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Publisher Summary This chapter discusses the epidemiology and classification of traumatic peripheral nerve injuries, the effects of these injuries on nerve and muscle, and how electrodiagnosis is used to help classify the injury. Traumatic injury to peripheral nerves results in considerable disability across the world. In peacetime, peripheral nerve injuries result commonly from motor vehicle accident trauma and less commonly from penetrating trauma, such as falls and industrial accidents. If plexus and root injuries are also included, the incidence is about 5%. In the upper limb, the nerve injured most commonly is the radial nerve, followed by the ulnar and median nerves. Lower limb peripheral nerve injuries are less common, and the sciatic nerve is injured most frequently, followed by the peroneal and rarely the tibial or femoral nerves. Peripheral nerve injuries may be seen in isolation, but they also often accompany central nervous system (CNS) trauma. Peripheral nerve injuries have significant impact, as they impede the recovery of function and return to work. There is also a risk of secondary disability from falls, fractures, or other injuries.

Background: The scratch collapse test (SCT) is a clinical examination maneuver that has been previously reported as a reliable and reproducible test to diagnose carpal tunnel syndrome (CTS). The initial study by Cheng et al in 2008 showed a simple test with high sensitivity. However, subsequent attempts to reproduce those findings have resulted in lower accuracy. Our goal was to evaluate the use of the SCT for patients presenting with symptoms of pain, numbness, or weakness in an upper extremity. Methods: Forty patients were referred to the electrodiagnostic (EDX) lab for evaluation of an upper extremity. One blinded examiner who was familiar with the maneuver performed the SCT on all 40 patients. Another physician or technician performed the nerve conduction study and electromyography. Patient history and accompanying physical examination findings were not revealed to the SCT examiner. Results: The relationship between the SCT performed by a blinded examiner and the EDX performed by blinded examiners was nonsignificant ( P = .676) and showed a sensitivity of 0.48, specificity of 0.59, positive predictive value of 0.61, and negative predictive value of 0.45. Conclusion: Based on this study and previous findings by other authors, we would advise against the use of the SCT in CTS for important patient-care decisions, such as surgical decision-making, until future research is done. It is possible that the SCT, in combination with other physical examination maneuvers, could increase diagnostic accuracy and enhance patient management.

Distal upper extremity weakness is a rare complication after herpes zoster, which can be easily misdiagnosed by other nerve entrapment syndromes. We present a 31-year-old immunocompromised woman who developed a claw-like deformity of her right hand after full medical treatment and resolution of herpes zoster. The electrodiagnostic finding was compatible with right multiple mononeuropathies of the median and ulnar nerves, ongoing axonal loss, unlike the nerve entrapment patterns. The early recognition and early electrodiagnosis of herpes zoster-induced distal motor weakness, especially in the upper extremity, is necessary to exclude the nerve entrapment syndrome and to be the baseline for functional motor recovery prediction. The prognosis of functional motor recovery is considered good but may take months to years to accomplish. Rehabilitation management plays an important role after full medical treatment.

Over the past 2 decades, the surgical treatment of brachial plexus and peripheral nerve injuries has advanced considerably. Nerve transfers have become an important surgical tool in addition to nerve repair and grafting. Electrodiagnosis has traditionally played a role in the diagnosis and localization of peripheral nervous system injuries, but a different approach is needed for surgical decision-making and monitoring recovery. When patients have complete or severe injuries they should be referred to surgical colleagues early after injury, as outcomes are best when nerve transfers are performed within the first 3 to 6 mo after onset. Patients with minimal recovery of voluntary activity are particularly challenging, and the presence of a few motor unit action potentials in these individuals should be interpreted on the basis of timing and evidence of ongoing reinnervation. Evaluation of potential recipient and donor muscles, as well as redundant muscles, for nerve transfers requires an individualized approach to optimize the chances of a successful surgical intervention. Anomalous innervation takes on new importance in these patients. Communication between surgeons and electrodiagnostic medicine specialists (EMSs) is best facilitated by a joint collaborative clinic. Ongoing monitoring of recovery post-operatively is critical to allow for decision making for continued surgical and rehabilitation treatments. Different electrodiagnostic findings are expected with resolution of neurapraxia, distal axon sprouting, and axonal regrowth. As new surgical techniques become available, EMSs will play an important role in the assessment and treatment of these patients with severe nerve injuries.

INTRODUCTION/AIMS: Isolated injuries to the lateral cutaneous nerve of the calf (LCNC) branch of the common peroneal nerve can cause obscure chronic posterolateral knee and upper calf pain and sensory symptoms. Routine examination and electrodiagnostic testing do not detect them because the LCNC has no motor distribution and it is not interrogated by the typical peroneal nerve conduction study. There are only about 10 prior cases, thus scant physician awareness, so most LCNC injuries remain misdiagnosed or undiagnosed, hindering care. METHODS: We extracted pertinent records from seven patients with unexplained posterolateral knee/calf pain, six labeled as complex regional pain syndrome, to investigate for mononeuropathies. Patients were asked to outline their skin area with abnormal responses to pin self-examination independently. Three underwent an LCNC-specific electrodiagnostic study, and two had skin-biopsy epidermal innervation measured. Cadaver dissection of the posterior knee nerves helped identify potential entrapment sites. RESULTS: Initiating events included knee surgery (three), bracing (one), extensive kneeling (one), and other knee trauma. All pin-outlines included the published LCNC neurotome. One oftwo LCNC-specific electrodiagnostic studies revealed unilaterally absent potentials. Longitudinal, controlled skin biopsies documented profound LCNC-neurotome denervation then re-innervation contemporaneous with symptom recovery. Cadaver dissection identified the LCNC traversing through the dense fascia of the proximolateral gastrocnemius muscle insertion. DISCUSSION: Isolated LCNC mononeuropathy can cause unexplained posterolateral knee/calf pain syndromes. This series characterizes presentations and supports patient pin-mappings as a sensitive, globally available, low-cost diagnostic aid. Improved recognition may facilitate more rapid, accurate diagnosis and, thus, optimize management and improve outcomes.

