Motor unit potential recruitment reference values in common upper and lower extremity muscles.

Objective: To define reference values for motor unit (MU) recruitment during needle EMG of six commonly examined muscles at low to moderate contraction.

Methods: Needle examination was performed for each muscle in a total of 111 subjects without neuromuscular disorders. Fastest firing rates and recruitment ratios (RRs) were calculated in at least 5 sites within each muscle.

The role of electrodiagnosis in focal neuropathies.

Electrodiagnostic (EDX) testing plays an important role in confirming a mononeuropathy, localizing the site of nerve injury, defining the pathophysiology, and assessing the severity and prognosis. The combination of nerve conduction studies (NCS) and needle electromyography findings provides the necessary information to fully assess a nerve. The pattern of NCS abnormalities reflects the underlying pathophysiology, with focal slowing or conduction block in neuropraxic injuries and reduced amplitudes in axonotmetic injuries.

Electrodiagnostic Characteristics Suggestive of Muscle-Specific Kinase Myasthenia Gravis.

Background And Objectives: Muscle-specific kinase (MuSK) antibody-positive myasthenia gravis (MuSK + MG) is a form of MG with bulbar-predominant symptoms often resistant to conventional treatments. Patients with MuSK + MG may have an electrodiagnostic (EDX) profile distinct from other MG. This study compares EDX features of MuSK + MG with acetylcholine receptor (AChR) antibody-positive MG (AChR + MG) to discern whether any unique EDX pattern exists that can aid in clinical diagnosis.

Small Fiber Neuropathy Incidence, Prevalence, Longitudinal Impairments, and Disability.

Background And Objectives: There are limited population-based data on small fiber neuropathy (SFN). We wished to determine SFN incidence, prevalence, comorbid conditions, longitudinal impairments, and disabilities.

Methods: Test-confirmed patients with SFN in Olmsted, Minnesota, and adjacent counties were compared 3:1 to matched controls (January 1, 1998-December 31, 2017).

Electromyography Case Examples: Practical Approaches to Neuromuscular Symptoms.

Many neuromuscular complaints are evaluated with electrodiagnostic testing. In practice, physicians must plan the electrodiagnostic study to provide the most useful information addressing patients' symptoms. The approach to each study must be individualized based on the symptoms and findings of each previous result.

Yield of Head Imaging in Ambulatory and Hospitalized Patients With SARS-CoV-2: A Multi-Center Study of 8675 Patients.

Background And Purpose: To describe the neurological and cerebrovascular findings in patients who tested positive for SARS-CoV-2 and underwent head imaging in ambulatory and inpatient settings.

Methods: Consecutive patients aged ≥18 years with SARS-CoV-2 infection diagnosed or treated at Mayo Clinic sites from 3/11/2020 to 7/23/2020 with head CT or brain MRI within 30 days of SARS-CoV-2 diagnosis were included. Demographics, medical history, indication for SARS-CoV-2 testing, neurologic symptoms, indication for brain imaging, neuroimaging findings, etiology of cerebrovascular events, and hospital course were abstracted from medical records.

Deep vein thrombosis and pulmonary embolism among hospitalized coronavirus disease 2019-positive patients predicted for higher mortality and prolonged intensive care unit and hospital stays in a multisite healthcare system.

Objective: We assessed the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) in hospitalized patients with coronavirus disease 2019 (COVID-19) compared with that in a matched cohort with similar cardiovascular risk factors and the effects of DVT and PE on the hospital course.

Methods: We performed a retrospective review of prospectively collected data from COVID-19 patients who had been hospitalized from March 11, 2020 to September 4, 2020. The patients were randomly matched in a 1:1 ratio by age, sex, hospital of admission, smoking history, diabetes mellitus, and coronary artery disease with a cohort of patients without COVID-19.

Diagnostic modelling and therapeutic monitoring of immune-mediated necrotizing myopathy: role of electrical myotonia.

Delayed diagnosis of immunemediated necrotizing myopathy leads to increased morbidity. Patients with the chronic course without 3-hydroxy-3-methylglutaryl-coenzyme-A reductase-IgG or signal recognition particle-IgG are often challenging to diagnose. Immunotherapy response can also be difficult to assess.

Sensitivity and specificity of repetitive nerve stimulation with lower cutoffs for abnormal decrement in myasthenia gravis.

Introduction: The sensitivity of repetitive nerve stimulation (RNS) in myasthenia gravis (MG) is dependent on the cutoff for abnormal decrement.

Methods: RNS data of adults with and without MG from 2014 to 2017 were reviewed retrospectively. The maximum reliable RNS amplitude/area decrement before and after exercise from facial, spinal accessory (SA), ulnar, and fibular nerves was recorded.

Characteristics and significance of doublets on needle EMG.

Introduction: Voluntary doublets are electrophysiological phenomena thought to be associated with metabolic derangements or neuromuscular conditions.

Methods: We prospectively studied 232 consecutive patients examined by a single examiner during routine electromyography (EMG) to determine the frequency of doublets in individual patients, specific muscles, neuromuscular conditions, electrolyte levels, and doublet characteristics.

Results: Of 232 patients, 25 (10.