脑卒中后肩关节半脱位对偏瘫侧上肢周围神经电生理特征的影响

目的:探讨脑卒中后肩关节半脱位对偏瘫侧上肢周围神经电生理参数的影响。方法:纳入20例脑卒中伴肩关节半脱位的患者,分别对患者双上肢肩胛上神经、腋神经、肌皮神经、桡神经、正中神经、尺神经的运动神经传导及桡神经、正中神经、尺神经的感觉神经传导进行评估,并对偏瘫上肢冈上肌、三角肌、肱二头肌、伸指总肌、拇短展肌和小指展肌进行静息...     

Paired study of the dorsal cutaneous ulnar and superficial radial sensory nerves

Nerve conduction studies of the dorsal cutaneous ulnar nerve (DCU) have been suggested as a useful technique for identifying distal ulnar nerve lesions. In this study a standardized method was used to establish normal conduction parameters of the DCU that were compared to conduction parameters of the superficial radial sensory nerve (SR) in the same extremity. Fifty-five extremities of 33 neurologically healthy subjects aged 22 to 69 years (mean = 37; SD = 13) were examined. Dorsal hand skin temperature of each subject was 31 to 36 C. The DCU and SR were antidromically stimulated 14cm proximal to plastic-mounted bipolar electrodes placed on the dorsum of the hand over each nerve. Latency to onset, latency to peak, and amplitude (mean +/- 2SD) for the DCU were 2.2 +/- 0.3msec, 2.8 +/- 0.5msec, and 24 +/- 17 microV; and for the SR were 2.2 +/- 0.3msec, 2.8 +/- 0.3msec, and 32 +/- 18 microV, respectively. Significant correlations (p less than 0.005) were found between the DCU and SR latencies to onset, and DCU and SR latencies to peak. These results suggest that distal sensory latencies of the DCU and SR are similar, and that a paired study of these nerves may be useful in distinguishing distal ulnar nerve entrapment syndromes when routine studies are equivocal.     

正中神经压迫试验对腕管综合征神经传导速度的影响

目的比较正中神经压迫试验对腕管综合征（carpal tunnel syndrome,CTS）患者正中神经传导速度的影响。方法设置CTS组和对照组两个组别,共29例受试者纳入研究。CTS组为14例CTS患者,对照组为15例健康受试者。神经传导速度测定包括正中神经和尺神经的感觉传导末端潜伏期（distal sensory latency,DSL）、感觉神经动作电位（sensory nerve action potential,SNAP）、跨腕关节感觉传导速度（sensory conduction velocity,SCV）、运动传导末端潜伏期（distal motor latency,DML）及复合肌肉动作电位（compound muscle action potential,CMAP）。先测感觉传导,再测运动传导。正中神经压迫试验5min后再次测量上述指标。结果正中神经压迫试验前后电生理检查考虑诊断CTS分别为22侧和24侧。压迫正中神经后,CTS组正中神经DSL较压迫前显著延长（P〈0.05）。CTS组尺神经和对照组正中神经及尺神经的各参数在压迫前后均无显著改变（P〉0.05）。与对照组相比,在压迫试验前后CTS组的正中神经DSL和DML均明显延长（P〈0.05）,尺神经DSL和DML均无显著改变（P〉0.05）。结论正中神经压迫试验5min能使CTS患者正中神经的感觉传导末端潜伏时明显延长,有助于提高神经传导测定对早期CTS的诊断率。     

Ulnar nerve involvement in carpal tunnel syndrome

This is a retrospective study of the involvement of the ulnar nerve in patients with electrodiagnostic evidence of carpal tunnel syndrome as defined by median sensory nerve action potential (SNAP) greater than 3.6msec at the wrist and/or motor distal latency in excess of 4.3msec. The study included 248 patients, 63 (25%) with unilateral and 185 (75%) with bilateral carpal tunnel syndrome. The electrodiagnostic criteria for ulnar nerve involvement was a SNAP peak latency greater than 3.7msec and/or motor distal latency in excess of 4.2msec. One hundred fourteen patients (46%) had delayed ulnar SNAP peak at the wrist; of these, 100 cases had bilateral ulnar nerve involvement and 14 had unilateral abnormalities. Slowing of the motor nerve conduction velocity for the elbow-wrist segment was noted in 24% and 15% of the study group for the median and ulnar nerves, respectively. An incidental finding was the presence of "double crush syndrome" in 35 patients (14%). The results of this study suggest the frequent association of ulnar nerve involvement at the wrist for sensory fibers and carpal tunnel syndrome.     

