• Annals of Clinical Neurophysiology
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• v.20 no.2
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• pp.71-78
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• 2018

Nerve conduction study (NCS) is an electrophysiological tool to assess the overall function of cranial and peripheral nervous system, therefore NCS has been diagnostically helpful in the identification and characterization of disorders involving nerve roots, peripheral nerves, muscle and neuromuscular junction, and are frequently accompanied by a needle Electromyography. Furthermore, NCS could provide valuable quantitative and qualitative results into neuromuscular function. Usually, motor, sensory, or mixed nerve studies can be performed with using NCS, stimulating the nerves with the recording electrodes placed over a distal muscle, a cutaneous sensory nerve, or the entire mixed nerve, respectively. And these findings of motor, sensory, and mixed nerve studies often show different and distinct patterns of specific abnormalities indicating the neuromuscular disorders. The purpose of this special article is to review the neurophysiologic usefulness of NCS, to outline the technical factors associated with the performance of NCS, and to demonstrate characteristic NCS changes in the setting of various neuromuscular conditions.

• Annals of Clinical Neurophysiology
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• v.10 no.1
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• pp.25-28
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• 2008

Diabetic polyneuropathy (DPN) is the most frequently encountered form of neuropathy in diabetic patients, and it either relentlessly progresses or remains relatively stable for many years, not showing any trend towards improvement. From this point of view, early detection of DPN is very important to prevent the irreversible change of the peripheral nerve from diabetic insults. Although a number of clinical symptoms and/or deficit scales have been developed for clinical or research purposes, nerve conduction study (NCS) has been known one of the most objective and sensitive tools to detect peripheral nerve dysfunctions in diabetic patients. NCS, however, also have several shortcomings. The next two consecutive articles will focus on debates about diagnostic usefulness of NCS and on recent updates of other diagnostic tests including quantitative sensory testings and skin biopsy in the field of diabetic polyneuropathy.

• Annals of Clinical Neurophysiology
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• v.21 no.1
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• pp.36-43
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• 2019

Background: Diabetic peripheral polyneuropathy (DPN) is associated with a variety of symptoms. Nerve conduction studies (NCSs) are considered to be the gold standard of nerve damage assessments, but these studies are often dissociated from the subjective symptoms observed in DPN patients. Thus, the aim of the present study was to investigate the correlations between NCS parameters and neuropathic symptoms quantified using the Michigan Neuropathy Screening Instrument (MNSI). Methods: Patients with type 2 diabetes mellitus (T2DM) with or without symptoms of neuropathy were retrospectively enrolled. Demographic data, clinical laboratory data, MNSI score, and NCS results were collected for analysis; DPN was diagnosed based on the MNSI score (${\geq}3.0$) and abnormal NCS results. Pearson's correlation coefficients were used to evaluate the relationships between MNSI score and NCS variables. Results: The final analyses included 198 patients (115 men and 83 women) with a mean age of $62.6{\pm}12.7$ years and a mean duration of diabetes of $12.7{\pm}8.4$ years. The mean MNSI score was 2.8 (range, 0.0-9.0), and 69 patients (34.8%) were diagnosed with DPN. The MNSI score was positively correlated with the median motor nerve latency and negatively correlated with the median motor, ulnar sensory, peroneal, tibial, and sural nerve conduction velocities (NCVs). When the patients were categorized into quartiles according to MNSI score, peroneal nerve conduction velocity was significantly lower in the second MNSI quartile than in the first MNSI quartile (p = 0.001). A multivariate analysis revealed that the peroneal NCV was independently associated with MNSI score after adjusting for age, sex, and glycosylated hemoglobin A1c (HbA1c) levels. Conclusions: The present results indicate that a decrease in peroneal NCV was responsible for early sensory deficits in T2DM patients.

