Needle Electromyography Studies Research Articles

Brain Mapping – Neuromuscular correlations in long-term Postsurgical rehabilitation of Adult Brachial Plexus Palsies

Abstract: Background: Correlations of Transcranial magnetic stimulation (TMS) mapping of the cortical area and electromyography (EMG) + dynamometric testing may demonstrate active neuroplas-ticity events that are reliant on rehabilitation therapy (RT) compliance in adult postsurgical brachial plexus (BP) injuries. Material and Methods: On the right (dominant) arm of two patients with chronic operated BP lesions, we evaluated the progress of functional recovery. The trau-matic event was dated more than 10 years ago for both patients. The first patient (male, 50 years old) and the second one (female, 58 years old) had a history of several microsurgical neurotiza-tion and muscle transfer procedures, with less amelioration of the motor deficit, especially re-lated to elbow flexion (MRC 1/5 and 2/5, respectively). We followed up their evolution by EMG parameters, dynamometry, MRC scaling, and TMS. The motor region of the limb was mapped using TMS to assess the amplitudes of the motor evoked potentials (MEP), on a 4-axis protocol. The patients were assessed twice, with the second examination performed after RT had just fin-ished. TMS findings were compared with EMG and dynamometric results. Results: Higher MEP amplitudes were associated with improved MEP latency during stimulation of the left cerebral hemisphere's cortical area, as well as at the cervical level. EMG findings, both nerve conduction and needle EMG studies showed nonsignificant improvements, as well as muscle strength (as measured by the hydraulic dynamometer). The best results for the first patient showed an in-crease in MEP’s amplitude increase from 1.08 mV to 1.49 mV (in the hotspot), which correlated with measurable latencies, as compared to the first TMS (when no response was obtained at cer-vical stimulation). The second patient also had improvements in latencies: from 37.1 msec. to 36.3 msec. (cervical stimulation with recording at bicipital level) and from 39.2 msec. to 37.9 (cervical stimulation recording at the first interosseous), with a hotspot increase from 1.35 mV to 1.98 mV. The results demonstrate cortical region reactivity in regard to therapeutic techniques. Central modifications do not correlate with visible EMG and dynamometric improvements. Pa-tients with traumatic BP palsy may receive several microsurgical reconstructive procedures, nevertheless, the rehabilitation of the upper limb’s functionality may sometimes still be limited. This increases the risk of discontinuity of the neuromotor RT. We aim to prove that in spite of little correlations with clinical and EMG findings, mapping the cortical area using TMS provides proof of ongoing neuroplasticity phenomena, dependent on adherence to RT. Conclusion: The evidence of continued brain activity supports the requirement for long-term adherence to treatment guidelines and long-term study protocols.

Electrophysiological Investigations in DiabetıC Patients

Introduction: The aim of the study is to search proximal nerve involvement by using proximal root stimulation and possible autonomic neuropathy in type 2 diabetic patients with and without distal symmetric sensorimotor polyneuropathy (DSPN). Patients and Methods: Forty patients with type 2 diabetes and ten volunteers who had no history of diabetes and neuropathy were included. Diabetic patients were equally distributed into two groups according to nerve conduction studies (NCSs): First group comprised of with electrophysiologically confirmed DSPN and second group with normal NCSs. Electrophysiological tests included motor and sensory nerve conduction, needle electromyography, F-response, H-reflex, R-R interval, and sympathetic skin responses (SSRs) studies as well as lumbar root stimulation and cauda equina motor conduction time (CEMCT) calculation. Results: The patients with DSPN had significantly longer F-response latencies and had no H-reflex while H-reflex was observed in 35% of the patients in second group. In the first group, SSRs could not be obtained from both upper and lower limbs in 45% of the patients; however, in the second group, they were absent only in 10% of patients in lower limbs. R-R interval variability was significantly lower in both diabetic groups than volunteers. When compared to the volunteers, cauda equine motor conduction time was significantly prolonged in all diabetic patients, but there was no significant difference between the patient groups. Conclusions: CEMCT prolongation, absence of H-reflex, and decreased R-R interval abnormalities indicating dysautonomia were the most important findings of our study. These results show that early electrophysiological examinations using these methods are important in diabetic patients without polyneuropathy.