BACKGROUND Herpes zoster is a painful infectious disease caused by the varicella zoster virus. Herpes zoster radiculopathy, which is a type of segmental zoster paresis, can complicate the disease and cause motor weakness. This complication should be considered when a patient with a rash complains of acute-onset motor weakness, and the diagnosis can be verified via electrodiagnostic study. CASE SUMMARY A 64-year-old female with a history of asthma presented to the emergency department with stabbing pain, an itching sensation, and a rash on the right anterior shoulder that had begun 5 d prior. Physical examination revealed multiple erythematous grouped vesicles in the right C4-5 and T1 dermatome regions. Because herpes zoster was suspected, the patient immediately received intravenous acyclovir. On the third hospital day, she complained of motor weakness in the right upper extremity. Magnetic resonance imaging of the cervical spine revealed mild intervertebral disc herniation at C4-C5 without evidence of nerve root compression. On the 12th hospital day, electrodiagnostic study revealed right cervical radiculopathy, mainly in the C5/6 roots. Six months later, monoparesis resolved, and follow-up electrodiagnostic study was normal. CONCLUSION This case emphasizes that clinicians should consider the possibility of post-herpetic paresis, such as herpes zoster radiculopathy, and that electrodiagnostic study is useful for diagnosis and follow-up.

Elsberg syndrome is a rare cause of lumbosacral radiculitis with concomitant thoracic and lumbosacral myelitis that can be seen after an acute or reactivated viral infection. After the initial coronavirus surge in New York City, a 68-year-old man developed progressive lower extremity weakness and a defined sensory level at the lower abdomen. He had highly elevated SARS-CoV-2 IgG antibodies despite an absence of preceding COVID-19 symptoms. Serial electrodiagnostic testing revealed absent lower extremity late responses, with otherwise normal distal sensorimotor conductions. Electromyography revealed active neurogenic changes and reduced motor unit recruitment in the L3-L4 myotomes. Treatment with methylprednisolone and intravenous immunoglobulin was followed by minimal clinical improvement but re-emergence of the lower extremity late responses on electrodiagnostic testing. We report here, to the best of our knowledge, the first case of suspected COVID-19-associated Elsberg syndrome, which expands the spectrum of neuromuscular manifestations associated with SARS-CoV-2 infection and sheds light on ways to approach diagnostic and treatment options for these patients.

Nerve conduction studies and electromyography are useful diagnostic tools that neurologists use to diagnose diseases of the peripheral nerves, neuromuscular junction, and muscles. These tests are considered an extension of clinical history and examination, and their results should always be interpreted with the clinical context. Neuromuscular diseases are common and affect a large proportion of the elderly population. With an aging population in expansion, these diseases are expected to become even more prevalent. It is important to highlight the basics of electrophysiology and provide a reference for providers who are planning to send their patients to electromyographers for these studies.V.

Dougho Park,1 Byung Hee Kim,1 Sang-Eok Lee,1 Dong Young Kim,2 Yoon Sik Eom,2 Jae Man Cho,3 Joong Won Yang,3 Mansu Kim,3 Heum Dai Kwon3 1Department of Rehabilitation Medicine, Spine and Joint Center, Pohang Stroke and Spine Hospital, Pohang, Republic of Korea; 2Department of Orthopedic Surgery, Spine and Joint Center, Pohang Stroke and Spine Hospital, Pohang, Republic of Korea; 3Department of Neurosurgery, Spine and Joint Center, Pohang Stroke and Spine Hospital, Pohang, Republic of KoreaCorrespondence: Dougho ParkDepartment of Rehabilitation Medicine, Spine and Joint Center, Pohang Stroke and Spine Hospital, 352, Huimang-Daero, Nam-Gu, Pohang, 37659, Republic of KoreaTel +82 54 289 9171Fax +82 54 289 9100Email parkdougho@gmail.comPurpose: A bifid median nerve (BMN) is not a rare variant. This study aimed to investigate the features of carpal tunnel syndrome (CTS) accompanied by BMN.Patients and Methods: In this retrospective study, we defined a BMN group as CTS with BMN and a non-bifid median nerve (NMN) group as CTS without BMN. All hands were assigned to four severity grades according to the findings of electrodiagnosis (EDx): very mild, mild, moderate, and severe. The cross-sectional area (CSA) of the median nerve, palmar bowing of the flexor retinaculum, and persistent median artery (PMA) were assessed by ultrasonography. Numerical pain rating scale (NRS) and symptom duration were assessed as clinical variables.Results: Sixty-four hands (57 patients) and 442 hands (341 patients) were enrolled in the BMN and the NMN groups, respectively. BMN was prevalent in 12.6% of all CTS hands. The distribution of EDx severity grade was milder in the BMN group than in the NMN group (P< 0.001). The CSA of the BMN group was 16.2± 4.1 mm2, slightly larger than 15.1± 4.2 mm2 in the NMN group (P=0.056). The BMN group showed higher NRS than the NMN group (5.5± 1.5 and 4.4± 1.7, respectively; P< 0.001). In the subgroup analysis, NRS was significantly higher in the BMN group than in the NMN group at all EDx severity grades. In the BMN group, the PMA group showed greater EDx severity (P=0.037) and higher NRS (6.0 and 5.0, respectively; P=0.012) than the non-PMA group. The radial side branch’s CSA was larger than that of the ulnar side branch (10.0 mm2 and 6.0 mm2, respectively; P< 0.001).Conclusion: CTS with BMN presented more severe symptoms and relatively milder EDx severity. When assessing the severity of CTS with BMN, the clinical symptoms should primarily be considered, as well as we should complementarily evaluate the EDx and ultrasonography.Keywords: carpal tunnel syndrome, bifid median nerve, electrodiagnosis, diagnostic ultrasound, pain measurement