• Annals of Clinical Neurophysiology
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• v.19 no.1
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• pp.28-33
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• 2017

Background: Previous studies of radial nerve conduction study (NCS) did not present how to measure the length of the radial nerve across the elbow, and did not even mention how to manage the spiral course of the nerve. This study aimed to applicate the most reliable method to measure the length of the radial nerve during NCS. Methods: Three points (A, B, and C) were determined along the relatively straight course of the radial nerve. The distance was measured using three different methods: L1) straight distance corresponding to the A-C distance, L2) sum of the distances corresponding to the A-B-C distance, L3) based on the L2, but the elbow is flexed at a $45^{\circ}$ angle. We compared the three methods of distance measurement and the calculated nerve conduction velocities (V1, V2, and V3) in normal healthy subjects. Results: 19 normal participants were enrolled. The mean value for method L1, L2 and L3 were $22.5{\pm}1.8cm$, $24.0{\pm}2.1cm$, and $23.2{\pm}2.1cm$ (p < 0.001). Calculated conduction velocities using those distance measurement methods as follows (p < 0.001): V1 ($60.9{\pm}2.7m/s$), V2 ($64.6{\pm}3.3m/s$), and V3 ($63.4{\pm}3.9m/s$). V2 was significantly greater than V1 and V3 (p < 0.001, p = 0.010, respectively). Conclusions: The distance measurement using a stopover point near the lateral epicondyle between two stimulus points in position of a fully extended elbow with forearm pronation is the most appropriate posture for radial motor NCS.

• Annals of Clinical Neurophysiology
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• v.2 no.2
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• pp.89-94
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• 2000

Purpose : Carpal tunnel syndrome (CTS) is a disorder of median nerve at wrist. It is usually diagnosed through clinical manifestation and nerve conduction study (NCS). However, sometimes, NCS does not provide a reliable evidence to reach the diagnosis. Thus, authors performed this study to determine whether NCS was correlated with specific parameters measured on magnetic resonance imaging (MRI) which might become a potential complemental diagnostic tool. Methods : We performed MRI in 34 wrists of 18 patients with clinical manifestations of CTS and pathologic nerve conduction values and analyzed them at levels of the distal radioulnar joint, pisiform and hook of hamate, Results : Increase in the cross-sectional area of the median nerve at the pisiform level and flattening, increased signal intensity, and contrast enhancement of the median nerve at levels of the pisiform and hook of hamate were statistically significant. Change in cross sectional areas between the distal radioulnar joint and hamate and the signal intensities at levels of pisiform and hamate were well correlated with the median nerve conduction velocity. Conclusions : Characteristic MRI findings in CTS reported previously were well demonstrated and some of MRI parameters are well correlated with nerve conduction study. MRI, despite cost, may help in evaluating CTS.

• Annals of Clinical Neurophysiology
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• v.15 no.2
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• pp.48-52
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• 2013

Background: Meralgia paresthetica (MP) is a mononeuropathy affecting the lateral femoral cutaneous nerve. The disease is often diagnosed clinically, but electrophysiological tests play an important role. The aim of this study is to clarify clinical characteristics of MP as well as the role of sensory nerve conduction study (NCS) in the diagnosis of MP. Methods: Sixty-five consecutive patients with clinical diagnosis of MP between March 2001 and June 2012 were retrospectively reviewed at a single tertiary center. General demographics, clinical characteristics and sensory NCS findings were investigated. Measurements of sensory NCS included the baseline-to-peak amplitude, side-to-side amplitude ratio and the conduction velocity. To compare between the normal and abnormal NCS groups, independent t-tests and chisquare test were performed. Results: Sixty-five patients had male predominance (56.9%) with mean age of $48.4{\pm}13.4$ years (range: 16-75). Seven patients (13.5%) had undergone operation or procedure before the symptom onset. The sensory nerve action potentials were obtainable in 52 (80%) of 65 clinically diagnosed MP patients. Sensory NCS revealed abnormalities in 38 patients (73.1%), and others (n=14, 26.9%) showed normal findings. Between the normal and abnormal NCS groups, there is no statistically significant difference on demographics or clinical features. Conclusions: We clarify the clinical features and sensory NCS findings of MP patients. Due to several limitations of sensory NCS, the diagnosis of MP could be accomplished both clinically and electrophysiologically.

• Annals of Clinical Neurophysiology
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• v.5 no.2
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• pp.192-196
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• 2003