A Young Man With Acute-Onset Bilateral Arm Weakness After Traumatic Sciatic Neuropathy: A Clinical Vignette.

A Young Man With Acute-Onset Bilateral Arm Weakness After Traumatic Sciatic Neuropathy: A Clinical Vignette.

Lower motor neuron involvement in patients with neuromyelitis optica spectrum disorders

BackgroundInvolvement of the central gray matter of spinal cord is a characteristic magnetic resonance imaging (MRI) feature of aquaporin-4-immunoglobulin G antibodies (AQP4-IgG) positive neuromyelitis optica spectrum disorders (NMOSD). However, there has been no systemic electrophysiological study investigating the frequency of lower motor neuron involvement in NMOSD patients. MethodsWe retrospectively reviewed a cohort of 59 NMOSD patients with results of concentric needle electromyography (EMG) and nerve conduction studies (NCS) that were admitted to the Department of Neurology of Chinese PLA General Hospital between January 2016 and December 2019. ResultsAcute and/or chronic denervation was found in 22.0% (13/59) of the NMOSD patients by EMG. Peripheral or cranial neuropathy indicated by abnormal NCS changes was found in 11.9% (7/59) of the NMOSD patients. Denervation indicated by EMG that can be accounted for by abnormal NCS was found in 6.8% (4/59) of the NMOSD patients, while 3.4% (2/59) of the NMOSD patients had NCS abnormality without denervation indicated by EMG. Accordingly, 9 of the 59 NMOSD patients (15.3%) had lower motor neuron involvement, and moreover, 6.8% (4/59) of the NMOSD patients had corresponding spinal cord or brainstem lesions on MRI. ConclusionNot uncommon lower motor neuron involvement exists in NMOSD patients, so needle EMG and NCS studies should be performed in NMOSD patients with suspected lower motor neuron involvement.

Preoperative electrophysiologic assessment of C5-innervated muscles in predicting C5 palsy after posterior cervical decompression.

To investigate the feasibility of both needle electromyography (EMG) and proximal nerve conduction studies (NCS) in predicting C5 palsy after posterior cervical decompression. This study included 192 patients with cervical myelopathy undergoing laminoplasty or laminectomy. Preoperatively, all patients accepted bilateral needle EMG detection and proximal NCS that consisted of supramaximally stimulating Erb's point and recording compound muscle action potential (CMAP) from bilateral deltoid. In the present study, 11 (11/192, 5.7%) patients developed unilateral C5 palsy after operation, and more patients with C5 palsy showed abnormal spontaneous activity in C5-innervated muscles compared to those without C5 palsy (8/11 vs. 16/181, p < 0.05). The sensitivity and specificity of spontaneous activity in C5-innervated muscles in predicting postoperative C5 palsy were 72.7% and 91.2%, respectively. Furthermore, there were significant left-to-right differences of deltoid CMAP amplitudes between the patients with and without C5 palsy (p < 0.05), and this measurement was also demonstrated to be useful for distinguishing patients with C5 palsy from cases without C5 palsy by receiver operating characteristic (ROC) curve analysis (cut-off value: 2.1mV, sensitivity: 63.6%; specificity: 95.0%). In addition, the sensitivity and specificity of a series application of these two measurements were 63.6% and 100.0%, respectively. The findings of this study support the hypothesis that pre-existing progressive C5 root injury may be a risk factor for C5 palsy after posterior cervical decompression. Clinically, the estimation of NCS and needle EMG in C5-innervated muscles may provide additional useful information for predicting C5 palsy after cervical spinal surgery. Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Safety of Needle Electromyography in Critically Ill Patients