Objective To assess the relevance of electrodiagnosis (EDX) in the cross-sectional area (CSA) of the nerve root of patients with cervical radiculopathy (CR) by using high-resolution ultrasonography (HRUS).Methods The CSAs of the cervical nerve roots at C5, C6, and C7 were measured bilaterally using HRUS in 29 patients with unilateral CR whose clinical symptoms, magnetic resonance imaging (MRI) findings, and EDXresults corresponded with each other (CR-A group), and in 26 patients with unilateral CR whose clinical symptoms and MRI findings matched with each other but did not correspond with the EDX findings (CR-B group). Results The CSA of the affected side in each nerve root was significantly larger than that of the unaffected side in both the CR-A and CR-B groups. The side-to-side difference in the bilateral CSAs of the nerve root and the ratio of the CSAs between the unaffected and affected sides were statistically larger in the CR-A group than in the CR-B group.Conclusion The increased CSAs in the CR-A group reflect the physiological changes of the cervical nerve root, which is supported by the EDX findings.

➤ Nerve injuries during shoulder arthroplasty have traditionally been considered rare events, but recent electrodiagnostic studies have shown that intraoperative nerve trauma is relatively common. ➤ The brachial plexus and axillary and suprascapular nerves are the most commonly injured neurologic structures, with the radial and musculocutaneous nerves being less common sites of injury. ➤ Specific measures taken during the surgical approach, component implantation, and revision surgery may help to prevent direct nerve injury. Intraoperative positioning maneuvers and arm lengthening warrant consideration to minimize indirect injuries. ➤ Suspected nerve injuries should be investigated with electromyography preferably at 6 weeks and no later than 3 months postoperatively, allowing for primary reconstruction within 3 to 6 months of injury when indicated. Primary reconstructive options include neurolysis, direct nerve repair, nerve grafting, and nerve transfers. ➤ Secondary reconstruction is preferred for injuries presenting >12 months after surgery. Secondary reconstructive options with favorable outcomes include tendon transfers and free functioning muscle transfers.

Background Isolated musculocutaneous nerve injury is a rare condition. Herein, we report the first case of bilateral musculocutaneous neuropathy after vigorous stretching of both upper extremities with normal results of sensory nerve action potential. Clinicians should be aware of this rare condition that can appear bilaterally. In addition, the interpretation of the aberrant electrodiagnostic study results of this case was discussed. Case summary A 29-year-old male complaining of bilateral forearm tingling and upper extremity weakness visited the outpatient clinic. The symptoms began 6 mo prior, and he visited another hospital before visiting our department. The diagnosis was not made even after cervical spine magnetic resonance imaging, electrodiagnostic study, brain magnetic resonance imaging, and arteriography were conducted. The patient performed unique exercises that stretched the pectoralis minor and coracobrachialis muscles. On the follow-up electrodiagnostic study, abnormal spontaneous activities in the bilateral biceps and brachialis muscles were observed. The patient was diagnosed with bilateral musculocutaneous neuropathy. Steroid pulse therapy was administered for approximately 6 wk. After treatment, his muscle strength returned to the predisease condition. Conclusion Clinicians should be aware of this condition, have adequate understanding of anatomy, and advise to correct inappropriate exercises.

Background: Internationally approved electrodiagnostic criteria for Guillain Barre syndrome lack in children. We intended to compare the diagnostic accuracy of the currently available five electrophysiological criteria for childhood Guillain Barre Syndrome (GBS) at the time of sentinel assessment. Methodology: In this single-center study, data of children diagnosed with GBS between January 2013 to December 2017 were retrieved. Patient charts were reviewed for clinical features, electrophysiological recordings. The electrodiagnostic results (4 motor nerves and two sensory nerves in upper limbs and lower limbs) were reanalyzed and were classified based on Dutch group; Ho; Hadden; Hughes and Rajabally criteria for GBS. Results: During this study period, of the 205 children with clinical features of GBS, 15 children had incomplete electrophysiological data, and four children were excluded due to missing data. The mean age of onset of the 186 children enrolled was 77 months; the median duration from symptom onset to electrodiagnostic evaluation was seven days; pure motor and motor-sensory form of GBS was seen in 71 and 115 children. Based on the Hadden criteria, a demyelinating pattern was noted in 57 children; axonal in 37; Inexcitable in 84 and Equivocal in 8 children. The sensitivity of the various criteria ranged from 71% to 100% for demyelination, 97% to 100% for axonal. The degree of agreement using Hadden and Rajabally criteria for Equivocal subtypes was 0.93. Conclusions: The Rajabally criteria showed the best sensitivity, specificity and diagnostic accuracy for electrodiagnosis of GBS in children when compared against Hadden criteria.

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.

Monoclonal gammopathy is encountered quite frequently in the general population. This type of hematologic abnormality may be mild, referred to as monoclonal gammopathy of undetermined significance or related to different types of hematologic malignancies. The association of a peripheral neuropathy with monoclonal gammopathy is also fairly common, and hemopathy may be discovered in an investigation of peripheral neuropathy. In such a situation, it is essential to determine the exact nature of the hematologic process in order not to miss a malignant disease and thus initiate the appropriate treatment (in conjunction with hematologists and oncologists). In this respect, nerve biopsy (discussed on a case-by-case basis) is of great value in the management of such patients. We therefore propose to present the objectives and main interests of nerve biopsy in this situation.

