运动神经元病162例的节段性运动神经传导测定分析

目的探讨运动神经元病(motor neuron d isease,MND)常规节段运动神经传导和位移技术检测的特点。方法对162例MND患者和60名健康对照进行常规节段运动神经传导测定,同时对部分神经采用位移技术测定,并进行分析比较。结果(1)健康人常规节段运动神经传导测定显示:近端与远端比较,波幅和面积下降程度均小于20%,时限增宽小于15%;(2)在MND患者,常规节段测定共有76个节段(5.57%)波幅下降超过20%,45个节段(3.30%)面积下降超过20%,76个节段(5.57%)时限延长超过15%。仅有4例(2.5%)患者4条神经的4个常规节段(0.29%)达到运动神经部分性传导阻滞标准,但采用位移技术测定时均未达到短节段传导阻滞的诊断标准。结论在大部分MND患者常规节段运动神经传导测定正常,在部分患者也可以出现“传导阻滞样”的电生理表现,但其发生率极低,进一步采用位移技术测定有助于鉴别。     

CMT1A型与遗传性压迫易感性周围神经病的神经电生理对比研究

目的比较腓骨肌萎缩症1A型(CMT1A)与遗传性压迫易感性周围神经病(HNPP)神经电生理差异,总结CMT1A和HNPP的神经电生理特点。方法以10例CMT1A患者和14例HNPP患者为对象,使用Viking Quest肌电图诱发电位仪测定神经传导速度等神经电生理指标并进行比较。结果 CMT1A组运动神经传导速度显著慢于HNPP组,波幅下降明显,末端潜伏期延长,CMT1A组与HNPP组在运动神经传导速度方面差异有统计学意义(P0.05)。CMT1A组正中神经、腓肠神经传导速度和波幅与HNPP组显著下降(P0.05),2组尺神经指V波幅、腓神经波幅、胫骨小头下波幅等差异无统计学意义(P0.05)。CMT1A组尺神经、腓总神经短节段电位未见传导阻滞,HNPP组在尺神经肘部、腓总神经腓骨小头处可见局部传导阻滞。结论 CMT1A和HNPP在神经电生理方面具有一定差异,神经电生理检测可作为辅助判断手段,提高两种疾病的区别准确性。     

正中神经和尺神经分段刺激在慢性炎性脱髓鞘性多发性神经病中的电生理研究

目的 探讨运动神经传导速度(MCV)、复合肌肉动作电位(CMAP)与肌力减退的关系和传导阻滞(CB)在慢性炎性脱髓鞘性多发性神经病(chronic inflammatory demyelinating polyradiculoneuritis,CIDP)中的表现特点.方法 30例CIDP患者在进行常规MCV、远端潜伏期(DML)、F波、感觉神经传导速度(SCV)、肌电图(EMG)测定的基础上,在正中神经采用由远到近的“腕-肘-腋-Erb's点”4点3段刺激,尺神经采用由远到近的“腕-肘下-肘上-腋-Erb's点”5点4段刺激,记录各段刺激后CMAP各参数及MCV的变化.结果 CMAP波幅衰减、面积衰减、时程增加以及MCV减慢与临床肌力减退无相关性,dCMAP波幅与上肢远端肌力呈正相关;患者中80.00％在正中神经、73.33％在尺神经发现了1个或多个节段的CB,且出现节段无明显选择性.结论 dCMAP波幅降低与CIDP患者肌力减退有相关性.在CIDP中CB出现率高,且较为弥散地在各节段中出现.     