Introduction: To evaluate the safety of needle electromyography (EMG) in critically ill intensive care unit (ICU) patients who are on anticoagulants and have comorbidities that increase the risk of bleeding and infections.&#x0D; Methods: We conducted a retrospective chart review of critically ill patients who underwent needle EMG studies. The most common complications followed by needle EMG were reviewed and classified based upon common terminology criteria for adverse events (CTAC) criteria. Descriptive statistics were reported using the frequencies and percentages for categorical variables. The mean and interquartile range is used for continuous variables. All analyses were conducted using the Statistical Package for the Social Sciences (IBM SPSS Statistic Version 21, IMB Inc., Chicago, IL.&#x0D; Results: Twenty-nine patients were included. 17 (58.6%) were males with a mean age of 60.8 +/- 16.7 years. The mean PT, PTT, and INR were 15.2 sec, 36.5 seconds, and 1.13, respectively. Fourteen (48.2%) patients in this cohort were treated with low molecular weight heparin (LMWH), and an additional 8 (27.5%) patients were administered subcutaneous (SC) heparin for deep vein thrombosis prophylaxis. Therapeutic heparin was being used in 3 (10.3%) patients and sequential compression devices (SCDs) in 4 (13.7%) patients. A total of 228 muscles were tested. Among them, 38 (16.6%) were deep muscles. There were no major bleeding complications at the time of the procedure and for the next seven days in any of the patients, including those with multiple medical comorbidities. All our patients met the grade 1 scale in the severity of adverse events criteria proposed by CTCAE.&#x0D; Conclusion: Needle EMG is safe in critically ill ICU patients on anticoagulants and multiple comorbidities including those that increase the risk of bleeding and infection.

Clinical, neuroimaging, and nerve conduction characteristics of spontaneous Conus Medullaris infarction

BackgroundSpontaneous conus medullaris infarction is a rare disease. We describe two patients with spontaneous conus medullaris infarction presenting as acute cauda equina syndrome and their unique electromyography (EMG) findings.Case presentationTwo patients developed acute low back pain with mild asymmetric paraparesis, loss of perianal sensation and sphincter dysfunction. Ankle deep tendon reflexes were reduced in bilaterally. Neither patient had cardiovascular risk factors. Magnetic Resonance imaging showed infarction in the conus medullaris. Functional recovery was good in both patients, but progressive asymmetric calf wasting and sphincter dysfunction remained. EMG studies at follow-up of at least 3 years demonstrate active denervation at the muscles innervated by the first sacrum anterior horn cells.ConclusionSpontaneous conus medullaris infarction can occur in healthy individuals and presents as cauda equina syndrome. Findings of needle EMG studies indicate a progressive course of sacrum anterior horn cell disorder during long-term follow-up.

Hematoma Risk After Needle Electromyography in Patients Using Newer Oral Anticoagulants.

To assess the safety of needle electromyography in patients on non-vitamin K oral anticoagulants (NOACs) compared with warfarin. A retrospective chart review was done in patients who underwent needle electromyography studies while they were using warfarin and NOACs. After the needle electromyography, all the patients were monitored for 2 hours and ultrasound of high-risk muscle groups was done. The complications were classified based on the International Society on Thrombosis and Hemostasis definitions. Fifty-eight patients were included: 29 were using NOACs and the other 29 were on warfarin. The mean age was 59.33 ± 16 years. Hemorrhagic complications from needle electromyography were noted in 9 patients: 7 (77.7%) NOACs and 2 (22.3%) warfarin. Among them, 6 patients (66.6%) met the diagnostic criteria for Clinically Relevant Non-Major Bleeding criteria proposed by International Society on Thrombosis and Hemostasis and 3 patients (33.4%) had an asymptomatic hematoma on ultrasound evaluation. A total of 267 muscles were tested and only 9 (3.3%) muscles had hemorrhagic complications. One patient (rivaroxaban) had acute bleeding requiring pressure bandage, five patients (two apixaban, two rivaroxaban, and one warfarin) had clinical hematoma that required ice packs, and three patients (two rivaroxaban and one warfarin) had a hematoma on ultrasound of deep muscles. Patients on NOACs had minimal risk of clinically relevant hemorrhagic complications, and the risk is not significantly different from those on warfarin.

O-04 Peripheral movement disorders

Movement disorders are clinical syndromes which present either an increase or decrease of voluntary and involuntary movements. Although the neural mechanism underlying most of these syndromes involves the central nervous system, a much smaller group has a peripheral nervous system aetiology. While surface electromyography (EMG) is more conventionally used in movement disorders in order to characterize the abnormal muscle contractions, it is not as useful in the study movement disorders of peripheral origin. Nevertheless, conventional needle EMG provides information enough to determine the origin and suffices for diagnosis in these syndromes. We have revised all the movement disorders cases between 2015 and 2018. They were referred to our laboratory for a surface EMG study. In these period, 63 patients were studied. 3 of these patients (less than 5%) were finally diagnosed of a peripheral movement disorder. All the 3 patients were referred to the EMG department with the diagnosis of a central nervous system movement disorder. Due to the clinical examination, we suspected a peripheral involvement and thus, needle EMG was performed instead. EMG findings (fasciculations, fibrillations, normal MUPs) led to the diagnosis of a continuous muscle fibre activity syndrome of peripheral origin. Peripheral movement disorders are an infrequent condition and therefore difficult to suspect. Needle EMG studies are decisive for the correct diagnosis in this syndromes. Conventional needle EMG, even if not established as part of the diagnostic protocol, may contribute in those cases in which questions about a central or peripheral origin arise, since clinical manifestations often overlap.

