Background
Clinical spectrum of immunoglobulin M (IgM) monoclonal gammopathy varies from IgM monoclonal gammopathy of unknown significance (IgM-MGUS) to hematological malignancies. We evaluated the clinical features, electrophysiological characteristics, and prognosis of patients with peripheral neuropathy associated with IgM monoclonal gammopathy (PN-IgM MG).
Methods
We retrospectively evaluated 25 patients with PN-IgM MG. Peripheral neuropathy was classified as axonal, demyelinating, or undetermined, based on electrophysiological studies. We classified the enrolled patients into the IgM-MGUS and malignancy groups, and compared the clinical and electrophysiological features between the groups.
Results
Fifteen patients had IgM-MGUS and 10 had hematologic malignancies (Waldenström’s macroglobulinemia: two and B-cell non-Hodgkin’s lymphoma: eight). In the electrophysiological evaluation, the nerve conduction study (NCS) criteria for demyelination were met in 86.7% of the IgM-MGUS group and 10.0% of the malignancy group. In particular, the distal latencies of the motor NCS in the IgM-MGUS group were significantly prolonged compared to those in the malignancy group (median, 9.1 ± 5.1 [IgM-MGUS], 4.2 ± 1.3 [malignancy], p = 0.003; ulnar, 5.4 ± 1.9 [IgM-MGUS], 2.9 ± 0.9 [malignancy], p = 0.001; fibular, 9.3 ± 5.1 [IgM-MGUS], 3.8 ± 0.3 [malignancy], p = 0.01; P-posterior tibial, 8.3 ± 5.4 [IgM-MGUS], 4.4 ± 1.0 [malignancy], p = 0.04). Overall treatment responses were significantly worse in the malignancy group than in the IgM-MGUS group (p = 0.004), and the modified Rankin Scale score at the last visit was higher in the malignancy group than in the IgM-MGUS group (2.0 ± 1.1 [IgM-MGUS], 4.2 ± 1.7 [malignancy], p = 0.001), although there was no significant difference at the initial assessment.
Conclusions
The risk of hematological malignancy should be carefully assessed in patients with PN-IgM MG without electrophysiological demyelination features.

Tram-track and doughnut-shaped enhancements of the optic nerve sheath in axial and coronal magnetic resonance imaging (MRI) views, respectively, play crucial roles in the diagnosis of optic nerve sheath meningioma (ONSM). However, this finding is not specific to ONSM since it can also be observed in optic perineuritis (OPN). Here we report a 42-year-old female with ONSM who presented with clinical and MRI findings similar to those of OPN.

Citations

• Freiburg Neuropathology Case Conference: Progressive Optic Nerve Lesion Over a 16-Year Period
  I. E. Duman Kavus, R. Sankowski, R. Rölz, A. Dressing, M. Prinz, H. Urbach, D. Erny, C. A. Taschner
  Clinical Neuroradiology.2025; 35(1): 215.     CrossRef

Neurolymphomatosis is the direct endoneurial infiltration of lymphoma cells. Bone marrow biopsy is a widely practiced procedure that is generally considered to be relatively safe. However, bone marrow biopsy can also result in pain and long-term consequences such as nerve injury. Here we report a case of a 68-year-old male who presented with lumbosacral plexopathy due to neurolymphomatosis that was superimposed on a probable traumatic lumbosacral plexopathy mostly involving the sciatic nerve immediately after a bone marrow biopsy.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a chronic recurrent acquired immune-mediated disease of the peripheral nerves that presents with progressive sensory and motor deficits in all four limbs. Cranial nerve involvement is not as common as in Guillain-Barre syndrome, and central nervous system involvement including optic neuritis has rarely been reported in patients with CIDP. We recently experienced a case with classic CIDP involving bilateral facial and trigeminal nerves, right lower cranial nerves, and the right optic nerve.

Ultrasonography is currently being developed as a tool for evaluating peripheral neuropathy. It is one of the painless and least-invasive methods of medical diagnostic testing that yields anatomic views of the nerves and their surrounding structures. Here I first describe the equipment settings and technique for nerve ultrasound along with typical sonographic findings for normal nerves. I then address frequently used parameters for nerve measurements that facilitate diagnoses of focal and generalized neuropathies.

Citations

• A soft, scalable and adaptable multi-contact cuff electrode for targeted peripheral nerve modulation
  Valentina Paggi, Florian Fallegger, Ludovic Serex, Olivier Rizzo, Katia Galan, Alice Giannotti, Ivan Furfaro, Ciro Zinno, Fabio Bernini, Silvestro Micera, Stéphanie P. Lacour
  Bioelectronic Medicine.2024;[Epub]     CrossRef

Muscle and nerve biopsy may be vital diagnostic tools in various neuromuscular disorders. Since these procedures are invasive, it matters to decide when to perform a biopsy, which muscle or nerve to be selected, and how to interpret the pathologies. This review addresses the indications, methods of biopsies, and also significant pathological findings frequently encountered in muscle and nerve pathology.