A literature review was performed on the use of electrodiagnostic (EDX) tests including nerve conduction study, electromyography, exteroceptive reflex, blink reflex, and late response in the evaluation of patients with stiff person syndrome (SPS). A web survey was conducted to report the extent of EDX testing usage in the evaluation of SPS among laboratories accredited by the American Academy of Neuromuscular and Electrodiagnostic Medicine. Coactivation of selected agonist and antagonist muscles was performed in 5 healthy subjects to determine its specificity for SPS. Observation of continuous motor unit activity on electromyography and elicitation of exteroceptive reflexes by electric stimulation are informative in assisting a diagnosis of SPS, but further studies focusing on their sensitivities in diagnosing SPS and specificities in differentiating SPS from other movement disorders are needed. The value of EDX testing in SPS lies in ruling out other neuromuscular disorders.

Highlights • In Berrettinni anastomosis, frequently a sensory communicating branch from ulnar nerve supplies digit 3. • Despite anatomical evidence of ulnar communicating branch providing sensory supply to digit 2, there are no electrodiagnostic descriptions of the same. • Electrodiagnostic findings in a patient with median nerve laceration were suggestive of ulnar sensory innervation of digit 2. • Knowledge of existence of these communications and their electrodiagnostic features can prevent misdiagnosis and iatrogenic injuries., Introduction Berrettini Anastomosis is a common purely sensory anastomosis between ulnar and median nerves in palm. Here, via a communicating branch, ulnar nerve can provide sensory supply to digits 3 and 2.There have been electrodiagnostic (EDX) descriptions of the former. However, till date, to the best of our knowledge, there have been no EDX descriptions of the latter. Here, in our case report we would like to describe first instance of the same. Presentation of case During an assault with a knife a 25-year-old male sustained laceration injury of right median nerve and flexor tendons which were repaired surgically. During rehabilitation, a nerve conduction study (NCS) was performed which incidentally revealed that ulnar nerve was responsible for sensory innervation of digit 2. Discussion Until recently, it was generally believed that EDX of BA was not possible. However, recent studies on EDX features in BA, have recorded small sensory nerve action potentials (SNAP) from digit 3 on distal ulnar nerve stimulation. But there are no published reports where SNAP from digit 2 on ulnar nerve stimulation were studied, even though anatomical evidence of the same exists. In our patient, we incidentally recorded the same. Conclusion Although our patient had a complete laceration of median nerve, he did not have major sensory disturbances. NCS findings suggested sensory supply of digits 5, 4, 3 and 2 were by ulnar nerve. Without adequate knowledge of communicating branch crossovers in palm, there is a possibility that clinical findings can be misdiagnosed and NCS features can be misinterpreted. For surgeons, awareness of these communicating branches can prevent iatrogenic injuries during surgical interventions.

Background The clinical characteristics of electrophysiological subtypes and prognostic factors of Mexican adults diagnosed with Guillain-Barre Syndrome (GBS) have not been described. Materials and methods A single center, ambispective, cohort study was performed (2015–2019). GBS was defined following the Asbury and Cornblath criteria. Electrodiagnosis was made according to Hadden criteria. Clinical, biochemical and electrodiagnostic parameters were described, compared and analyzed using a multivariate model. Only patients who completed a 3-month follow-up were included. Results 137 GBS patients (92 males; mean age 46.6 ± 16.6). 132 (96.3%) underwent an electrodiagnostic assessment. 68 (51.5%) were classified as axonal GBS, with further classified into two groups: acute motor axonal neuropathy (AMAN) 45.4%, and acute motor and sensory axonal neuropathy (AMSAN) 8,6%. The following characteristics were lower in the AMAN group: Medical Research Counsel sumscore (MRC) 30.1 ± 16.3 vs 36.4 ± 14.4, unilateral facial palsy 10% vs 25.9% and albuminocytologic dissociation 41.3% vs. 71.7%. Multivariate analysis found AMAN as an independent predictor of an unfavorable outcome OR: 3.34 (p = 0.03) Conclusions AMAN subtype is the most frequent presentation of GBS in Mexican adult patients and an independent predictor of inability to walk independently at 3 months after discharge.

Objective To identify the difference of quantitative radiologic stenosis between a normal latency group and an abnormal latency group, and to investigate the association of dermatomal somatosensory-evoked potential (DSEP) with magnetic resonance imaging (MRI) findings of narrowing in patients with lumbar spinal stenosis (LSS).Methods We retrospectively reviewed the clinical records and P40 latencies of L5 DSEP of 40 patients with unilateral symptoms of LSS at the L4–5 disc level. Quantitative assessments of stenosis in lumbar spine MRI were performed with measurements of the anteroposterior diameter (APD), cross-sectional area (CSA) of the dural sac, ligamentous interfacet distance (LID), CSA of the neural foramen (CSA-NF), and subarticular zone width. Analyses were conducted through comparisons of radiologic severity between the normal and abnormal latency groups and correlation between radiologic severity of stenosis and latency of DSEP in absolute (APD

