低钾型周期性瘫痪患者运动诱发试验中肌力和肌电图改变与血钾的关系

目的 通过长时运动诱发试验,观察低钾型周期性瘫痪患者肌力和肌电图的变化与血钾之间的关系.方法 收集确诊为低钾型周期性瘫痪患者78例,对小指展肌进行运动诱发试验测定,以拇短展肌作为对照,观察120 min,测定运动诱发前后尺神经/小指展肌和正中神经/拇短展肌复合肌肉动作电位(compound muscle action potential,CMAP)波幅变化,同时观察患者小指外展和小指内收肌力以及拇短展肌肌力的变化,部分患者测定运动前后血钾水平.分析运动后不同肌肉的肌力、CMAP波幅与血钾之间的关系.结果 在小指外展运动后,78例患者尺神经CMAP波幅运动后比运动前明显下降,分别为(4.6±2.7)、(9.6±3.2)mV(t=16.047,P=0.000),而正中神经CMAP波幅在小指外展运动后与运动前相比无明显差异,分别为(10.9±4.2)、(11.2±3.9)mV(t=0.673,P=0.822).在运动后,76例小指外展肌力下降;有41例小指外展肌力小于Ⅲ级,但同侧小指内收和拇短展肌肌力仍为V级,对其中10例患者在运动前和运动后测定血钾,结果无明显差异,分别为(3.8±0.3)、(3.9±0.4)mmol/L(t =0.395,P=0.702).结论 在低钾型周期性瘫痪患者进行运动诱发试验时,血钾并非影响肌力和CMAP波幅变化的关键因素.     

神经肌肉病患者电生理神经传导检测和超声下神经横截面面积的关系研究

目的探讨神经肌肉病患者电生理神经传导检测各参数和神经横截面面积(CSA)的关系。方法记录2022年3月3日至2023年5月4日就诊于北京天坛医院的21例神经肌肉病患者正中神经和尺神经不同位点的CSA, 同时进行常规神经传导检测, 分别记录每个位点附近正中神经和尺神经的运动神经传导速度(MCV)、复合肌肉动作电位(CMAP)波幅, 记录正中神经和尺神经腕部的感觉神经传导速度(SCV)及感觉神经动作电位波幅(SNAP)。分析同一位点MCV、CMAP波幅、SCV、SNAP波幅与CSA的关系。采用线性回归模型进行数据分析。结果共记录了180组同一位点的MCV和CSA, 其中正中神经102组, 尺神经78组;220组同一位点的CMAP波幅和CSA, 其中正中神经104组, 尺神经116组;60组腕部的SCV和CSA、SNAP波幅和CSA, 其中正中神经32组, 尺神经28组。正中神经和尺神经MCV与CSA的线性相关均有统计学意义(正中神经r2=0.10, 调整r2=0.09, P=0.001;尺神经r2=0.18, 调整r2=0.17, P<0.001)。CSA>10 mm2时, 正...     

肯尼迪病患者自动递增刺激法运动单位估数的测定

目的研究肯尼迪病(KD)患者运动单位估数(MUNE)的变化并探讨其临床意义。方法收集KD患者20例和健康对照者30名,分别用自动递增磁刺激法检测受试者大、小鱼际肌MUNE数值及正中神经、尺神经最大复合肌肉动作电位(CMAP)波幅。比较KD组和对照组大小鱼际肌MUNE的差异;比较KD组患者大小鱼际肌MUNE异常率与正中神经、尺神经CMAP异常率的差异。同时,对KD患者病程与MUNE的相关性进行分析。结果与对照组比较,KD患者大、小鱼际肌MUNE数值降低(82.16±49.37比251.12±68.89,94.26±44.56比235.63±63.02,均P0.01)。KD患者大、小鱼际肌MUNE异常率分别为85.0%和80.0%,而正中神经、尺神经CMAP异常率均为15.0%,KD患者大小鱼际肌MUNE异常率与正中神经、尺神经CMAP异常率比较差异均有统计学意义(P0.01)。KD患者MUNE数值与病程呈负相关(P0.05)。结论 MUNE作为一种无创的电生理学技术,可能对早期及精确地判断KD患者下运动神经元受损情况有所帮助。     

