• Annals of Clinical Neurophysiology
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• v.8 no.2
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• pp.152-157
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• 2006

Background: Meralgia paresthesia (MP) is characterized by sensory impairment in the anterolateral aspect of the thigh and usually caused by a lateral femoral cutaneous nerve (LFCN) lesion. It is well known that several physiologic factors including age, obesity, and sex can affect nerve conduction. This study aimed to determine whether body mass index (BMI) and age can influence on the conduction velocity and action potential amplitude of the LFCN. Methods: Fifty six individuals without any previous neuromuscular disease participated in this study. LFCN was studied orthodromically, distally from the anterior superior iliac spine. The values, such as sensory nerve action potential (SNAP) amplitude and sensory nerve conduction velocity (NCV) were obtained. SNAP of the LFCN were formed on both sides in forty three individuals. Results: No difference of demographic factors was observed between two groups divided according to the presence of SNAP formation. BMI had a significant relationship with SNAP amplitude and NCV of the LFCN. Moreover, Multiple regression analyses of nerve conduction values showed the significant correlation of body mass index and age with nerve conduction velocity. Conclusions: We may suggest that nerve conduction of the LFCN can be affected by age and BMI. Further study to obtain normal nerve conduction data and compare these data with those of meralgia paresthetica patients should be continued.

• Biomedical Science Letters
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• v.11 no.2
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• pp.193-199
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• 2005

The present study was performed to assess peripheral neural involvement by exposure to hand-arm vibration. Segmental sensory nerve conduction in the median and ulnar nerves were measured in shipyard workers exposed to vibration. The subjects were 47 male adults exposed to hand-arm vibration and 7 healthy male controls. The subjects underwent an extensive bilateral neurophysiological examination. Sensory compound nerve action potential (SNAP) of the median and ulnar nerves in palm-finger and wrist-palm segments were measured by antidromic method. And SNAP of the median and ulnar nerves in wrist-proximal finger and wrist-distal finger segments were measured by orthodromic method. Result of sensory nerve conduction study was abnormal in 31 patients $(66\%)$ and normal in 16 patients $(34\%)$ of subjects. The pathological pattern in the hand-arm vibration exposed group was 13 patients $(28\%)$ of carpal tunnel syndrome, 18 patients $(38\%)$ of distal sensory neuropathy, 7 patients $(15\%)$ of multifocal and 1 patient $(2\%)$ of Guyon syndrome. The present study indicates that vibration-induced nerve impairments exist both in the finger-palm and palm-wrist segment of median and ulnar sensory nerves. The results suggest that segmental sensory nerve conduction study would be useful as objective indication of peripheral nerve impairment induced by the hand-arm vibration.

• Journal of the Ergonomics Society of Korea
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• v.15 no.2
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• pp.139-147
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• 1996

It is known fact that the CTS patients have lower pinch strength than the normal people. And we can assume that the sensory nerve action potential(SNAP) and the nerve conduction velocity(NCV) of the CTS group are lower or slower than the normal subjects. This paper analysed the grip strength and performed EMG experiment for the group Norm, G1 and G2. The results are as follows: 1) CTS patients have lower pinch strength than normal people. 2) There was no significant difference on SNAP between the CTS group and the normal group. 3) There was significant difference on NCV among Norm, G1, and G2 group. Especially, significant level was higher in the evening after the continuous use of wrist.

