Somatosensory evoked potential in neurosyphilis

Since the development of effective antibiotic therapy, the occurrence of neurosyphilis has become less frequent. The number of syphilitic patients is gradually increasing as a complication in acquired immunodeficiency syndrome, but the diagnosis of neurosyphilis sometimes is difficult. We describe six patients with neurosyphilis and an analysis of their tibial nerve somatosensory evoked potentials. Four of them, including two with no tabes dorsalis symptoms, had delayed P15-N21 or the absence of N21. These abnormalities were ameliorated by treatment for syphilis. Analysis of tibial nerve SEPs provides a useful tool for the diagnosis of neurosyphilis and the evaluation of the extent to which neurosyphilis has progressed. Received: 20 December 2001, Received in revised form: 15 March 2002, Accepted: 18 March 2002     

Somatosensory evoked potentials in the evaluation of patients with stocking/glove paresthesias

We studied 10 patients referred for suspicion of peripheral neuropathy. They all complained of paresthesias with a stocking distribution. As EMG, motor and sensory nerve conduction studies failed to confirm the clinical diagnosis, we studied somatosensory evoked potentials (SEP) following median and tibial nerve stimulation. The SEP findings were compared with controls and 10 spastic paraplegias. The evoked potential study revealed prolonged latencies of cortical potentials after tibial nerve stimulation in all the patients with paresthesias and were considered evidence of myelopathy.     

Electrophysiological analysis of motor control in patients with vascular hemichorea

An AMG analysis of motor control was performed in 4 patients with unilateral choreic movements of sudden onset, 3 of whom presented CT scan evidence of lacunar infarcts involving the contralateral striatum. The choreic dyskinesias were correlated with EMG bursts of variable duration occurring with a random order of activation. Ballistic elbow flexion movements were performed with a normal triphasic EMG pattern, but both size and duration of the first agonist burst were increased on the affected side. Abnormalities of cerebral somatosensory evoked responses were observed in 3 patients on stimulation of the side with choreic movements.

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Sommario é stato effecttuato uno studio elettrofisiologico del controllo motorio in 4 pazienti con movimenti coreici unilaterali ad esordio acuto, 3 dei quali presentavano alla TC cerebrale infarti lacunari interessanti lo striato controlaterale. Le discinesie erano correlate a scariche EMG di durata variabile con ordine coreico di attivazione casuale. I movimenti ballistici di flessione del gomito erano caratterizzati da un normale ≪pattern≫ trifasico, ma la durata e l'ampiezza della prima scarica del muscolo agonista erano aumentate. In 3 pazienti erano presenti alterazioni dei potenziali somestesici evocati da stimolazione del lato con movimenti coreici.

     

Electrophysiological studies of myoclonic jerks provoked by photic stimulation

A patient with a type of myoclonus produced by somatosensory and photic stimuli was studied electrophysiologically. Jerk-locked averaging showed cortical spikes in association with the spontaneous myoclonus. High amplitude somatosensory evoked potentials and high amplitude visual evoked potentials were observed. Somatosensory and photic stimuli produced 2 or 3 successive electromyographic (EMG) discharges. The time interval from the onset of the preceding EMG discharge to that of the following EMG discharge produced by photic stimulation corresponded to the latency of a long-loop reflex. It also corresponded to the time interval from the onset of the preceding EMG discharge to that of the following EMG discharge produced by somatosensory stimulation. Not only somatosensory but also photic stimuli might excite the loop of a long-loop reflex and cause myoclonic jerks.     

Subclinical lithium neurotoxicity: correlation of neural conduction abnormalities and serum lithium level in manic-depressive patients with lithium treatment

Nerve conduction velocities (NCVs) and multimodality evoked potentials were studies in 28 manic-depressive patients under lithium prophylaxis with serum lithium levels between 0.320 and 0.980 mEq/L. Slowing of motor and sensory NCVs and prolonged central neural conduction times obtained from somatosensory and brainstem auditory evoked potentials were found to correlate with serum lithium levels. Lithium-induced changes in cell membrane conductivity and in the synaptic transmission are considered responsible for the neurotoxic effects of lithium.     