ObjectiveTo improve myasthenia gravis (MG) autoantibody testing.MethodsMG serologic tests with confirmatory or refuting clinical–electrodiagnostic (EDX) testing and cancer evaluations were reviewed over 4 years (2012–2015). All patients had acetylcholine receptor–binding (AChR-Bi), modulating (AChR-Mo), and striational (STR) autoantibody testing, and negatives reflexed to muscle-specific kinase (MuSK). Thymoma and cancer occurrences were correlated with STR and reflexed glutamic acid decarboxylase 65 (GAD65), ganglionic acetylcholine receptor (α3), collapsin response mediating protein-5, and voltage-gated potassium channel complex autoantibodies.ResultsOf 433 samples tested, 133 (31%) met clinical–EDX criteria for MG. Best sensitivity (90%) occurred at AChR-Bi >0.02 nmol/L, leaving 14 negative (6 ocular MG, 7 generalized MG, 1 MuSK MG) with specificity 90% (31 false-positives). Using AChR-Mo antibodies (>20% loss), specificity was better (92%, 24 false-positives), but sensitivity dropped (85%). Specificity improved (95%) by testing AChR-Mo when AChR-Bi are positive, resulting in 45% reduction of false-positives (31–17), maintaining AChR-Bi 90% sensitivity. Cutoff values recommended by area under the curve analysis did not outperform this approach. AChR-Bi and AChR-Mo values were significantly higher in true-positives. CT evaluations in 121 MG samples revealed 16 thymomas. Historical or subsequent cancers occurred in 22. STR and reflexed autoantibodies were not more common in MG with thymoma or other cancers. Full-body CT (n = 34) was performed in those with STR and reflex autoantibody positivity, but without additional cancers found.ConclusionAccuracy of MG serologic testing is improved by reflexing AChR-Bi–positive cases to AChR-Mo. STR and other reflexed cancer evaluation autoantibodies did not provide value beyond standard CT chest imaging at the time of MG diagnosis. Diagnostic certainty is informed by AChR-Bi and AChR-Mo with higher values increasing specificity.

OBJECTIVE To compare the grating visual acuity (VA) measured by visual evoked potentials (VEP) in phakic, aphakic, and pseudophakic Poodles. ANIMALS STUDIED Thirty-six Poodle dogs aged from 4 to 14 years. PROCEDURES Animals were allocated into three different groups according to their lens status: phakic group (n = 12), aphakic group (n = 12), and pseudophakic group (n = 12). Grating VA was measured in cycles/degree (cpd) in all animals using the electrodiagnosis system Roland RETIport® in a dark room without using any mydriatic, sedative, or anesthetic drugs. RESULTS The mean grating VA in the phakic, aphakic, and pseudophakic groups was 5.9 ± 1.0 cpd (20/102-Snellen equivalent), 2.6 ± 0.7 cpd (20/231), and 5.2 ± 1.1 cpd (20/116), respectively. The VA from aphakic eyes was significantly lower when compared to the phakic and pseudophakic eyes (P

Persons with back, neck, and limb symptoms constitute a major referral population to specialists in electrodiagnostic (EDX) medicine. The evaluation of these patients involves consideration of both the common and less common disorders. The EDX examination with needle electromyography (EMG) is the most important means of testing for radiculopathy. This test has modest sensitivity but high specificity and well complements imaging of the spine. Needle EMG in combination with nerve conduction testing is valuable in excluding entrapment neuropathies and polyneuropathy-conditions that frequently mimic radicular symptoms. In this first of a two-part review, the optimal EDX evaluation of persons with suspected radiculopathy is presented. In part two, the implications of EDX findings for diagnosis and clinical management of persons with radiculopathy are reviewed.

Deep gluteal syndrome is an increasingly recognized disease entity, caused by compression of the sciatic or pudendal nerve due to non-discogenic pelvic lesions. It includes the piriformis syndrome, the gemelli-obturator internus syndrome, the ischiofemoral impingement syndrome, and the proximal hamstring syndrome. The concept of the deep gluteal syndrome extends our understanding of posterior hip pain due to nerve entrapment beyond the traditional model of the piriformis syndrome. Nevertheless, there has been terminological confusion and the deep gluteal syndrome has often been undiagnosed or mistaken for other conditions. Careful history-taking, a physical examination including provocation tests, an electrodiagnostic study, and imaging are necessary for an accurate diagnosis. After excluding spinal lesions, MRI scans of the pelvis are helpful in diagnosing deep gluteal syndrome and identifying pathological conditions entrapping the nerves. It can be conservatively treated with multidisciplinary treatment including rest, the avoidance of provoking activities, medication, injections, and physiotherapy. Endoscopic or open surgical decompression is recommended in patients with persistent or recurrent symptoms after conservative treatment or in those who may have masses compressing the sciatic nerve. Many physicians remain unfamiliar with this syndrome and there is a lack of relevant literature. This comprehensive review aims to provide the latest information about the epidemiology, aetiology, pathology, clinical features, diagnosis, and treatment. Cite this article: Bone Joint J 2020;102-B(5):556–567.

Automatic sleep staging methods usually extract hand-crafted features or network trained features from signals recorded by polysomnography (PSG), and then estimate the stages by various classifiers. In this study, we propose a classification approach based on a hierarchical neural network to process multi-channel PSG signals for improving the performance of automatic five-class sleep staging. The proposed hierarchical network contains two stages: comprehensive feature learning stage and sequence learning stage. The first stage is used to obtain the feature matrix by fusing the hand-crafted features and network trained features. A multi-flow recurrent neural network (RNN) as the second stage is utilized to fully learn temporal information between sleep epochs and fine-tune the parameters in the first stage. The proposed model was evaluated by 147 full night recordings in a public sleep database, the Montreal Archive of Sleep Studies (MASS). The proposed approach can achieve the overall accuracy of 0.878, and the F1-score is 0.818. The results show that the approach can achieve better performance compared to the state-of-the-art methods. Ablation experiment and model analysis proved the effectiveness of different components of the proposed model. The proposed approach allows automatic sleep stage classification by multi-channel PSG signals with different criteria standards, signal characteristics, and epoch divisions, and it has the potential to exploit sleep information comprehensively.

