The Clinical Features of LRP4/Agrin Antibody‐Positive Myasthenia Gravis: A Multi‐center Study

Muscle disorders are characterized by differential involvement of various muscle groups. Among these, weakness predominantly affecting finger flexors is an uncommon pattern, most frequently found in sporadic inclusion‐body myositis. This finding is particularly significant when the full range of histopathological findings of inclusion‐body myositis is not found on muscle biopsy. Prominent finger flexor

With the exception of thymectomy, immune modulatory treatment strategies and clinical trials in myasthenia gravis over the past 50 y were mainly borrowed from experience in other nonneurologic autoimmune disorders. The current experimental therapy paradigm has significantly changed such that treatments directed against the pathological mechanisms specific to myasthenia gravis are being tested, in some

As the world accommodates to the COVID‐19 pandemic, routine in‐person medical services are resuming. The resumption of non‐urgent electrodiagnostic (EDX) testing faces unique challenges due to the long duration of the procedure and direct close contact with patients, including studies with risk of exposure to oropharyngeal secretions. We provide consensus guidance for resumption of EDX testing, addressing

INTRODUCTION Patients with myasthenia gravis (MG) may experience worsening symptoms outside of a clinical setting. A method of diagnosing and triaging such individuals would be valuable. This study gauged the viability of a nurse-administered single breath count test (SBCT) over the telephone for assessing MG exacerbations. METHODS This was a retrospective, single-center review of a pilot study of

Coronavirus disease 2019 (COVID‐19), caused by severe acute respiratory coronavirus 2 (SARS‐CoV‐2), is associated with Guillain‐Barré syndrome (GBS).1-8 We describe a patient with quadriplegic GBS with dysautonomia preceded by mild COVID‐19–induced diarrhea. A 72‐year‐old man with coronary artery disease, hypertension, and alcohol abuse presented to a tertiary hospital with symmetric paresthesias and

COVID-19 has created unprecedented challenges for amyotrophic lateral sclerosis (ALS) clinical care and research in the United States. Traditional evaluations for making an ALS diagnosis, measuring progression, and planning interventions rely on in-person visits that may now be unsafe or impossible. Evidence- and experience-based treatment options such as multidisciplinary team care, feeding tubes

ALS has the largest drug pipeline among neuromuscular diseases, with over 160 companies actively involved in ALS research. There is a growing need to recruit trial participants, but ALS patients often have limited mobility and most ALS trials are conducted in a small number of major centers. These factors effectively limit patient participation, particularly for those in rural areas. The current COVID-19

INTRODUCTION In contrast to needle EMG, surface electromyographic (EMG) recordings are painless. It is of interest to develop methods to analyze surface EMG for diagnostic purposes. METHODS Surface EMG interference pattern (SIP) recordings from the abductor pollicis brevis muscle of healthy subjects and subjects with amyotrophic lateral sclerosis (ALS) were analyzed by measuring root mean square (RMS)

Compound muscle action potential (CMAP) scan and MScanFit have been used to understand the consequences of denervation and reinnervation. This study aimed to monitor these parameters during Wallerian degeneration (WD) after acute nerve transections (ANT).

The loss of upper limb motor function can have a devastating effect on people's lives. To restore upper limb control and functionality, researchers and clinicians have developed interfaces to interact directly with the human body's motor system. In this invited review, we aim to provide details on the peripheral nerve interfaces and brain-machine interfaces that have been developed in the past 30 years

By head to head comparison Higashihara et al. analyze the reproducibility of two different methods estimating the number of functioning motor neurons: MScanFit motor unit number estimation (MUNE) and motor unit number index (MUNIX).. Their results reveal good reproducibility and feasibility for both methods in healthy individuals. Further, they provide the time for individual assessments, which is

In a recent article published in your journal, Kassardjian and the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) Quality and Patient Safety Committee have drafted a practical guidance for managing electromyographic (EMG) requests and testing during the coronavirus disease 2019 (COVID‐19) pandemic.1 I read with great interest this study, and I agree that electrodiagnostic

INTRODUCTION Coronavirus disease 2019 (COVID-19) has rapidly become a global pandemic, but little is known about its potential impact on patients with myasthenia gravis (MG). METHODS We studied the clinical course of COVID-19 in five hospitalized patients with autoimmune MG (four with acetylcholine receptor antibodies, one with muscle-specific tyrosine kinase antibodies) between April 1, 2020-April

