Neuromuscular Medicine Research Articles

Efgartigimod Demonstrates Consistent Improvements in Generalized Myasthenia Gravis Patients of Shorter Disease Duration (P1-5.015)

Efgartigimod Demonstrates Consistent Improvements in Generalized Myasthenia Gravis Patients of Shorter Disease Duration (P1-5.015)

Achievement of Improved Post-Intervention Status in Patients with Generalized Myasthenia Gravis Treated with Ravulizumab during the CHAMPION MG Study (S5.008)

Achievement of Improved Post-Intervention Status in Patients with Generalized Myasthenia Gravis Treated with Ravulizumab during the CHAMPION MG Study (S5.008)

Dose Selection and Clinical Development of Efgartigimod PH20 Subcutaneous in Patients with Generalized Myasthenia Gravis (P1-5.017)

Dose Selection and Clinical Development of Efgartigimod PH20 Subcutaneous in Patients with Generalized Myasthenia Gravis (P1-5.017)

Long-Term Safety, Tolerability, And Efficacy of Efgartigimod in Patients with Generalized Myasthenia Gravis: Concluding Analyses from the ADAPT+ Study (S5.006)

Long-Term Safety, Tolerability, And Efficacy of Efgartigimod in Patients with Generalized Myasthenia Gravis: Concluding Analyses from the ADAPT+ Study (S5.006)

Guidelines for Qualifications of Neurodiagnostic Personnel: A Joint Position Statement of the American Clinical Neurophysiology Society, the American Association of Neuromuscular & Electrodiagnostic Medicine, the American Society of Neurophysiological Monitoring, and ASET-The Neurodiagnostic Society.

The Guidelines for Qualifications of Neurodiagnostic Personnel (QNP) document has been created through the collaboration of the American Clinical Neurophysiology Society (ACNS), the American Society of Neurophysiological Monitoring (ASNM), the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM), and ASET-The Neurodiagnostic Society (ASET). The quality of patient care is optimized when neurophysiological procedures are performed and interpreted by appropriately trained and qualified practitioners at every level. These societies recognize that neurodiagnostics is a large field with practitioners who have entered the field through a variety of training paths. This document suggests job titles, associated job responsibilities, and the recommended levels of education, certification, experience, and ongoing education appropriate for each job. This is important because of the growth and development of standardized training programs, board certifications, and continuing education in recent years. This document matches training, education, and credentials to the various tasks required for performing and interpreting neurodiagnostic procedures. This document does not intend to restrict the practice of those already working in neurodiagnostics. It represents recommendations of these societies with the understanding that federal, state, and local regulations, as well as individual hospital bylaws, supersede these recommendations. Because neurodiagnostics is a growing and dynamic field, the authors fully intend this document to change over time.

Respiratory phenotypes of neuromuscular diseases: A challenging issue for pediatricians.

Neuromuscular disease (NMDs) encompass a heterogeneous group of genetic disorders, with respiratory problems of variable intensity and progression described at any pediatric age, from infancy to adolescence, and they are largely associated with significant lifelong morbidity and high mortality. Restriction of breathing, impaired gas exchange, decline of lung function and sleep disordered breathing progressively develop because of muscular weakness and culminate in respiratory failure. Depending on the disease progression, airways manifestations can take weeks to months or even years to evolve, thus depicting two major respiratory phenotypes, characterized by rapid or slow progression to respiratory failure. Assessing type and age at onset of airways problems and their evolution over time can support pediatricians in the diagnostic assessment of NMD. In addition, knowing the characteristics of patients' respiratory phenotype can increase the level of awareness among neonatologists, geneticists, neurologists, pulmonologists, nutritionists, and chest therapists, supporting them in the challenging task of the multidisciplinary medical care of patients. In this review we examine the issues related to the pediatric respiratory phenotypes of NMD and present a novel algorithm that can act as a guide for the diagnostic agenda and the key preventive or therapeutic interventions of airways manifestations. With prolonged survival of children with NMD, the advent of neuromuscular respiratory medicine, including accurate assessment of the respiratory phenotype, will help physicians to determine patients' prognoses and to design studies for the evaluation of new therapies.

What's New in Hand and Wrist Surgery.

What's New in Hand and Wrist Surgery.