慢性炎性脱髓鞘性多发神经根神经病的肌电图异常特点和诊断价值研究

目的探讨慢性炎性脱髓鞘性多发神经根神经病(CIDP)的肌电图特点和评价病情严重程度的价值。方法收集39例2018年9月至2020年12月收治的CIDP患者的临床资料。采用Hughes残疾评分评估患者病情严重程度。肌电图检查(1)4条运动神经:正中神经、尺神经、胫神经、腓神经的复合肌肉动作电位(CMAP)波幅、运动传导速度(MCV)和F波潜伏期;(2)3条感觉神经:正中神经、尺神经、腓肠神经的感觉神经传导速度(SCV)、动作电位(SNAP)波幅。根据电生理检测结果将患者分为A组(所测神经均可引出波形)和B组(≥1条神经测不出波形)。用Pearson相关性分析MCV、CMAP波幅和F波潜伏期与CIDP病情严重程度的相关性;用受试者工作特征曲线(ROC)评价MCV、CMAP及F波潜伏期对CIDP的诊断价值。结果与A组比较,B组Hughes残疾评分、脑神经受累、肢体无力、腱反射减弱、肌肉萎缩比例,MCV和CMAP波幅、F波潜伏期、SNAP波幅异常率以及F波潜伏期显著增加;而MCV、CMAP波幅均显著降低(均P0.05)。正中神经和尺神经MCV,胫神经CMAP波幅与病情严重程度呈显著负相关;正中神经、尺神经F波潜伏期与病情严重程度呈显著正相关(均P0.05)。ROC曲线分析结果显示,4条运动神经的MCV、CMAP及F波潜伏期均在CIDP的诊断中具有一定价值(均AUC0.07),3项指标联合可显著提高CIDP诊断的敏感度和特异度。结论 CIDP神经电生理表现为MCV明显减慢、CMAP波幅降低和F波潜伏期延长,神经损伤严重的CIDP患者此3项指标异常率更高,联合MCV、CMAP及F波潜伏期3项指标可提高CIDP诊断的敏感度和特异度。     

腕管综合征电诊断敏感性研究

目的研究腕管综合征(CTS)更敏感的电诊断指标,并结合电生理探讨CTS特征性体征与病变程度的关系。方法2009年2月～2010年2月间就诊于本科,符合纳入标准的CTS患者72例(121只腕)行神经传导检测(NCS),记录腕-拇短展肌/小指展肌末端运动潜伏期(DML)、拇短展肌复合肌肉动作电位(CMAP)波幅、腕-食指/环指/小指感觉传导速度(SCV)、正中/尺神经感觉潜伏期差(?DSL)和感觉神经动作电位(SNAP)波幅。结果(1)拇短展肌CMAP波幅(mV)低于小指展肌(7.40±3.25v.s.10.74±2.23,t=-9.22、P0.001),环指记录的正中神经SNAP波幅(μV)低于尺神经(9.77±7.46v.s.23.67±9.92,t=-10.70、P0.001);(2)腕-拇短展肌DML延长、腕-食指和腕-环指SCV减慢、?DSL增加,阳性率分别为89.1%(106/119)、79.6%(78/98)、85.1%(57/67)和95.5%(64/67)(χ2=9.66,P=0.022);(3)与阴性者比较,Tinel征阳性者DML(ms)延长更多(5.65±1.62v.s.4.89±1.61,t=2.13、P=0.035),Phalen征阳性者腕-食指SCV减慢更多(35.57±7.49v.s.39.84±7.66,t=-2.39、P=0.019),其余各参数均无差异(P0.05)。结论?DSL诊断CTS最敏感,怀疑CTS时可作为首选的方法;Tinel征和Phalen征不能完全反映CTS严重程度。     

45例正中神经腕管卡压神经电生理检测与临床分析

目的探讨正中神经腕管卡压(CTS)神经电生理检测价值。方法对临床的症状及体征符合CTS的45例患者行正中神经运动神经的传导速度与尺神经运动神经的传导速度检测;桡神经与正中神经拇指-腕感觉潜伏期时差值;正中神经与尺神经无名指-腕感觉潜伏期时差值;双侧正中神经F波的检测;拇短展肌、小指展肌的肌电图检测。结果 45例患者中63只异常,双侧病变18例,单侧病变27例,正中神经运动末端潜伏期延长或(及)传导速度减慢异常率31.5%,波幅减低异常率28.3%;正中神经拇指-腕感觉神经潜伏期延长异常率71.5%;合并波幅减低者异常率占79.3%;正中神经环指-腕感觉神经传导潜伏期延长异常率81.6%,合并波幅减低异常率89.4%;正中神经F波异常率33.6%;拇短展肌呈神经源性改变异常率20.1%。结论神经电生理的常规检测联合运用感觉神经潜伏期时差值法对CTS有更敏感、更精确的诊断价值。     