INTRODUCTION Research has shown that quality of health-care services is often suboptimal. Little is known about the quality of electrodiagnostic testing. METHODS We prospectively recruited 477 adults with workers' compensation claims for carpal tunnel syndrome (CTS) from 30 occupational health clinics and evaluated whether electrodiagnostic testing adhered to five process-oriented quality measures. RESULTS Among patients who had surgery for CTS, nearly all underwent recommended preoperative electrodiagnostic testing (measure #1, 170 of 174, 97.7%). Most electrodiagnostic tests included essential components (measure #2, 295 of 379, 77.8%). However, few reports documented skin temperature (measure #3, 93 of 379, 24.5%) and criteria were seldom met for interpreting test findings as consistent with CTS (measure #4, 41 of 284, 14.4%) or "severe" CTS (measure #5, 8 of 46, 17.4%). DISCUSSION Most patients underwent testing before surgery, but test quality was often suboptimal. This work lays the groundwork for future efforts to monitor and improve the quality of electrodiagnostic testing for CTS.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is considered to be an immune-mediated heterogeneous disease involving cellular and humoral immunity. In recent years, autoantibodies against nodal/paranodal protein neurofascin155 (NF155), neurofascin186 (NF186), contactin-1 (CNTN1), and contactin-associated protein 1 (CASPR1) have been identified in a small subset of patients with CIDP, which disrupt axo-glial interactions at nodes/paranodes. Although CIDP electrodiagnosis was made in patients with anti-nodal/paranodal component autoantibodies, macrophage-induced demyelination, the characteristic of typical CIDP, was not observed. Apart from specific histopathology, the pathogenic mechanisms and clinical manifestations of CIDP with autoantibody are also distinct. We herein compared pathogenesis, histopathology, clinical manifestations, and therapeutic response in CIDP with autoantibody vs. CIDP without autoantibody. CIDP with autoantibodies should be considered as an independent disease entity, not a subtype of CIDP due to many differences. They possibly should be classified as CIDP-like chronic nodo-paranodopathy, which can better characterize these disorders, help diagnose and make the most effective therapeutic decisions.

Objective : Gastric slow wave abnormalities have been associated with gastric motility disorders. Invasive studies in humans have described normal and abnormal propagation of the slow wave. This study aims to disambiguate the abnormally functioning wave from one of normalcy using multi-electrode abdominal waveforms of the electrogastrogram (EGG). Methods : Human stomach and abdominal models are extracted from computed tomography scans. Normal and abnormal slow waves are simulated along stomach surfaces. Current dipoles at the stomachs surface are propagated to virtual electrodes on the abdomen with a forward model. We establish a deep convolutional neural network (CNN) framework to classify normal and abnormal slow waves from the multi-electrode waveforms. We investigate the effects of non-idealized measurements on performance, including shifted electrode array positioning, smaller array sizes, high body mass index (BMI), and low signal-to-noise ratio (SNR). We compare the performance of our deep CNN to a linear discriminant classifier using wave propagation spatial features. Results : A deep CNN framework demonstrated robust classification, with accuracy above 90% for all SNR above 0 dB, horizontal shifts within 3 cm, vertical shifts within 6 cm, and abdominal tissue depth within 6 cm. The linear discriminant classifier was much more vulnerable to SNR, electrode placement, and BMI. Conclusion : This is the first study to attempt and, moreover, succeed in using a deep CNN to disambiguate normal and abnormal gastric slow wave patterns from high-resolution EGG data. Significance : These findings suggest that multi-electrode cutaneous abdominal recordings have the potential to serve as widely deployable clinical screening tools for gastrointestinal foregut disorders.

Purpose: To evaluate effectiveness of ultrasonographic measurement of carpal tunnel by anatomical area and correlation with electrodiagnostic study in diagnosis of carpal tunnel syndrome.Methods: From September 2018 to March 2019, we performed the ultrasonography for 30 cases with carpal tunnel syndrome diagnosed with electrodiagnosis and 30 cases as control group. We measured median nerve diameter, cross-sectional area (CSA), and flattening ratio (FR) by area of carpal tunnel. We analyzed the difference of measurement between two groups and correlate the measurement with electrodiagnosis findings.Results: There was significant statistically differences in sonographic measurement between two groups by independent t-test (CSA zone 1, p=0.01; FR zone 2, p=0.000; FR zone 3; p=0.001). With Pearson correlation test, there was correlation between sonographic measurement and electrodiagnostic findings (terminal latency and nerve conduction velocity) statistically, but the Pearson coefficient was low (r

INTRODUCTION Brody myopathy (BM) is a recessive condition caused by mutations in the ATP2A1 gene and usually induces impaired muscle relaxation during and after exercise. Diagnosis relies on needle electromyography showing electrical silence, muscle biopsy with decreased sarcoplasmic reticulum calcium adenosine triphosphatase activity, and genetic analysis. Electrodiagnostic functional analyses are useful in the diagnosis of channelopathies, and thus may be impaired in BM. METHODS We performed exercise tests and repetitive nerve stimulation (RNS; 10 supramaximal stimuli at 3 Hz) in 10 patients with BM. RESULTS All participants showed incremental responses on RNS. Compound muscle action potential amplitude was increased and duration was decreased, especially in the ulnar nerve (+30.2 ± 7.1% and - 30.3 ± 2.8%, respectively; both P

Objectives: Although compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes of the nerves are reduced in sciatic nerve injury due to intramuscular injection (SNIII), they may still be higher than the reference values if there is a mild axonal degeneration. In this case, comparing the outcomes of nerve conduction studies of intact and affected lower extremities becomes important. We aimed to determine the role of this comparison in the diagnosis of SNIII. Methods: Patients with SNIII were included. Reference values for lower extremity nerve conduction studies were obtained from healthy participants. Peroneal, posterior tibial, superficial peroneal, and sural nerve conduction studies were performed in both lower extremities. In the first analysis, the CMAP or SNAP amplitude of the nerve was considered abnormal if it was less than the reference value. In the second analysis, the CMAP or SNAP amplitude of the nerve was considered abnormal if it was less than the reference value or