INTRODUCTION In this study we collected reference values for the across-tarsal-tunnel conduction of the motor tibial nerve (mTN). METHODS The mTN compound muscle action potentials (CMAPs) from the abductor hallucis muscle were obtained by stimulating below/above the malleolus and the popliteal fossa. The effect of weight, height, body mass index (BMI), foot and leg length, sex, and age were evaluated

INTRODUCTION Fatigue is a recognized manifestation of immune-mediated neuropathies, but its causes and implications are unclear. In this study, we explored the correlates of fatigue among a number of clinical parameters in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) to better understand potential contributing factors and resulting consequences. METHODS Twenty-six clinically

BACKGROUND We investigated the risk of carpal tunnel syndrome (CTS) in diabetic polyneuropathy (DPN). METHODS This study was conducted using records from the National Health Insurance System (NHIS). We divided patients diagnosed with diabetes mellitus (DM) into those with and without DPN. We assessed the effect of DPN on the risk of CTS using Cox proportional hazards regression analyses. RESULTS DPN

INTRODUCTION Monitoring grip strength at home may detect improvement between intravenous immunoglobulin (IVIg) treatments in patients with chronic inflammatory neuropathies (CINs). METHODS Fifteen patients recorded grip strength each day, from one IVIg treatment until the next. We analyzed grip strength changes comparing thresholds of 8 kPa and 14 kPa. "Random" fluctuations of grip strength were distinguished

BACKGROUND Conventional processing of nerve for histomorphometry is resource-intensive, precluding use in intraoperative assessment of nerve quality during nerve transfer procedures. Stimulated Raman scattering (SRS) microscopy is a label-free technique that enables rapid and high-resolution histology. METHODS Segments of healthy murine sciatic nerve, healthy human obturator nerve, and human cross-facial

INTRODUCTION Emery-Dreifuss muscular dystrophy (EDMD) is a disease characterized by skeletal muscle wasting, major tendon contractures, and cardiac conduction defects. Mutations in the gene encoding emerin cause EDMD1. Our previous studies suggested that emerin activation of histone deacetylase 3 (HDAC3) to reduce histone 4-lysine 5 (H4K5) acetylation (ac) is important for myogenic differentiation

INTRODUCTION The mechanism by which weakness develops in idiopathic inflammatory myopathies (IIMs) is still unclear. This study investigated the maximum force of single muscle fibers from patients with IIMs. METHODS Permeabilized single muscle fibers from patients with IIMs and healthy controls were subjected to contractility measurements. Maximum force and specific force production (maximum force

INTRODUCTION We assessed clinical predictors of mechanical ventilation in children with Guillain-Barré syndrome (GBS) in order to help identify patients who require mechanical ventilation. METHODS We retrospectively collected the clinical, laboratory and electrophysiological data of 103 children with GBS. Patients were categorized into two groups based on the requirement for mechanical ventilation

INTRODUCTION The exact mechanisms underlying neuroinflammation and how they contribute to amyotrophic lateral sclerosis (ALS) pathogenesis remain unclear. One possibility is the secretion of neurotoxic factors, such as lipocalin-2 (LCN2), that lead to neuronal death. METHODS LCN2 levels were measured in human post-mortem tissue using western blot, qPCR, and immunofluorescence, and in plasma by ELISA

INTRODUCTION Quantitative Myasthenia Gravis (QMG) and Myasthenia Gravis Activities of Daily Living (MG-ADL) scales were compared using the data from the MGTX study. METHODS Correlation between QMG and MG-ADL raw and change-from-baseline scores was calculated every 3 months for 60 months based on treatment groups and minimal manifestation status (MMS). RESULTS QMG and MG-ADL change-from-baseline scores

BACKGROUND Motor unit number index (MUNIX) is a validated electrophysiological biomarker in amyotrophic lateral sclerosis. MUNIX studies in spinal muscular atrophy (SMA) are limited. METHODS Later-onset SMA children (n = 13; three SMN2 copy number) were evaluated for Hammersmith Motor Function Scale Expanded (HMFSE) and MUNIX of right abductor pollicis brevis (APB) and abductor digiti minimi (ADM)

INTRODUCTION The best treatment strategy for mild ulnar neuropathy at the elbow (UNE) is not known, due to lack of trials comparing surgery versus conservative treatment. METHODS Patients with clinical symptoms and signs of mild UNE and an electrophysiologically or sonographically confirmed diagnosis were recruited. Patients were randomly allocated to either in situ decompression or conservative treatment