Slowed conduction velocity of the median sensory nerve across the carpal tunnel in normal adults

OBJECTIVE: To examine the difference of using onset or peak latency in the segmental conduction study of the median nerve in normal adults without carpal tunnel syndrome. DESIGN: We investigated 60 hands of 30 young healthy adults (15 men and 15 women; mean age, 27.1 yrs; range, 18-36 yrs). We performed the mid-palm segmental conduction study using antidromic and orthodromic techniques in the median sensory nerves of the second and third digits and the onset and peak latencies of the proximal (wrist-palm) and distal (palm-digit) segments were measured. The distoproximal latency ratios were compared between onset and peak latencies and were compared with the ratios of the superficial radial sensory nerve. RESULTS: Distoproximal peak latency ratios in the median and superficial radial sensory nerves were always >1.0 in both the antidromic and orthodromic conduction studies. However, distoproximal onset latency ratios in the median sensory nerve were >1.0 in only 35% and 21.7% of second digits and in only 25% and 11.7% of third digits in orthodromic and antidromic studies, respectively (P < 0.05). The results of distoproximal onset latency ratios in the superficial radial sensory nerve were 93.3% in the orthodromic study and 86.7% in the antidromic study (P < 0.05). CONCLUSION: Prolongation of onset latency across the carpal tunnel during segmental conduction study of the median sensory nerve was common in healthy adults. When comparing proximal and distal segments for diagnosis of carpal tunnel syndrome, using onset latency as a diagnostic variable may cause greater reporting of false positives.     

Ultrasound of radial, ulnar, median, and sciatic nerves in healthy subjects and patients with hereditary motor and sensory neuropathies.

This study was conducted to evaluate the capability of ultrasonography to visualize extremity nerves. Fifty healthy women and men and 10 patients suffering with hereditary motor and sensory neuropathy (HMSN) were examined. The radial nerve lateral to the humerus, ulnar nerve distal to the cubital tunnel, median nerve in the middle of the forearm and proximal to the palmar crease, sciatic nerve in the middle of the thigh and tibial and common peroneal nerves just distal to their bifurcation, were investigated, employing a 7.5-MHz electronic linear-array transducer. In healthy subjects, the median, ulnar and radial nerves could be identified in all cases, the sciatic nerve in 37 cases, the tibial and peroneal nerves in 10 cases. The median values of thicknesses were about 3 mm for arm nerves and 6 to 7 mm for the sciatic nerve. Nerve sizes did not correlate with subjects' height, weight or age. In the majority of the patients, arm and sciatic nerves were also visible. Thicknesses were normal in 34, increased in 11 and decreased in six of 51 nerves. In conclusion, ultrasonography allows reliable imaging of the major arm nerves and, occasionally, facilitates visualization of the sciatic, tibial and peroneal nerves in healthy subjects. Nerve size and structure did not differ significantly between patients with HMSN and healthy subjects.     

Compound nerve action potentials from the median and ulnar nerves

The compound nerve action potentials from mixed motor/sensory (MNAP) and sensory (SNAP) nerve stimulation in the median and ulnar nerves were recorded in both arms of 20 able-bodied subjects. Intranerve and internerve peak-to-peak amplitudes were compared. An SNAP/MNAP amplitude ratio greater than 0.25 exceeded the mean by 2SD. The fastest, intermediate, and slowest conduction velocities were calculated from chosen points on the biphasic waveform. An intermediate MNAP conduction velocity for the median and ulnar nerves of less than 49.5m/sec exceeded more than 2SD below the mean. Likewise, an intermediate SNAP conduction velocity of less than 45.5m/sec exceeded 2SD below the mean. Median MNAP latency across the carpal tunnel was 1.0 +/- 0.3 and ulnar MNAP conduction velocity across the elbow was 59.7 +/- 3.8m/sec. This technique may supplement traditional electrodiagnostic studies in evaluating upper extremity neuropathies.     

