Issues & Opinions: Practice parameter for electrodiagnostic studies in carpal tunnel syndrome: Summary statemem: American association of electrodiagnostic medicine,american academy of neurology,american academy of physical medicine and rehabilitation

Carpal tunnel syndrome (CTS) is the most common peripheral mononeuropathy and often requires one or more therapies including surgery. The results of electrodiagnostic (EDX) studies have been found to be highly sensitive and specific for the diagnosis of CTS. This document defines the standards, guidelines, and options for EDX studies of CTS based on a critical review of the literature.     

面肌痉挛显微血管减压术的诱发肌电图监测和评估

目的探讨面神经诱发肌电图对面肌痉挛显微血管减压（ＭＶＤ）治疗的术中监测作用和术后疗效的评估。方法对２６例典型面肌痉挛患者，于ＭＶＤ术前、术中、术后，经皮刺激痉挛侧（手术侧）面神经下颌缘支，记录诱发同侧眼轮匝肌肌电位（ＭＤ－ＯＣ反应）变化，并以正常侧作对照检查。结果２６例术前均记录到痉挛侧ＭＤ－ＯＣ反应，在术中操作不同阶段，２１例见ＭＤ－ＯＣ反应消失，术后１周至３个月随访此２１例，痉挛完全消失１２例，明显减退５例，ＭＤ－ＯＣ反应不复存在，部分减轻４例再记录到ＭＤ－ＯＣ反应。另术中、术后均记录到ＭＤ－ＯＣ反应的５例，症状则无改善。结论面神经诱发肌电图用于ＭＶＤ术中监测和预后判断，有其实用价值。     

Paraspinal mapping: Quantified needle electromyography in lumbar radiculopathy

In the diagnosis of low back pain, the presence of a high percentage of false positive findings on radiologic imaging studies has lead to a more definitive role for electrodiagnosis as a confirmatory test. The paraspinal muscles are a crucial part of the electrodiagnostic examination for radiculopathy. To date, no technique for paraspinal evaluation has been validated. Based on previously documented anatomical techniques, we have designed a method of paraspinal examination termed “paraspinal mapping” (PM). Electromyographic (EMG) needles are placed in five carefully chosen locations and inserted in multiple directions. Individual scores for these insertions are added to determine a total PM sensitivity score. The first 50 studies using PM were compared to peripheral EMG, imaging studies, and pain drawings. Results indicate that the technique is easy to perform. Sensitivity scores relate well with these tests. In this limited and uncontrolled population, PM had higher sensitivity for abnormalities than either peripheral EMG or imaging studies. Because of the anatomical validity of PM, future studies may show it to be useful in localizing the level of radiculopathy independently from peripheral EMG, and to support clinical findings and imaging studies. © 1993 John Wiley & Soncs, Inc.     

A comparison of electroneuronography with facial nerve latency testing for prognostic accuracy in patients with Bell's palsy

The purpose of this study was to evaluate the ability of electroneuronography (ENOG), also called evoked electromyography (EEMG), and facial nerve latency testing (FNLT) to assess the prognosis of facial nerve palsy, using the House-Brackmann facial nerve grading system as criterion. From 1988 to 1994 these tests were employed at the ORL Clinic of the University of Ioannina in 250 patients with idiopathic facial nerve palsy. The ENOG test results indicated that when the amplitude of the compound muscle action potentials ranged from 51% to 95% of the normal value, 97% of the patients achieved complete functional recovery (grade 1) within at least 2 months. When the muscle action potential decreased to a value below 51% of normal values, prognosis for recovery was considerably worse. FNLT test results indicated that as the latency time extended, the recovery grade of the facial nerve worsened. When latency time was within the normal range (group A patients), about 92% of patients had complete functional recovery. In contrast all patients having either a very extended latency time or unable to be monitored (groups C and D) demonstrated incomplete functional recoveries that ranged from grade 11 to grade VI. Comparing each test with the House-Brackmann facial nerve grading system, we ascertained that the percent accuracy for ENOG was 97.6%, and that for FNLT was 94.4%.     

Monitoring of neuromuscular transmission by electromyography (II)

The feasibility of the compound electromyogram (EMG) was evaluated during onset and recovery from pancuronium block in the tibialis anterior muscle of ten cats. The evoked EMG area, amplitude and duration of the total response and of the major negative deflection were evaluated and compared to the mechanomyogram during 0.1 Hz and train-of-four (TOF) stimulation. EMG areas and amplitudes were found to be linearly and similarly related to the mechanomyogram during onset and recovery. Slopes of the regression lines ranged between 1.00–1.02 and between 1.10–1.22 during onset and recovery, respectively, with high individual correlation coefficients (>0.95). The TOF ratio of the mechanomyogram was linearly related to the EMG TOF ratio during onset and to the square root of the EMG TOF ratio during recovery, with no differences between EMG areas and amplitudes, suggesting a higher initial recovery of the TOF ratio of the mechanomyogram during recovery. EMG duration increased as the level of block increased but was unsuitable for neuromuscular monitoring. Evaluation of the agreement between the two methods showed that the EMG may be from 15% below to 10% above the mechanomyogram during onset and from 40% below to 45% above the mechanomyogram during recovery, in spite of high correlation coefficients. In contrast, agreement between EMG parameters was found to be high. In conclusion, EMG is more reliable than the mechanomyogram for evaluation of neuromuscular transmission in the cat. EMG amplitudes and areas both reflect the degree of neuromuscular blockade equally well     

Morphological abnormalities of the terminal neuromuscular apparatus in recent juvenile diabetes

Summary Muscle biopsies from eight cases of acute juvenile diabetes (a few weeks after the beginning of the disease) revealed well marked degenerative changes combined with vigorous regeneration of the terminal neuromuscular apparatus. This observation is in accordance with previous demonstrations of neurophysiological disturbances at this early stage of diabetes.

