Electrodiagnostic examination of lumbosacral radiculopathies

To determine the diagnostic efficacy of late responses and of magnetic stimulation in the electrodiagnostic evaluation of lumbosacral radiculopathies, 42 patients with acute monoradiculopathies of L5 or S1 were examined. We performed conventional nerve conduction studies, F-wave studies, needle electrode examination (NEE) and magnetic stimulation. The results were compared with a control group of 36 persons. In the patients with weakness, we found a diagnostic sensitivity for NEE of 90% in L5 and of 80% in S1. F-waves had the same sensitivity as NEE in the patients with weakness and were more sensitive in the group of patients without weakness (L5 80%, S1 67%). Magnetic stimulation had a sensitivity of 40% in all groups. There were also abnormalities of NEE and of F-wave studies in the patients with abnormal magnetic stimulation. It is concluded that NEE is the single most effective method in acute LSR and that F-wave studies are able to provide complementary information. Magnetically evoked motor nerve root stimulation was not found of clinically relevant diagnostic value.     

Comparison of the sensitivities of plantar nerve conduction techniques for early detection of diabetic sensory polyneuropathy

The purpose of this study was to determine the most sensitive diagnostic test for nerve conduction study (NCS) of the foot for early detection of diabetic polyneuropathy. We compared the sensitivities for diagnosis of sensory polyneuropathy of four different nerve conduction techniques in the same nerves: nerve conduction studies of the medial plantar nerve with surface electrodes using three different techniques and a nerve conduction study of the digital and interdigital nerves of the foot using a near-nerve needle technique. In 25 patients with diabetic polyneuropathy with normal routine NCS, diagnosis of sensory neuropathy was confirmed by medial plantar NCS in 5 patients (20.0%) using Guiloff's method, in 5 patients (20.0%) using Ponsford's method and in 9 patients (36.0%) using Hemmi's method. In digital and interdigital NCS of the foot, a definite neuropathy pattern was observed in 15 patients (60.0%). The most common abnormality was low amplitude of sensory nerve action potential, indicating axonal degeneration. This study demonstrated that digital and interdigital NCS using the near-nerve needle technique is a more sensitive method for detection of early-stage diabetic polyneuropathy.     

Asymptomatic electrophysiologic carpal tunnel syndrome in diabetics: entrapment or polyneuropathy

Electrophysiologic carpal tunnel syndrome (CTS) is common and is frequently asymptomatic in diabetics. In order to evaluate the clinical significance of asymptomatic electrophysiologic CTS, the nerve conduction studies (NCS) of 48 diabetics with asymptomatic electrophysiologic CTS were compared with those of 56 age and gender-matched controls, as well as 50 patients with symptomatic CTS without diabetes. Nerve conduction velocities of the ulnar, peroneal, and posterior tibial nerves were significantly slower in diabetics with asymptomatic electrophysiologic CTS than in normal controls. Compared to symptomatic non-diabetic CTS, there was also significant slowing of the median and ulnar nerve conduction velocities in asymptomatic diabetic CTS. However, in diabetics with asymptomatic CTS, abnormalities of the distal segment of the median NCS were more prominent compared with those of all the other tested nerves. These findings suggested that asymptomatic electrophysiologic CTS in diabetics is a manifestation of increased vulnerability to the entrapment of the peripheral nerve.     

Median nerve compression at the wrist: is it ever unilateral?

OBJECTIVE: Carpal Tunnel Syndrome (CTS) is commonly bilateral, but symptoms and EMG/NCS abnormalities may be seen unilaterally. This study was designed to determine whether there are any subclinical nerve conduction abnormalities on the "uninvolved" side. DESIGN: Statistical analysis of electrodiagnostic data. SETTING: Outpatient academic electrodiagnostic laboratory. PATIENTS: Twenty-two successive patients referred for bilateral upper extremity NCS/EMG with no symptoms or physical signs of CTS and totally normal results, and ten successive patients with an EMG/NCS diagnosis of CTS on one side, and completely normal EMG/NCS on the contralateral side. RESULTS: The median motor and sensory latencies at the wrist were significantly longer in the contralateral "uninvolved" limb than normals (median motor latency 3.75 vs. 3.30 msecs, p = 0.0005, median sensory latency 3.40 vs 3.00 msecs, p = 0.0002). Median sensory amplitude was smaller in the contralateral limb (30.5 uV vs. 41.5 uV, p = 0.0062). The (median-radial) D1 sensory latency difference was greater in the contralateral wrist (0.2 vs. 0.0 msecs, p = 0.0217). The (median-ulnar) sensory latency difference was not significantly increased (0.15 vs. 0.10 msecs, p = 0.2020). CONCLUSIONS: The contralateral limbs of patients with unilateral CTS show significant differences from normals in 4 out of 5 nerve conduction parameters. There is evidence of frequent subclinical median nerve compression in this group.     