肯尼迪病患者60例神经电生理研究

目的对肯尼迪病患者进行神经电生理检测, 了解其神经功能状况。方法对2010年11月至2022年11月北京大学第三医院门诊和病房收治的60例肯尼迪病患者(根据是否合并糖尿病分为单纯肯尼迪病组29例、肯尼迪病合并糖尿病组31例)及60例糖尿病周围神经病(DPN)患者, 分别进行肌电图、神经传导、体感诱发电位(SEP)、接触性热痛诱发电位(CHEP)及三重刺激技术(TST)检测。采用t检验分别对组内及组间神经传导速度及动作电位波幅、SEP各波潜伏期和波间期、CHEP起始峰潜伏期等参数进行比较。结果与正常值比较, 肯尼迪病组患者感觉神经动作电位(SNAP)波幅明显降低[正中神经(0.7±0.4)μV, 尺神经(0.8±0.3)μV, 腓肠神经(1.8±0.1)μV, 波幅下降30%～80%], 正中神经和尺神经波幅低于腓肠神经(t=2.43, P=0.010;t=2.40, P=0.010);SEP和CHEP的周围段异常(潜伏期延长115%～130%), SEP中枢段异常(潜伏期延长104%～115%), 17例TST结果异常(TST测试/TST对照波幅比下降40%～60%)。DPN组患者SN...     

术中神经电生理监测和刺激尺神经治疗肘管综合征

目的 评估尺神经松解前置术结合术中超强电刺激治疗肘管综合征的治疗效果.方法 30例中重度肘管综合征患者首先进行尺神经松解前置术,测定并记录松解后小指展肌复合肌肉动作电位(CMAP)的潜伏期及波幅;然后给予尺神经超强电刺激治疗(80 mA,2Hz,10 min),按照同样的方法再次记录小指展肌CMAP的潜伏期及波幅,并将刺激前后的数据进行统计学分析.结果 患者尺神经外膜松解后与超强电刺激后小指展肌CMAP的波幅分别为(2.5±0.4) mV和(6.2±0.8)mV,潜伏期分别为(12.0±0.6)ms和(10.3±0.3)ms,经比较有统计学意义(P＜0.05).超强电刺激后小指展肌CMAP的潜伏期较前平均缩短15.7％,波幅平均增大约2倍.结论 术中超强电刺激对肘管综合征患者的尺神经功能恢复具有辅助治疗作用.     

Kennedy病患者电生理、病理学特点及临床误诊分析

目的研究肯尼迪病(Kennedy disease,KD)患者电生理学特征和肌肉病理学特点,探讨临床误诊原因,以加强对此病电生理学改变和肌肉病理学的认识,减少误诊误治。方法对9例经基因确诊的KD患者行针极肌电图、神经传导、F波和H反射检测。肌电图取舌肌、胸锁乳突肌、三角肌、第一骨间肌、胸椎旁肌、股四头肌、胫前肌。神经电图取双侧正中神经、尺神经、腓总神经、腓肠神经和胫神经。1例患者取股四头肌肌肉活检行病理学检查。结果肌电图检查显示9例肯尼迪病患者均表现为广泛的慢性神经源性损害。CMAP和SNAP波幅均显著降低(P0.01),以腓肠神经动作电位波幅异常率最高(88.89%),腓总神经和腓肠神经传导速度减慢(P0.01),正中神经和胫神经远端潜伏期延长(P0.01),正中神经和胫神经F波响应率降低,胫神经的H反射潜伏期延长(P0.01)。肌活检示神经源性肌损害,表现为肌纤维萎缩,萎缩纤维群组化分布。结论 KD患者电生理以广泛的慢性神经源性损害为最主要改变,感觉和运动神经传导异常,且感觉神经受累较运动神经受累更多见,病理学表现为肌肉萎缩及群组化分布。电生理和肌肉活检对该病的早期诊断和减少误诊率有重要指导价值。     