The Lateral dorsal cutaneous branch of sural nerve (LDCB) is a terminal sensory branch of lower extremities. It can be injured frequently in peripheral nerves. However, the normal data of each component of nerve conduction study (NCS) of were not studied at this time. The Nerve Conduction Study of LDCB adults were assessed for amplitude, area, duration and nerve conduction velocity (NCV) in normal fifty. We also evaluated how age, sex and dexterity affect the various components of NCS. The Mean amplitude of LDCB was $9.45{\pm}1.93{\mu}V$, area was $4.05{\pm}0.55{\mu}V/s$, duration was $1.50{\pm}0.13s$, and NCV was $37.9{\pm}3.09m/s$, respectively. The amplitude of right was $10.1{\mu}V$ in men, $8.65{\mu}V$ in women. The area of right was $3.83{\mu}V/s$ in less than 40 years and $4.24{\mu}V/s$ in older than 40 years. The areas of left was $3.86{\mu}V/s$ in less than 40 years and $4.30{\mu}V/s$ in older than 40 years. The NCV was 39.0 m/s in less than 40 years and 36.7 m/s in older than 40 years. All of above differences were statistically significant. There were no statistically significant differences between right and left NCS. Normal data of LDCB could be applicable in peripheral neuropathy or nerve injury.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5305-5310
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• 2012

This study is Carpal tunnel syndrome(CTS) disorder of median nerve at wrist. It is usually diagnosed through clinical manifestation and Nerve Conduction Study(NCS). NCS of the median nerve before and after operation were compared in twenty four patient's with CTS, in order to seventeen patient's evaluate the prognostic value of that findings. Analysis result symptom profile of CTS in total number of patient's 17 (Female:17, Male:0), 21 hands (Rt:9, Lt:4, Both:4), Ages(31~60), Mean duration of symptom months($46.6{\pm}36.1$), Mean interval between 1st and 2nd NCS months($20.5{\pm}7.1$), Sensory symptoms(Tingling:21, Numbness:19, Noctunal paresthesia:17), Motor symptoms(Thenar atrophy:20, Trigger finger:2, Morning stiffness:3), Post-operative symptoms(Free:38.1%, >50% improve:52.4%, <50% improve:9.5%). NCS was normal range after operation than before in Sensory nerve conduction study 4 patients's and Motor nerve conduction study 5 patients. Surgery before and after Sensory nerve action potential (SNAP) responses showed improvement over the previous results. Forward by the patient's occupation and occupation patterns of CTS, other treatment methods and surgical treatment of CTS by comparing the degree of improvement to identify and correct nerve conduction study to judge whether the patient's operation.

• Annals of Clinical Neurophysiology
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• v.19 no.2
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• pp.125-130
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• 2017

Background: Routine nerve conduction study (NCS) can only be used to evaluate the function of large fibers, and the results of NCS are often normal in patients with distal sensory polyneuropathy. The measurement of the current perception threshold (CPT) has been reported to represent a variety of peripheral nerve fiber functions. This study was performed to investigate the value of measuring CPT in patients with diabetic sensory polyneuropathy who have no abnormalities in routine NCS. Methods: Twenty-seven diabetic patients with sensory polyneuropathy and normal routine NCS and 18 age-matched control subjects participated in this study. The CPT was measured on the unilateral index finger and great toe of each subject at frequencies of 5 Hz, 250 Hz, and 2,000 Hz. Results: CPT values were significantly higher in the patient group than in the control group, especially with stimuli at the lowest frequency of 5 Hz (p < 0.05). There were significant correlations between the CPT values obtained at three different frequencies in the patient group, whereas the correlation was only significant in the pair of 250 Hz/5 Hz (both in the hands and feet), and in the pair of 2,000 Hz/250 Hz (in the feet) for the control group. Conclusions: Our data suggest that the CPT test, especially at a stimuli frequency of 5 Hz, may be a useful screening tool for diabetic polyneuropathy in patients who show no abnormalities in routine NCS.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.2
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• pp.156-162
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• 2024

Nerve conduction study (NCS) is an essential test for the diagnosis and follow-up of peripheral neuropathy. NCS can objectively quantify peripheral nerve function. NCS is affected by physiological factors such as height, age, body mass index, etc. Hence, the American Association of Neuromuscular & Electrodiagnosis Medicine (AANEM) is currently forming a Normal Data Task Force (NDTF) to present the normal value, but the number is significantly less. Currently, no research has been carried out on the correlation between nerve conduction speed and height and lower limb length in Koreans. Hence, this study sought to compare the nerve conduction velocity of the lower limbs according to the height and lower limb length. A total of 49 subjects were recruited. When the motor nerve conduction velocity and sensory nerve conduction velocity were compared according to the height and leg length, there was a statistically significant negative correlation of the peroneal and left tibial motor nerves with the height. Also, a statistically significant negative correlation was observed with the superficial peroneal sensory nerve and the sural nerve and the leg length. However, in this study, all the subject are in twentys age, whereas the NDTF is divided by age. Hence, additional studies involving subjects of various age groups are needed.