Guidelines for Qualifications of Neurodiagnostic Personnel: A Joint Position Statement of the American Clinical Neurophysiology Society, the American Association of Neuromuscular & Electrodiagnostic Medicine, the American Society of Neurophysiological Monitoring, and ASET – The Neurodiagnostic Society

ABSTRACT The Guidelines for Qualifications of Neurodiagnostic Personnel (QNP) document has been created through the collaboration of the American Clinical Neurophysiology Society (ACNS), the American Society of Neurophysiological Monitoring (ASNM), the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM), and ASET – The Neurodiagnostic Society (ASET). The quality of patient care is optimized when neurophysiological procedures are performed and interpreted by appropriately trained and qualified practitioners at every level. These Societies recognize that Neurodiagnostics is a large field with practitioners who have entered the field through a variety of training paths. This document suggests job titles, associated job responsibilities, and the recommended levels of education, certification, experience, and ongoing education appropriate for each job. This is important because of the growth and development of standardized training programs, board certifications, and continuing education in recent years. This document matches training, education, and credentials to the various tasks required for performing and interpreting Neurodiagnostic procedures. This document does not intend to restrict the practice of those already working in Neurodiagnostics. It represents recommendations of these Societies with the understanding that federal, state, and local regulations, as well as individual hospital bylaws, supersede these recommendations. As Neurodiagnostics is a growing and dynamic field, we fully intend this document to change over time.

Mixed Nerve Conduction Study in the Diagnosis of Ulnar Neuropathy at the Elbow

Purpose: This study aims to investigate the ulnar-median mixed nerve latency difference (U-MLD) recorded from the medial aspect of the arm both in patients with ulnar neuropathy at the elbow (UNE) and in healthy individuals and thus to assist in the diagnosis of UNE. Materials and Methods: Twenty-nine patients meeting electrophysiological criteria defined by the American Association of Neuromuscular and Electrodiagnostic Medicine for diagnosis of UNE, and 50 healthy individuals were included in the study retrospectively. All participants' data were evaluated, such as median/ulnar motor and sensory response, U-MLD and the percentage of ulnar mixed nerve response amplitude difference between sides. Results: The U-MLD was significantly higher in patients with UNE than in the control group (1.78 ± 0.64 ms vs. 0.6 ± 0.22 ms, P = 0.000). The percentage of the ulnar mixed nerve response amplitude loss was significantly higher in the patient group compared to the control group (43.9% ± 30.3% vs. 21.4% ± 12.2%, P = 0.018). The U-MLD was significantly higher in the patients with amplitude loss ≥50%, and the ulnar mixed nerve response amplitude loss was ≥50% in all five patients with the ulnar sensory nerve action potential pathology. Conclusions: U-MLD is higher in patients with UNE; it can provide additional data in mild cases regarding the diagnosis of UNE, especially. Furthermore, the criterion that the ulnar mixed nerve response amplitude difference between the sides ≥50% suggests that it can be used to evaluate the severity of UNE.

Year in review 2021: Neuromuscular diseases.

In this years' review of neuromuscular respiratory medicine, there were a series of articles on home mechanical ventilation, real-world studies assessing the impact of nusinersen, and studies describing upper airway dysfunction. Beyond this, we highlight two excellent reviews regarding cardiac dysfunction in neuromuscular diseases.

Quantitative parameters of diffusion tensor imaging in the evaluation of carpal tunnel syndrome.

To explore the value of diffusion tensor imaging (DTI)-derived metrics in quantitative evaluation of carpal tunnel syndrome (CTS). This prospective cross-sectional study included 39 wrists from 24 symptomatic CTS patients, who underwent clinical, electrophysiological, and magnetic resonance imaging (MRI) evaluations. In addition, 10 wrists of 6 healthy participants were included as controls. Clinical and nerve conduction study (NCS) findings were evaluated and graded according to the Boston Carpal Tunnel Questionnaire (BCTQ) and the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM), respectively. We performed MRI using a 1.5 Tesla scanner. Mean diffusivity (MD), fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) of the median nerve at the distal radioulnar joint (DRUJ) (d), the inlet of the carpal tunnel (CT) at the pisiform level (i), the middle of the CT (m) and the outlet of the CT at the level of the hook of hamate (o), cross-sectional area at the inlet of the CT (iCSA), and the difference between MD and FA of the DRUJ and the outlet of CT (Delta MD and Delta FA) were measured. The CTS patients had significantly lower FA [for example, oFA: mean difference 0.09, 95% confidence interval (CI): 0.05 to 0.12] and significantly higher MD than healthy participants (for example, iMD: mean difference 0.3, 95% CI: 0.03 to 0.57). There was a negative correlation between iCSA with iFA and between mFA and oFA (-0.5<R<-0.4). There was a positive correlation between distal motor latency time and Delta MD (R=0.57) and a negative correlation between distal motor latency time and Delta FA (R=-0.51). The FA demonstrated a somewhat strong negative correlation with the Boston scores for symptom and function. The DTI-derived quantitative metrics add potential value to the evaluation of CTS. Alterations in the FA of the median nerve along the CT are the most significant features of CTS and reflect the degree of median nerve compression and clinical deficit. With a cutoff value of 0.45, FA at the carpal outlet has a sensitivity and specificity of 87.5% and 85.7% in the diagnosis of CTS, respectively.