Background
Unilateral peripheral facial nerve palsy may have a detectable cause (secondary facial nerve palsy) or may be idiopathic (Bell’s palsy). Facial palsy is attributable to various causes ranging from mild infection to severe neurological disorders. We investigated the prevalence and types of serious neurological disorders in patients with unilateral facial palsy.
Methods
We reviewed the medical records of patients with unilateral facial nerve palsy and identified patients diagnosed with facial palsy secondary to serious or life-threatening causes. We investigated the clinical characteristics, as well as electrodiagnostic and imaging findings in these patients.
Results
Of 924 patients with facial palsy, 11 patients (1.2%) were diagnosed with the following serious neurological disorders: acoustic schwannoma in two patients, facial nerve schwannoma, glossopharyngeal schwannoma, meningioma, epidermoid cyst, parotid gland tumor, pontine infarct, skull base osteomyelitis, brain metastasis, and pachymeningitis.
Conclusions
Although unilateral facial palsy is rarely associated with serious neurological disorders, early detection of the etiopathogenetic contributors is important for prompt initiation of optimal management. Therefore, clinicians should be mindful of disorders that can mimic Bell’s palsy.

Background
Pain and autonomic dysfunction are prominent symptoms in some patients with carpal tunnel syndrome (CTS). Infrared thermography (IRT) has been used to evaluate CTS by measuring the cutaneous temperature and sympathetic vasomotor function.
Methods
This study enrolled the 66 hands of 33 subjects, some of which had clinical CTS and the others were healthy. The enrolled patients completed the Boston Carpal Tunnel Questionnaire (BCTQ) and Historical-Objective scale, and underwent nerve conduction studies (NCSs) and IRT. Skin temperature was measured at the fingertips and the thenar and hypothenar regions in each hand. We analyzed (1) the correlations between self-reported severity, physician-assessed severity, and test results, and (2) the sensitivity and specificity of IRT in diagnosing CTS.
Results
No significant correlation was observed between the results of the BCTQ, NCS, and IRT. IRT had a low sensitivity and high specificity in diagnosing CTS.
Conclusions
IRT cannot replace NCS in diagnosing CTS, nor did it provide an advantage in combination with NCS. However, lower temperatures at the median nerve in some hands with moderate-to-severe CTS suggested the involvement of sympathetic nerve fiber function. Follow-up studies with a larger-scale and complementary design are required to elucidate the relationships.

Citations

• Infrared medical thermography, medical applications, and its basic principles: A review
  Ali Faisal Abdulkareem, Auns Qusai Hashim, N. Aldahan, A.J. Ramadhan
  BIO Web of Conferences.2024; 97: 00140.     CrossRef

Congenital myasthenic syndromes (CMSs) are rare genetic disorders characterized by weakness and fatigue resulting from impaired neuromuscular transmission. Genetic testing can confirm the diagnosis for some types of CMS; however, variations in genotype, clinical phenotypes, age at disease onset, and responses to treatment make diagnosis very difficult. Here we present two adult patients who had significant decremental responses in repetitive nerve stimulation testing and multi-minicore pathology, and who responded to treatment with a cholinesterase inhibitor.

Citations

• Gross and Micro-Anatomical Study of the Cavernous Segment of the Abducens Nerve and Its Relationships to Internal Carotid Plexus: Application to Skull Base Surgery
  Grzegorz Wysiadecki, Maciej Radek, R. Shane Tubbs, Joe Iwanaga, Jerzy Walocha, Piotr Brzeziński, Michał Polguj
  Brain Sciences.2021; 11(5): 649.     CrossRef

Neuromuscular ultrasonography has emerged over the last decade as a useful tool for diagnosing peripheral nerve disorders. It has been studied extensively with a particular focus on the assessment of compression neuropathies. Neuromuscular ultrasonography complements electrodiagnostic studies well by visualizing both the nerve anatomy and surrounding structures, providing useful data that cannot be obtained using the latter methodology only. This review article summarizes and synthesizes the literature focusing on the diagnostic role of neuromuscular ultrasonography in common compression neuropathies of the upper limb.

Citations

• Residual limb neuropathic pain association with neuroma, prosthetic, function, and participation outcomes in individuals living with a transtibial amputation: an exploratory study
  Camille Fournier-Farley, Mathieu Boudier-Revéret, Dany H. Gagnon
  Journal of Rehabilitation Medicine.2025; 57: jrm40551.     CrossRef

No abstract available.

Acute ophthalmoparesis that includes the oculomotor, trochlear, or abducens nerve may occur as an initial presentation of Miller Fisher syndrome (MFS). The symptoms of MFS or variant forms of Guillain-Barre syndrome are pathogenically related to anti-GQ1b antibodies. We report a case of a 36-year-old man with unilateral isolated abducens nerve palsy associated with anti-GM1 antibody. To the best of our knowledge, this is the first report of unilateral isolated abducens nerve palsy with positivity for anti-GM1 immunoglobulin M antibody.