慢性炎性脱髓鞘性多发神经根神经病和多灶性运动神经病临床对比分析

目的对比分析慢性炎性脱髓鞘性多发神经根神经病(CIDP)和多灶性运动神经病(MMN)的临床特征和肌电图特点,以期指导临床诊疗。方法收集2015-01—2020-01徐州医科大学附属医院收治的MMN患者8例,并与17例同期住院治疗的与之性别、年龄相匹配的CIDP患者临床表现、肌电图特点和脑脊液结果进行比较。结果 CIDP组患者症状多表现为对称性双下肢远端麻木或无力,多从远端向近端进展,而MMN组患者以不对称上肢肌无力为主,两者相比差异有统计学意义(P0.05)。CIDP组感觉障碍和腱反射减弱比例高于MMN组,而肌肉萎缩比例低于MMN组,差异有统计学意义(P0.05)。CIDP组脑神经麻痹比例较MMN组稍高,但两者相比差异无统计学意义(P0.05)。与正常对照组相比,CIDP组和MMN组均有复合肌肉动作电位(CMAP)波幅减低、运动神经传导速度(MNCV)减慢和F波潜伏期延长;CIDP组还表现为明显的远端潜伏期(DL)延长;MMN组虽无DL延长,但有明显的运动神经传导阻滞;CIDP组在MNCV减慢、DL延长、F波潜伏期延长、CMAP波幅减低方面的程度比MMN组重。与正常对照组相比,CIDP组感觉神经动作电位波幅(SNAP)明显减低、感觉神经传导速度(SNCV)明显减慢(P0.001),而MMN组与正常对照组相比差异则无统计学意义(P0.05)。结论 CIDP组为弥漫性对称性的运动神经感觉神经脱髓鞘,MMN组为仅累及运动神经的局灶性脱髓鞘改变,2组患者均有继发性轴索损害,而CIDP组较重。     

POEMS综合征神经传导异常分析

目的 阐明POEMS综合征的电生理特点.方法 对比分析22例POEMS综合征与22例慢性炎症性脱鞘性多发性神经根神经病(CIDP)患者的电生理资料.结果 POEMS组运动神经传导速度(MNCV)较CIDP组减低,但差异无统计学意义(P＞0.05);远端运动潜伏期(DML)明显减低,远端潜伏期指数(TLI)明显增高,差异均有统计学意义(P均＜0.05);POEMS组神经传导阻滞出现率较CIDP组低,差异有统计学意义(P＜0.05);POEMS组胫神经复合肌肉动作电位(CMAP)较CIDP组减低,差异有统计学意义(P＜0.05),而正中神经两组差异无统计学意义(P＞0.05);POEMS组下肢肌异常肌电出现率较上肢高,差异有统计学意义(P＜0.05).结论 POEMS综合征神经传导速度减慢主要在周围神经中间部分,传导阻滞出现率低,神经传导异常可能与上下肢体有关.     

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。     

远端潜伏期指数在POEMS综合征和慢性炎症性脱髓鞘性多发性神经根神经病鉴别诊断中的价值研究

目的探讨远端潜伏期指数(TLI)在鉴别POEMS综合征和慢性炎症性脱髓鞘性多发性神经根神经病(CIDP)中的应用价值。方法分析18例POEMS综合征(POEMS组)、58例CIDP患者(CIDP组)和30名正常者(对照组)的正中神经和尺神经运动传导参数,包括远端潜伏期、传导速度和TLI。结果 POEMS组与CIDP组正中神经和尺神经传导速度以及TLI存在差异。POEMS组TLI大于正常上限的比例在正中神经和尺神经分别为55.6%(10/18)和52.9%(9/17);CIDP组大于正常上限的比例分别为25.9%(15/58)和24.1%(13/58),小于正常下限的比例分别为22.4%(14/58)和20.7%(12/58),POEMS与CIDP组间差异有统计学意义(P0.05)。CIDP组TLI大于正常上限的患者多伴有传导阻滞或波形离散。结论 POEMS综合征和CIDP的髓鞘脱失各具特征。TLI与传导阻滞和波形离散等参数相结合有利于鉴别POEMS综合征和CIDP。     

低钾性周期性麻痹的神经电生理观察

目的：充分了解低钾性周期性麻痹患者神经传导的特点。方法：对比35例低钾性周期性麻痹患者于补钾治疗前后神经传导的远端潜伏期、波幅、传导速度、F波、H反射的变化。结果：10例发作期存在感觉神经传导速度减慢;31例发作期存在运动神经传导远端潜伏期延长,传导速度慢或波幅低,F波、H反射潜伏期正常或延长;补钾治疗至血钾正常后,神经传导完全恢复正常。结论：低钾性周期性麻痹可以出现感觉神经传导障碍,有感觉异常症状。     

尺神经复合肌肉动作电位改变在吉兰-巴雷综合征和慢性炎性脱髓鞘性周围神经病中的特点

目的：探讨节段和短段刺激尺神经后不同节段复合肌肉动作电位（CMAP）负波各参数变化及传导阻滞在吉兰-巴雷综合征（GBS）和慢性炎性脱髓鞘性周围神经病（CIDP）中的意义。方法：20例GBS和12例CIDP患者行尺神经5点分段刺激（腕、肘下、肘上、腋和Erb＇s点）和短段刺激，记录CMAP负波波幅、时程和面积的变化，分析各参数与临床肌力的相关性。结果：在GBS中，尺神经CMAP负波的时程、波幅和面积的变化在Erb’s点到腕部的各节段中差异很大；波幅与面积的衰减与临床肌力呈高度相关（r=-0.905和-0.907）；传导阻滞多见于近端和肘部，时程离散不明显。在CIDP中，各节段中的参数变化差异不大；远端波幅与临床肌力相关（r=0.586）；传导阻滞在各节段均可出现，常伴明显的时程延长。结论：GBS和CIDP中尺神经CMAP负波的波幅、面积和时程3个参数，可从电生理角度帮助我们认识脱髓鞘疾病的特点。     