Spinal Accessory Nerve Injury Induced by Manipulation Therapy: A Case Report.

Spinal accessory nerve (SAN) injury mostly occurs during surgical procedures. SAN injury caused by manipulation therapy has been rarely reported. We present a rare case of SAN injury associated with manipulation therapy showing scapular winging and droopy shoulder. A 42-year-old woman visited our outpatient clinic complaining of pain and limited active range of motion (ROM) in right shoulder and scapular winging after manipulation therapy. Needle electromyography and nerve conduction study suggested SAN injury. Physical therapy (PT) three times a week for 2 weeks were prescribed. After a total of 6 sessions of PT and modality, the patient reported that the pain was gradually relieved during shoulder flexion and abduction with improved active ROM of shoulder. Over the course of 2 months follow-up, the patient reported almost recovered shoulder ROM and strength as before. She did not complain of shoulder pain any more.

F70. Hand reinnervation after a bilateral proximal forearm transplantation, 5 years evolution

Introduction After hand transplantation distal muscles may become useless well before they can be reinnervated. This is a major reason why proximal forearm transplants remain controversial. Sensory and autonomic reinnervation is a complex process which has not been studied even in peripheral nerve injured. Methods A 52 year old male, underwent forearm transplantation. The following studies have been performed regularly on both arms: Motor neurography studies to ulnar, median and radial nerves, sensory neurography studies to median and ulnar nerves, needle electromyographic studies on intrinsic hand muscles, somatosensory evoked responses and autonomic neurophysiologic studies. Results Median and ulnar motor nerve neurography studies have shown continuous increase of all values of compound muscle action potentials (CMAP) in the five year observation period. Needle electromyographic studies show reinnervation signs on motor unit action potentials (MUAPS) of intrinsic muscles of both hands, neurography sensory studies have not shown a reliable measure of sensory nerve action potential (SNAPS), somatosensory evoked potentials (SEP) with stimulus at wrist elicited almost normal cortex responses at 3 years post-transplantation, autonomic reinnervation is present. Conclusion Motor, sensory and autonomic reinnervation to the hand has been a continuous process in the five years observation period in this transplanted patient.Intrinsic muscles in the hand show neurophisiologic signs of being reinervated. We still expect neurophysiologic and clinical improvement.

Normal contractile algorithm of swallowing related muscles revealed by needle EMG and its comparison to videofluoroscopic swallowing study and high resolution manometry studies: A preliminary study

The purpose of this study was to investigate the function and importance of infrahyoid muscles with the suprahyoid muscles during swallowing, and to investigate swallowing sequences using kinematic analysis, high-resolution manometry (HRM) and electromyography (EMG). As a preliminary study, ten healthy subjects were prospectively enrolled. A needle EMG evaluated the onset latency, peak latency and duration of the suprahyoid and infrahyoid muscles. HRM measured the time intervals among the velopharynx, tongue base, and upper esophageal sphincter. We also evaluated hyoid motion using an automated kinematic analysis software® (AKAS). All of these parameters were synchronized with a tilting motion of the epiglottis. In the EMG analysis, the activations of the suprahyoid muscles developed about 300ms earlier than that of the infrahyoid muscles. There was a significant relationship between the differences of suprahyoid and infrahyoid muscles’ latency and total duration of the hyoid motion (p<0.05). The interval time of anterior hyoid motion has a significant correlation in the upper esophageal sphincter (UES) opening time. In conclusions, the functions of the infrahyoid muscles are also as important as that of the suprahyoid muscles for prolonged laryngeal elevation and UES opening. Moreover, kinematic analysis of videofluoroscopic swallowing study (VFSS) and HRM studies could reflect results of needle EMG study and replace EMG study.