Citations

• Ganglioside (GM1) Immunoglobulin G Antibody Chronic Bilateral Ophthalmoplegia
  Jesse Cheung, Saif Aldeen Alryalat, Osama Al Deyabat, Andrew G. Lee
  Journal of Neuro-Ophthalmology.2025; 45(1): e31.     CrossRef
• Isolated facial diplegia variant of Guillain–Barré syndrome with anti-GM1 IgG antibody
  Jin Ho Jung, Sukyoon Lee, Jung Hwa Seo, Jong Seok Bae, Kyong Jin Shin, Jong Kuk Kim, Byeol-A Yoon, Seong-il Oh
  Annals of Clinical Neurophysiology.2022; 24(1): 17.     CrossRef

Electrodiagnostic tests (EDX) is essential for the diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP). EDX could provide information about demyelinating pathology in the peripheral nerves. According to phenotypes, CIDP could be classified several phenotypes, which has different clinical manifestations, EDX could present a different distribution pattern of demyelinating lesions. In addition, EDX could be useful markers for predicting treatment response of prognosis of CIDP.

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.

Citations

• Confirmation of epidural anesthesia with bupivakain in cats by ınfrared thermographic ımaging and SEP
  Muammer Ayberk Kara, Özlem Şengöz Şirin
  Ankara Üniversitesi Veteriner Fakültesi Dergisi.2025; 72(2): 165.     CrossRef
• The Use of Nerve Conduction Study to Evaluate the Effects of Frozen Sock Treatment on Docetaxel-Induced Peripheral Neuropathy in Breast Cancer Patients: A Prospective Clinical Trial
  Eun-Young Kim, Mi-Yeon Lee, Bum-Chun Suh
  Journal of Clinical Medicine.2025; 14(3): 864.     CrossRef
• Pmp2+ Schwann Cells Maintain the Survival of Large-Caliber Motor Axons
  Mikolaj M. Kozlowski, Amy Strickland, Ana Morales Benitez, Robert E. Schmidt, A. Joseph Bloom, Jeffrey Milbrandt, Aaron DiAntonio
  The Journal of Neuroscience.2025; 45(13): e1362242025.     CrossRef
• Volume loss during muscle reinnervation surgery is correlated with reduced CMAP amplitude but not reduced force output in a rat hindlimb model
  Alexis L. Lowe, Maria V. Rivera Santana, Taylor Bopp, Kiara N. Quinn, Johnnie Johnson, Christopher Ward, Tae Hwan Chung, Sami Tuffaha, Nitish V. Thakor
  Frontiers in Physiology.2024;[Epub]     CrossRef
• A combined functional dorsal nerve model of the foot
  Muhammad Z. Ul Haque, Peng Du, Leo K. Cheng
  Mathematical Biosciences and Engineering.2022; 19(9): 9321.     CrossRef
• Anatomical considerations for obturator nerve block with fascia iliaca compartment block
  Thomas Fichtner Bendtsen, Erik Morre Pedersen, Bernhard Moriggl, Peter Hebbard, Jason Ivanusic, Jens Børglum, Thomas Dahl Nielsen, Philip Peng
  Regional Anesthesia & Pain Medicine.2021; 46(9): 806.     CrossRef
• Peripheral Nerve Regeneration Using a Nerve Conduit with Olfactory Ensheathing Cells in a Rat Model
  Jong-Yoon Lee, Young-Ho Kim, Boo-Young Kim, Dae-Hyun Jang, Sung-Wook Choi, So-Hyun Joen, Hyungyun Kim, Sang-Uk Lee
  Tissue Engineering and Regenerative Medicine.2021; 18(3): 453.     CrossRef
• Protective Effects of Oxytocin and Progesterone on Paclitaxel-Induced Neuropathy in Rats
  Mehmet Ekici, Muharrem Balkaya1
  Neurological Sciences and Neurophysiology.2021; 38(4): 262.     CrossRef

Electrodiagnostic studies such as nerve conduction studies (NCS) and needle electromyography (EMG) provide important and complementary information for evaluating patients with suspected neuromuscular disorders. NCS and needle EMG are reasonably safe diagnostic investigations and are generally associated with only mild transient discomfort when performed by experienced physicians. However, there is the risk of complications in some patients, because NCS involve the administration of electric current and EMG involves inserting a needle percutaneously into muscle tissue. This article reviews the potential risks of NCS and needle EMG.