慢性炎症性脱髓鞘性多发性神经病多节段神经电生理研究

目的分析慢性炎症性脱髓鞘性多发性神经病(CIDP)节段性神经电生理表现。方法收集2013年1月~2014年8月于吉林大学第一医院神经内科就诊的22例CIDP患者,行正中神经及尺神经多节段神经电生理检测,正中神经刺激点包括:腕、肘、腋、Erb’s点;尺神经刺激点包括:腕、肘下、肘上、腋、Erb’s点。分析各节段神经电生理改变。结果 22例患者电生理各节段均出现明显的脱髓鞘改变,正中神经各节段(腕以下、腕-肘、肘-腋、腋-Erb’s点)运动传导时间较正常值延长分别为:125%、70%、122%、134%;尺神经各节段(腕以下、腕-肘下、肘下-肘上、肘上-腋、腋-Erb’s点)运动传导时间较正常值延长分别为84%、97%、140%、146%、149%。正中神经各刺激点(肘、腋、Erb’s点)传导阻滞(CB)例数分别为:2、6、14;尺神经各刺激点(肘下、肘上、腋、Erb’s点)CB例数分别为:5、4、10、16。结论 CIDP存在明显脱髓鞘的电生理改变,但在周围神经近端各节段脱髓鞘程度较远端重,CB以近端腋点、Erb’s点明显,多节段神经电生理检测更有利于协助CIDP的诊断并判断神经损害的严重程度。     

Dispersion of compound muscle action potential in hereditary neuropathies and chronic inflammatory demyelinating polyneuropathy

Distal compound muscle action potential (DCMAP) dispersion, defined as a DCMAP duration > or = 9 ms, and proximal-distal (P-D) CMAP dispersion are considered useful in the electrodiagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP). Distal and P-D CMAP dispersion have not been fully studied in hereditary neuropathies, and it is not known whether these measures distinguish hereditary from acquired demyelination. We compared DCMAP duration and P-D CMAP dispersion in 91 genetically characterized hereditary neuropathies and 33 subjects with CIDP. DCMAP dispersion was more frequent in nerves affected by CIDP (41.5%) than in Charcot-Marie-Tooth disease (CMT)1A (24.4%), CMT1B (7.4%), hereditary neuropathy with liability to pressure palsies (HNPP) (10.5%), or CMTX (9.8%). P-D CMAP dispersion was more frequent in CIDP (27.7% of nerves) than in hereditary neuropathies (16.3%) when applying American Academy of Neurology (AAN) criteria; however, its frequency was similar in CIDP and the hereditary neuropathies using the more restrictive criteria of the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM). Although dispersion is more common in CIDP than in the hereditary neuropathies, DCMAP and P-D dispersion occur in at least one motor nerve in a significant proportion of hereditary neuropathies, and cannot be used in isolation to distinguish acquired from hereditary demyelination.     