The coronavirus disease 2019 (COVID-19) pandemic has resulted in the reorganization of health-care settings affecting clinical care delivery to patients with Duchenne and Becker muscular dystrophy (DBMD) as well as other inherited muscular dystrophies. The magnitude of the impact of this public health emergency on the care of patients with DBMD is unclear as they are suspected of having an increased

INTRODUCTION To develop a new method to quantify the density of nerves, vessels, and the neurovascular contacts, we studied skin biopsies in diabetes and control subjects. METHODS Skin biopsies with dual immunofluorescent staining were used to visualize nerves and blood vessels. The density of nerves, vessels, and their neurovascular contacts were quantified with unbiased stereology. Results were compared

INTRODUCTION Biallelic mutations in TBC1-domain containing kinase (TBCK) lead to hypotonia, global developmental delay with severe cognitive and motor deficits, and variable presentation of dysmorphic facial features and brain malformations. It remains unclear whether hypotonia in these individuals is purely neurogenic, or also caused by progressive muscle disease. METHODS Whole exome sequencing was

INTRODUCTION Dysferlin-deficient murine muscle sustains severe damage after repeated eccentric contractions. METHODS With a robotic dynamometer, we studied the response of dysferlin-sufficient and -deficient mice to 12 weeks of concentrically- or eccentrically-biased contractions. We also studied whether concentric contractions before or after eccentric contractions reduced muscle damage in dysferlin-deficient

INTRODUCTION Myotonic dystrophy type 1 (DM1) is a multisystemic neuromuscular disease that causes balance problems. The objective of this study was to assess the construct validity of the Mini-BESTest among adults with DM1. METHODS Fifty-nine individuals with late-onset or adult phenotypes of DM1 were recruited. Participants performed the Mini-BESTest, 10-Meter Walk Test (10mWT), 6-Minute Walk Test

The coronavirus disease 2019 (COVID-19) pandemic has resulted in reorganization of healthcare settings affecting the delivery of clinical care to patients with spinal muscular atrophy (SMA). There is a concern that patients with SMA may be at increased risk of manifesting severe symptoms of COVID-19. Currently approved therapies for SMA improve survival and motor function; however, their delivery requires

BACKGROUND The treatment of spinal muscular atrophy (SMA) with nusinersen requires intrathecal medication administration, which can be challenging in individuals with complicated spines. This retrospective case series reviews the nusinersen treatment experience at one academic medical center with children and adults with SMA and complicated spines. METHODS Twenty medical records of individuals receiving

INTRODUCTION Radiologically inserted gastrostomy (RIG) placement in patients with amyotrophic lateral sclerosis (ALS) carries risks related to periprocedural sedation and analgesia. To minimize these risks, we used a paravertebral block (PVB) technique for RIG placement. METHODS We retrospectively reviewed patients with ALS undergoing RIG placement under PVB between 2013 and 2017. RESULTS Ninety-nine

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

BACKGROUND The influence of demographic and anthropometric factors on nerve cross-sectional area (CSA) reference values in high-resolution ultrasound was evaluated in a prospective observational study. METHODS We measured CSA of median, ulnar, radial, and sural nerves in 80 healthy adults from 18 to 98 years of age. Pearson's correlation and multiple linear regression with age, gender, body mass index

In 1999, the International Federation of Clinical Neurophysiology (IFCN) published the second edition of its guidelines for the practice of clinical neurophysiology, which included a glossary for electromyography (EMG).1 Sixteen years later, in 2015, the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM) published the most recent version of its glossary of terms for use in

Modern neuromuscular electrodiagnosis (EDX) and neuromuscular ultrasound (NMUS) require a universal language for effective communication in clinical practice and research and, in particular, for teaching young colleagues. Therefore, the AANEM and the IFCN have decided to publish a joint glossary as they feel the need for an updated terminology to support educational activities in neuromuscular EDX

SECTION 1: Alphabetic list of terms with definitions SECTION 2: Illustrations of electrodiagnostic waveforms SECTION 3: Illustrations of ultrasound images SECTION 4: Abbreviations of units of measurements and of frequently used terms SECTION 5: References

Since March 2020, the COVID-19 pandemic has led to the need to re-think the delivery of services to patients with chronic dysimmune neuropathies. Telephone/video consultations have become widespread but have compounded concerns about objective evaluation. Therapeutic decisions need, more than ever before, to be considered in the best interests of both patients, and society, while not denying funct

INTRODUCTION Evidence for the efficacy of distal corticosteroid injection compared with proximal injection in carpal tunnel syndrome (CTS) is inadequate. METHODS We conducted a randomized, double-blind noninferiority trial of 131 wrists with CTS. Forty milligrams of methylprednisolone was injected medial to the palmaris longus tendon 2 cm proximal to the wrist crease, or at the volar aspect, 2 to 3

See article on pages 575–579 in this issue.

