met this standard and thus gave a false-positive result. Logistic regression analysis of the data showed that both a stimulus threshold of 0.05 mA or less and a response amplitude of 240 microV or greater predicted a House-Brackmann Grade I or II outcome with a 98% probability. However, stimulus threshold or response amplitude alone had a much lower probability of the same result. In addition, although tumor size was found to independently predict facial nerve outcomes at 1 year, it did not improve the ability to predict facial nerve function over a model using stimulus intensity and amplitude alone. CONCLUSION: Individually, minimal stimulus intensity or response amplitude was less successful in predicting long-term postoperative facial nerve function. However, if both parameters are considered together, the study demonstrates that they are good prognostic indicators for facial nerve function at 1 year after surgery.     

面神经术中监测的技术参数与神经识别

目的评价面神经术中实时监测在耳显微外科手术中的作用及监测方法,探讨全身麻醉对神经监测的影响,为减少医源性神经损伤提供安全保障。方法2001～2004年在45例耳显微神经外科手术中应用神经监护仪行术中实时监测,其中先天性耳畸形手术18例,中耳乳突手术27例,大部分采用插管全身麻醉,记录诱发面肌肌电图反应的电刺激最小电流阈值。结果45例患者面神经功能术后均保留完好,术后复查与术前检查一致,未发生医源性面瘫。面肌肌电图反应的最小电刺激阈值为0.08mA,适宜刺激电流范围为0.2～1.0mA。结论术中面神经监测可以帮助术者进行神经定位,辨认神经,并提供预警,避免医源性面神经损伤。     

Optimal stimulus duration for intraoperative facial nerve monitoring.

OBJECTIVES/HYPOTHESIS: The charge delivered to the facial nerve during intraoperative facial nerve monitoring (IOFNM) is the product of the stimulation amplitude and the duration for which the pulse of charge is applied. In the literature, no standard for pulse duration exists, precluding meaningful comparison of IOFNM between studies. The optimal stimulus pulse duration can be derived from facial nerve strength duration curve analysis and calculation of chronaxy. Chronaxy is directly related to the time constant, tau, of the neuronal membrane, and is a function of neuronal membrane resistance and capacitance. STUDY DESIGN: A prospective trial of facial nerve stimulation in both an animal and a human model. METHODS: Five rabbits and 17 humans underwent intraoperative stimulation of healthy facial nerves. Pulse durations using pulses of 10, 20, 50, and 100 microseconds were employed, and the corresponding threshold stimulation amplitudes were recorded. From these data sets, strength duration curves were plotted and chronaxy values calculated. RESULTS: Average chronaxy values of 18 microseconds in the rabbit and 32 microseconds in the human were found. Given IOFNM system accuracy limitations, the optimal pulse duration for facial nerve stimulation is 50 microseconds. CONCLUSION: Most commercially available intraoperative monitoring systems employ a pulse duration default setting of 100 microseconds. Doubling of the 50-microsecond optimal pulse duration may result in a loss of sensitivity of predictive facial nerve data. Both the stimulation amplitude and the selected pulse duration should be reported by investigators so that meaningful comparison of the IOFNM data in the literature can be made.     

Prediction of postoperative facial nerve function in acoustic neuroma surgery

There is a need for an uncomplicated, consistent method to predict facial nerve function after acoustic neuroma surgery. A prospective study with a 2-year follow-up of 35 patients undergoing acoustic neuroma surgery was performed assessing how well intraoperative facial nerve monitor electrophysiological thresholds and facial function postsurgery can predict ultimate nerve function. Tumour size was a strong predictor of immediate (P-value < 0.0005) and long-term facial nerve function (P-value = 0.004). Immediate facial nerve function was strongly predicted by stimulus intensity (P-value = 0.007) and there was a suggestion of a relationship between long-term facial nerve response and stimulus intensity. It was not possible to predict delayed facial dysfunction nor the extent or timing of recovery of abnormal function. It is concluded that the combination of facial function at 1 month postsurgery with tumour size and stimulus thresholds is the best available indicator of ultimate facial function.     

激光多普勒血流计测量家兔面神经微循环

OBJECTIVE: To study the microcirculation disorder of the facial nerve entrapment in rabbits. METHODS: Laser Doppler Flowmetry (LDF) was used in the blood flow measurement of the horizontal segment of the facial nerve and other adjacent structures in 32 New Zealand White rabbits. The repeated test was used to evaluate the stability of LDF. RESULTS: An animal model was established to study the microcirculation of the facial nerve in rabbits. The record of repeat test showed that LDF is a stable method. LDF of the horizontal segment of the facial nerve is higher in the proximal end but lower in distal. LDF in the distal part of the horizontal facial nerve (57.96 +/- 24.59) is higher than the semicircle canal(21.16 +/- 6.39), the medial wall of the attic(21.17 +/- 6.21), the tendon of the tensor tympani muscle(10.40 +/- 5.97) and other adjacent structures (P < 0.05). LDF probe may become a detector for surgeon to find the facial nerve in the complicated operation fields and prevent the iatrogenic facial paralysis. Because the press on the nerve can induce the decrease of the LDF, we estimate LDF may be very useful in the study of facial nerve entrapment. CONCLUSIONS: LDF is a new, stable, objective method for microcirculation study on facial nerve, and very useful in pathophysiological investigation of peripheral facial paralysis.