Clinical and electrophysiologic features of HNPP patients with 17p11.2 deletion

OBJECTIVES: Although the diagnosis of hereditary neuropathy with liability to pressure palsies (HNPP) is important for correct prognostic evaluation and genetic counseling, the diagnosis is frequently missed or delayed. Our main aim on undertaking this study was to characterize the electrodiagnostic features of HNPP. MATERIAL AND METHODS: Clinical, electrophysiologic and molecular studies were performed on Korean HNPP patients with 17p11.2 deletion. The results of electrophysiologic studies were compared with those of Charcot-Marie-Tooth disease type 1 A (CMT1A) patients carrying 17p11.2 duplication. RESULTS: Eight HNPP (50 motor, 39 sensory nerves) and six CMT1A (28 motor, 16 sensory nerves) patients were included. Sensory nerve conduction was slow in 97% of HNPP nerves. Motor nerve conduction at common entrapment sites was also abnormally slow in 87.5%, whereas at non-entrapment sites conduction slowing was infrequent. Distal motor latency (DML) was prolonged in 80% of HNPP nerves, and terminal latency index (TLI) was significantly lower in HNPP than in normal controls and in CMT1A patients (P < 0.01). In contrast to CMT1A, where severity of nerve conduction slowing was not different among nerve groups, HNPP sensory nerve conduction was more slowed in the median and ulnar nerves than in the sural nerve (P < 0.01), and DML was more prolonged in the median nerve than in the other motor nerves (P < 0.01). TLIs were significantly lower in HNPP than in the normal control and CMT1A patients for the median and ulnar nerves (P < 0.01), and were also significantly reduced for the peroneal nerve (P < 0.05) compared with those of the normal controls. CONCLUSION: HNPP is characterized electrophysiologically by a generalized neuropathy, superimposed by focal entrapment neuropathies. The slowing of sensory conduction in nearly all nerves and the distal accentuation of motor conduction abnormalities are the main features of background polyneuropathy in HNPP. The distribution and severity of the background electrophysiologic abnormalities are closely related to the topography of common entrapment or compression sites, which suggests the possible pathogenetic role of subclinical pressure injury at these sites in the development of the distinct background polyneuropathy in HNPP.     

Can electrophysiology differentiate polyneuropathy with anti-MAG/SGPG antibodies from chronic inflammatory demyelinating polyneuropathy?

OBJECTIVES: Patients with polyneuropathy and antibodies to myelin-associated glycoprotein (MAG) and sulphated glucuronyl paragloboside (SGPG) differ from chronic inflammatory demyelinating polyneuropathy (CIDP) because of a slower, progressive course, symmetrical and predominantly sensory involvement of legs, predominantly distal slowing of motor conductions, and poorer response to therapy. We studied whether a wide set of electrophysiologic parameters may differentiate these two neuropathies. METHODS: We reviewed the electrophysiological studies of 10 patients with anti-MAG/SGPG antibodies and 22 with CIDP examining: (1) motor conduction velocity and distal compound muscle action potential amplitude; (2) conduction block (CB) and temporal dispersion; (3) distal motor latency and terminal latency index (TLI); (4) F wave and proximal conduction time; and (5) sensory conduction and occurrence of abnormal median with normal sural sensory potential. RESULTS: Anti-MAG/SGPG neuropathies showed: (1) more severe involvement of peroneal nerves; (2) more frequent disproportionate distal slowing of motor conductions (TLI< or =0.25) and absent sural potential, and (3) no CB. However 3/22 CIDP patients also had at least two nerves with TLI< or =0.25 and no CB. CONCLUSIONS: Electrophysiologic findings suggest in anti-MAG/SGPG neuropathy a length-dependent process with a likely centripetal evolution. A disproportionate slowing of conduction in distal segments of motor nerves suggests the diagnosis of anti-MAG/SGPG neuropathy, although it is not pathognomonic.     

Comparison of electrophysiological findings between CIDP and HMSN-1]

Chronic inflammatory demyelinating polyneuropathy (CIDP) and hereditary motor sensory neuropathy type 1 (HMSN-1) are representative myelinopathies. In order to differentiate changes in acquired and congenital demyelinating neuropathies, we studied electrophysiologically 9 patients with active phase of CIDP (36.0 +/- 17.6 years old; mean +/- SD) and 7 patients with genetically-proven HMSN-1 A (56.0 +/- 13.6 years old). Motor conduction studies demonstrated longitudinal uniformity in HMSN-1, contrariwise focal conduction block or conduction delay in CIDP. The mean median nerve conduction velocity in the forearm segment and the mean CMAP amplitude stimulated at the wrist were not different between CIDP and HMSN-1 group; 31.8 +/- 7.2 m/sec and 5.6 +/- 2.8 mV in CIDP, and 26.7 +/- 9.8 m/sec and 3.2 +/- 2.6 mV in HMSN-1, respectively. Upper extremity polyneuropathy index (PNI), a mean percentage of normal for 6 indices concerning to the velocity and latency over two nerves obtained by motor conduction studies, was equal and around 50% on the average in each group. Conduction blocks were presented in 7 patients with CIDP and only one patient with HMSN-1. No sensory nerve action potential was recorded in 6 out of 9 patients with CIDP, and in 6 out of 7 patients with HMSN-1. Intrafascicular neurography of the median nerve, stimulated at the wrist and recorded from intrafascicularly inserted microelectrode at the elbow, revealed irregular multiphasic waves which signify severe temporal dispersion. Maximum conduction velocity was similarly reduced to 48 m/sec in CIDP and 44 m/sec in HMSN-1 on the average, but in one patient with HMSN-1 it was maintained to 63 m/sec with conspicuous temporal dispersion of the waveform. Amplitude of the compound nerve action potential (CNAP) decreased more (p < 0.01) in HMSN-1 (26 +/- 11 micro V) than in CIDP (72 +/- 25 micro V). Temporal dispersion of CNAP was prominent in HMSN-1 than in CIDP. In conclusion, electrophysiological changes were more homogeneous in the longitudinal distribution but more heterogeneous in the cross-sectional distribution in HMSN-1 than in CIDP.     