See article on pages 640–644 in this issue.

BACKGROUND Radiculopathies caused by spinal stenosis in the upper lumbar spinal canal (L1/2, L2/3, L3/4) have not been comprehensively investigated. METHODS This retrospective study reviewed 14 patients from a tertiary hospital outpatient clinic. The inclusion criteria were upper lumbar stenosis seen on MRI and radiculopathies with active denervation confirmed on electromyography. Patients with any

INTRODUCTION Evaluation of nerve mechanical properties has the potential to improve assessment of nerve impairment. Shear wave velocity, as measured by using shear wave (SW) ultrasound elastography, is a promising indicator of nerve mechanical properties such as stiffness. However, elucidation of external factors that influence SW velocity, particularly nerve tension, is required for accurate interpretations

INTRODUCTION Recombinant human insulin-like growth factor-1 (rhIGF-1) is a growth factor and has anabolic effects on muscle. We investigated whether rhIGF-1 therapy: 1) improves or preserves muscle function; and 2) improves growth in boys with Duchenne muscular dystrophy (DMD). METHODS In this study we compared prepubescent, ambulatory, glucocorticoid-treated boys with DMD (n = 17) vs controls (glucocorticoid

BACKGROUND Various techniques are described for proximal motor nerve conduction studies (NCSs). We investigated alternative reference electrode (E2) locations for accessory and axillary NCSs. METHODS Multi-channel recordings were made from trapezius or deltoid referred to different sites, and from those sites referred to a remote electrode. Responses were compared using grouped statistics, and correlation

INTRODUCTION We investigated the mechanisms underlying immobilization-induced muscle pain in rats. METHODS In rat skeletal muscle, pressure pain threshold (PPT) of the gastrocnemius muscle was measured, and nerve growth factor (NGF) level, peripheral nerve fiber density, macrophage number, and interleukin-1β (IL-1β) mRNA expression were examined. An NGF receptor inhibitor was injected intramuscularly

BACKGROUND Increment of compound muscle action potential amplitude is a diagnostic hallmark of Lambert-Eaton myasthenic syndrome (LEMS). Making a diagnosis can be challenging, therefore, a proper cutoff for abnormal increment is highly relevant for improved recognition of this rare disease. METHODS We determined the sensitivity and specificity of 60% and 100% cutoff values in all consecutive patients

INTRODUCTION Many reports have indicated that adipose-derived stem cells (ADSCs) are effective for nerve regeneration. We investigated nerve regeneration by combining a polyglycolic acid collagen (PGA-c) tube, which is approved for clinical use, and Schwann cell-like differentiated ADSCs (dADSCs). METHODS Fifteen-millimeter-long gaps in the sciatic nerve of rats were bridged in each group using tubes

INTRODUCTION Our aim in this study was to determine whether intravenous immunoglobulin (IVIg) or plasma exchange (PLEx) for treatment of neurologic disease is a trigger for thrombotic events. METHODS Using administrative data from 2005 to 2014, we identified index admissions for thrombotic events. We performed case-crossover analyses for these admissions with previous admissions for neurologic disease

INTRODUCTION Late-onset myasthenia gravis (LOMG; onset >50 years) has different therapeutic decision-making challenges than MG in younger patients. METHODS This is a retrospective series of seven patients with acetylcholine receptor antibody-positive MG, treated with rituximab. RESULTS The mean age of onset was 66 years. Three patients were non-responders to previous therapy and six had developed side

Myotonic dystrophies (DM), the most common muscular dystrophies, are known to have significant sleep disturbances. We analyzed the literature on sleep and excessive daytime sleepiness (EDS) in DM over the past 30 years. In this review we provide a brief overview of sleep, sleep disorders, and methods of assessment. We also analyze data regarding major sleep disorders in DM patients, including: sleep‐disordered