Citations

• Bioelectric medicine: unveiling the therapeutic potential of micro-current stimulation
  Hana Lee, Seungkwan Cho, Doyong Kim, Taehyun Lee, Han Sung Kim
  Biomedical Engineering Letters.2024; 14(3): 367.     CrossRef
• Needle electromyography does not meaningfully impact findings in MR‐neurography/−myography
  Stefan Sondermann, Tobias Boppel, Katharina Fieseler, Peter Schramm, Tobias Bäumer, Peter Trillenberg
  Muscle & Nerve.2024; 69(4): 409.     CrossRef

Skin biopsy and staining the specimens with immuno-reactive markers has been proven to be a useful method to demonstrate the pathologic status of small nerve fibers. Quantification of intraepidermal nerve fiber density using anti-protein gene product 9.5 antibody is a standard method to diagnose small fiber neuropathy. Skin biopsy also makes it possible to differentiate the nerve fibers according to their function by using different markers. Quantification of dermal structures with different types of nerve fibers could reveal the pathophysiologic mechanism of the disease state.

Citations

• Neurological aspects of anhidrosis: differential diagnoses and diagnostic tools
  Kee Hong Park, Ki-Jong Park
  Annals of Clinical Neurophysiology.2019; 21(1): 1.     CrossRef
• Microneedle-mediated delivery of cosmeceutically relevant nucleoside and peptides in human skin: challenges and strategies for dermal delivery
  Ae-Ri Cho Lee
  Journal of Pharmaceutical Investigation.2019; 49(6): 587.     CrossRef

Skin biopsy with investigation of small nerve fiber in human epidermis and dermis has been proven to be a useful method for demonstration of small fiber neuropathy. Quantification of intraepidermal nerve fiber density using anti-Protein Gene Product 9.5 (PGP 9.5) antibody is standardized method to diagnose the small fiber neuropathy. Skin biopsy method also makes it possible to differentiate the type of nerve fibers by using different antibodies. Quantification of dermal structures with different type of nerve fibers could be used to invest pathophysiologic mechanism of diseased state.

Background: Early detection of neuropathy may prevent further progression of this complication in the diabetic patients. The purpose of this study was to evaluate the prevalence of early neuropathic complication in patients with newly diagnosed type 1 and type 2 diabetes. Methods: Nerve conduction studies (median, ulnar, posterior tibial, peroneal, and sural nerves) were performed for 49 type 1 (27 males, mean 14.1±7.5 years) and 40 type 2 (27 males, 42.0±14.1 years) diabetic patients at onset of diabetes. Children with age at onset under 4 years and adults over 55 years were excluded to eliminate the aging effect and the influence of obstructive arteriosclerosis. Neuropathy was defined as abnormal nerve conduction findings in two or more nerves including the sural nerve. Results: Mean HbA1c level was 12.6±3.3% for type 1 and 10.5±2.9% for type 2 diabetes. The prevalence of neuropathy was 12.2% for type 1, and 35.0% for type 2 diabetes, respectively. There were significant trends in the prevalence of neuropathy with increasing age (p<0.05). The effect of the mean level of glycosylated hemoglobin on the prevalence of polyneuropathy at onset of diabetes was borderline (p=0.0532). Neither sex of the patients nor the type of diabetes affected the neurophysiologic abnormalities at the diagnosis. Conclusions: Even in a population with diabetes at the diagnosis, the prevalence of subclinical neuropathy was not low. Neuropathy has been significantly associated with increasing age indicating the possibility of longer duration of undetected diabetes among them, especially in type 2 diabetes.

Citations

• A Case of Ramsay-Hunt Syndrome with Dysphagia Treated by a Comprehensive Traditional Korean Medicine Regimen Including Pharmacopuncture and Herbal Medicine
  Geun-mo Kim, Hee-doh Kwon, So-hyun Pak, Ji-hong Park, Chang-min Shin, Hyun-Seob Park, Kyung-won Ha, Jong-Cheol Seo, Cheol-Hong Kim, Shin-young Kim, Hyun-Min Yoon
  Journal of Acupuncture Research.2024;[Epub]     CrossRef

Background: Electrophysiological study has been known as a useful method to evaluate the therapeutic effect of operation in idiopathic carpal tunnel syndrome (CTS). The purpose of this study was to evaluate the clinical and electrophysiological changes after carpal tunnel release (CTR) compared to the preoperative results. Methods: We analyzed the changes of nerve conduction study (NCS) before and after minimal open carpal tunnel release in 18 patients (25 hands) with CTS. Follow-up study was performed over 6 months after operation. Results: Clinical improvement was seen in all cases after CTR. In contrast, electrophysiological improvement was various depending on the parameters; the mean median sensory latency and nerve conduction velocity (NCV) improved significantly (p = 0.001). The mean median motor latency also improved, but NCV and compound muscle action potential (CMAP) amplitude did not change. The extent of improvement was evident in moderate CTS, but not in severe CTS. Conclusions: In this preliminary study, all subjects who underwent CTR achieved a clinical relief along with a significant improvement of electrophysiological parameters such as median sensory latency, sensory NCV and median distal motor latency. After CTR, a number of cases with mild to moderate CTS showed a prominent improvement of clinical and electrophysiological parameters, while fewer improvements were seen in severe CTS, although it did not reach the statistical significance.

