一氧化二氮滥用所致周围神经病的神经电生理特点

目的探讨一氧化二氮(N_2O;俗称"笑气")滥用导致的中毒性周围神经病的神经电生理特点。方法回顾性分析2015-07—2018-03期间中日友好医院神经科就诊的15例N_2O滥用导致的周围神经病患者的临床表现,实验室检查,头、颈、胸椎MRI及神经传导检查情况。对照组44例(肢带型肌营养不良23例、脂质沉积病5例、低钾性周期性麻痹8例、视神经脊髓炎8例)行神经传导检查,所检神经的神经传导速度和动作电位波幅均在正常范围,并排除周围神经病变。其中作为正中神经对照23例(29条)、尺神经对照20例(22条)、腓神经对照25例(25条)、胫神经对照25例(32条)。结果 15例患者均临床表现为肢体无力和麻木,下肢肌力下降及感觉损害程度均较上肢为著。其中8例患者MRI显示颈段或颈胸段脊髓后索倒"V"型长T2病灶。与对照组比较,病变组正中神经、尺神经、腓神经、胫神经运动传导速度(MCV)平均值分别下降14.1%、11.1%、18.3%、21.5%;远端复合肌肉动作电位(CMAP)波幅分别下降29.6%、19.5%、63.6%、82.5%(均P0.05);与对照组比较,病变组上、下肢感觉传导速度(SCV)减慢、下肢感觉神经动作电位(SNAP)波幅下降(均P0.05)。7条腓神经和3条胫神经复合肌肉动作电位波幅未测出。2例患者存在运动神经传导阻滞。结论 N_2O滥用可导致神经系统损害,以颈胸段脊髓后索病变和周围神经病变多见。周围神经损害可同时累及运动纤维及感觉纤维,包括轴索变性和脱髓鞘,下肢损害程度较上肢为著。运动轴索较感觉轴索更易受损。受累神经可出现运动传导阻滞。     

糖尿病周围神经病电生理特点及与血糖水平的关系

目的研究糖尿病周围神经病的神经电生理特点以及与血糖水平的关系。方法分析2013年3月~2014年3月于本院神经内科住院的108例糖尿病周围神经病患者,测定其正中、尺、胫、腓总神经的运动传导速度(MCV)和复合肌肉动作电位波幅(CMAP),以及正中、尺、腓肠神经、腓浅神经的感觉传导速度(SCV)和感觉神经动作电位波幅(SNAP),比较上、下肢和运动、感觉神经异常情况,分析糖化血红蛋白(HbA1C)、餐后2 h血糖对神经传导速度(NCV)的影响。结果糖尿病患者下肢运动神经病变重于上肢,且差异明显(P<0.05)。感觉神经损害重于运动神经,且差异明显(P     

感觉性共济失调型格林-巴利综合征3例临床与电生理

目的 :了解感觉性共济失调型格林 -巴利综合征的临床与电生理特点。方法 :观察临床及电生理表现 ,测定了正中神经、尺神经、腓神经末端潜伏期 ,运动神经传导速度 ,运动诱发波幅 ;感觉神经传导速度 ,感觉诱发波幅。结果 :临床表现 :1.急性起病。 2 .病前有感染史。 3.感觉减退或消失、感觉性共济失调。 4.脑脊液蛋白细胞分离。电生理检查 :1.感觉神经传导速度减慢。 2 .感觉神经诱发波幅降低或缺失。结论 :临床及电生理特点可作为感觉性共济失调型格林 -巴利综合征的诊断标准之一。     

糖尿病周围神经病病情分级与电生理的相关性

目的探讨糖尿病周围神经病病情分级与电生理的相关性。方法依据糖尿病性周围神经病的诊断标准确定入选对象;依据糖尿病周围神经病病情分级对入选对象进行临床分级;应用丹麦产DANTEC CANTATA型肌电图仪,进行运动神经和感觉神经传导功能检查。结果腓肠神经、正中神经诱发感觉动作电位波幅(SNAP)和腓总神经复合肌肉动作电位波幅(CMAP)随病情分级的升高而明显减低(P<0.05);腓肠神经、正中神经感觉传导速度(SCV)和腓总神经、正中神经运动传导速度(MCV)3级与1、2两级比较显著减慢(P<0.05)。结论神经电生理改变,尤其感觉神经电生理改变,易此作为糖尿病周围神经病情程度评定的指标。     