Patients with post-polio syndrome are more likely to have subclinical involvement as compared to polio survivors without new symptoms.

Background:Post-polio syndrome (PPS) is a condition that affects polio survivors decades after recovery from an initial acute attack. It is a well-known entity that limbs thought to be nonaffected by polio survivors commonly demonstrate electromyography (EMG) evidence of prior polio. Although the diagnosis of PPS requires a remote history of acute paralytic polio, clinically unapparent damage caused by poliovirus can be associated with PPS later in life.Objective:To evaluate EMG abnormalities and late progressive symptoms in limbs thought to be nonaffected by polio survivors, in order to determine the prevalence of subclinical motor neuron involvement in those fulfilling criteria for PPS comparing to those without such symptoms.Materials and Methods:Clinical and EMG findings of 464 limbs in 116 polio survivors who had been admitted to our clinic were analyzed. Affection of the limbs by polio was classified based on the patient's self-report on remote weakness during the acute phase of poliomyelitis, muscle strength measured by manual muscle testing, and four-limb needle EMG.Results:Seventy-six of the patients (65.5%) met the criteria of PPS. Needle EMG studies revealed subclinical involvement in 122 out of 293 (42%) limbs with no history of remote weakness during the acute phase of poliomyelitis. Prevalence of subclinical involvement was found 47% in polio survivors who met the criteria of PPS compared to 33% in those without PPS (P = 0.013). Among the limbs that had developed new weakness in PPS patients, 33.5% had subclinical involvement.Discussion and Conclusion:Subclinical involvement is common in limbs thought to be nonaffected by polio survivors, and this is especially present in those fulfilling criteria for PPS. New muscle weakness may develop in apparently nonaffected, subclinically involved muscles. Thus we believe that four-limb EMG studies should be performed in all polio survivors, especially in those with the symptoms of PPS.

Mobile electrodiagnostic laboratories provide substandard patient care: An educational report.

Mobile electrodiagnostic (EDx) laboratories often do not appear to comply with Medicare rules or the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) standards. The AANEM Professional Practice Committee reached a consensus based on expert opinion on the typical deficiencies of EDx studies performed by mobile EDx laboratories and made recommendations on proper performance. Mobile EDx laboratories should be registered as independent diagnostic testing facilities (IDTFs) and be held to the standards established by the Centers for Medicaid and Medicare Services. Testing performed in a mobile EDx laboratory is often performed: (1) without a physical exam by a qualified EDx physician; (2) without adequate physician supervision; (3) without interpretation "on site" or in "real time"; (4) without an accompanying needle electromyography study; and (5) with an excessive number of tests. The AANEM recommends that payers require companies that perform studies in a mobile EDx laboratory but have failed to register as an IDTF to be held to the standards listed in the federal rules.

Botulinum Toxin Injection for Spastic Scapular Dyskinesia After Stroke

Spastic scapular dyskinesia after stroke is rare, which causes impaired shoulder active range of motion (ROM). To date, there has been no report about botulinum toxin injection to spastic periscapular muscles. This study presents botulinum toxin A injection for management of spastic periscapular muscles after stroke in 2 cases.This is a retrospective study of 2 cases of spastic scapular dyskinesia after stroke. Spasticity of periscapular muscles including rhomboid and lower trapezius was diagnosed by physical examination and needle electromyographic study. Botulinum toxin was injected into the spastic periscapular muscles under ultrasound imaging guidance.During the 3-week follow-up visit after injection, both patients showed increased shoulder active ROM, without any sign of scapular destabilization.The results suggest that botulinum toxin injection to spastic periscapular muscles can increase shoulder active ROM without causing scapular destabilization in patients with poststroke spastic scapular dyskinesia.