多种诱发电位用于糖尿病神经系统并发症的研究

选择糖尿病患者１０７例进行ＭＥＰ、ＳＥＰ、ＢＡＥＰ、ＥＣｏｃｈＧ联合检测。结果ＥＰ异常率：ＭＥＰ６５例，占６１％；ＳＥＰ８８例，占８３％；ＢＡＥＰ６６例，占６２％；ＥＣｏｃｈＧ１０１例，占９４％。ＭＥＰ异常与其他ＥＰ间的卡方检验：与ＳＥＰＸ２＝０．０２７，Ｐ＝０．９９２；与ＢＡＥＰＸ２＝２．１０７，Ｐ＝０．３５０；与ＥＣｏＧＸ２＝４．５０７，Ｐ＝０．１０５。ＭＥＰ各波与正常对照：ｔ值为２．９９３～１１．４４６，Ｐ＝０．０００。中枢及周围神经损害下肢较上肢显著：ＭＥＰＸ２＝４．２１９，Ｐ＝０．０４；ＳＥＰＸ２＝１１．７４８，Ｐ＝０．００１。听神经周围损害较中枢显著，Ｐ＜０．００５。神经损害与病程，血糖控制水平显著相关，γ值为０．２４３～０．３６７，Ｐ＜０．００５。     

Abnormal somatosensory evoked potentials in two patients with conversion disorder

On clinical grounds, somatosensory evoked potentials (SEP) and motor evoked potentials (MEP) are currently used to discriminate between hysterical and neurological conditions. The present paper reports on two patients with severe gait disturbance who had the near-total absence of SEP responses on the scalp during the symptomatic period, which normalized after recovery. These findings, along with others, may shed light on the brain correlates of conversion phenomena.     

脑干三叉神经诱发电位的电生理学特征

目的研究脑干三叉神经诱发电位（BTEP）的波形特征。方法选择全麻开颅手术非三叉神经痛病人20例,采用针形电极刺激其三叉神经周围支,在头顶记录BTEP波形,统计潜伏期、波幅和波间期。结果本组均可记录到W1、W2、W3三个波形,其中W1为高幅三相波,W2、W3为单相负波。在一定范围内,随着刺激强度增大,W1、W2、W3波幅增大而潜伏期不变。结论采用针形电极刺激能获得满意的BTEP波形,为进一步研究三叉神经痛病人在微血管减压术前后BTEP的变化提供依据。     

Neural generators of tibial nerve P30 somatosensory evoked potential studied in patients with a focal lesion of the cervicomedullary junction

The tibial nerve P30 potential was studied in 6 patients with focal lesions located in the vicinity of the cervicomedullary junction. P30 potential was unaffected while cortical P39 was abnormal in the patients with a supramedullary lesion affecting the somatosensory pathway just above its decussation. Conversely, P30 was abnormal in the presence of a lesion situated caudally to the cervicomedullary junction affecting the lower limb sensory fibers just below their decussation. Median nerve P14 behaved similarly to the P30 potential in these cases. These clinical observations suggest that P30 potential, as P14 of median nerve somatosensory evoked potentials, is generated in the lower brain stern probably before the decussation of the sensory fibers; nucleus gracilis and medial lemniscus fibers in the lower brain stem are probably the anatomical structures generating P30 potential. This suggests that P30 potential may be used to study intraspinal and intracranial conduction times separately in the afferent somatosensory pathways. © 1996 John Wiley & Sons, Inc.     

女性糖尿病患者的阴部神经电生理表现

目的:探讨女性糖尿病患者阴部神经电生理表现。方法:对42例女性糖尿病患者(糖尿病组)进行球海绵体肌反射(BCR)及阴部神经体感诱发电位(SSEP)潜伏期及波幅的检测,并与40例不伴有周围或中枢神经病变的成年女性患者40例(对照组)进行比较。结果:糖尿病组BCR和SSEP潜伏期延长,与对照组比较差异有统计学意义(P<0.05)。结论:糖尿病患者存在阴部神经的损害,BCR和SSEP检测有助于诊断。     

接触性热痛诱发电位对糖尿病小纤维神经病变的评价作用

目的 借助接触性热痛诱发电位(CHEP)为糖尿病神经病变的小纤维神经损害寻求一种新的无创客观定量方法.方法 选取糖尿病患者46例和健康人40名,应用CHEP刺激器,控制温度52℃,分别刺激所有受试者右侧前臂、手背、小腿皮肤,采用Keypoint.net肌电图仪于cz点分别记录N波潜伏期及N-P波波幅;同时行右侧上下肢感觉传导测定.结果 健康对照组各个刺激部位CHEP的引出率为100%,而糖尿病组46例中前臂7例、手背9例、小腿16例未引出肯定CHEP波形.糖尿病组较对照组N波潜伏期延长,N-P波波幅减低.糖尿病组中25例上肢感觉传导正常,其前臂刺激Cz记录的N-P波波幅较对照组减低[分别为(34.0±12.6)、(48.4 ±17.5)μV,Z=-3.151,P<0.01],N波潜伏期差异无统计学意义;手背刺激CHEP潜伏期较对照组延长[分别为(420.4±27.8)、(407.2±24.6)ms,t=2.015,P=0.048],波幅减低[分别为(28.2±10.1)、(43.0±16.6)μV,Z=-3.712,P<0.01].18例下肢感觉传导正常,其小腿刺激CHEP潜伏期延长[分别为(473.5±46.6)、(448.6±35.0)ms,t=2.219,P=0.031],波幅减低[(23.8±7.4)、(41.5±18.5)μV,Z=-3.855,P<0.01].结论 糖尿病患者在早期即有小纤维神经选择性受累,CHEP能够为其提供新的客观定量方法,具有潜在的临床应用价值.     