腕管综合征的肌电图与临床分析

目的探讨肌电图检测在腕管综合征诊断中的价值。方法对30例临床诊断为腕管综合征的患者行神经传导速度和针极肌电图检查。结果 30例患者中,8条正中神经感觉传导速度测定未引出动作电位,其余均有感觉传导潜伏期延长、波幅降低和(或)感觉神经传导速度减慢。28条伴正中神经运动末端潜伏期延长和(或)波幅降低。26块拇短展肌可见失神经电位和(或)运动单位电位平均时限延长。结论肌电图检查对腕管综合征有重要诊断及鉴别诊断价值。     

亚急性自主神经和感觉神经节病临床与病理

目的探讨亚急性自主神经和感觉神经节病的病因、病理及临床特点。方法收集并分析7例亚急性自主神经和感觉神经节病患者的临床资料、神经电生理学、神经影像学和病理学检查结果。结果 7例患者主要临床表现包括四肢深感觉障碍、感觉性共济失调、手袜套样浅感觉减退或痛觉过敏、假性手足徐动征、神经痛。自主神经功能障碍包括Adie瞳孔、无汗、体位性低血压、假性肠梗阻。颈部MRI检查显示脊髓后索长T2信号。体感诱发电位检查显示外周传导异常,脊髓至皮质传导障碍。神经传导检查显示感觉神经动作电位波幅降低或消失。神经活检结果显示有髓和无髓神经均严重丢失,轴索变性。结论亚急性自主神经和感觉神经节病为累及后根神经节、交感神经节的免疫介导性疾病,具有独特的临床表现,预后不良。     

重度骨质疏松症患者周围神经传导功能的定量分析

目的定量分析重度骨质疏松症患者周围神经传导功能的变化与特点。方法检测重度骨质疏松症患者四肢周围神经的传导功能,并与正常值进行定量对比分析。结果所有患者的检测结果均提示四肢多发性周围神经损害或神经根损害,即运动末端潜伏期延长,运动传导速度和感觉传导速度减慢,复合肌肉运动动作电位和感觉神经动作电位波幅降低,F波潜伏期延长且出现率下降,H反射消失等。结论重度骨质疏松症患者均存在不同程度的周围神经病变,其周围神经存在明显的脱髓鞘改变,也存在明确的轴索变性,而且具有四肢神经远近段同时受累,近段受累甚于远段,下肢受累甚于上肢等特点。     

糖尿病性多发性神经病神经传导异常与临床评分相关性分析

目的分析糖尿病性多发性神经病患者神经电生理改变及其与临床评分的相关性。方法回顾性分析36例中日友好医院内分泌科住院的2型糖尿病性多发性神经病患者神经电生理异常特点并统计分析其与密歇根量表评分之间的相关性。结果本研究入组的36例糖尿病性多发性神经病患者中,周围神经传导检查下肢重于上肢(100%vs 83. 3%),感觉传导异常比运动传导异常多见(100%vs 83. 3%),以下肢感觉传导感觉神经动作电位(SNAP)波幅下降最为常见(36/36,100%);运动神经传导异常则以运动传导速度(MCV)减慢相对常见(30/36,83. 3%),复合肌肉动作电位(CMAP)波幅下降及运动传导远端潜伏期(DML)延长相对少见(11. 1%,5. 6%);神经损害电生理评分与密歇根量表评分之间具有显著相关(P 0. 01)。结论感觉传导波幅下降及轻度的运动传导速度减慢为常见的糖尿病性多发性神经病电生理改变特点;神经传导异常评分与密歇根量表评分具有显著相关,可用于疾病严重程度随访。     

神经电生理检测对多灶性运动神经病诊断价值的初步研究

目的 探讨神经电生理检查在多灶性运动神经病(MMN)中的诊断价值。方法对16例MMN患者及16名健康对照进行运动神经传导速度和感觉神经传导速度检查，记录刺激引出的复合肌肉动作电位的波幅、波宽、面积、位相和时限，进行对比分析，判定是否有运动神经传导阻滞(CB)或暂时性离散(TD)，并有选择性地进行常规肌电图检查。结果16例患者均可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CD。其中13例双上肢正中神经，尺神经出现CB，3例以正中神经、尺神经的远端出现CB首发，随病情进展出现下肢腓深神经CB。仅有2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神经源性损害。结论MMN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的主要神经电生理表现。     