ObjectiveCompare high-resolution ultrasound (HRUS) and electrodiagnostic examination (EDX) in the diagnostic workup of patients with scapulae alatae.Methods27 patients with scapulae alatae and 41 healthy subjects (HS) and underwent a standardized clinical examination (CEX), EDX and HRUS. We measured the thickness of the serratus anterior (SER), rhomboid major and trapezius muscles and the diameter of the long thoracic (LTN), dorsal scapular and spinal accessory nerves (SAN).ResultsTwenty patients showed medial winging and six patients showed lateral winging on CEX. One patient had both lateral and medial winging. In patients with medial winging, the SER muscle was thinner and the LTN diameter was larger on the symptomatic side compared with the asymptomatic side and with the dominant side in HS. In this group, both EDX and HRUS detected abnormalities of SER muscle/ LTN with sensitivity of 65%, and with specificity of 100% and 57%, respectively.EDX and HRUS detected abnormalities of the trapezius muscle/ SAN with sensitivity of 60% and 40%, and specificity of 91%, and 86 % a, respectively. There was no significant difference between the two methods.ConclusionHRUS can contribute to the diagnostic workup of scapulae alatae by demonstrating atrophy of muscles and enlargement in nerve diameter.SignificanceHRUS supplements EDX in the diagnostic workup of scapulae alatae.KeywordsScapulae alataeScapular wingingLong thoracic nerveSerratus anterior musclebrachial plexusspinal accessory nerve

Neonatal brachial plexus palsy (NBPP) is a prominent form of newborn morbidity with a potentially disabling persistence. Neurosurgical intervention is indicated in select NBPP patients. Early prognostic assessment would facilitate rational selection of those infants for surgery. We conducted a systematic literature review to determine the prognostic value of early electrodiagnosis (EDx) in NBPP. We included 16 observational studies with a total sample size of 747 children. Risk of bias and quality of evidence were rated. Wide variation was found in EDx techniques, outcome algorithms, and decisionmaking. Nevertheless, the most methodologically sound studies support the use of EDx, at standardized time-frames, as a key prognostic modality for complementing clinical judgment and neuroimaging. An accurate knowledge of the underlying anatomy of the nerve injury helps to counsel families and to guide reconstructive strategy.

Background & aimsInvasive gastric electrical mapping has revealed spatial abnormalities of the slow wave in subjects with gastroparesis and functional gastrointestinal disorders. Cutaneous high-resolution electrogastrography (HR-EGG) is a non-invasive method that can detect spatial features of the gastric slow wave. We performed HR-EGG in subjects with active foregut symptoms to evaluate associations between gastric myoelectric abnormalities, symptoms (based on a validated questionnaire), and gastric emptying.MethodsWe performed a case-control study of 32 subjects, including 7 healthy individuals (controls), 7 subjects with functional dyspepsia and normal gastric emptying, and 18 subjects with gastroparesis, from a tertiary care program. All subjects were assessed by computed tomography imaging of the abdomen and HR-EGG and completed the PAGI-SYM questionnaire on foregut symptoms, which includes the gastroparesis cardinal symptom index. We performed volume reconstruction of the torso and stomach from computed tomography images to guide accurate placement of the HR-EGG array.ResultsSpatial slow-wave abnormalities were detected in 44% of subjects with foregut symptoms. Moreover, subjects with a higher percentage of slow waves with aberrant propagation direction had a higher total gastroparesis cardinal symptom index score (r= 0.56; P < .001) and more severe abdominal pain (r= 0.46; P= .009). We found no correlation between symptoms and traditional EGG parameters.ConclusionsIn case-control study, we found that the genesis of symptoms of functional dyspepsia and gastroparesis is likely multifactorial, including possible contribution from gastric myoelectric dysfunction. Abnormal spatial parameters, detected by cutaneous HR-EGG, correlated with severity of upper gastrointestinal symptoms, regardless of gastric emptying. This noninvasive, repeatable approach might be used to identify patients for whom gastric myoelectric dysfunction contributes to functional dyspepsia and gastroparesis.