• The Korean Journal of Pain
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• v.34 no.1
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• pp.124-131
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• 2021

Background: Sciatic nerve injury due to intramuscular injection (SNIII) is still a health problem. This study aimed to determine whether there is a correlation between neuropathic pain and electrodiagnostic findings in SNIII. Methods: Patients whose clinical and electrodiagnostic findings were compatible with SNIII participated in this retrospective cohort study. Compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes of the sural, superficial peroneal, peroneal, and tibial nerves were graded from 1 to 4. Leeds assessment of neuropathic symptoms and signs scale (LANSS) was applied to all patients. Results: Forty-eight patients were included in the study, 67% of whom had a LANSS score ≥ 12. Sural SNAP amplitude abnormalities were present in 8 (50%) out of 16 patients with a LANSS score < 12, and 28 (87.5%) out of 32 patients with a LANSS score ≥ 12, with significant differences between the groups (P = 0.011). There was a positive correlation between the LANSS score and the sural SNAP amplitude grading (P = 0.001, r = 0.476). A similar positive correlation was also found in the LANSS score and the tibial nerve CMAP amplitude grading (P = 0.004, r = 0.410). Conclusions: This study showed a positive correlation between the severity of tibial nerve CMAP/sural SNAP amplitude abnormality and LANSS score in SNIII. Neuropathic pain may be more common in SNIII patients with sural nerve SNAP amplitude abnormality.

• Annals of Clinical Neurophysiology
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• v.3 no.2
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• pp.156-159
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• 2001

Miller Fisher syndrome(MFS) has been the focus of conflicting opinions regarding the peripheral versus the central nature of the site of major neural injury. We present our electrophysiological findings in one case of MFS to help clarify the pattern of peripheral nerve injury in this syndrome. A 45-year-old man visited our hospital due to sudden diplopia. Initial examination revealed internuclear opthalmoplegia. The next day, his symptoms rapidly aggravated to complete external ophthalmoplegia, ataxia, and areflexia with hand and foot numbness. Serial electrophysiological studies were performed. The results of brainstem evoked potential(BAEP) and blink reflex were normal in the serial studies. Motor and sensory nerve conduction study(NCS) were normal findings in second hospital day, but ulnar sensory nerve shows no sensory nerve action potential(SNAP) and sural sensory conduction velocity was delayed in 7th hospital day. Our patient's clinical presentation began to improve on 15th hospital day, and his electrophysiologic study showed improvement on 29th hospital day. We believe that all the manifestations of MFS can be explained by the involvement of peripheral nerves without brainstem or cerebellar lesion with the serial electrophysiological studies.

• 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.6 no.1
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• pp.31-34
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• 2004

Backgrounds: The pathway of the sural nerve (SN) is variable, but usually divided into medial and lateral sural branches joining the posterior tibial nerve (PTN) and the peroneal nerve (PN). The sural nerve may be affected by PN palsy. The frequency or the severity of SN involvement in peroneal palsy is not known. The purpose of the study is to investigate the frequency and the severity of the SN involvement by the peroneal nerve palsy. Methods: Total 85 patients were included with peroneal palsy. Amplitudes of distal peroneal, sural, and superficial peroneal nerves (SPN) were compared between normal and paralyzed sides. The frequency and severity of SN involvement by peroneal palsy were investigated. Results: Mean age was $48.4{\pm}17.4$ years old at the time of the test. Peroneal palsy was right side in 32, left in 38, and bilateral in 15 patients. Mean amplitudes of affected distal PN, SPN, and SN were $1.51{\pm}1.64mV$, $3.50{\pm}4.86{\mu}V$, and $10.42{\pm}6.59{\mu}V$ in right side, and $1.19{\pm}1.57mV$, $4.38{\pm}5.67{\mu}V$, and $11.06{\pm}6.87{\mu}V$ in left side, respectively. Sensory nerve action potential (SNAP) amplitude of the SN in the affected side was average $73.7{\pm}33.1%$ of normal, which was significantly lower than that in the normal side(p<0.01). The decrease of the sural SNAP amplitude was more than 15% in 39 out of 70 patients with unilateral peroneal palsy. Peroneal compound muscle action potential (CMAP) amplitude was not correlated with the amplitude of the sural SNAP. By complete peroneal palsy, SN SNAP amplitude was decreased to 4% of SNAP and $57.7{\pm}31.8%$ of that in normal side. Conclusions: PN injury without PTN involvement may induce reduction of sural SNAP amplitude. Because of the anatomic variation of SN, the electrophysiological findings are variable. It should be considered to interpret the location of the PN lesion.