Citations

• Analysis of Electrodiagnostic Recovery after Carpal Tunnel Release: A Retrospective Study
  Hyungsun Peo, Jun Gyu Lee, Yoonhee Kim, Don-Kyu Kim, Hyun Iee Shin, Du Hwan Kim
  Journal of Electrodiagnosis and Neuromuscular Dise.2022; 24(3): 70.     CrossRef

.

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±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.

Citations

• A cook with ‘burning in the thigh’ and a ‘hotspot’ in the groin!
  Wai Lun Moy
  Oxford Medical Case Reports.2021;[Epub]     CrossRef

Background
It is generally accepted that upper motor neuron (UMN) lesion can alter lower motor neuron (LMN) functionby the plasticity of neural circuit. However there have been only few researches regarding the axonal excitability of LMNafter UMN injury especially during the acute stage. The aim of this study was to investigate the nerve excitability propertiesof the LMNs following an acute to subacute supratentorial corticospinal tract lesion. Methods: An automated nerve excitabilitytest (NET) using the threshold tracking technique was utilized to measure multiple excitability indices in median motoraxons of 15 stroke patients and 20 controls. Testing of both paretic and non-paretic side was repeated twice, during theacute stage and subacute stage. The protocols calculated the strength-duration time constant from the duration?릀harge curve,parameters of threshold electrotonus (TE), the current-threshold relationship from sequential sub-threshold current, and therecovery cycle from sequential supra-threshold stimulation. Results: On the paretic side, compared with the control group,significant decline of superexcitablity and increase in the relative refractory period were observed during the subacute stageof stroke. Additionally, despite the absence of statistical significance, a mildly collapsing in (

Background
ad Aims : Nerve conduction study is invaluable in clinical neurology, especially for assessing peripheral neuropathies. Abnormal nerve conduction studies may result not only from peripheral nerve dysfunction itself, but also from other various mechanical, technical, and physiological factors such as age, sex, height and temperature. So we conducted this study to establish the our own normal values. Methods : In this study, from March. 1997 to July. 1998, 40 Korean adults among person came to Health Promotion extremity and distal segments. Physiological factors such as age, height and temperature affect the results of nerve conduction studies in multiple regression analysis. The sex difference is recognized over peroneal motor nerve. There are no sex difference in amplitude transformed into normal distribution. The significant physiological factor affecting

The measurement of nerve conduction is an expression of the pathophysiological state of the nerves and an essential tool for the study of various neuropathies. The clinical usefulness of nerve conduction studies(NCS) in the diagnosis of diffuse and focal neuropathies has been thoroughly validated. This article decribes the general guidelines for performing nerve conduction studies including H-reflex and F-wave. And the basic skills of NCS, the factors (physiological and nonphysioloigcal) affecting nerve conduction and clinical applications will be briefly discussed.

and others underwent flash goggle VEPs. Results : Brain imaging were abnormal in 29 and were normal in 2. Of the 29 abnormal scans, lesions in posterior visual pathway were detected in 21 scans(predictive value=68%). The predictive value ws not significantly different between flash goggle VEP(75%) and pattern reversal VEP(68%). The predictive value was higher in patient with visual field defect(100%) than those without visual field defect(25%). The pathologic nature of lesion also showed close relations to the predictive value. VEPs is usually paradoxically lateralized(78%), but in all patients. Conclusion : VEPs abnormalities suggesting retrochiasmal lesion were usually corresponded with brain MRI findings. Diagnostic reliability could be increased when considering the visual field defect and nature of lesion. Therefore, the authors suggest that VEPs studies could be useful in evaluating the patients with the retrochismal lesion.

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 a 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.

Background
: Carpal tunnel syndrome(CTS) is the most common entrapment neuropathy that refers to a group of signs and symptoms resulting from compression of the median nerve at the wrist. The course of CTS on older patients is different from the younger patients. This difference may be the result of different underlying mechanisms. The different nerve conduction studies of CTS may signify different approaches in management. This study was done to assess the differences in nerve conduction study of CTS I younger and older patients. Methods : This study involved 224 patients who visited Gachon Medical School, Gil Medical Center and was diagnosed by nerve conduction study from October 1997 to October 1999. We compared the results of nerve conduction study to age, especially in between those under 60 years and those 60 years or over CTS patients. Nerve conduction study consists of motor studies of both median nerve(terminal latency, compound action potential) and sensory studies(nerve conduction velocity, nerve action potential). And we also evaluated the variable between younger and older patients group. Those variables include sex, symptom period, laterality, abnormal physical findings and radiculopathy. Results : We found that a significant increase of terminal latency(p<0.1), but a decrease in compound motor action potential(p<0.05) in older patient's group. There was no significant differences in sensory nerve conduction velocity and action potential between those under 60 years and those 60 years or even patients. And also there was no significant difference in sex, symptom period, laterality, abnormal physical findings, radiculopathy between older and younger patients. Conclusions: This study showed a significant increase in the terminal latency and a decrease I compound action potential in older patients. The different nerve conduction studies of CTS by age effect may need different approaches in management.