Conventional parameters used in electrodiagnosis of ulnar neuropathy at elbow (UNE) are: (i) absolute across-elbow ulnar nerve motor conduction velocity (MCV), (ii) reduction rate of composed muscle action potential (CMAP) amplitude from above to below elbow stimulation, and (iii) MCV difference between forearm and across-elbow segment. We aimed to search the diagnostic accuracy values of these parameters on UNE, and their correlations with axonal dysfunction of ulnar nerve fibers.Arms with clinical signs of UNE and two-fold healthy controls were included. We detected the best cut off points of the measured parameters and their possible combinations. Their diagnostic accuracy values and correlations with parameters reflecting the axonal functions were analyzed, statistically.Totally, 118 arms with UNE and 236 controls were included. Absolute across-elbow MCV yielded a higher accuracy than MCV difference and reduction rate of CMAP amplitude (p = 0.010 and p˂0.001, respectively). Besides, combining it with other parameters did not increase the diagnostic yield. Correlation analyses revealed that the only parameter having positive linear correlations with sensory nerve action potential amplitudes both in the control and the disease groups is the absolute across-elbow MCV. The absolute across-elbow MCVs have also positive linear correlation with CMAP amplitudes in disease group.The absolute across-elbow MCV is the most valuable conventional parameter for the electrodiagnosis of UNE. It is also the most correlated parameter with the electrodiagnostic parameters reflecting the axonal functions of the ulnar nerve fibers.A könyök területén jelentkező ulnaris neuropathia (UNE) elektrodiagnózisa során alkalmazott szokványos paraméterek a következők: 1. abszolút könyökátmetszeti ulnaris motoros idegvezetési sebesség (MCV), 2. a könyök feletti és könyök alatti táv stimulációja során mért összetett akcióspotenciál-amplitúdó (CMAP) csökkenési aránya, 3. az alsókar és a könyökszegmens közötti MCV-különbség. A vizsgálat célja az volt, hogy meghatározzuk ezen paraméterek szükséges diagnosztikus pontosságát UNE esetében, és leírjuk az ulnaris idegrostok axonalis diszfunkciójával kapcsolatos összefüggésüket.Az UNE klinikai tüneteit mutató karokat és kétszeres mennyiségű egészséges kontrollkart vontunk be a vizsgálatba. Meghatároztuk a mért paraméterek és lehetséges kombinációik legjobb határértékét. Statisztikai módszerekkel elemeztük ezek diagnosztikus pontosságát és leírtuk az axonalis funkciókat leíró paraméterekkel való összefüggéseiket.Összesen 118 UNE-s kart és 236 kontroll­kart vontunk be a vizsgálatba. Az abszolút könyökátmetszeti MCV nagyobb pontosságot eredményezett, mint az MCV- kü­lönbség és a CMAP-amplitúdó csökkenési aránya (p = 0,010 és p ˂ 0,001). Ezenfelül az MCV és a többi para­mé­ter kom­bi­nációja nem növelte a diagnosztikus pontosságot. A korrelációs analízisek feltárták, hogy egyedül az ab­szolút kö­nyök­átmetszeti MCV mutat pozitív lineáris összefüggést a szenzoros idegvezetési akcióspotenciál-ampli­tú­dók­kal a kontroll- és a betegcsoportban egyaránt. Az ab­szolút könyökátmetszeti MCV pozitív lineáris összefüggésben áll a betegcsoportban mérhető CMAP-amplitúdókkal is.Az abszolút könyökátmetszeti MCV az UNE elektrodiagnosztizálásában használható legértékesebb konvencionális paraméter. Ezenkívül az abszolút kö­nyökátmetszeti MCV esetén a legnagyobb az összefüggés az ulnaris idegrostok axonalis funkcióját jelző elektrodiagnosztikai paraméterekkel.

This article discusses the electrodiagnostic assessment of radiculopathy. Relevant anatomy initially is reviewed followed by discussion surrounding the approach to nerve conduction studies and needle electrode examination when it comes to radiculopathy evaluation. Pitfalls of the electrodiagnosis versus clinical diagnosis of radiculopathy and the definitions of acute versus chronic, and active versus inactive, are reviewed.

This article focuses on principles of nerve conduction studies and needle electromyography applied to the electrodiagnosis of polyneuropathy. The components of the electrodiagnostic evaluation of polyneuropathy and the electrophysiological characteristics of axonal and demyelinating neuropathies and nodo-paranodopathies are reviewed.

INTRODUCTION/AIMS Neurophysiological patterns in patients with foodborne botulism are rarely described after the acute phase. We report data from a large Italian outbreak of botulism, with patients evaluated at different timepoints after poisoning. METHODS Eighteen male patients (mean age 47 ± 8.4 y) underwent 22 clinical and neurophysiological evaluations (4 patients were re-evaluated). The resting compound muscle action potential (CMAP) amplitude, postexercise CMAP amplitude, CMAP change after high-frequency (50 Hz) repetitive nerve stimulation (HFRNS), and motor unit action potentials (MUAPs) were assessed in the acute (4-8 days after poisoning; 5 patients), early post-acute (32-39 days after poisoning; 5 patients), and late post-acute (66-80 days after poisoning; 12 patients) phases. RESULTS In the acute, early post-acute, and late post-acute phases, respectively, reduced CMAP amplitudes were found in 100%, 20%, and 17% of patients; abnormal postexercise CMAP facilitation was observed in 100%, 40%, and 0% of patients; and pathological incremental responses to HFRNS were found in 80%, 50%, and 8% of patients. Baseline CMAP amplitudes, postexercise CMAP facilitation, and CMAP increases in response to HFRNS differed significantly between the acute and post-acute phases. Small MUAPs were found in 100% of patients in the acute and early post-acute phases and in 50% of patients in the late post-acute phase. DISCUSSION The neurophysiological findings of foodborne botulism vary considerably according to the evaluation time point. In the post-acute phase, different neurophysiological techniques must be applied to support a diagnosis of botulism.

A síndrome do túnel cárpico (STC) afeta 3% da população e deve-se à compressão do nervo mediano no túnel cárpi­co. Este artigo pretende rever a evidência científica sobre a STC.Realizou-se uma revisão narrativa. Identificaram-se 161 artigos na pesquisa e incluíram-se na revisão dados referen­tes a 26 referências bibliográficas. A STC afeta mais as mulheres. O diagnóstico é clínico, sendo os sintomas clássicos dor, disestesias e/ou parestesias na região palmar, desde o polegar até à face radial do anelar. Quando positivas, as manobras provocatórias aumentam a suspeita diagnóstica. Os testes eletrodiagnósticos são importantes para confirmação diagnóstica, estratificação da gravidade e definição do tratamento. Perante doença ligeira/moderada, inicialmente recomenda-se tratamento conservador. Perante quadros moderados/graves, recomenda-se cirurgia.A STC é incapacitante. Perante sintomas sugestivos, deve-se equacionar este diagnóstico e realizar provas provoca­tórias. Os testes eletrodiagnósticos são importantes para diagnóstico e definição da terapêutica.