2型糖尿病体感诱发电位研究

目的 通过对2型糖尿病（DM）患者进行刺激正中神经（MN）和胫后神经（PTN）诱发的体感诱发电位（SEP）的检查,了解病人躯体深感觉通路功能状态,早期发现病人的神经病变。方法 用Nicolet Viking　TV型肌电图/诱发电位仪对30例2型DM患者进行SEP的检测并与正常人对照。应用SPSS统计软件采用t检验、卡方检验及多元逐步回归分析比较两组间SEP各项参数的差异,分析DM组SEP参数变化与血糖、血脂、肾功能之间的关系。结果①DM组MNSEP异常20例（66.7％）,PTNSEP异常22例（73.3％）,表现为波形缺失、波潜伏期延长及波幅下降。②DM组MNSEP的N9～N20潜伏期、波幅异常（P<0.05）;PTNSEP的N9～P38潜伏期、波幅异常（P<0.05）。③DM组SEP异常与病程、血糖、血脂、肾功能有关P<0.05）。结论①SEP是检测2型DM神经病变的敏感指标。②控制血糖、血脂、保护肾功能有利于阻止神经病变的发展。     

急性一氧化碳中毒后迟发性脑病患者下肢体感诱发电位的研究

目的探讨急性一氧化碳(CO)中毒后迟发性脑病(DEACMP)患者下肢体感诱发电位(SEPs)的变化。方法对40例DEACMP患者(病例组)和32名健康成人(正常对照组)进行SEPs的N22、P40、N50、P60、N75各波潜伏期和N22~P40峰间期测量。结果病例组30例(75%)患者出现下肢SEPs异常,皮质电位各波潜伏期分别为P40(41.92±2.49)ms、N50(52.13±4.29)ms、P60(64.37±4.98)ms、N75(80.84±4.73)ms,较对照组显著延长(均P<0.01),腰髓诱发电位两组间差异无统计学意义。治疗3个月后,10例SEPs正常的患者总有效率为100%(10/10),30例SEPs异常患者的总有效率为86.7%(26/30),两者差异有统计学意义(P<0.01)。结论DEACMP患者下肢SEPs的变化对病情及预后判断有一定价值,其中皮质电位的变化较腰髓电位敏感。     

Study of visual evoked potentials in diabetics without retinopathy: correlations with clinical findings and polyneuropathy

To evaluate central optic pathways' involvement in diabetics, visual evoked potentials (VEP), in particular the latency of positive peak (LP100), were studied in 35 patients without retinopathy (4 insulin-dependent, 31 non-insulin-dependent) and 35 normal controls using reversal pattern stimulation. LP100 was significantly delayed in diabetics at both binocular and monocular stimulation. Furthermore, the delay in LP100 was significantly longer in the diabetics with polyneuropathy than in those without, particularly after binocular stimulation. A positive correlation was found between latencies of VEP and HbA1, duration of disease, and neurologic score. VEP measurement seems a simple and sensitive method for detecting early alterations in central optic pathways in diabetics.     

Somatosensory and visual evoked potentials in children with cerebral palsy: Correlations and discrepancies with MRI findings and clinical picture

Purpose: To determine if there is any association between the findings of visual evoked potentials (VEPs), somatosensory evoked potentials (SEPs), and magnetic resonance imaging (MRI) findings with the neurodevelopment and severity in children with cerebral palsy (CP). Methods: The present study included 15 children with spastic diplegic CP and five children with spastic hemiplegic CP and 42 healthy children as controls. The number of the controls was two-times greater than the study group to increase statistical power of this study. VEPs and SEPs were recorded in the CP children and compared with healthy controls. All MR scans were obtained using a 1.5 T MR scanner. Results: A significant difference was found in the latencies P100 (VEP) between the CP and controls. No correlations between increased P100 latencies and asphyxia, prematurity, the CP severity, MRI findings and mental retardation were noted. A significant difference in N13–N20 conductions (SEPs) between the subjects with CP and the control group was found. SEPs were positively correlated with mental retardation in CP children. The brain lesions in MRI showed a significant correlation with the CP severity scores and mental retardation. Conclusion: The differences in VEPs and SEPs were determined between CP children and healthy children. The MRI findings were positively correlated with the CP severity and mental retardation.     