Anorexia nervosa(AN) is a disorder characterized by disturbance of body image, fear of gaining weight, severe weight loss and, in female, amenorrhea. Compared with normal persons, patients with AN have neuropathic symptoms more frequently. But electrophysiologic abnormalities have rarely been reported. We experienced a case with recurrent neuropathic symptoms after severe weight loss. Further evaluation revealed AN. Electrophysiologic study showed sensorimotor polyneuropathy and focal neuropathy with conduction block. As far as we know, this feature of neuropathy in AN has not been described. We describe unusual feature of neuropathy in our patient with literature review.

Nerve compression of the suprascapular nerve by a suprascapular notch occasionally occurs, but comperssion by a ganglion is very rare. We had experienced a case of compression of the suprascapular nerve by ganglionic cyst at the suprascapular notch, which confirmed by electromyographic studies after the diagnosis was suspected. MRI scan showed multiobulated cyst at the right suprascapular notch. The patient was treated by excision of the ganglion and had excellent result.

In the normal neuromuscular junction, the nerve action potential(NAP) opens the P-type calcium channels, and resultant influx of calciumions produces the simultaneous exocytosis of

Background
and Objective : Carpal tunnel syndrome(CTS) is the most common mononeuropathy encountered in clinical practice. No single procedure or group of procedures has demonstrated adequate sensitivity. F-wave study in CTS is very rarely reported. To determine the diagnostic usefulness of new parameters of F-wave and comparative study of F-wave parameters of median and ulnar nerves in patients with CTS. Methods : F-wave responses of median and ulnar nerves were analyzed from 27 patients with clinically diagnosed CTS and 22 age and gender-matched normal control. Conventional F-wave parameters were studied. Also, the usefulness of new parameters such as mean and maximal ulnar-median F-wave latency differences, ulnar-median F-wave persistence and chronodispersion differences, median/ulnar F-wave amplitude ratio, and F-wave conduction velocity(FCV) using mean and maximal latency were assessed. Results : Compared with controls, median F-wave minimal, maximal and mean latencies, mean F-wave amplitude/M-wave amplitude, minimal, mean and maximal ulnar-median F-wave latency differences, and FCVs using minimal, maximal and mean latency difference, and FCVs using minimal, maximal and mean latency showed high sensitivity and specificity. Mean ulnar-median F-wave latency difference and FCVs using maximal and mean latency were new parameters. Conclusion : New F-wave parameter including mean ulnar-median F-wave latency difference and FCVs using maximal and mean latency may be a useful to assess the CTS. Also, median F-wave minimal, maximal and mean latencies, and FCV using minimal latency may be included in routine diagnostic tests in CTS

Electrodiagnostic studies are valuable in confirming the diagnosis of a disorder of neuromuscular transmission. They are used to distinguish presynaptic and postsynaptic abnormalities. These studies provide an objective measure of the severity of the illness and may be useful in assessing the response to therapy. This article reviews the electrodiagnostic techniques that are commonly used today and highlights their specificity, sensitivity, and pitfalls. Repetitive nerve stimulation test (RNST) and single-fiber electromyography (SFEMG) are the most available electrophysiologic test in the diagnosis of neuromuscular junction disorders. RNS showing 10% decrement in amplitude from the first to fourth or fifth intravolley waveform while stimulating at 2~5 Hz is valid for the diagnosis of MG. The degree of increment needed for the diagnosis of LEMS is at least 25% but most accurate when greater than 100%. Abnormal jitter or impulse blocking are the appropriate criteria for diagnosis of NMJ disorders when using SFEMG. SFEMG is more sensitive than RNS for the diagnosis of disorders of neuromuscular transmission, especially in MG but may be less specific or may not be available.

Background
s 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/lunar 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 subject. 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 age-matched 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 polynerupathy, 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.