Early peripheral nerve abnormalities in impaired glucose tolerance

Increased prevalence of impaired glucose tolerance (IGT) has been recently detected in patients with painful sensory neuropathy. To determine whether nerve abnormalities are present in IGT we investigated IGT subjects without clinical neuropathy. Nerve conduction studies (NCS) were performed in 12 subjects with IGT without symptoms and signs of neuropathy. The results were compared with those obtained from 12 patients with type 2 diabetes (DM) without clinical neuropathy and 12 healthy controls. Sensory NCS of the sural nerve were performed on different segments, the distal-leg (10 cm proximal to the lateral malleolus) and the proximal-leg segment (10 cm more proximal). The distal conduction velocity of the sural nerve was increased in IGT subjects, compared both to healthy controls and DM patients. No difference was found among the groups with respect to the sensory conduction velocity of the sural nerve fibers in the proximal-leg segment. A reduction of both distal and proximal amplitudes of the sural nerve action potentials was detected in DM patients compared with IGT subjects and controls. The abnormal conduction velocity in the distal segment of the sural nerve, observed in IGT subjects without clinical neuropathy, suggests that the myelin dysfunction of the distal sensory fibers represents the earliest detectable nerve response to the hyperglycemia. The reduced amplitude of the sural nerve action potential in asymptomatic patients with DM arises from the axonal degeneration and represents a more advanced stage of nerve disease.     

Quantitative thermal sensory testing in patients with monomelic amyotrophy

BACKGROUND: Quantitative thermal sensory testing (QST) is a non-invasive method to assess somatic small fibre dysfunction, which is not evaluated with routine nerve conduction studies (NCS). Monomelic amyotrophy (MMA), is a pure motor disorder with no sensory abnormalities on routine NCS, and has not been evaluated using QST. AIMS AND OBJECTIVE: Present study aimed to evaluate somatic small fibre involvement in MMA patients. Forty patients with MMA with no sensory abnormalities or routine NCS were evaluated using QST for thresholds of cold sensation (CS), warm sensation (WS), cold pain (CP) and warm pain (WP), using method of limits. These were compared with 40 age-matched controls. RESULTS: No abnormalities in thresholds for CS, WS, CP and WP were found in MMA group as compared to controls. CONCLUSION: QST thus failed to demonstrate any abnormality. Hence we conclude that MMA is a pure motor disorder, with no involvement of somatic small sensory fibres (A delta and C).     

Carpal tunnel syndrome: comparison of the median sensory nerve conduction findings from the index and middle fingers

The sensory nerve conduction study (NCS) is a sensitive means for demonstrating the localized median nerve dysfunction at the wrist in carpal tunnel syndrome (CTS). We reviewed the sensory NCS data of 102 patients (178 median nerves) with CTS and tried to determine if there were significant differences in the findings between the index and middle fingers. There was no statistically significant difference in the amplitudes of the compound sensory nerve action potentials (CSNAPs) recorded antidromically from the index and middle fingers during median nerve stimulation at the palm and wrist. Moreover, there was no statistically significant difference in the finger-to-palm and palm-to-wrist sensory nerve conduction velocities (CVs) between the index and middle fingers. The mean CSNAP amplitudes and mean sensory CVs were comparable in values from these two fingers and they showed a high and positive correlation. It appears that the sensory nerves to the index and middle fingers are compromised to a similar degree in CTS, and neither finger will reveal significantly more sensory conduction abnormalities than the other will.     