一氧化二氮滥用致周围神经病患者的神经电生理特点

目的探讨一氧化二氮(N_2O)滥用致中毒性周围神经病患者的神经电生理特点。方法回顾性分析10例N_2O滥用导致的周围神经病患者的神经电生理(神经传导速度测定、针极肌电图检查、F波、H波)特点。结果与正常参考值相比,上、下肢近端所检运动纤维及上、下肢远端所检运动纤维异常率分别为0、40%、37.5%、90%,异常运动纤维远端潜伏期(MLAT)分别延长0、36.1%、17.8%、37.2%,复合肌肉动作电位(CMAP)分别下降0、88.6%、31.4%、64.5%;上、下肢远端运动纤维运动传导速度测定(MCV)分别延长10.4%、16.4%;上、下肢远端感觉纤维异常率分别为7.5%、80%;上、下肢异常感觉纤维波幅分别下降7.5%、79.4%,感觉传导速度测定分别延长0、8.6%;上、下肢F波异常率分别为0、50%;双下肢H波异常率100%;双上肢针极肌电图异常率30%,双下肢针极肌电图异常率90%(P<0.05)。结论N2O滥用致周围神经损害可同时累及运动纤维与感觉纤维,以轴索损害为主,下肢受累为著,远端受累较近端受累为重,具有长度依赖性及对称性。针极肌电图可早期出现中-多量失神经电位,大力收缩募集减少,伴或不伴运动单位时限增宽。神经电图提示F波出现率减少或H波波幅降低,伴或不伴潜伏期延长。     

Superiority of intrafascicular neurography over conventional nerve conduction studies in evaluating axonal degeneration]

We investigated conventional motor and sensory nerve conduction studies (MCS & SCS) with regard to the sensitivity in detecting axonopathies. Twelve patients with axonal type of polyneuropathy, 2 vincristin neuropathy and 10 cisplatin neuropathy, were examined by MCS & SCS. Their data were compared with those by intrafascicular microneurography (MNG) of the median nerve. Nerve conduction velocities were within normal limits or slightly reduced to 87-99% of the normal. Amplitude of compound muscle action potential (CMAP) by MCS decreased to 4 or 5 mV in vincristin neuropathy, though cisplatin neuropathy presented normal amplitude. Amplitude of sensory nerve action potential (SNAP) by SCS was undetected in one median nerve and in three sural nerves. While, compound nerve action potential (CNAP) by MNG was all recorded, and presented the amplitude value of below 150 microV in seven patients. The waveform was normal or mild neuropathic pattern. No patients presented normal CNAP amplitude and reduced SNAP amplitude. But there were three patients who had normal SNAP amplitude and reduced CNAP amplitude. In SCS we could recognize abnormal only after CNAP amplitude by MNG dropped to below 100 microV. Cisplatin neuropathy demonstrates reduction of CNAP or SNAP amplitude, and vincristin neuropathy further presents reduction of CMAP amplitude. Evaluation of axonopathy is best achieved by nerve action potential amplitude. Conventional surface electrode methods are available for this purpose, but MNG is more sensitive and is capable of quantitative analysis even in severely damaged nerves.     

Increased sensory nerve action potential amplitudes after plasma exchanges in a patient with acute sensory neuropathy]

Acute sensory neuropathy (ASN) is characterized by rapidly progressive sensory ataxia and areflexia without motor weakness. The disease has been thought to be due to dorsal root ganglionitis which leads to secondary sensory nerve axonal degeneration. In contrast, we here report a patient with ASN, in whom results of nerve conduction study pointed to a direct involvement of the sensory nerve axons. A 33-year-old man was admitted to our hospital because of a few days history of progressive numbness in his extremities and unsteadiness of gait. The results of motor nerve conduction studies were normal. Amplitudes of sensory nerve action potentials (SNAPs) decreased within a few days after admission, whereas sensory nerve conduction velocities were preserved. Cerebrospinal fluid examination showed an elevated protein level without pleocytosis. He was diagnosed as having ASN, and was treated with four times of plasma exchange which rapidly restored SNAP amplitudes to normal. However, a few days after the plasma exchanges, SNAP amplitudes decreased again. Second series of plasma exchanges one month after admission transiently increased SNAP amplitudes again but not to normal range. These electrophysiologic changes were not associated with clinical improvement. A sural nerve biopsy one month after admission revealed axonal degeneration. These findings suggest that our patient's sensory impairment is caused by reversible sensory axonopathy due to humoral factors that can be removed by plasma exchange, as well as acute irreversible ganglionopathy which may lead to secondary axonal degeneration as shown by sural nerve biopsy.     