Electrodiagnostic studies can be a valuable method in the diagnosis and follow-up study of various neuromuscular diseases. They must be used as an extension of the clinical evaluation, however, and not as routine tests. After the physician decides what kinds of pathophysiology could explain the patient? signs and symptoms, he or she is then in a position to request specific electromyography (EMG) studies to shed light on diseases that could affect the anterior horn cells, nerve roots, peripheral nerve, neuromuscular junctions, or muscles. Nerve conduction studies (NCS) assess peripheral motor and sensory functions by recording the evoked response to stimulation of peripheral nerves. Motor NCS require stimulation of a peripheral nerve while recording from a muscle innervated by that nerve. Sensory NCS are performed by stimulating a mixed nerve while recording from a cutaneous nerve or by stimulating a cutaneous nerve while recording from a mixed or cutaneous nerve. Motor and sensory NCS studies have been used clinically for many years to identify the location of peripheral nerve disease in single nerves and along the length of nerves and to differentiate these disorders from diseases of muscle or the neuromuscular junction. NCS also can help to distinguish between axonal degeneration, segmental demyelination, and abnormal nerve irritability. But it is important to recognize the inherent limitations of the EMG study. First, the kinds of tests and the muscles or nerves to be tested must be determined by clinical findings. Then, the EMG findings must be interpreted in light of the clinical findings because no EMG results are pathognomonic of a specific disease entity. For these reasons, it is essential that the clinical problem be assessed throughly and that a careful neurological examination be performed before the electrophysiologic study.

Background
and Objectives: A nerve conduction study (NCS) has been known as a useful method to evaluate thetherapeutic effect of operation in carpal tunnel syndrome (CTS). To evaluate the temporal relationship between symptomaticand electrophysiological improvement, we compared the preoperative symptoms and electrophysiological resultswith postoperative those.Methods: We analyzed the NCS changes before and after minimal release of carpal tunnel in 26 patients (34 hands)with CTS. The time of postoperative symptomatic changes, postoperative electrophysiological changes and temporalrelationship between symptomatic and electrophysiological changes were evaluated.Results: The mean age was 49

The Lateral dorsal cutaneous branch of sural nerve (LDCB) is a terminal sensory branch of lower extremities. It canbe 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 thevarious components of NCS. The Mean amplitude of LDCB was 9.45

Background
s and objectives: POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes)syndrome is the rare cause of polyneuropathy. Although the polyneuropathy is essential for the diagnosis of the disease,the pattern of electrodiagnostic abnormalities has not been characterized in detail. The purpose of this study was to elucidatethe features of nerve conduction abnormalities in POEMS syndrome. Methods: We reviewed the medical recordsand nerve conduction studies (NCS) of 12 consecutive patients with POEMS. Results: A total of 68 motor and 46 sensorynerves were examined. Compound muscle action potentials (CMAPs) and sensory nerve action potentials wereabnormally attenuated or not elicited in majority of motor and sensory nerves (80.88% in motor, and 82.6% in sensorynerves). Frequency of the nerves with no potential was significantly higher in lower limbs than in upper limbs (p<0.01in both motor and sensory nerves), and CMAP amplitude was more reduced in lower limbs than in upper limbs(p<0.01). Conduction slowing was very frequently observed with 95% and 76% of motor and sensory nerves, respectively,having the abnormally reduced values of conduction velocity. Distal motor latencies were abnormally prolongedin 75% of motor nerves, and terminal latency indices were significantly higher in patients than in normal controls (p <0.05). Conduction block was observed only in 5% of motor nerves. Conclusions: NCS in POEMS syndrome showedcharacteristic patterns, in which conduction abnormalities were more frequently and severely affected in the lowerlimbs, and more predominantly in the intermediate nerve segments than in the distal portions. The recognition of thesecharacteristic patterns may be helpful in early diagnosis of polyneuropathy in POEMS syndrome.

B a c k g r o u n d s: The pathway of the sural nerve (SN) is variable, but usually divided into medial and lateral suralbranches joining the posterior tibial nerve (PTN) and the peroneal nerve (PN). The sural nerve may be affected by PNpalsy. The frequency or the severity of SN involvement in peroneal palsy is not known. The purpose of the study is toinvestigate 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 superficialperoneal nerves (SPN) were compared between normal and paralyzed sides. The frequency and severity of SN involvementby peroneal palsy were investigated.Results: Mean age was 48.4

Background
Carpal tunnel syndrome (CTS) is a common condition characterized by entrapment neuropathy of themedian nerves. Clinical manifestations are the most important findings for diagnosis and assessment of therapeuticeffects. But, objective indicators, such as electrophysiological findings, are also valuable supplementary tools. Thisstudy investigated the relationship between clinical grading and sensory nerve conduction velocity (SNCV) of medianproper palmar digital nerve (MPPDN) in CTS patients.Method: This study was done on 90 upper limbs of 53 patients with CTS (men: 6, women: 47, age: 26~69 years,mean age; 52 years). Each SNCV of MPPDN was recorded with bar electrode using antidromic method. Each SNCVwas compared with clinical grading of CTS. The clinical grades of CTS were designated as follows; group 1 is mildsymptoms, 2 is moderate symptoms, and 3 is severe and longstanding symptoms.Result: In thumb, the SNCV of MPPDN was not different significantly between 3 groups (p=0.817). In the index finger,the SNCV was the fastest in the group 1, but faster in group 3 than in group 2 (p=0.001). In the middle and ring fingers,SNCV was decreased in higher clinical grading groups (middle finger: p=0.015, ring finger: p=0.044).Conclusion: SNCV of MPPDN of middle and ring finger correlated with the clinical grading of CTS. SNCV of indexfinger was the fastest in group 1. But SNCV of thumb did not correlate with the clinical grading of CTS.