视神经脊髓炎谱系疾病周围神经病变的相关神经电生理研究

目的探讨视神经脊髓炎谱系疾病(NMOSD)周围神经病变的神经电生理改变。方法对15例NMOSD患者(NMOSD组)及20名健康对照者(正常对照组)进行EMG检查。结果 NMOSD组中,10例(66.7%)患者的EMG检查有异常改变,主要表现为运动或感觉神经传导速度减慢,波幅减低,F波出现率下降和H反射的潜伏期延长。与正常对照组比较,NMOSD组胫神经及腓总神经运动神经传导速度显著降低(均P0.01),正中神经远/近段潜伏期、胫神经远端潜伏期显著升高(均P0.05),胫神经、腓总神经运动神经远/近端波幅显著降低(均P0.01)。与正常对照组比较,NMOSD组尺神经、正中神经、腓肠神经感觉神经传导速度显著减慢(均P0.01),腓肠神经感觉神经潜伏期显著升高(P0.01),正中神经、腓肠神经感觉神经波幅显著降低(均P0.01)。NMOSD组H反射潜伏期(26.22±10.10)与正常对照组(24.36±0.63)差异无统计学意义(P0.05)。结论 NMOSD患者可以合并周围神经系统受损。EMG检查主要表现为运动或感觉神经传导速度减慢,波幅减低,F波出现率下降和H反射的潜伏期延长。     

Initial positive deflection of the compound muscle action potential in the median nerve conduction studies can be originated from lumbrical muscles in patients with carpal tunnel syndrome]

In motor nerve conduction studies we sometimes encounter a small initial positive deflection (IPD) of the compound muscle action potential (CMAP). This potential represents a volume conduction from nearby muscles other than the objective muscle. We demonstrated recordings of motor nerve conduction studies from two patients with carpal tunnel syndrome (CTS). In patients with CTS IPDs can be recorded from a surface electrode above the abductor pollicis brevis when intense stimuli to the median nerve provoked a stimulus spread to the ulnar nerve. However, without this stimulus spread to the ulnar nerve, IPDs can be observed by contraction of median nerve innervated muscles. In the CTS thenar branch of the median nerve is apt to be more severely damaged than lumbrical branch. In such an occasion volume conduction from the lumbrical muscles is relatively large, which gives rise to the IPD in the CMAP recorded from abductor pollicis brevis. We reported two cases of IDPs originated from lumbrical muscles. The peak latencies were identical between IDP of abductor pollicis brevis recording and negative potential of lumbrical recording. These potentials didn't change by median nerve stimulation at the elbow 3 msec after the ulnar nerve stimulation at the wrist (collision technique). Finally, we repeat that IPDs in the median nerve conduction studies can be originated from not only the stimulus spread to the ulnar nerve but also the median nerve innervated lumbrical muscles in patients with CTS.     

Riche-Cannieu anastomosis and a paradoxical preservation of thenar muscles in carpal tunnel syndrome: a case report]

A 72-year old woman had been suffered from a dysesthesia in the left median nerve distribution, followed by a dysesthesia in the right ulnar distribution. Neurological examination revealed weakness in the right intrinsic hand muscles with the ipsilateral thenar and hyothenar atrophy. Paradoxical preservation of the left thenar muscles was a clinical challenge. Nerve conduction studies disclosed bilateral carpal tunnel syndrome and the right cubital tunnel syndrome. In needle electromyography, however, the left abductor pollicis brevis and opponens pollicis muscles had normal motor unit potentials without denervation activity. The needle recording of the left abductor pollicis brevis muscle showed a good motor response with a negative deflection by the left ulnar nerve stimulation, indicating an ulnar to median nerve innervation, i.e., Riche-Cannieu anastomosis. A Riche-Cannieu anastomosis in a setting of a median or ulnar nerve injury can produce confusing clinical and electrodiagnostic findings. We reviewed clinical findings, electrophysiological data, and the impact of a Riche-Cannieu anastomosis in median nerve injury.     