Electrophysiological testing in chronic inflammatory demyelinating polyneuropathy patients treated with subcutaneous immunoglobulin: The Polyneuropathy And Treatment with Hizentra (PATH) study

ObjectiveTo assess electrophysiology parameters that can reflect patients' clinical status and show changes in nerve function with treatment, in a study of subcutaneous immunoglobulin in chronic inflammatory demyelinating polyneuropathy.MethodsNerve conduction studies (latency, conduction velocity, conduction block and compound muscle action potential [CMAP] on upper limb median, ulnar, and lower limb peroneal motor nerves) were conducted in the placebo-controlled PATH (Polyneuropathy And Treatment with Hizentra) study of two doses of maintenance subcutaneous immunoglobulin (SCIG) IgPro20 in CIDP.ResultsAveraged proximal latency substantially increased with placebo (+1.1 ms) indicating electrophysiologic deterioration but remained stable with IgPro20 (0.2 g/kg bodyweight [bw]: +0.1 ms; 0.4 g/kg bw: −0.1 ms). Distal latencies were also more prolonged with placebo versus IgPro20. Averaged motor nerve conduction velocity substantially decreased with placebo (−1.6 m/s) versus increasing in both IgPro20 groups (+0.2 m/s and +1.0 m/s, respectively). Conduction block and CMAP amplitudes did not change substantially.ConclusionThese findings support the effectiveness of maintenance IgPro20, as nerve function changed in the direction of increasing nerve dysfunction with placebo but remained stable with ongoing IgPro20 therapy.SignificanceElectrophysiology testing can support assessment of clinical status in CIDP to determine treatment efficacy.     

COLD PRESSOR TEST DEMONSTRATES RESIDUAL SYMPATHETIC CARDIOVASCULAR ACTIVATION IN FAMILIAL DYSAUTONOMIA

Objectives: Patients with polyneuropathy and antibodies to myelin-associated glycoprotein (MAG) and sulphated glucuronyl paragloboside (SGPG) differ from chronic inflammatory demyelinating polyneuropathy (CIDP) because of a slower, progressive course, symmetrical and predominantly sensory involvement of legs, predominantly distal slowing of motor conductions, and poorer response to therapy. We studied whether a wide set of electrophysiologic parameters may differentiate these two neuropathies. Methods: We reviewed the electrophysiological studies of 10 patients with anti-MAG/SGPG antibodies and 22 with CIDP examining: (1) motor conduction velocity and distal compound muscle action potential amplitude; (2) conduction block (CB) and temporal dispersion; (3) distal motor latency and terminal latency index (TLI); (4) F wave and proximal conduction time; and (5) sensory conduction and occurrence of abnormal median with normal sural sensory potential. Results: Anti-MAG/SGPG neuropathies showed: (1) more severe involvement of peroneal nerves; (2) more frequent disproportionate distal slowing of motor conductions (TLI less than or equal to 0.25) and absent sural potential; and (3) no CB. However 3/22 CIDP patients also had at least two nerves with TLI 0.25 and no CB. Conclusions: Electrophysiologic findings suggest in anti-MAG/SGPG neuropathy a length-dependent process with a likely centripetal evolution. A disproportionate slowing of conduction in distal segments of motor nerves suggests the diagnosis of anti-MAG/SGPG neuropathy, although it is not pathognomonic.     