Sensory palmar stimulation in the diagnosis of carpal tunnel syndrome

The measurement of motor and sensory latencies of the median and ulnar nerves using conventional techniques in able-bodied subjects and patients with a history compatible with carpal tunnel syndrome (CTS) is described. The results obtained by conventional techniques are compared with measurement of median nerve sensory latency obtained by palmar stimulation and the difference of median-ulnar nerve distal sensory latencies. It is concluded that the use of measurement of median palmar sensory latency under the flexor retinaculum adds to the sensitivity of the nerve conduction studies in the diagnosis of CTS. It is suggested that, in patients with suspected CTS in whom conventional nerve conduction studies are normal, other techniques such as the measurement of palmar sensory latency, difference between median and ulnar nerve distal sensory latency and examination of all the digits should be carried out.     

神经传导速度差异规律量化评估肌萎缩侧索硬化症

背景肌电图的神经传导速度异常是肌萎缩侧索硬化( amyotrophic lateral sclerosis,ALS)的诊断标准之一,可否以其变化差异规律来量化患者病情变化和评估预后? 目的研究肌萎缩侧索硬化 (amyotrophic lateral sclerosis,ALS)患者中神经传导速度的改变,建立量化评定肌萎缩侧索硬化病情及其预后的神经生理指数. 设计回顾性分析. 地点和对象本研究的地点为北京大学第三医院神经科,研究对象为北京大学第三医院神经内科 1997-02/1999-03住院患者. 方法对 21名 ALS患者的 30条尺神经、 32条正中神经及 24名健康对照组的 38条尺神经、 40条正中神经进行运动传导速度 (motor conduction velocity, MCV)及感觉传导速度( sensory conduction velocity, SCV)和 F波进行检测.两组间数据进行统计学分析. 主要观察指标两组正中神经神经传导速度与 F波, ALS组患者小指展肌的肌力与 CMAP波幅 /DML× F出现率数值的相关性. 结果 ALS组正中神经、尺神经运动传导速度的远端潜伏期 (distal motor latency, DML)、肌肉动作电位( compound muscle action potential, CMAP)波幅及面积、 F波的出现率较对照组有显著性差异.而两组 MCV、 SCV、 F波的潜伏期差异无显著性. ALS组中 10名小指展肌的肌力与 CMAP波幅 /DML× F出现率的数值有显著的相关性 (r=0.89,P< 0.01). 结论 CMAP波幅 /DML× F波的出现率是一种有效的客观的电生理指数,可对 ALS病情及其预后进行量化评估.     

正常人周围神经传导速度40例分析

目的:研究健康成人周围神经运动传导速度(motor-nerveconductionve-locity,MCV)和感觉传导速度(sensory-nerveconductionvelocity,SCV)的正常值,为诊断周围神经疾病提供依据。方法:健康志愿者40例,年龄22～53岁,男女各20例。分别检测双侧正中神经、尺神经、胫神经及腓神经MCV和双侧正中神经、尺神经及胫神经SCV。分析指标包括潜伏期、波幅及神经传导速度(nerveconductionvelocity,NCV)。结果:NCV在正常人男女之间、左右侧肢体之间的差异在统计学上无显著性意义(P>0.05),并且随着年龄的增加而逐渐减慢。结论:NCV检测是周围神经病的重要诊断技术之一,而正常值的确定是临床诊断的前提。不同年龄组应采用各自的正常值。     

Electrodiagnostic evidence of subclinical disease states in drug abusers.