Assessing electrodiagnostic skills among residents and fellows: Relationships between workplace-based assessments using the Electromyography Direct Observation Tool and other measures of trainee performance.

Graduate medical education programs must ensure residents and fellows acquire skills needed for independent practice. Workplace-based observational assessments are informative but can be time- and resource-intensive. In this study we sought to gather "relations-to-other-variables" validity evidence for scores generated by the Electromyography Direct Observation Tool (EMG-DOT) to inform its use as a measure of electrodiagnostic skill acquisition. Scores on multiple assessments were compiled by trainees during Clinical Neurophysiology and Electromyography rotations at a large US academic medical center. Relationships between workplace-based EMG-DOT scores (n=298) and scores on a prerequisite simulated patient exercise, patient experience surveys (n=199), end-of-rotation evaluations (n=301), and an American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) self-assessment examination were assessed using Pearson correlations. Among 23 trainees, EMG-DOT scores assigned by physician raters correlated positively with end-of-rotation evaluations (r=0.63, P=.001), but EMG-DOT scores assigned by technician raters did not (r=0.10, P=.663). When physician and technician ratings were combined, higher EMG-DOT scores correlated with better patient experience survey scores (r=0.42, P=.047), but not with simulated patient or AANEM self-assessment examination scores. End-of-rotation evaluations can provide valid assessments of trainee performance when completed by individuals with ample opportunities to directly observe trainees. Inclusion of observational assessments by technicians and patients provides a more comprehensive view of trainee performance. Workplace- and classroom-based assessments provide complementary information about trainee performance, reflecting underlying differences in types of skills measured.

New Patient Access via Telehealth in Neuromuscular Medicine During COVID-19 (P1-1.Virtual)

New Patient Access via Telehealth in Neuromuscular Medicine During COVID-19 (P1-1.Virtual)

Magnetic resonance imaging as a first-choice imaging modality in carpal tunnel syndrome: new evidence.

Carpal tunnel syndrome (CTS) is the most common type of peripheral nerve compression. Magnetic resonance imaging (MRI) is becoming more popular in practice in the evaluation of CTS. To evaluate the diagnostic value of MRI in CTS. A cross-sectional study of 39 wrists was conducted. Clinical and nerve conduction study findings were evaluated and graded according to the Boston Carpal Tunnel Questionnaire (BCTQ) and the American Association of Neuromuscular and Electrodiagnostic Medicine. MRI was performed using a 1.5-T scanner. MRI parameters included cross-sectional area (CSA) of the median nerve and the ratio change in CSA at four levels: distal radioulnar joint (DRUJ-CSA); pisiform (p-CSA); middle of the carpal tunnel (i-CSA); and hook of hamate. The ratio change in CSA was expressed as p-CSA/DRUJ-CSA and ΔCSA (difference between iCSA and DRUJ-CSA), the flattening ratio of the median nerve, the thickness of the flexor retinaculum, flexor retinaculum bowing ratio, signal intensity ratio of the median, nerve and hypothenar muscle signal intensity. With a cutoff point of 10.9 mm2 of the p-CSA, MRI had a sensitivity and specificity of 97.4% and 80% for diagnosis of CTS, respectively. There was a significant association between the clinical and electrophysiological stage with MRI findings (P < 0.001). There was a positive correlation between the BCTQ score and MRI parameters (0.5 < r < 0.7, P < 0.01). MRI has good diagnostic value in evaluating CTS. We recommend using p-CSA ≥10.9 mm2 and ΔCSA ≥2.3 mm2 as MRI diagnostic criteria of CTS.