Electrophysiological features of chronic inflammatory demyelinating polyradiculoneuropathy associated with IgG4 antibodies targeting neurofascin 155 or contactin 1 glycoproteins

ObjectiveChronic inflammatory demyelinating polyradiculoneuropathies (CIDP) with antibodies against neurofascin 155 (Nfasc155) or contactin-1 (CNTN1) have distinctive clinical features. Knowledge on their electrophysiological characteristics is still scarce. In this study, we are investigating whether these patients have specific electrophysiological characteristics.MethodsThe electrophysiological data from 13 patients with anti-Nfasc155 IgG4 antibodies, 9 with anti-CNTN1 IgG4 antibodies were compared with those of 40 consecutive CIDP patients without antibodies.ResultsAll the patients with antibodies against Nfasc155 or CNTN1 fulfilled the EFNS/PNS electrodiagnostic criteria for definite CIDP. There was no electrophysiological difference between patients with anti-CNTN1 and anti-Nfasc155 antibodies. Nerve conduction abnormalities were heterogeneously distributed along nerves trunks and roots. They were more pronounced than in CIDP without antibodies. Motor conduction velocity on median nerve <24 m/s or motor velocity on ulnar nerve <26 m/s or motor distal latency on ulnar nerve >7.4 ms were predictive of positive antibodies against the node of Ranvier with a sensitivity of 59% and a specificity of 93%.ConclusionsMarked conduction abnormalities may suggest the presence of positive antibodies against the node of Ranvier.SignificanceAnti-Nfasc155 and anti-CNTN1 antibodies target the the paranodal axo-glial domain but are associated with nerve conduction abnormalities mimicking a “demyelinating” neuropathy.     

Proximal nerve conduction studies in chronic inflammatory demyelinating polyneuropathy.

OBJECTIVE: The purpose of this study was to evaluate the sensitivity and specificity of proximal upper limb motor nerve conduction study abnormalities in chronic inflammatory demyelinating polyneuropathy (CIDP), using standard percutaneous stimulations up to Erb's point. METHODS: Electrophysiologic data relating to proximal conductions of median and ulnar nerves of 22 patients with CIDP were retrospectively analyzed and compared to those of 22 controls with sensory neuropathy. Distal conduction results were also reviewed. RESULTS: The findings demonstrate independent high sensitivity of abnormal upper limb proximal nerve conduction studies in CIDP. Demonstration of conduction block of >20% and temporal dispersion of >15% had low specificity. However, conduction block was highly specific with cut-off values of >30% at axilla and >50% at Erb's point. Specificity was considerably improved using a cut-off value of >30% at proximal levels for temporal dispersion. Diagnostic sensitivity improved significantly with proximal studies with the criteria used in this population. No adverse effects had occurred as result of proximal stimulations. CONCLUSIONS: Proximal studies are safe, sensitive and reliable procedures in cases of suspected CIDP. Their use appears justified although adequate cut-off values are desirable to optimize their specificity. SIGNIFICANCE: This study indicates that proximal upper limb nerve conductions are appropriate in investigating suspected CIDP, as detailed in recently established electrophysiologic criteria. However, specificity is largely dependent on cut-off values for conduction block and temporal dispersion.     

A Case of Cauda Equina Syndrome in Early-Onset Chronic Inflammatory Demyelinating Polyneuropathy Clinically Similar to Charcot-Marie-Tooth Disease Type 1

To present a case of cauda equina syndrome (CES) caused by chronic inflammatory demyelinating polyneuropathy (CIDP) which seemed clinically similar to Charcot-Marie-Tooth disease type1 (CMT1). CIDP is an immune-mediated polyneuropathy, either progressive or relapsing-remitting. It is a non-hereditary disorder characterized by symmetrical motor and sensory deficits. Rarely, spinal nerve roots can be involved, leading to CES by hypertrophic cauda equina. A 34-year-old man presented with low back pain, radicular pain, bilateral lower-extremity weakness, urinary incontinence, and constipation. He had had musculoskeletal deformities, such as hammertoes and pes cavus, since age 10. Lumbar spine magnetic resonance imaging showed diffuse thickening of the cauda equina. Electrophysiological testing showed increased distal latency, conduction blocks, temporal dispersion, and severe nerve conduction velocity slowing (3 m/s). We were not able to find genetic mutations at the PMP 22, MPZ, PRX, and EGR2 genes. The pathologic findings of the sural nerve biopsy revealed thinly myelinated nerve fibers with Schwann cells proliferation. We performed a decompressive laminectomy, intravenous IgG (IV-IgG) and oral steroid. At 1 week after surgery, most of his symptoms showed marked improvements except foot deformities. There was no relapse or aggravation of disease for 3 years. We diagnosed the case as an early-onset CIDP with cauda equine syndrome, whose initial clinical findings were similar to those of CMT1, and successfully managed with decompressive laminectomy, IV-IgG and oral steroid.