Nerve conduction and biopsy correlation in over 100 consecutive patients with suspected polyneuropathy

Neuropathy was classified physiologically and histologically as normal, axonal, demyelinative, or indeterminate using specific motor nerve conduction (NC) and sural sensory nerve biopsy (NB) criteria. Physiological and histological diagnoses were concordant in 63%, and minimally discordant in 14% of patients. The most important discordant patients were 6 with demyelinative neuropathy, 4 by NC, of which 2 were pure motor syndromes, and 2 by NB, both predominantly sensory syndromes. In the 55 patients with predominant axonal degeneration on biopsy, the extent of NC slowing was determined. As compound motor and sensory nerve action potential (CMAP and SNAP) amplitude declined, distal motor latency increased, whereas motor and sensory conduction velocity (CV) did not. Minimum F response latency increased as motor CV decreased, more in lower than upper extremity nerves. We conclude that: (1) except for sensory neuropathy, routine motor NC studies generally suffice in identifying demyelinative neuropathy; (2) NC slowing in axonal neuropathy is usually slight but may result in significantly prolonged distal motor latencies when CMAP amplitude is very low, and prolonged F wave latency when motor CV is slightly low; and (3) The physiologic criteria employed in this study rarely misclassifies neuropathy as demyelinative in patients with predominant axon loss on biopsy. © 1994 John Wiley & Sons, Inc.     

Pregnancies and deliveries in patients with Charcot-Marie-Tooth disease

The authors performed nerve conduction studies in nine PARK2 and eight idiopathic Parkinson disease patients and found a significant reduction of sural sensory nerve action potential (SNAP) amplitude in eight PARK2 patients who mostly remained asymptomatic. These data suggest that sensory axonal neuropathy may be a common clinical feature of PARK2 and a reduced amplitude of sural SNAP could be a diagnostic indicator of PARK2.     

Neuropathy caused by cisplatin. Clinical, electrophysiological and morphological study

Seven patients with cancer presented a sensory peripheral neuropathy induced by cisplatinum. This drug was used alone in 1 case and, in 6 other cases it was associated with drugs without any toxicity for the peripheral nervous system. Every patient had an electromyogram and motor and sensory nerve conduction studies. A sural nerve biopsy was performed in 5 cases for light and electron microscopic studies as well as for teasing and quantitative studies. Electromyograms and motor nerve conductions were normal. Sensory nerve conductions were slowed with very low amplitude sensory action potentials. Such results suggested axonal changes. Nerve biopsies showed typical axonopathic changes with secondary demyelination. Morphometric studies confirmed a loss of myelinated fibers affecting the large fibers in all cases, according to the slowed sensory nerve conductions. This study confirmed that the cisplatinum-induced neuropathy is a new form of toxic distal axonal neuropathy. The hypothesis of a primary demyelination of peripheral nerves, which has been proposed, could not be retained.     

Do patients having a decrease in SNAP amplitude during the course of MMN present with a different condition?

A decrease in sensory nerve action potentials (SNAP) amplitude has been recently reported in some patients during the course of multifocal motor neuropathy with conduction blocks (MMNCB). It is not known if those patients have different clinical expression and disability when compared with typical MMNCB. Clinical, biological and electrophysiological assessments were performed in 15 patients fitting the diagnosis criteria of MMNCB, including normal SNAP amplitude at initial examination. Patients presenting with nerve entrapment or associated disease causative of sensory neuropathy were excluded. Median time of follow-up was 3 years (1–17 years). At the last examination, four patients had at least one SNAP amplitude below 50% of normal value. None had clinically objective sensory loss. Clinical and electrophysiological data obtained at the last examination were compared between patients with normal SNAP amplitude and patients with decreased SNAP amplitude. No difference between both population in term of age, sex, disease duration, anti-GM1 antibody titers, CSF data and number of conduction blocks was noted. In contrast, patients with decreased SNAP amplitude had worse overall neuropathy limitation scale (ONLS) scores (7 vs. 2; p = 0.02), a higher number of affected nerves (12.5 vs. 4; p = 0.018), a higher number of affected limb regions (6 vs. 2; p = 0.019) and lower median CMAP amplitude (2 mV vs. 6.5 mV; p = 0.04). They were all dependent on higher doses of IVIg (1.4 g/(kg 4 weeks vs. 0.6; p = 0.018). A reduction in SNAP amplitude during the course of MMNCB is associated with a more severe disease and a more prominent axonal loss. This result needs to be confirmed in a larger cohort.     