One hundred drug abusers, free of clinical signs or symptoms of disease, were examined by electrodiagnostic techniques. Sensory conduction of median, ulnar and sural nerves was evaluated in terms of latency, velocity and amplitude of evoked potential. Motor nerve latencies and conduction velocities of median, ulnar and personeal nerves were determined. Definite changes in the evoked sensory potentials of median and sural nerves of subjects using heroin or LSD were demonstrated. The sensory amplitude changes were suggestive of axonal degreneration because of normal duration. Maximum motor conduction velocity was abnormal in one patient who admitted using a variety of drugs; five heroin and two barbiturate users showed dispersed motor responses suggesting small fiber involvement. No abnormality could be shown in marjuana smokers. Signifcance of these findings is explained, emphasizing important potential for recognition of subclinical abnormalities and the opportunity for disease prevention.     

New criteria for sensory nerve conduction especially useful in diagnosing carpal tunnel syndrome

This article reports a technique for determining new standard values for median sensory nerve latencies, amplitudes, and durations. Use of these values should significantly improve the ability to diagnose carpal tunnel syndrome and to reduce the number of false negative results. Forty-five median sensory nerves of 30 neurologically healthy subjects were evaluated with rigid techniques and temperature control at stimulation and recording points. Latencies for antidromic and orthodromic conduction from wrist-to-thumb, wrist-to-index finger, wrist-to-middle finger, and wrist-to-ring finger (all 14 cm distances) are reported. Conduction time for nerve impulses through the transcarpal segment via ulnar and radial nerves was also measured for comparison with median nerve latencies. In addition to latency measurements, characteristics of electrical responses evoked by stimulation were described. These include amplitude of the recorded response measured from baseline to negative peak and from negative peak to positive peak, duration of the negative response wave (from baseline to return to baseline) and duration measured from onset of the negative wave to the positive peak. According to our data, a distal median nerve sensory latency of more than 3.3 ms (the mean of 2.9 ms plus two standard deviation values of 0.18 ms) when measured to the peak of the negative wave is indicative of abnormality.     

Orthodromic vs antidromic sensory nerve latencies in healthy persons

Sensory nerve action potentials may be evoked antidromically (AD) by stimulating a nerve proximally and recording distally, or orthodromically (OD) by stimulating distally and recording over the nerve trunk proximally. The objective of this study was to compare OD and AD distal latencies in healthy subjects. Fifty-two volunteers (average age 30 years) were tested. Orthodromic and AD sensory distal latencies of the median and ulnar nerves of the nondominant hand were obtained. Hand temperature was controlled at 32C. Six subjects were also tested at a hand temperature of 24C. In all subjects tested the OD latency was shorter than the AD latency. Median nerve AD = 3.14 +/- 0.20 (mean latency in ms +/- 1 standard deviation); median nerve OD = 2.94 +/- 0.20; ulnar nerve AD = 3.07 +/- 0.22; ulnar nerve OD = 2.85 +/- 0.19. Mean difference between the latencies obtained (OD vs AD) for the median and ulnar nerves was statistically significant (p less than 0.001). In addition, this difference was over twice as great at 24C compared to 32C for both median and ulnar nerves. Because of the difference between OD and AD sensory latencies, the standard values obtained using one method cannot be rigorously applied when utilizing the other method. Individual laboratories should develop their own normal values for both OD and AD methods, or be specific in performance of the studies when utilizing standards from the literature.     

Electrophysiologic studies of the median nerve and its palmar cutaneous branches after nerve grafting

Electromyography (EMG) and nerve conduction studies were performed on a patient with an incomplete lesion of the median nerve involving the motor fibers to the thenar muscles, the palmar cutaneous branches, and the sensory fibers to the index finger. The studies were done before, and 13 weeks, 16 weeks, and one year after grafting. The preoperative electrodiagnostic evaluation showed abnormalities involving the median motor fibers and the palmar cutaneous branch. Electromyography of the opponens pollicis and abductor pollicis brevis before surgery showed severe active denervation. Thirteen weeks after nerve grafting, the median motor distal latency was prolonged and the amplitude of the evoked potential of the median motor and index finger digital sensory nerves were decreased. At 16 weeks, both the latency and amplitude showed improvement, as did EMG of the affected muscles. One year later, the electrophysiologic findings were normal except for a slightly prolonged median motor distal latency. Clinical and functional improvement after grafting correlated well with the electrophysiologic findings. We conclude that EMG and nerve conduction studies are useful tools for following the progression of recovery after nerve grafting.     