P 73 Muscle relaxation in myotonia and longitudinal nerve mobility in carpal tunnel syndrome as possible clinical applications for “dynamic” ultrasound shear-wave elastography

Shear wave elastography (SWE) is an emerging modality in clinical ultrasound. Using acoustic radiation force impulses to generate transversal shear waves and fast imaging to track their propagation, it enables the non-invasive estimation of two-dimensional maps of tissue elasticity. Various applications in neuromuscular medicine have been investigated, e.g., altered muscle elasticity has been reported in muscular dystrophy and inflammatory myopathies, and elasticity of the median nerve at the wrist has been shown to be increased in carpal tunnel syndrome. Currently available SWE systems have a temporal resolution of about 1/second, making “dynamic”, functional assessments of nerve or muscle possible; we propose two such possible applications: (1) Myotonia describes delayed muscle relaxation in rare hereditary muscle disorders. In six patients with different myotonic muscle disorders and six controls, we performed SWE of the flexor digitorum superficialis muscle in the forearm with a frequency of one measurement per second. From measurements before, during and after brief voluntary contraction, the relaxation time to 10% of normalized shear wave velocity (RT0.1) was determined. 46 imaging sequences were acquired, with a mean RT0.1 of 7.38 s in patients and 1.36 s in control subjects, which is comparable to data obtained by mechanical dynamometry. (2) In carpal tunnel syndrome, reduced nerve mobility mostly in the lateral plane, but also longitudinally, has been described. Wrist and elbow movements, in healthy subjects, are known to alter median nerve tension and, thus, elasticity as detectable by SWE. We present a protocol to investigate whether entrapment at the carpal tunnel affects these posture-induced changes, an effect that might similarly occur in other compressive or traumatic neuropathies. These applications demonstrate how resolving functional manoeuvres by “dynamic” ultrasound SWE may be utilized for clinical diagnostic assessments.

The Evolution of Complex Muscle Cell In Vitro Models to Study Pathomechanisms and Drug Development of Neuromuscular Disease.

Many neuromuscular disease entities possess a significant disease burden and therapeutic options remain limited. Innovative human preclinical models may help to uncover relevant disease mechanisms and enhance the translation of therapeutic findings to strengthen neuromuscular disease precision medicine. By concentrating on idiopathic inflammatory muscle disorders, we summarize the recent evolution of the novel in vitro models to study disease mechanisms and therapeutic strategies. A particular focus is laid on the integration and simulation of multicellular interactions of muscle tissue in disease phenotypes in vitro. Finally, the requirements of a neuromuscular disease drug development workflow are discussed with a particular emphasis on cell sources, co-culture systems (including organoids), functionality, and throughput.

The neuromuscular fellowship portal and match.

For many years, Neuromuscular Medicine programs lacked a standardized means of handling fellowship applications and offering positions. Programs interviewed applicants and made offers as early as the first half of Post Graduate Year 3 (PGY3), a suboptimal timeline for applicants who may have had little prior exposure to neuromuscular or electrodiagnostic medicine. In 2021, the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) developed the Neuromuscular Fellowship Portal to standardize a later timeline and establish a process for fellowship applications and offers. In its first year, the Neuromuscular Fellowship Portal used a unique one‐way match, in which the portal released serial offers to applicants based on rank order lists submitted by programs. Fifty‐two Neuromuscular Medicine programs and seven electromyography (EMG)‐focused Clinical Neurophysiology programs participated. Sixty‐eight positions were filled, a similar number to previous years. A survey of fellowship directors and applicants following this process showed overwhelming support for the standardized timeline and application portal, but all program directors and most applicants favored moving to a traditional match. To maintain the existing application timeline and minimize costs for all parties, the AANEM Neuromuscular Fellowship Portal will host a two‐way match, based on existing commercial match algorithms, in 2022. A match will afford a fair and efficient process for all involved. Both Neuromuscular Medicine and EMG‐focused Clinical Neurophysiology programs will be encouraged to participate. The process undertaken by the AANEM can stand as an example for other neurologic subspecialties who are interested in standardizing their application timeline.