Peripheric and automatic neuropathy in children with type 1 diabetes mellitus: the effect of L-carnitine treatment on the peripheral and autonomic nervous system

OBJECTIVES: To determine neuropathy frequency with electromyography (EMG) in asymptomatic diabetic children, and to demonstrate whether the electromyographical abnormalities noted improve after L-carnitine treatment. PATIENTS AND METHODS: This study was carried out on 51 type 1 diabetes mellitus patients (of whom, 26 were female; average age 12) and 21 healthy children as the control group. Thirty four patients, whose nerve conduction velocity (NCS) was diagnosed as pathological, were treated with L-carnitine (dosage: 2 g/m2/day) for two months and their NCS checked at the end of the treatment period. RESULTS: At least one electrophysiological parameter was abnormal in 38 out of 51 patients (74.6%). At the end of the treatment, Stage 1 a patients (NCS pathologic and neurologic examination normal) demonstrated a 44% improvement in all pathologic NCS parameters and a 50% improvement in sympathetic skin responses (SSR), while in Stage 1 b patients (NCS and neurologic examination pathologic) a matching ratio of improvement was detected in SSR but no definite improvement was noted in the all pathologic NCS parameters. CONCLUSION: Starting carnitine treatment in the early stages may be more effective in the treatment of sub-clinical neuropathy. A two-month treatment period may not be sufficient in detecting an electrophysiological improvement in cases where neurological deficits had been determined     

Quantitative thermal sensory testing in patients with amyotrophic lateral sclerosis using reaction time exclusive method of levels (MLE)

OBJECTIVES: Quantitative thermal sensory testing (QST) systems are used for the noninvasive quantification of sensory nerve function including the small myelinated and unmyelinated fibres which is not provided by classical sensory nerve conduction studies. Although Amyotrophic Lateral Sclerosis (ALS) is a pure motor disorder, nevetheless involvement of the sensory fires has been reported occasionally by various techniques. In the present study Reaction Time Exclusive Method of Levels (MLE) was used to detect somatic small fibre involvement in ALS patients with no sensory abnomalities on routine NCS. MATERIAL & METHOD: Twenty patients of clinically definite ALS, were evaluated with QST using the reaction time exclusive method of Levels (MLE) for detecting the thresholds of cold sensation (CS) and warm sensation (WS). They were compared with 20 age matched controls. RESULTS: No abnormalities were detected in the thresholds for CS and WS in patients with ALS as compared to the controls. CONCLUSION: Thus ALS is essentially a pure motor disorder with normal thermal thresholds as revealed by QST.     

Facioscapulohumeral muscular dystrophy. Multimodal evoked potentials and electroretinogram

BACKGROUND: Clinical or subclinical abnormalities of the central nervous system (CNS) have been reported in a range of primary muscle diseases, including the muscular dystrophies. PURPOSE: To ascertain by neurophysiologic techniques evidence of CNS dysfunction in a relatively large, homogeneous group of patients with facioscapulohumeral muscular dystrophy (FSHD). METHODS: Standard evoked potential (EP) and electroretinogram techniques were used to study the visual, auditory and somatosensory pathways in 20 patients with FSHD. RESULTS: Abnormal values were recorded in 70% (14/20) of patients, specifically of visual pathways (4/20), brainstem auditory pathways (4/20), median (5/20) and tibial nerve (2/20) somatosensory pathways, and of the retina (2/18). Abnormal results did not correlate with clinical parameters of patient age, disease duration and degree of weakness. CONCLUSIONS: Any process that caused CNS conduction delays was tentatively associated with FSHD. Sensorineural hearing deficit and vascular retinopathy were rare causes of abnormal EPs. Peripheral conduction delay of the arms was ascribed to mechanical factors secondary to shoulder girdle weakness. Progress in genetics and molecular pathogenesis of FSHD may shed further insight into the association between the myodystrophic process and nervous system abnormalities.     

