Neurophysiological and psychological disorders and occupational exposure to organic solvents

A number of reports, particularly from Scandinavian countries, claim that painters and workers in other trades in which prolonged occupational exposure to organic solvents may occur develop a type of mental illness characterized principally by impairment of memory and co-ordination and some deterioration of personality. The condition, called 'organic solvent disease', is recognized as a cause of premature retirement and is classed as an occupational disease in certain countries. The conclusions of these reports have been contested and the existence of such a disease entity has been questioned. The publications reporting adverse neurological, neurophysiological and psychological disorders in solvent-exposed workers, and the methods used to determine adverse effects, have therefore been evaluated. In addition, data from animal behavioural studies have been examined but were found to have little or no to have little or no relevance to the reported human disease. The human data indicate that, of the solvents studied, only CS2 provided clear evidence of neurotoxic damage detectable by clinical and pathological examination as well as by neurophysiological measurements (e.g. nerve conduction velocity and nerve action potentials) or neuropsychological techniques (e.g. Rorschach inkblot test and WAIS intelligence tests). In the case of several other solvents and mixtures of solvents commonly used in industry, the evidence of CNS impairment, based principally on the response to questionnaires and the results of neuropsychological and neurophysiological examinations was questionable. A critical evaluation of the reliability of these methods in detecting minor deviations from normal and of their ability to provide acceptable evidence of CNS dysfunction or damage leaves little doubt that these methods are of value in investigating personality, intelligence and memory in the clinical examination of individual patients. However, evidence indicates that they are not suitable for use in epidemiological studies, principally because the variability of response in normal individuals is ill-defined and insufficiently investigated. The same conclusion was arrived at in evaluating the contribution of electroencephalography, computerized axial tomography scanning and other electrophysiological examinations to the diagnosis of brain changes in groups of solvent-exposed and unexposed workers. Furthermore, the personality changes identified (by neuropsychological tests) in painters and other workers exposed to solvents could well be produced by ageing, exposure to lead or mercury, excessive alcohol intake, psychoactive drugs or the ordinary stresses of everyday life.(ABSTRACT TRUNCATED AT 400 WORDS)     

Myelin structure is unaltered in chemotherapy-induced peripheral neuropathy

Purpose

Alterations in mRNA for myelin proteins are reported in animal models of chemotherapy-induced peripheral neuropathies (CIPN); however, ultrastructural changes in aldehyde-fixed and plastic-embedded myelin are not evident by electron microscopy. Therefore, we used X-ray diffraction (XRD) to investigate more subtle changes in myelin sheath structure from unfixed nerves.

Experimental design

We used in vivo chronic animal models of CIPN in female Wistar rats, administering cisplatin (CDDP 2 mg/kg, i.p. twice/week), paclitaxel (PT 10 mg/kg, i.v. once/week) or bortezomib (0.20 mg/kg, i.v. three times/week) over a total period of 4 weeks. Animal weights were monitored, and tail nerve conduction velocity (NCV) was determined at the end of the treatments to assess the occurrence of peripheral neuropathy. Sciatic nerves were collected and the myelin structure was analyzed using electron microscopy (EM) and XRD.

Results

All the rats treated with the chemotherapy agents developed peripheral neuropathy, as indicated by a decrease in NCV values; however, light and electron microscopy indicated no severe pathological alterations of the myelin morphology. XRD also did not demonstrate significant differences between sciatic nerves in treated vs. control rats with respect to myelin period, relative amount of myelin, membrane structure, and regularity of membrane packing.

Conclusions

These results indicate that experimental peripheral neuropathy caused by CDDP, PT, and bortezomib—which are among the most widely used chemotherapy agents—does not significantly affect the structure of internodal myelin in peripheral nerve.     

腰椎间盘脱出患者EMG、NCV、SEP联合检测的意义

目的：观察腰椎赣肋痈出患者神经根损害的神经电生理表现。方法：对451例临床确诊的腰椎间盘脱出患者的针电极肌电图（EMG）、神经传导速度（NCV）、体感诱发电位（SEP）进行分析。结果：EMG异常298例（66.1%)，均进行手术治疗，胫神经H反射异常165例（36.6%)；NCV异常16例（3.5%)，提示同时伴有周围神经病；SEP异常372例（82.6%)，以P40潜伏期延长为特点，而3例合并脊髓压迫的患者主要为波幅降低或未引出，结论：EMG、NCV、SEP三项联合检测，不仅可以提高腰椎间盘脱出患者神经根损害电生理检测异常率，还可以对神经根损害程度，范围以及对周围神经，脊髓损害等提供可靠的诊断依据。     

腓骨肌萎缩症患者的临床与神经电生理特征分析

目的:探讨腓骨肌萎缩症(Charcot-Marie-Tooth disease,CMT)的临床与神经电生理特征;方法:应用肌电图仪检测和分析21例腓骨肌萎缩症患者的电生理特征,包括肌电图和运动、感觉神经传导速度;分析电生理特征与临床之间的关系;结果:16例患者肌电图出现纤颤电位和(或)正锐波,17例患者运动单位(MUP)时限延长。11例腓总神经、13例胫神经运动传导速度(MCV)未引出,1例正中神经、2例尺神经MCV未引出,3例正中神经、2例尺神经MCV正常,其余均有不同程度减慢;15例腓肠神经感觉神经传导速度(SCV)未引出,3例正中神经、6例尺神经SCV未引出,7例正中神经、5例尺神经SCV正常,其余均有不同程度减慢。结论:CMT患者的神经电生理特征大多数呈神经原性损害,运动和感觉神经传导速度有不同程度的受累,下肢的神经病变重于上肢,临床表现结合神经肌电图检查有助于CMT的确诊。     