神经电图-肌电图检测对多灶性运动神经病的评估作用

目的:探讨神经电图(ENG)和肌电图(EMG)检查对多灶性运动神经病(multifocalmotorneuropathy,MMN)的诊断价值及康复干预的评估作用。方法:对16例诊断为MMN的患者进行电生理检查,受试者为MMN组16例和正常组16例,分别进行运动神经传导速度(MCV)和感觉神经传导速度(SCV)检查,记录刺激引出的复合肌肉动作电位(compoundmus-cleactionpotentials,CMAP)的波幅、波宽、面积、位相、时限进行对比分析,判定是否有运动神经传导阻滞(conductionblock,CB)或暂时性离散(temporaldispersion,TD)。并有选择性地进行常规肌电图检查。结果:16例患者中均见有一根以上运动神经或至少一根运动神经的一个以上部位出现CB或TD。其中13例双上肢正中神经,尺神经出现CB,3例首发为正中神经尺神经的远端出现CB,随病情进展出现下肢腓深神经CB。仅有两例感觉神经传导速度稍有减慢,波幅略有降低。16例患者神经受累区域以下所支配肌肉肌电图检查见有运动神经源性受损改变。结论:MMN病是一种以远端神经受累为主的不对称性周围神经病,神经电生理检查对诊断和鉴别诊断MMN起重要作用,CB是MMN特征性表现。     

Effect of Hand Warming on Electrodiagnostic Testing Results and Diagnosis in Patients With Suspected Carpal Tunnel Syndrome

Burnham RS, Burnham TR. Effect of hand warming on electrodiagnostic testing results and diagnosis in patients with suspected carpal tunnel syndrome.

Objectives

To evaluate the effects of hand warming on electrodiagnostic (EDX) parameters of carpal tunnel syndrome (CTS). Specifically, to evaluate the type and magnitude of change in EDX values; to determine whether warming can change the EDX diagnosis of CTS and, if so, to determine whether specific EDX tests are more vulnerable to the effects of warming.

Design

Interventional before-after trial.

Setting

Community EDX laboratory.

Participants

Consecutive patients (N=33) referred for EDX evaluation of suspected CTS.

Intervention

Each upper limb was tested at room temperature (average hand temperature, 31.9°C) and retested after 20 minutes of heating pad warming (average hand temperature, 33.5°C).

Main Outcome Measures

Median and ulnar nerve motor and sensory latency, conduction velocity, and amplitude.

Results

Warming resulted in significantly faster transcarpal tunnel sensory and motor conduction (6%–10%), reduced median: ulnar sensory latency to digit 4 difference (23%), and reduced sensory nerve and compound motor action potential amplitude (10% and 13%, respectively). The changes resulted in 15% fewer limbs meeting the EDX conduction velocity criteria of CTS and 9% fewer by median: ulnar sensory latency to digit 4 difference. Waveform amplitudes became abnormally low after warming in 12% of limbs.

Conclusions

Hand warming using a heating pad for 20 minutes increases median nerve transcarpal tunnel conduction velocity and reduces amplitude. These phenomena introduce potential sources of diagnostic error, particularly in borderline cases. Generally, within hand, between nerve, and within nerve comparison techniques are less susceptible to the conduction velocity effects of warming.     