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Morphologische Anomalien der neuromuskulären Endplatte bei frisch entdeckten juvenilen Diabetikern

Zusammenfassung Muskelbiopsien von 8 Patienten mit akutem juvenilem Diabetes (einige Wochen nach Krankheitsausbruch) zeigten ausgeprägte degenerative Veränderungen mit kräftigen Regenerationserscheinungen an der neuromuskulären Endplatte. Diese Befunde stimmen mit früher mitgeteilten Beobachtungen neurophysiologischer Störungen dieses Frühstadiums des Diabetes überein.

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Anomalies morphologiques de l'appareil neuro-musculaire terminal dans le diabète juvénile récent

Résumé Dans huit cas de diabete juvénile aigu (quelques semaines après le début de la maladie) des biopsies musculaires ont révélé des modifications dégénératives bien marquées, associées á une puissante régénération de l'appareil neuro-musculaire terminal. Cette observation est en accord avec les démonstrations précédentes de troubles neurophysiologiques à ce stade précoce du diabète.

     

Microsurgical results with large vestibular schwannomas with preservation of facial and cochlear nerve function as the primary aim

Summary Objective. To evaluate our microsurgical results in dealing with vestibular schwannomas (VS) greater than or equal to 30 mm when preservation of cranial nerve function was considered more important than total tumour removal.Methods. Sixteen consecutive cases were operated on by the same neurosurgeon according to a prospective protocol using intraoperative neuro-monitoring (IONM) based on electromyographic and brain stem auditory evoked potential recordings. Facial nerve function was evaluated on the House-Brackmann Scale and cochlear nerve function on the Gardner-Robertson Scale. Someone not involved in the clinical management of our patients collected all data.Results. Fifteen patients showed facial nerve (FN) function of House-Brackmann grade (HBG) I or II at one year postoperatively and one kept the HBG IV she had preoperatively. Two patients of four maintained a cochlear nerve function of Gardner-Robertson grade (GRG) II. The tumour excision rates were: total, 68.7%; near total, 6.3%; subtotal, 18.7%, and partial, 6.3%. The average follow-up was 55 months (1–106). Three patients underwent radiotherapy later with growth stabilisation and no additional morbidity.Conclusion. When dealing with VS greater than or equal to 30 mm, microsurgery guided by IONM, with a rate of total or near-total tumour excision of about 75%, can retain socially acceptable facial nerve function (HBG I or II) in all cases and serviceable hearing (GRG I or II) in two cases out of four. Maintaining serviceable cranial nerve function should take precedence over total tumour excision.     

Progressive supranuclear palsy: Electromyographic examinations of eye muscles

Electromyographic examination of vertical and lateral extraocular muscles was carried out in five patients suffering from progressive supranuclear palsy, and incapable of performing voluntary vertical eye movements. No evidence of a lower motor neurone lesion or paradoxical innervation of eye muscles was noted.
Reciprocal inhibition of antagonist vertical muscles though present in oculocephalic (doll's head) stimulation, was incomplete on attempted voluntary movement. This factor is held to be the probable immediate cause of the vertical gaze palsy.     

Nociceptive spinal withdrawal reflexes but not spinal dorsal horn wide-dynamic range neuron activities are specifically inhibited by halothane anaesthesia in spinalized rats

The aim of the present study was to investigate the spinal cord effects and sites of action of different inhaled concentrations (0.5-2%) of the anaesthetic, halothane. Simultaneous recordings were made of 3 Hz, suprathreshold (1.5 x T) electrically evoked spinal dorsal horn (DH) wide-dynamic range (WDR) neuron responses and of single motor unit (SMU) electromyographic (EMG) responses underlying the spinal withdrawal reflex in spinalized Wistar rats. Compared with the baseline responses obtained with 0.5% halothane, the electrically evoked early responses of the DH WDR neurons as well as the SMUs were only depressed by the highest, 2% concentration of halothane. In contrast, 1.5% halothane markedly inhibited the late responses of the DH WDR neurons, whereas 1% halothane started to significantly depress the late responses of the SMUs. Likewise, wind-up of the WDR neuron late responses was inhibited by 1.5-2% halothane, whereas 1-2% halothane significantly depressed wind-up of the SMU EMG late responses. The inhibitory effects of 2% halothane on the early and the late responses of the DH WDR neurons, but not of the SMUs, were completely reversed by opioid micro-receptor antagonist naloxone (0.04 mg/kg). However, no significant effects of naloxone were found on different responses of the DH WDR neurons as well as the SMUs at 0.5-1% halothane, suggesting that different concentrations of halothane may modulate different spinal receptors. We conclude that halothane at high concentrations (1.5-2%) seems to play a predominant inhibitory role via spinal multireceptors on ventral horn (VH) motor neurons, and less on DH sensory WDR neurons, of the spinal cord.