Sensory nerve conduction in demyelinating and axonal Guillain-Barré syndromes

Guillain-Barré syndrome is divided into acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN) based on motor nerve conduction studies. We investigated whether sensory nerve conduction studies contribute to the electrodiagnosis of AIDP and AMAN. In consecutive 59 patients with AIDP (n = 26) or AMAN (n = 33), results of sensory nerve conduction studies in the median, ulnar and sural nerves were reviewed. Sensory nerve conduction abnormalities were found for 85% of AIDP patients and for only 6% of AMAN patients. In AIDP patients, the abnormalities were present in 85% of patients in the median nerves, 85% in the ulnar nerves and 38% in the sural nerves. AMAN is very rarely associated with sensory nerve involvement. Abnormal sensory nerve conduction is supportive of AIDP and is more frequently found for the median and ulnar nerves than sural nerves.     

Sensory nerve abnormalities in brachial plexopathy.

Sensory nerve action potential (SNAP) amplitude should be abnormal in brachial plexopathies (BP) which cause axonal degeneration in distal segments. Fifty-six patients with BP were identified. In diffuse BP, 22/25 (88%) showed low amplitude or absent median or ulnar SNAP. Three of 5 patients with upper trunk BP had low amplitude or absent SNAP (1 median, 1 radial, 1 lateral antebrachial cutaneous). Seventy-five percent of patients with lower trunk/medial cord BP had low amplitude or absent SNAP (8/24 median, 18/24 ulnar). Overall, 82.5% of patients had low amplitude or absent SNAP when a sensory nerve in the distribution of signs was studied. Testing multiple sensory nerves to include symptomatic regions enhances the diagnostic yield of SNAP in BP.     

Electrophysiological sensory demyelination in typical chronic inflammatory demyelinating polyneuropathy

Background: The presence of electrophysiological demyelination of sensory nerves is not routinely assessed in the evaluation of suspected chronic inflammatory demyelinating polyneuropathy (CIDP). Whether this can be useful is unknown. Methods: We compared, using surface recording techniques, in 19 patients with typical CIDP and 26 controls with distal large fibre sensory axonal neuropathy, the forearm median sensory conductions, sensory nerve action potential (SNAP) amplitudes and durations and sensory nerve conduction velocities (SNCVs) of median, radial and sural nerves. Results: Median nerve sensory conduction block (SCB) across the forearm was greater in CIDP patients than in controls (P = 0.005). SNAP durations were longer in CIDP patients for median (P = 0.001) and sural nerves (P = 0.004). Receiver operating characteristic (ROC) curves provided sensitive (>40%) and specific (>95%) cut‐offs for median nerve SCB as well as median and sural SNAP durations. SNCVs were significantly slower for median and sural nerves in CIDP patients, but ROC curves did not demonstrate cut‐offs with useful sensitivities/specificities. Median SCB or prolonged median SNAP duration or prolonged sural SNAP duration offered a sensitivity of 73.7% for CIDP and specificity of 96.2%. Used as additional parameters, they improved diagnostic sensitivity of the American Academy of Neurology (AAN) criteria for CIDP of 1991, from 42.1% to 78.9% in this population, with preserved specificity of 100%. Discussion: Sensory electrophysiological demyelination is present and may be diagnostically useful in typical CIDP. SCB detection and SNAP duration prolongation appear to represent more useful markers of demyelination than SNCV reduction.     

Peripheral neuropathy associated with; plasma cell dyscrasia: a clinical and electrophysiological follow-up study

Thirteen patients with polyneuropathy associated with plasma cell dyscrasia had serial electrophysiological studies. Five patients with monoclonal IgG had motor and/or sensory symptoms of which 4 correlated with slow motor and sensory nerve conduction. The 4 patients with monoclonal IgM reactive with myelin-associated glycoprotein (MAG), had predominantly motor symptoms, demyelination in the nerve biopsy and slow motor and sensory nerve conduction. Four patients with monoclonal IgM without anti-MAG activity had mainly sensory symptoms, axonal neuropathy on nerve pathology and slow or absent sensory nerve conduction. After treatment with plasmapheresis and chemotherapy 9 patients improved clinically and 4 were unchanged. Criteria for electrophysiologic improvement were presence of sensory or motor responses that were absent before treatment, conduction velocity increased by more than 10 m/s and increase of amplitude by more than 100%. Electrophysiological studies showed improvement in 7, were unchanged in 4, and worse in 2. Sensory velocities in ulnar and sural nerves were significantly improved following treatment (P less than 0.002) and the same trend was noted for the sensory velocity in the median nerve (P less than 0.19). We conclude that nerve conduction studies in combination with clinical examinations are useful in documenting the effects of treatment in these neuropathies.