尺神经共同刺激影响腕管综合征正中神经远端潜伏期：避免误差的定量测定

目的研究尺神经-大鱼际复合肌肉动作电位(CMAP)潜伏期正常值,以定量分析尺神经共同刺激所致腕管综合征(CTS)患者正中神经-大鱼际潜伏期的误差。 方法正常组112例,记录224侧正中神经-拇短展肌（APB）和224侧尺神经-大鱼际的CMAP潜伏期和波幅。另对其中10例20侧正中神经,分别记录以正中神经-APB最大波幅之刺激强度的30%、50%、70%、100%刺激时的CMAP潜伏期和波幅。其中4例分别予以120%、150%和200%的超强刺激,记录CMAP潜伏期和波幅。CTS组16例,记录到正中神经-APB的CMAP最大波幅后,继续增大刺激强度,记录尺神经共同刺激效应后的正中神经-大鱼际CMAP。 结果①正常组：尺神经-大鱼际远端潜伏期为（3.17±0.25）ms,波幅为（6.60±1.07）mV;正中神经-APB远端潜伏期为(3.45±0.31)ms,波幅为(6.47±1.08)mV。当正中神经刺激强度从引出最大CMAP波幅之强度的30%、50%、70%增加至100%,正中神经远端潜伏期相应缩短0.1~0.3ms;达到最大波幅后继续增加刺激强度至120%、150%和200%的超强刺激,则潜伏期不再继续缩短。②CTS组：尺神经共同刺激所引起的正中神经-大鱼际CMAP潜伏期缩短范围为0.5~8.7ms,导致正中神经-APB的错误潜伏期范围为(2.9~4.1)ms。 结论CTS患者正中神经检测时,若正中神经-APB CMAP潜伏期随刺激强度增大而缩短超过0.3ms,并且达到2.9~4.1ms的范围,则提示可能发生了尺神经共同刺激。     

Handcuff neuropathy: two unusual cases

Handcuff applications may result in compression of peripheral nerves at the wrist, and most reported cases involve only the superficial radial nerve. In this report, two cases of bilateral handcuff neuropathy involving multiple nerves were confirmed by electrodiagnostic findings of membrane instability, prolonged latencies and/or conduction block. In addition to the superficial radial nerves, one case involved the median nerves, and a second case the ulnar nerves. It was postulated that injury might occur to any nerve at the wrist as a result of pressure and edema from handcuffs, with the radial nerve most frequently involved due to its superficial location. Radial nerve injury has been described as functionally insignificant; however for the two cases presented, in which the median or ulnar nerves were involved, significant disability resulted, and a rehabilitation program was indicated.     

An electrodiagnostic study in chronic alcoholic subjects

Electrodiagnostic tests were performed on 16 alcoholic subjects and 15 age-matched controls. The tests were done to determine whether nerve conduction parameters differentiate between healthy and alcoholic subjects, and if so, which of these are most useful. Significant differences between alcoholic subjects and controls were found in the following variables: median nerve motor velocity; median nerve sensory latency, amplitude and velocity; ulnar nerve motor amplitude and velocity; ulnar nerve sensory amplitude, latency and velocity; sural nerve sensory amplitude and velocity; and peroneal motor amplitude and velocity. The combination of ulnar and sural sensory conduction velocity tests identified 85% of the chronic alcoholic subjects by stepwise discriminant analysis. Tibial nerve H-reflex latencies were either absent or prolonged in 63% of the subjects. Bilateral facial nerve amplitudes and latencies were normal. The ulnar sensory amplitude and ulnar sensory velocity inversely correlated with the duration of excessive alcohol drinking.     

Temperature effect on antidromic and orthodromic sensory nerve action potential latency and amplitude

The measurement of sensory nerve action potential (SNAP) latency and amplitude is often necessary to accurately diagnose disorders of peripheral nerves. The sensory evoked response can be obtained using either the antidromic (AD) or orthodromic (OD) technique. In a previous study we demonstrated that in healthy subjects the AD SNAP distal latency of median and ulnar nerves at 14 cm distance is approximately 0.2 msec slower than the OD SNAP distal latency at 32C. The AD SNAP amplitude was also two times greater than the OD SNAP amplitude. In this study we observed that these differences between the AD and OD SNAP latency and amplitude varied significantly as temperature changed. The AD median nerve SNAP distal latency was delayed by .06 msec/degree with cooling. The OD median nerve SNAP distal latency was delayed by .03 msec/degree with cooling. These values represent less of a slowing per degree centigrade cooling than has been previously noted in the literature. The median nerve SNAP amplitude was found to increase with upper extremity cooling with the AD and OD technique by 3.5 microV and 0.5 microV per degree, respectively. For accurate interpretation of SNAP latency and amplitude, the electromyographer must be familiar with the technique used and the differing effect of the temperature with each technique.