• Annals of Clinical Neurophysiology
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• v.9 no.1
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• pp.33-35
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• 2007

Meralgia paresthetica (MP) is a benign entrapment neuropathy which is characterized by sensory impairment and paresthesia in the cutaneous distribution of the lateral femoral cutaneous nerve. A 79-year-old woman presented with intermittent right inguinal burning sensation. The sensory nerve conduction study (NCS) showed decreased right side sensory nerve action potential (SNAP) on lateral femoral cutaneous nerve compared to the contralateral one. Abdomino-pelvic CT showed bilateral huge renal cysts (The size of largest one on right side: about $6.2{\times}5.0cm$). We report a case of MP caused by a huge abdominal renal cyst, which should be considered when conventional examination reveals no responsible etiology.

• Annals of Clinical Neurophysiology
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• v.10 no.1
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• pp.43-47
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• 2008

Background: Acute brachial plexitis is an acute idiopathic inflammatory disease affecting brachial plexus, which is characterized by initial severe pain in shoulder followed by profound weakness of affected arm. This is a retrospective study to evaluate the clinical and electrophysiological profile of acute brachial plexitis. Methods: Sixteen patients with acute brachial plexitis were sampled. The electrodiagnostic studies included motor and sensory nerve conduction studies (NCSs) of the median and ulnar, sensory NCSs of medial and lateral antebrachial cutaneous nerves, and needle electromyography (EMG) of selected muscles of upper extremities and cervical paraspinal muscles. The studies were performed on both sides irrespective of the clinical involvement. Results: In most of our patient, upper trunk was predominantly affected (14 patients, 87.50%). Only two patients showed either predominant lower trunk affection or diffuse affection of brachial plexus. All had an acute pain followed by the development of muscle weakness of shoulder girdle after a variable interval ($7{\pm}8.95$ days). Ten patients (62.50%) had severe disability. In NCSs, the most frequent abnormality was abnormal lateral antebrachial cutaneous sensory nerve action potentials (SNAPs). On needle EMG, all the patients showed abnormal EMG findings in affected muscles. Conclusions: In this study, pain was the presenting feature in all patients, and the territory innervated by upper trunk of the brachial plexus was most frequently involved. The most common NCS abnormality was abnormal SNAP in lateral antebrachial cutaneous nerve. Our findings support that the electrodiagnostic test is useful in localizing the trunk involvement in acute brachial plexitis.

• Annals of Clinical Neurophysiology
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• v.5 no.1
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• pp.34-38
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• 2003

Backgrounds and Objectives: In the length-dependent axonal polyneuropathy like diabetic polyneuropathy (DPN), the distal part of the longer axons are affected earlier. In cases of minimal distal axonal changes, nerve conduction studies (NCS) are frequently normal. If sural nerve is affected in the early stage of DPN, supportive parameters to detect the early axonal degeneration may be helpful. We investigated whether the sural/ulnar SNAP amplitude ratio (SUAR) may be a more sensitive indicator than sural amplitude alone in the diagnosis of early diabetic polyneuropathy. Methods: We analyzed medical records and electrophysiological studies of 141 patients with DM and 30 healthy subjects. The patients with early stage of DPN were defined as those having symptoms of neuropathy and normal NCS findings among the patients with DM. We compared SUAR between 57 patients with early stage of DPN and 71 agematched control subjects. Results: Fifty seven patients had an average SUAR of 0.8, compared to that of 1.1 in the 71 normal controls. The SUAR of less than 0.9 was supplementary predictor of axonal polyneuropathy, with the best balance of sensitivity and specificity (70%). The SUAR did not vary significantly with age, height or duration of DM. Conclusions: We conclude that the SUAR is a useful electrodiagnostic indicator to detect early stage of DPN.