Prevalence of Martin-Gruber anastomosis on motor nerve conduction studies]

Prevalence of median to ulnar anastomosis in the forearm(Martin-Gruber anastomosis; MGA) to the first dorsal interosseous(FDI), abductor digiti quinti (ADQ) and adductor pollicis(AP) was investigated. Subjects contained 106 patients with normal nerve conduction or patients with various neuropathies. Recording electrodes were placed on the motor point of FDI, ADQ and AP. Supramaximal stimulations were given to the median and ulnar nerves at the wrist or above the elbow. The diagnosis of MGA was made by the following criteria; amplitude of compound muscle action potential(CMAP) increased after elbow stimulation as compared with the wrist stimulation in median nerve conduction studies. The corresponding decrease in CMAP amplitude was found after above elbow stimulation as compared with the wrist stimulation in ulnar nerve conduction studies. No MGA was found in 80(75%) out of 106 patients. MGA to FDI was found in all 26 patients who had MGA. MGA to ADQ and AP was found in 11% and 10% of the patients, respectively. Only 8 out of 26 patients had MGA to all 3 muscles. In the presence of MGA median motor nerve conduction studies demonstrate larger CMAP, with a small initial positivity, after elbow stimulation than after wrist stimulation. And moreover, ulnar motor nerve conduction studies reveal a conduction block-like finding in the forearm. In this study MGA was found in 25% of the patient to FDI, in 11% to ADQ and in 10% to AP. Although a very small MGA might be overlooked in our method, such a small MGA doesn't mislead us into erroneous interpretation of motor nerve conduction studies.     

Alteration of proximal conduction velocity at distal nerve injury in carpal tunnel syndrome: demyelinating versus axonal change.

The objective of this study was to determine the cause of median forearm motor conduction velocity (FMCV) slowing in patients with carpal tunnel syndrome, due to either focal conduction abnormality over wrist or retrograde conduction slowing, and to decide whether the slowing is related to severity of compression or not. Fifty carpal tunnel syndrome patients confirmed by conventional nerve conduction study with abnormal electromyography of the abductor pollicis brevis muscle were group 1, and 100 with normal electromyography, group 2. One hundred volunteers served as controls. In addition to conventional nerve conduction study of median and ulnar nerves, palmar stimulations for median mixed and motor nerves were also performed to calculate wrist-palm mixed nerve conduction time and motor conduction velocity (W-P MCV). For group 1, group 2, and control subjects, respectively, W-P MCV were 19.73+/-7.65 (mean+/-SD), 32.7+/-6.83, and 52.75+/-6.4 m/s, whereas median FMCV were 48.63+/-8.32, 54.42+/-2.11, and 57.86+/-4.24 m/s. There was a significant reduction in the W-P MCV (62.6%, P<0.00001) and a decrease in the median FMCV (15.95%, P<0.00001) in group 1, and 38% reduction in W-P MCV (P<0.00001) and 5.9% decrease in median FMCV (P<0.00001) in group 2 when compared with controls, but ulnar FMCV and sensory nerve conduction study results did not, suggesting the reduction of median W-P MCV is not parallel with that of median FMCV in both patients groups. Furthermore, there is a poor correlation of median FMCV and W-P MCV in patient groups, implying conduction blockage of the large myelinating fibers at the wrist, leaving only slower axons to be measured, is not the likely cause of reduction of FMCV. In addition, the reduction of compound muscle action potential amplitude of abductor pollicis brevis muscle, conduction block at wrist and weak correlation of median FMCV and compound muscle action potential amplitude of abductor pollicis brevis exclusively occurred in group 1. Therefore, the retrograde conduction slowing really occurs among patients with carpal tunnel syndrome-markedly in those with abnormal electromyography and mildly in those with only demyelination. This finding counters conventional wisdom that nerve function changes only in segments distal to injured sites.     

Marinacci communication: an electrophysiological study

OBJECTIVE: Prevalence of Martin-Gruber anastomosis, an anomalous median-to-ulnar forearm communication, is well reported in literature while Marinacci communication, the reverse of Martin-Gruber with a forearm ulnar-to-median communication is under-recognized. We systematically evaluated the presence of Marinacci communication in a series of patients referred for electrophysiological studies. METHODS: One hundred consecutive patients referred to the electrophysiological laboratory for various diagnoses were studied using standard techniques for motor, sensory and f wave studies. RESULTS: Of the 100 patients (200 arms) studied, electrophysiological features of Marinacci communication were observed in 4 patients (7 arms). Median stimulation with recording over abductor pollicis brevis (APB) revealed a pseudo-conduction block over the forearm segment while on ulnar stimulation and recording over abductor digiti minimi (ADM), the amplitude of the compound muscle action potential (CMAP) obtained on proximal stimulation was higher than that obtained on distal stimulation. Ulnar stimulation at the elbow but not at the wrist revealed CMAP from APB without initial positivity. Its amplitude was 50% of the amplitude obtained on median stimulation at the wrist. CONCLUSIONS: Marinacci communication is not uncommon in the general population. A pseudo-conduction block on median stimulation and higher CMAP amplitude on proximal than distal stimulation provide valuable clues to its recognition.     