Ultrasonography for carpal tunnel syndrome in pregnancy: a prospective cross-sectional study

Confirmation of carpal tunnel syndrome (CTS) diagnosis with sonographic measurement of the median nerve cross sectional area (MN-CSA) is increasing in popularity. We aimed to analyse the ultrasonography (USG) values of MN-CSA in pregnant women with and without CTS symptoms. MN-CSAs of third trimester pregnant women were measured with USG and they were asked about the presence of CTS symptoms. Symptomatic participants were assigned to the CTS group and remaining participants were assigned to the Control group. The groups were compared according to MN-CSA. Twenty-five participants were grouped in CTS group and the remaining 64 participants were grouped in Control group. The MN-CSA was higher in the CTS group (9.44 ± 2.68) than in the Control group (7.20 ± 1.99), p = .00004. Obstetricians can use USG measurement of MN-CSA to confirm CTS diagnosis and consequently can offer conservative management, which is the widely accepted treatment modality in this cohort. Impact statement What is already known on this subject? CTS is the most common mononeuropathy of pregnancy, with up to 62% prevalence rates. The American Association of Neuromuscular & Electrodiagnostic Medicine practice guideline for the diagnosis of CTS recommends sonographic measurement of median nerve swelling at the carpal tunnel inlet as an accurate diagnostic test (Level A). What do the results of this study add? We found that a simple sonographic measurement of median nerve cross sectional area (MN-CSA) at the wrist appears to be a convenient method to confirm clinical CTS diagnosis in pregnant women. This study offers to use USG to confirm clinical CTS diagnosis in third trimester pregnant women before delivery. What are the implications of these findings for clinical practice and/or further research? This study will help to raise awareness of obstetricians about CTS during pregnancy. USG can be an effective first-line confirmatory test for CTS diagnosis in the pregnant population, but further research is necessary to determine a clear cut-off value for MN-CSA. We advise obstetricians to use sonographic measurement of MN-CSA in pregnant women with typical CTS symptoms, which will increase uniformity for consensus development. Obstetricians can offer advice for conservative management of CTS during pregnancy, which is the widely accepted treatment in this cohort.

Current status and trends in subspecialty certification in physical medicine and rehabilitation.

There is a need to better understand the overall state of sub-specialization in physical medicine and rehabilitation (PM&R). To examine the status and trends in subspecialty certification for each of the seven subspecialties approved for American Board of Physical Medicine and Rehabilitation (ABPMR) diplomates. Retrospective analysis of deidentified information from the ABPMR database. Physicians certified by ABPMR through 2019. Not applicable. For each subspecialty, we examined: (1) the number of certificates issued to ABPMR diplomates; (2) the recertification rate; (3) the yearly trends for total active, new, and expired certificates; and (4) for ABPMR-administered subspecialties, recertification rates for those entering the subspecialty through fellowship completion versus a "grandfathered" practice pathway. Of 11,421 ABPMR diplomates in the United States in 2019, a total of 3560 (31.2%) had 3985 active subspecialty certificates. Pain Medicine (PM) was the most common subspecialty certification (15.5% of all ABPMR diplomates) followed by Sports Medicine (SM, 6.6%), Brain Injury Medicine (BIM, 4.8%), Spinal Cord Injury Medicine (SCIM, 4.2%), Pediatric Rehabilitation Medicine (PRM, 2.5%), Neuromuscular Medicine (NMM, 0.7%), and Hospice and Palliative Medicine (HPM, 0.5%). For diplomates with more than one subspecialty certification, PM and SM was the most frequent combination. Both the recertification rate and the end of practice track eligibility influenced certification trends differently for individual subspecialties. The average number of new certificates added annually for every subspecialty was higher before than after the temporary practice track-based eligibility ended; the difference was statistically significant (p < .05) for SCIM, PM, SM, and NMM. The recertification rate for all subspecialties combined was 73.4%. For the subspecialties (SCIM, PRM) for which these data were available, fellowship candidates had higher recertification rates than those grandfathered through a practice track. This report informs stakeholders about the state and evolution of subspecialty certification in PM&R over time.

Guidelines for ethical behavior relating to clinical practice issues in neuromuscular and electrodiagnostic medicine.

The American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) developed guidelines to formalize the ethical standards that neuromuscular and electrodiagnostic (EDX) physicians should observe in their clinical and scientific activities. Neuromuscular and EDX medicine is a subspecialty of medicine that focuses on evaluation, diagnosis, and comprehensive medical management, including rehabilitation of individuals with neuromuscular disorders. Physicians working in this subspecialty focus on disorders of the motor unit, including muscle, neuromuscular junction, axon, plexus, nerve root, anterior horn cell, and the peripheral nerves (motor and sensory). The neuromuscular and EDX physician's goal, working with other allied health professionals, is to diagnose and treat these conditions to mitigate their impact and improve the patient's quality of life. The guidelines are consistent with the Principles of Medical Ethics adopted by the American Medical Association and represent a revision of previous AANEM guidelines.