肌萎缩侧索硬化患者可发生四肢体感诱发电位的变化

观察52例肌萎缩侧索硬化患者和30例健康人正中神经和胫后神经体感诱发电位变化,判断肌萎缩侧索硬化患者深感觉传导通路的功能状况。肌萎缩侧索硬化患者中,54%（28/52）出现体感诱发电位异常,且皆有下肢体感诱发电位异常。与健康对照者比较,近场皮质电位N20、P2、N2及中枢传导时间延长,可伴有波幅降低或者波形完全消失。表明54%肌萎缩侧索硬化患者体感诱发电位中四肢的中枢起源电位均发生明显异常,证实肌萎缩侧索硬化患者可伴有深感觉通路尤其是中枢深感觉传导障碍。     

Hypofunctioning of sensory gating mechanisms in patients with obsessive-compulsive disorder.

BACKGROUND: In obsessive-compulsive disorder (OCD) patients, functional abnormalities in basal ganglia/precentral circuitries cause cortical hyperexcitability and lack of inhibitory control. These loops can be partly explored by median-nerve somatosensory evoked potentials (SEPs), which functionally reflect the brain responsiveness to somatosensory stimuli. In healthy humans, SEPs' amplitude during voluntary finger movements is lower than during muscular relaxation (i.e., sensory gating). Cortical hyperexcitability in OCD could be eventually responsible for a reduction of sensory gating. This might have pathophysiologic implications for motor compulsions. METHODS: Median-nerve SEPs were recorded in 11 OCD patients and 9 healthy volunteers during muscle relaxation ("Relax") or finger movements of the stimulated hand ("Move"). Latencies and amplitudes of pre- and postcentral SEP components were compared between groups during "Relax" and "Move" conditions. RESULTS: In OCD patients, the responsiveness to sensory stimuli was enhanced for precentral SEPs. Sensory gating ("Relax" vs. "Move") in control subjects involved both pre- and postcentral SEPs, the former being reduced in amplitude by approximately 60%. In OCD patients, sensory gating was spatially restricted to precentral SEP components and was significantly reduced compared with control subjects (approximately 30%). CONCLUSIONS: Enhanced precentral SEPs and hypofunctioning of centrifugal sensory gating in OCD might reflect the inability to modulate sensory information due to a "tonic" high level of cortical excitability of motor and related areas, likely resulting from basal ganglia dysfunction. This might offer new insights into the pathophysiology of OCD.     

术中监护下神经导航显微手术切除功能区及深部病变

目的研究术中监护下神经导航手术切除功能区及深部病变的疗效.方法在神经导航引导的显微神经外科手术中,对32例脑功能区及深部病变病人进行正中神经N20、P25和胫后神经P40、N50体感诱发电位（SEP）监护,以及大鱼际肌和胫前肌运动诱发电位（MEP）监护,以指导手术操作.结果术后MR复查示均达到全切除.24例偏瘫病人中术后症状改善21例,17例癫癎病人中癫癎症状术后消失13例,12例失语病人中术后改善10例.术后未产生新的神经损害症状,无手术并发症及死亡.结论术中神经电生理监护对于提高脑功能区及深部区域病变的手术疗效和安全性有重要意义.     

Electrically evoked nociceptive potentials for early detection of diabetic small‐fiber neuropathy

Background and purpose: This study investigated the utility of pain‐related evoked potentials (PREP’s) elicited by a nociceptive electrical stimulation of the skin (= electrically evoked nociceptive potentials) in early detection of diabetic small‐fiber neuropathy. Methods: We studied 36 ‘young’ (19–35 years) and 24 ‘older’ (36–65 years) healthy subjects as well as 35 patients (35–64 years) with diabetes and neuropathic symptoms and 22 patients (34–64 years) with diabetes without neuropathic symptoms. Only patients with normal standard nerve conduction testing were included. Results: In patients with neuropathic symptoms, we found a significant increase in PREP latencies and decrease of amplitudes elicited from both, upper and lower limbs. In non‐symptomatic diabetic patients, we observed PREP abnormalities from lower limbs only. Conclusions: These data suggest that the method of pain‐related evoked potentials elicited by a nociceptive electrical stimulation of the skin may contribute to the early detection of diabetic sensory neuropathy.