Diagnostic utility of Sudoscan for detecting bortezomib-induced painful neuropathy: a study on 18 patients with multiple myeloma

IntroductionIn the past few years, treatment of multiple myeloma has undergone a deep change for the employment of novel treatment comprising proteasome inhibitors. Bortezomib is a first-line drug in therapy of multiple myeloma. The onset of peripheral neuropathy is a dose-limiting collateral effect of the drug. This neuropathy is a distal symmetric neuropathy that affects both large and small fibers. Nerve conduction study (NCS) can be used for the diagnosis of bortezomib neuropathy, but this technique demonstrates alterations of the large nerve fibers. Sudoscan is a novel technique utilized to offer an evaluation of sudomotor function. The main objective of this study was to compare the sensitivity and diagnostic specificity of Sudoscan with respect to the nerve conduction study after bortezomib treatment.Material and methodsA total of 18 multiple myeloma patients were studied, 10 (55.5%) men and 8 (44.5%) women. Patients were analyzed at baseline and after 6 months of treatment with bortezomib. Subjects were submitted to nerve conduction study and electrochemical skin conductance evaluation with the Sudoscan device. Patients were also submitted to a clinical measure of pain and neuropathy.ResultsAt baseline NCS showed that only the mean sural SAP amplitude was below the 2SD lower limit of normal in 3 (16.7%) patients, while at same time we found an alteration of Sudoscan profiles in 2 (11.1%) patients. After 6 months of treatment, the NCS profiles were altered in 13 (72.2%) patients, and the Sudoscan profiles were modified in 11 (61.1%) subjects.ConclusionsOur results suggest that Sudoscan can be considered for the diagnosis of bortezomib-induced neuropathy. It is objective, reproducible, and surely easier than the traditional nerve conduction study. Sudoscan may be a useful help to manage the therapeutic interventions in multiple myeloma.     

Current perception threshold: an adjunctive test for detection of acquired demyelinating polyneuropathies

Current Perception Threshold (CPT) evaluation quantifies the sensory threshold to transcutaneous electrical stimulation of three sensory fiber subtypes: A-beta (2,000 Hz), A-delta (250 Hz) and C fibers (5 Hz). Demyelinating polyneuropathies tend to affect larger myelinated fibers before smaller unmyelinated fibers, and they usually begin at the proximal nerve roots or terminal axons, due to relative weakness of the blood-nerve barrier in these locations. Axonal polyneuropathies tend to affect smaller fibers before larger fibers, in a distal to proximal gradient. Ten patients with demyelinating polyneuropathy and ten patients with axonal polyneuropathy underwent CPT testing. CPT comparisons were made with regard to side-to-side asymmetries, fiber type involvement, and the ratio of fiber types involved. The C2, lateral antebrachial cutaneous, and sural distributions were examined bilaterally. Demyelinating polyneuropathies were detected with 50% sensitivity and 100% specificity. This diagnostic sensitivity is similar to that of published criteria based upon motor nerve conduction. CPT testing can distinguish demyelinating from axonal polyneuropathies. It may be particularly helpful in patients with predominantly sensory symptoms in whom EMG/NCS data may be equivocal, or in patients who decline EMG/NCS studies.     

Role of Blink Reflex in diagnosis of subclinical cranial neuropathy in Diabetic Mellitus type II

BACKGROUND AND OBJECTIVES: Peripheral Neuropathy (PN) is one of the late complications of Diabetes Mellitus. Cranial nerves III, VII and V are among the most commonly affected in diabetic patients. Traditional Electrodiagnosis (Edx) studies are useful method for diagnosis of PN and symptomatic cranial neuropathy, and may not be useful for detecting subclinical involvement of cranial nerves. The main objective of this study is to evaluate the role of Blink Reflex (BR) for early diagnosis of cranial neuropathy in diabetic patients with PN. DESIGN: A prospective study was performed on NIDDM patients with a PN. 188 subjects were included in our study in which 142 acted as healthy subjects and 46 as diabetic patients. Patients were excluded with prior history of cranial nerve lesions, stroke, and other disease with polyneuropathy or drug-induced neuropathy. Routine nerve conduction studies were performed and only patients with PN were included in this study. RESULTS: Abnormalities were found in 54.4% of patients. R1, IR2 and CR2 were prolonged relative to healthy group. Statistically there was no significant difference in R/D ratio of patients (P = 0.201). Also there was a positive correlation between R1, IR2 and CR2 latencies with duration of diabetes and severity of polyneuropathy, but not for R/D. The greatest correlation was shown in R1 latency (69.9% abnormality). CONCLUSION: BR is a non-invasive and very useful method for evaluation and diagnosis of subclinical cranial nerve involvement in diabetic patients.     