Cyclist’s Neuropathy

Objective: Clinical presentation of the ulnar nerve lesions in the wrist and hand shows variations because of complex anatomic course of the nerve in distal sites. Cyclist’s palsy has been postulated to be an entrapment neuropathy of the ulnar nerve in the Guyon canal of the wrist. We report a case compression of the deep motor branch of the ulnar nerve as cyclist’s palsy in women learning to ride a bike. Case Report: Hand weakness with no evidence of sensory symptoms was the initial presentation that brought the patient to the physician. Her thumb adduction was grade 3/5, fingers’ adduction and abduction were grade 3/5, flexions from the fourth and fifth metacarpaphangeal joint were grade 4/5, and froment’s sign was positive. Routine motor nerve conduction studies on the left ulnar nerve recording from abductor digiti minimi muscle were normal. However, stimulation from the left wrist and recording from the first dorsal interosseous muscle revealed a small amplitude (2.2 mV) and a prolonged distal latency (4.7 ms). The needle electromyography studies showed fibrillation potentials and positive sharp waves in the left first and third interosseous muscles and the adductor pollicis muscle. Conclusions: This may be owing to the fact that tight grasp in an inappropriate position and hyperextension position of the hand during biking are thought to be the main mechanisms of this lesion type.

A study to analyze the prevalence of nervous anastomosis (Martin-Gruber) in medical students

Background: In nerve conduction laboratory, various types of cases are encountered. These are generally referred for electrophysiological investigation of the most common syndromes such as carpel tunnel syndrome where there is partial or total sparing of the thenar muscles from the effect of compression of their nerve supply. So for the assessment of traumatic and entrapment lesions of median and ulnar nerves, the knowledge of these anastomosis is important. Aims and Objectives: The purpose of this study was to assess the prevalence of this anastomosis in healthy individuals, to draw attention of clinicians or surgeons from neurophysiology field to this anastomosis, and to avoid misinterpretations of different studies of needle electromyography and other nerve conduction studies. Materials and Methods: A total of 150 healthy volunteers were selected from the medical students aged 17–30 years. Surface recording electrodes were placed on the hand abductor pollicis brevis, abductor digiti minimi, and the first dorsal interossei (FDI) of each subject. Using surface electrodes, we percutaneously stimulated the median and ulnar nerves at the wrist and the elbow. Rectangular pulses of 0.2 ms duration were used and the stimulus strength was supramaximal. Compound muscle action potential (CMAP) was recorded. CMAP from the FDI, hypothenar, and thenar muscles larger (at least 1.0 mV) on median nerve stimulation at the elbow than at the wrist and that from one or more of these sites larger (at least 1.0 mV) on stimulation of ulnar nerve at the wrist than at the elbow were accepted as indicators of the presence of the MGA. Analysis was carried out using Statistical Package for Social Sciences, version 10.0. P-value

Cervicobrachial polymyositis.

To characterize and analyze a subgroup of patients with polymyositis presented with predominant or isolated proximal upper limb and neck weakness. Patients with polymyositis, presenting with predominant or isolated weakness of upper limbs and the neck, were included. Bohan and Peter and Targoff criteria were used for the diagnosis of polymyositis. The study period was of 14 years (from 1999 to 2013). Detailed clinical, laboratory, histopathological, and/or radiological profiles were evaluated and analyzed in all patients. The mean age of presentation was 37 years (23-58 years), and 86% (12/14) patients were female. All patients developed progressive symmetrical weakness predominantly affecting upper limbs, and 50% (7/14) had weakness only in upper limbs. The referring diagnoses in all 14 patients were other than polymyositis, for example, motor neuron disease, cervical radiculopathy, brachial neuritis, chronic inflammatory demyelinating polyradiculoneuropathy, anti-MuSK myasthenia gravis, and facioscapulohumeral muscular dystrophy. Weakness in the neck and shoulder region was the most common presenting complaints, presenting in 71.4% (10/14) and 64.3% (9/14) of patients, respectively, followed by neck and shoulder pain in 57.14% (8/14) patients. The most severely affected muscles were neck flexors, neck extensors, the trapezius, and the deltoid. Less severe but preferential involvement of wrist and finger extensors was present. Serum creatine kinase was elevated (median CK, 1275 IU/L). Of note, 42.8% (6/14) had associated systemic autoimmune antibodies such as ANA, RA, and anti-Ro antibodies, whereas 36% (5/14) patients had associated interstitial lung disease (ILD). Active irritative myopathy was found in 93% (13/14) patients on needle electromyography studies, and all patients had evidence of inflammatory myopathy (polymyositis) on muscle biopsy. MRI of the cervicobrachial region was performed in the first 6 patients showing T2 hyper intensities (6/6) and contrast enhancement (4/4) of clinically affected muscles. Eighty-six percent (12/14) of patients responded to corticosteroids with an average response initiation time of 7.4 weeks (1-12 weeks). Subsequently used steroid sparing agents were azathioprine (6/14) and methotrexate (6/14). Intravenous immunoglobulin (IVIG) was used in 2 patients and plasmapharesis in 1 patient. Cervicobrachial polymyositis presents with predominant or isolated proximal upper limb and neck weakness. It has marked female preponderance and affects neck flexors and extensors and trapezius and deltoid muscles severely. Wrist and finger extensors are also weakened. In a proportion of patients, it is associated with serological markers of autoimmune disorders and interstitial lung disease. In addition to serum creatine kinase, electromyography, and muscle biopsy, magnetic resonance imaging forms a noninvasive adjunct test in the diagnostic process. Because of the pattern of weakness, cervicobrachial polymyositis tends to be confused with other common neurological conditions having upper girdle weakness, leading to delay in the diagnosis of this potentially treatable condition.