A novel homozygous MFN2 mutation associated with severe and atypical CMT2 phenotype

Background

Charcot-Marie-Tooth (CMT) neuropathies represent the most common forms of inherited polyneuropathies. CMT2A, the axonal form, accounts for about one third of all CMT cases. Variants in the MFN2 gene have been recognized to be a major cause of CMT2A. To date, more than 100 pathogenetic mutations in MFN2 have been identified, leading to different neurological clinical spectrum, varying from hereditary neuropathies to more severe clinical phenotypes. Pathogenic variants in MFN2 mainly act in a dominant manner, although in a few sporadic or familial cases, homozygous or compound heterozygous mutations have been reported.

神经肌电图检测对分娩性臂丛神经损伤的临床诊断价值

目的探讨神经肌电图评估分娩性臂丛神经损伤的临床价值。方法应用keypoint肌电-诱发电位仪对40例分娩性臂丛神经损伤患儿进行检测。测定臂丛神经主要支配肌肉的肌电图和神经传导速度,确定损伤部位、程度并评价预后。结果40例分娩性臂丛神经损伤患儿根据肌电图结果,按损伤部位分类:上干型12例,上中干型8例,下干型6例,中下干型6例,全臂丛8例。按损伤程度分类:完全损伤1例,不完全损伤39例,其中,严重损伤8例,轻度损伤31例。结论神经肌电图对分娩性臂丛神经损伤的客观定位、判断预后具有重要价值。     

天然细胞生长调控因子对大鼠坐骨神经损伤后再生和修复的神经电生理研究

目的观察局部应用天然细胞生长调控因子(NCGCF)对周围神经再生的神经电生理功能的影响,探讨其可能的作用机理.方法选用200～230g健康雌性大鼠65只,随机分为对照组和实验组,造成坐骨神经钳夹损伤模型,随后连续7天局部注射NCGCF.术后第14、21、28、42天对坐骨神经进行电生理功能指标观察,包括神经传导速度(NCV)、动作电位(AP)峰值等.结果两组间坐骨神经伤后NCV比较,第14、21和28天组间有非常显著差异(P＜0.01),第42天有显著差异(P＞0.05),实验组优于对照组.两组间坐骨神经伤后AP峰值比较,第14、21和28天比较组间有显著差异(P＜0.05),实验组优于对照组,第42天无显著差异(P＞0.05). 结论NCGCF能促进大鼠受损坐骨神经电生理功能的早期恢复,具体机理需进一步研究.     

A study of neurophysiological measurements and various function tests on workers occupationally exposed to vibration

Summary Seventy male air grinder operators and 72 age-matched control workers were examined. Both groups of workers worked in the warm climate (20°–33°C) of southern Taiwan. None of the workers had symptoms of white fingers. The investigation program comprised: (1) case history, (2) physical examination, (3) determination of maximal motor conduction velocity, proximal and distal sensory conduction velocity (NCV) of the median and ulnar nerves of the right upper extremity, (4) measurement of skin temperature, nail press test, pain threshold and vibratory sense threshold of the upper extremities, and (5) testing of the motor function. The dose-effect correlation between the NCV, various function tests and total operating time (TOT) was performed by multiple stepwise regression analyses. The regression analyses revealed a statistically significant correlation (dose/effect) between the six NCV, vibratory sense threshold, pain threshold and age, as well as TOT.     

Maladie de Charcot-Marie-Tooth associée au gène de la périaxine (CMT4F) : description clinique, électrophysiologique et génétique de 24 patients

Autosomal recessive Charcot-Marie-Tooth disease (AR-CMT) is often characterized by onset in early childhood and severe phenotype compared to the dominant forms. CMT disease associated with periaxin gene (PRX) is rare and characterized by demyelination limited to the major peripheral nerves. Following the discovery of a high frequency of a specific periaxin gene mutation (E1085fsX4 homozygote) in the Reunion Island, we examined all French patients known as carriers of the periaxin gene mutation. There were 24 patients. Eighteen were from the Reunion Island (6 families and 10 sporadic cases). The six remaining patients were in two families, each with two affected individuals, and two sporadic cases. The series included 17 female and seven male patients. Walking was acquired late, on average at 3.4 ± 1.6 years. One patient never learned to walk. The Charcot Marie Tooth Neuropathy Score (CMTNS) averaged 24.5 ± 8.1. Seven patients had been wheelchair-bound since the age of 24 ± 22. Other symptoms were: scoliosis most often observed after the age of 12 years and sometimes complicated by a restrictive respiratory syndrome; foot deformity in 24 patients; strabismus; glaucoma; myopia. When conduction recordings are available, median nerve motor conduction was slow (< 10 m/s), associated with a major lengthening of distal latencies. Study of the periaxin gene should be considered in patients with severe demyelinating neuropathy associated with early infantile scoliosis. This disease leads to major disability (29% of patients in this series were wheelchair-bound) and to respiratory insufficiency. Genetic counselling is highly recommended for consanguineous families.     

Comparison of Ultrasonography and Short-Segment Nerve Conduction Study in Ulnar Neuropathy at the Elbow

Objective

To assess the correlation between ultrasonographic and electrodiagnostic findings to determine the localization of the ulnar trapping at the elbow.