Bilateral brachial neuritis is clinically uncommon and accidentally involvement of bilateral phrenic nerves is rarely reported. We experienced a 26 year old man who developed subacute onset of asymmetric bilateral shoulder and arm weakness. The weakness slowly aggravated and finally suffered from dyspnea due to bilateral phrenic nerve palsy. Cervical spine MRI and CSF study showed no abnormality. Viral markers and other serological test showed no specific finding. Electromyographic study showed bilateral brachial axonal polyneuropathy with cervical and upper thoracic polyradiculopathy. And bilateral phrenic nerve conduction study showed no resopnse. He showed no improvement for 10 months after treatment and managed with continuous artificial ventilation. We report a case of idiopathic bilateral brachial neuritis accidentally involving bilateral phrenic nerves.

B a c k g r o u n d: The study of the medial antebrachial cutaneous nerve (MABCN) is an underused electrodiagnostic tool. But its use is often crucial for assessing mild lower brachial plexus or MABCN lesions, and sometimes for differentiating an ulnar mononeuropathy from a lower brachial plexopathy. This study was designed to know the difference of amplitude and velocity in a stimulation method (orthodromic vs antidromic), side of an arm and sex according by age.Method: MABCN conduction studies were performed orthodromically and antidromically in 90 subjects (42 women and 48 men, ranging from 22 to 79 years of age). We divided subjects into three groups by age (group 1: 20-39 years, group 2: 40-59 years, group 3: 60-79 years). The mean sensory nerve action potential amplitudes and sensory nerve conduction velocities in each group was compared by stimulation method, side of an arm and sex.Result: The amplitudes and velocities made a significant difference between orthodromic and antidromic method in all age groups. At comparison in amplitude and velocity by side of an arm, only amplitude was significantly higher in right arm than left by any stimulation method. The amplitudes and velocities were of no statistically differences in sexexcept amplitude checked orthodromically in right arm.Conclusion: This study suggests that there is the differences in conduction study of MABCN by stimulation method and side of an arm.

Background
The most distal sensory fibers of the feet are often affected first in polyneuropathy. However, they are not evaluated in routine nerve conduction studies. Thus we evaluated the dorsal sural sensory nerve in patients with sensorimotor polyneuropathy with normal sural response, in order to assess the usefulness in electrodiagnostic practice.Methods: In this study, 53 healthy subjects and 27 patients with clinical evidence of sensorimotor polyneuropathy were included. In all subjects, peripheral motor and sensory nerve studies were performed on the upper and lower limbs including dorsal sural nerve conduction studies. On electrodiagnostic testing, all patients had normal sural responses.Results: The dorsal sural sensory nerve action potentials (SNAPs) mean amplitude was 13.12

Isolated posterior antebrachial cutaneous (PABC) neuropathy is rare. A 62 year-old man presented with hypesthesia over the skin region of PABC nerve territory after an injection at the proximal to the lateral epicondyle. Antidromic sensory nerve conduction studies of PABC nerve was not evoked on the affected side. Our case showed that sensory nerveconduction of PABC nerve can be performed without much difficulty and that this test is useful in confirming PABC neuropathy.

Underlying neuropathies combined with amyotrophic lateral sclerosis (ALS) cast doubt on the diagnosis of ALS when present.Abnormal sural nerve conductions were found in 3 patients with clinically definite ALS. Pathologically demyelinating, axonal, or vasculitic neuropathy was suggested respectively. High dose oral corticosteroid had no effect and clinical courses were deteriorating in all the patients.The causes of combined neuropathies were unclear. Possibility of direct consequence of ALS, concomitant neuropathies, or rare variants of ALS should be considered in these cases.

Two cases of bilateral ulnar neuropathies caused by telephone overuse are described in people engaged in the job of longtime telephone use. They had worked using telephone all through the working hours. Although they were right handed, they usually used the telephone in their left hand so as to leave their right hand free for writing, and would lean his elbow on the desk. Telesales or teleconsultation is a rapidly expanding field of business. These cases highlights the need of proper training and supplies appropriate to do their job.

Repetitive nerve stimulation is a simple and widely used technique to demonstrate neuromuscular transmission defect. A significant decremental response for repetitive hypoglossal nerve stimulation was obtained from the surface recordings in the tongue of a patient with dysarthria and dysphagia. Repetitive hypoglossal nerve stimulation test may be useful in diagnosis of myasthenia gravis with bulbar symptoms only. We utilized repetitive hypoglossal nerve stimulation with tongue recordings and diagnosed a case of myasthenia gravis.