G.P.234: A family with late-onset spinal muscular atrophy with remarkable phenotypic variability, influenced by SMN2 copy number

Spinal muscular atrophy (SMA) is a heterogeneous neuromuscular disease of progressive degeneration of anterior horn motor neuron due to homozygous mutation of the survival motor neuron gene (SMN1). Recently, the difference in the SMN2 copy number is considered a critical factor influencing the severity of the disease. We present 2 patients of the same family diagnosed as late onset SMA, genetically confirmed to have homozygous deletion of exon 7 and 8 in SMN1 but showed marked intra-familial variability due to difference in the SMN2 copy number variation. A 43-year old female patient presented with progressive proximal limb weakness which started during high school but did not deteriorate until her age of 40. She visited our clinic at the age of 43 when she started to have difficulty in hiking. Her elder brother was also affected but remarkably more severe in weakness. He had running difficulties during high school but his limb weakness significantly deteriorated to lose independent ambulation since late teen. After nerve conduction study, needle electromyography, muscle imaging and genetic studies, SMN1 revealed the deletion of exon 7 and 8 to make genetic diagnosis of late onset type III SMA. We also measured copy number of SMN2 by MLPA method. Interestingly, SMN2 copy number inversely matched with the severity showing 4 copies with the proband, 3 copies with her brother. We clearly demonstrated the presence of phenotypic variability within the same family, clinically and neuro-radiologically, and it matched with the difference in SMN2 copy numbers. We suggest that SMN2 copy number may be a valuable tool to explain intra-familial variability of SMA severity, and to predict the prognosis with better precision.

G.P.298: A case of bilateral neuralgic amyotrophy combined with phrenic nerve palsy

Acute bilateral brachial plexopathy or neuralgic amyotrophy is an uncommon disorder of an unknown etiology. Characteristic symptoms include acute shoulder pain followed by profound weakness of the upper extremities that usually involves C5–6 innervated muscles. Rarely, it is reported to involve lower cranial nerves or phrenic nerve. We describe a patient with bilateral neuralgic amyotrophy with phrenic nerve palsy that was proven by electrodiagnostic and pulmonary function studies. A 59-year-old man presented with acute pain in both shoulders followed by bilateral arm weakness after a strenuous hiking. He also complained of orthopnea and he could not sleep in supine position. Initial neurological examination showed no cranial nerve involvement. His motor examination showed bilateral shoulder abduction weakness of MRC grade 3, internal and external rotation of both arm showed weakness of MRC grade 4. The nerve conduction study showed bilateral upper trunk plexopathy that involved bilateral lateral antebrachial and axillary nerves. The needle electromyography study showed active denervation potentials in deltoid, supraspinatus, infraspinatus and teres minor muscles. His chest computed tomography showed elevation of the left diaphragm that was compatible with phrenic nerve palsy and follow up nerve conduction study on bilateral phrenic nerves also demonstrated a markedly decreased CMAP. He was finally diagnosed as bilateral neuralgic amyotrophy with phrenic nerve palsy and we treated him with steroid. His shoulder pain and orthopnea showed a significant improvement after two weeks but there was no motor improvement. Phrenic nerve involvement is a rare in neuralgic amyotrophy. These patients are usually confusing and diagnosed lately due to orthopnea. Neurologists should be aware of such disease, as early diagnosis and prompt treatment is detrimental in relieving pain that consequently result in a faster recovery from various neurologic deficits.