Foot screening technique in a diabetic population

Foot complications are a well known factor which contribute to the morbidity of diabetes and increases the chance of amputation. A total of 126 consecutive diabetic patients were evaluated by diabetic foot screening. Forty-one patients showed an impaired protective sense when tested with Semmes-Weinstein monofilament 5.07 (10 g), and 92% of them showed peripheral polyneuropathy in nerve conduction study (NCS). The mean vibration score of the Rydel-Seiffer graduated tuning fork in patients with peripheral polyneuropathy in nerve conduction (NCV) study was 5.38+/-2.0, which was significantly different from that of patients without polyneuropathy in NCS. Among the deformities identified on examination, callus, corn, and hallux valgus were the greatest. While checking the ankle/ brachial index (ABI), we also evaluated the integrity of vasculature in the lower extremities. After extensive evaluation, we classified the patients into eight groups (category 0,1,2,3,4A,4B,5,6). The result of this study suggested that the Semmes-Weinstein monofilament test, Rydel-Seiffer graduated tuning fork test, and checking the ankle/brachial index were simple techniques for evaluating pathologic change in the diabetic foot by office screening, and that this screening based on treatment-oriented classification helps to reduce pedal complications in a diabetic population.     

The electrodiagnostic characteristics of Glycogen Storage Disease Type III

PurposeGlycogen Storage Disease Type III, also known as debrancher deficiency or Cori disease, is an autosomal recessive disorder recognized for both its hepatic and muscle manifestations. The neuromuscular manifestations of Glycogen Storage Disease Type III are not well characterized. In this study, we attempt to better define the disorder.MethodsThe medical records of 40 patients with Glycogen Storage Disease Type III seen at Duke University during 1990–2009 were reviewed. The medical records of all patients with nerve conduction studies and/or electromyography were examined.ResultsTwelve patients with Glycogen Storage Disease Type III (aged 5–55 years) had undergone nerve conduction studies ± electromyography. Three of these cases are presented in detail. Nine patients had Glycogen Storage Disease Type IIIa, two patients had Glycogen Storage Disease Type IIIb, and the clinical subtype of one patient was unknown. All had nerve conduction studies and of those nerves tested, abnormalities in the median motor response were most common, corresponding to previously described, intrinsic hand muscle weakness. Electromyography was performed in eight patients and myopathic findings were present in six individuals. Abnormal electrodiagnostic findings were more common in older patients. The two patients with Glycogen Storage Disease Type IIIb had electrodiagnostic evidence of nerve involvement with minor myopathic findings.ConclusionsThe neuromuscular manifestations of Glycogen Storage Disease Type III include myopathy and neuropathy and are more likely to occur with increasing age, even in those diagnosed with Glycogen Storage Disease Type IIIb. Intrinsic hand muscle weakness is likely due to a combination of nerve and muscle dysfunction, a finding that may have implications for treatment.     

神经电生理检查在肌萎缩侧索硬化症中的应用

目的:观察神经电生理检查在肌萎缩侧索硬化症(amyotrophic lateral sclerosis,ALS)中的应用价值。方法:分别对28例临床确诊ALS、6例临床拟诊ALS、4例临床可能ALS患者进行4个区域的共8块肌肉肌电图(EMG)分析,四肢的磁运动诱发电位(MEP),上肢正中神经、尺神经、下肢胫神经F波检查,在双侧腓肠肌记录H波,四肢远端神经传导测定,包括运动传导速度(MCV)、感觉传导速度(SCV)、复合运动神经动作电位(CMAP)、感觉神经动作电位(SNAP)以及运动末梢潜伏期(DML)进行测定并分析,并与健康对照组30例进行比较。结果:临床确诊ALS的神经电生理测定各值异常均高于拟诊ALS和可能ALS(P<0.05),拟诊ALS和可能ALS组比较没有明显统计学差异。ALS组EMG异常率85%,MEP异常率72.4%,神经传导异常主要表现为CMAP降低36.2%,SCV基本正常,F波出波率下降33.3%,F波振幅增高26.3%,H波振幅增高26.3%。结论:EMG对ALS患者下运动神经元损害有定位诊断价值,EMG是ALS诊断的重要依据;MEP对ALS患者上运动神经元损害有诊断价值,但特异性不高;F波、H波对ALS患者上下神经元神经损害定位有补充诊断价值,神经传导测定用于ALS的鉴别诊断。     