Riche-Cannieu anastomosis as an inherited trait.

OBJECTIVE: To explore the basis for the Riche-Cannieu anastomosis (RCA) and specifically whether this anomaly is an hereditary characteristic. METHODS: Three individuals from the same family were evaluated after initial studies in the index case indicated an RCA. Nerve conduction, needle electromyography (EMG), and axonal excitability studies of the median and ulnar nerves were undertaken in each case. RESULTS: In all subjects onset thresholds for CMAPs from abductor pollicis brevis (APB) were lower with ulnar nerve stimulation, but of similar latencies when compared with median nerve stimulation. Larger CMAP amplitudes were obtained with ulnar nerve stimulation, at lower stimulus intensities. No sensory anomalies were detected. Needle EMG confirmed dual innervation of APB by both median and ulnar nerves. Nerve excitability studies recorded from APB following ulnar nerve stimulation were within previously established normative limits for the median nerve. In the index case, no innervation anomaly was visible on magnetic resonance imaging from the forearm to hand. CONCLUSIONS: Dual innervation of APB by the median and ulnar nerves consistent with RCA was demonstrated in all 3 family members without co-existent sensory anomalies. SIGNIFICANCE: These findings infer an hereditary basis for RCA, consistent with an autosomal dominant pattern of inheritance.     

Syringomyelia presenting as ulnar neuropathy at the elbow.

OBJECTIVES: Syringomyelia may present with confusing, unilateral patterns of segmental muscle involvement and dissociated sensory loss. The objective of this study was to report a patient with Chiari malformation type 1 (CM1) and syringomyelia who had an unusual presentation suggesting ulnar neuropathy at the elbow. RESULTS: A 24-year-old woman presented with clinical evidence of ulnar neuropathy at the elbow except that there was disproportionate abductor digiti mini (ADM) atrophy and weakness, equivocal ipsilateral abductor pollicis brevis weakness and hyporeflexia in both arms. Nerve conduction studies revealed marked amplitude reduction of the left ulnar ADM-compound muscle action potential (ADM-CMAP) with a normal first dorsal interosseous-CMAP amplitude, no focal slowing or conduction block, and a normal ulnar sensory response amplitude. Electromyography (EMG) showed multi-segmental, left C7-T1 fibrillations and chronic reinnervation changes. Magnetic resonance imaging (MRI) of the cervical spine demonstrated CM1 and syringomyelia. CONCLUSIONS: Syringomyelia may clinically mimic ulnar neuropathy at the elbow.     

Distribution of electrophysiological abnormality in Lambert-Eaton myasthenic syndrome

OBJECTIVE—Toassess the distribution of electrophysiological abnormality inLambert-Eaton myasthenic syndrome (LEMS) to identify the most sensitivemuscle to use in routine examination.
METHODS—Surfacerecorded compound muscle action potential (CMAP) amplitudes were madefrom abductor digiti minimi, abductor pollicis brevis, anconeus, bicepsbrachii, and trapezius in 10 patients with LEMS. The effect of3,4-diaminopyridine (3,4-DAP) was recorded in each muscle in ninepatients. CMAP amplitudes were measured at rest and immediately after10 seconds maximal voluntary contraction in each muscle. Values werecompared with results obtained from 12 healthy controls.
RESULTS—Resting CMAPamplitudes were reduced in at least one muscle in all patients comparedwith controls, most markedly in abductor digiti minimi and anconeus.The administration of 3,4-DAP resulted in significantly improvedresting CMAP amplitudes in trapezius only. After maximal voluntarymuscle contraction, characteristic increments in CMAP amplitude of over100% above resting values were seen in abductor digiti minimi andabductor pollicis brevis in seven patients, anconeus and biceps brachiiin five patients. No patient had this level of increment in trapezius.
CONCLUSION—Despitepredominantly proximal limb weakness seen clinically in patientswith LEMS, the most sensitive muscles for detecting characteristicelectrophysiological abnormalities of low resting CMAP amplitude andincrement of over 100% after 10 seconds maximal voluntarycontraction are abductor digiti minimi, abductor pollicis brevis, and anconeus.