胫后神经体感诱发电位对脊髓病变的定位诊断

目的：研究胫后神经体感诱发电位对脊髓病变的定位诊断价值。方法：通过经皮恒流电刺激胫后神经，采用髂棘、脐部和头皮Fpz作参考电极，分别于第4腰椎棘突、第12胸椎棘突和头皮Cz’置记录电极，依次记录CE、N24和P40电位之峰潜伏期。共检测15例健康成人和29例经核磁共振证实的腰骶神经根或脊髓病变患者。结果：①CE、N24和P40电位均异常，见于腰骶神经根病变；②CE正常，N24和P40异常，见于腰骶髓病变；③CE、N24正常，P40异常，见于颈胸髓病变。结论：胫后神经体感诱发电位能够鉴别腰骶神经根或不同节段的脊髓病变，临床上具有定位诊断价值。但对于轻度的腰骶神经根或脊髓腹侧病变，结果可出现“假阴性”。     

Neuromuscular features in Marfan syndrome

Marfan syndrome is a clinically and allelic heterogeneous, heritable connective tissue disorder with infrequently reported neuromuscular features. This study is the first to delineate these symptoms in a non-selected population. Neuromuscular involvement was evaluated in 10 Marfan patients through a standardized questionnaire, physical examination, nerve conduction study (NCS), needle electromyography (EMG), muscle ultrasound, laboratory investigation, and muscle biopsy. Existing neuroimages were screened for dural ectasia and spinal meningeal cysts. Twenty healthy controls with similar age distribution completed the questionnaire.
The results showed that various neuromuscular symptoms occur more frequently in the patients. Four older patients reported muscle weakness, five patients had a mild-to-moderate reduction in vibration sense, and all older patients mentioned mild functional impairments. NCS showed axonal polyneuropathy in four and EMG myopathic and neurogenic changes in all patients. Increased echo intensity and atrophy on muscle ultrasound was found in more than half of the patients. Muscle biopsies obtained in two patients showed myopathic changes in the older, female patient.
In conclusion, the majority of Marfan patients exhibited neuromuscular symptoms characterized as myopathy or polyneuropathy or both, and signs of lumbosacral radiculopathy, with symptoms being most pronounced in the older patients. Although meriting corroboration, these findings indicate a need to further the awareness of neuromuscular involvement in this population.     

An increased frequency of carpal tunnel syndrome in sarcoidosis. Results of a study based on nerve conduction study

Sarcoidosis is a systemic disease which affects the musculoskeletal system; however, its association with carpal tunnel syndrome (CTS) has been reported only rarely. In our study, we tried to determine the prevalence of CTS in our consecutive sarcoidosis patients based on their symptoms and nerve conduction study (NCS). Fifty-six patients (mean age: 45.2) who were followed up with the diagnosis of sarcoidosis at our center and who gave informed consent for NCS were included into the study. The patients were questionned for the presence of hand symptoms: paresthesia, pain, nocturnal paresthesia and/or pain, and, they underwent NCS. Ten (17.9%) patients had recurrent paresthesia, 12 (21.4%) had pain, and 8 (14.3%) had nocturnal paresthesia and/or pain. The results of NCS showed that 41% of the patients had findings compatible with CTS. Extrapulmonary involvement was significantly more frequent in these patients when compared to patients without CTS (p=0.04). Also, patients with CTS were older than the others and CTS-associated symptoms were more frequent in them although this was not significant (p>0.05). In this study, by performing NCS we detected quite a high prevalence of CTS in our sarcoidosis patients. The fact that most of the patients were asymptomatic was interesting.     

磁刺激运动诱发电位对S_1神经根病的诊断价值

采用磁刺激腰骶部运动神经传导时间（ＭＮＣＴ）与磁刺激窝Ｆ波相结合测定运动神经根传导时间（ＭＲＣＴ）的方法，无痛无创地评估Ｓ１神经根功能。研究对象为５０名正常受试者和３０名Ｓ１神经根受损病人。结果表明：磁刺激ＭＮＣＴ在病人组均正常，而ＭＲＣＴ却明显异常，异常率为８７％，明显高于Ｆ波潜伏期的异常率７３％。因此，磁刺激运动诱发电位（ＭＥＰ）是诊断Ｓ１神经根病的一种有很大应用价值的方法。