Nerve Excitability in Asymptomatic Carriers and Amyotrophic Lateral Sclerosis Patients With C9orf72.

Objective: We investigated the effects of C9orf72 mutation carriership on peripheral nerve excitability in asymptomatic individuals from families with a history of C9orf72 amyotrophic lateral sclerosis (ALS) and patients.

Methods: We included 47 asymptomatic individuals from families with a history of C9orf72 ALS, of whom 23 were carriers (C9) and 24 were noncarriers (C9). In addition, 11 C9 and 110 C9 ALS patients and 50 healthy controls participated.

Fasciculation distribution in a healthy population assessed with diffusion tensor imaging.

Fasciculations, a hallmark of motor neuron diseases, also occur in healthy individuals, highlighting the need to understand fasciculation intensity and distribution. Motor unit MRI (MUMRI) can assess fasciculations in large volumes but is not widely applied. We hypothesize that a more common MRI technique, diffusion tensor imaging (DTI), can also detect fasciculation when correcting for low signal-to-noise ratios and signal variability.

Feasibility and Reliability of a Monitoring App for Chronic Inflammatory Neuropathies.

Background And Aims: Multifocal motor neuropathy (MMN) and chronic inflammatory demyelinating polyneuropathy (CIDP) are immune-mediated neuropathies characterized by muscle weakness and/or sensory deficits. Identifying treatment response, relapse, and stability can be challenging in these chronic, sometimes unpredictable, conditions. This study explores the potential of a monitoring app designed to address these challenges.

Sensory Nerve Action Potential Analysis in a Cohort of Patients With Spinal Muscular Atrophy Aged 12 Years and Older.

Introduction/aims: Survival Motor Neuron 1 (SMN1)-related spinal muscular atrophy (SMA) is characterized by α-motor neuron degeneration, with sensory function assumed to be clinically preserved. However, recent studies in severely affected patients and animal models have challenged this view. Therefore, we assessed the maximum sensory nerve action potential (SNAP) amplitude of the median nerve in patients with SMA and examined its changes during treatment with SMN-splicing modifying therapies.

Diagnostic Accuracy of Median Nerve Cross-Sectional Area in Suspected Amyotrophic Lateral Sclerosis.

Introduction/aims: Reduced nerve sizes obtained by nerve ultrasound (NUS) have been proposed as a potential diagnostic marker for amyotrophic lateral sclerosis (ALS). However, prospective studies evaluating patients with suspected ALS are currently lacking. We, therefore, evaluated the diagnostic accuracy of a standardized NUS protocol in a large sample of suspected ALS patients.

Patient-reported daily functioning after SARS-CoV-2 vaccinations in autoimmune neuromuscular diseases.

Background And Purpose: There are concerns for safety regarding SARS-CoV-2 vaccines for patients with autoimmune neuromuscular disease. We compared daily functioning using disease-specific patient-reported outcome measures (PROMs) before and after SARS-CoV-2 vaccinations.

Methods: In this substudy of a prospective observational cohort study (Target-to-B!), patients with myasthenia gravis (MG), chronic inflammatory demyelinating polyneuropathy (CIDP), multifocal motor neuropathy (MMN), and idiopathic inflammatory myopathy (IIM) vaccinated against SARS-CoV-2 were included.

Revisiting distinct nerve excitability patterns in patients with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis is a devastating neurodegenerative disease, characterized by loss of central and peripheral motor neurons. Although the disease is clinically and genetically heterogeneous, axonal hyperexcitability is a commonly observed feature that has been suggested to reflect an early pathophysiological step linked to the neurodegenerative cascade. Therefore, it is important to clarify the mechanisms causing axonal hyperexcitability and how these relate to the clinical characteristics of patients.

IgM anti-GM2 antibodies in patients with multifocal motor neuropathy target Schwann cells and are associated with early onset.

Background: Multifocal motor neuropathy (MMN) is a rare, chronic immune-mediated polyneuropathy characterized by asymmetric distal limb weakness. An important feature of MMN is the presence of IgM antibodies against gangliosides, in particular GM1 and less often GM2. Antibodies against GM1 bind to motor neurons (MNs) and cause damage through complement activation.

A 21-bp deletion in the complement regulator CD55 promotor region is associated with multifocal motor neuropathy and its disease course.

Background And Aims: To further substantiate the role of antibody-mediated complement activation in multifocal motor neuropathy (MMN) immunopathology, we investigated the distribution of promotor polymorphisms of genes encoding the membrane-bound complement regulators CD46, CD55, and CD59 in patients with MMN and controls, and evaluated their association with disease course.

Methods: We used Sanger sequencing to genotype five common polymorphisms in the promotor regions of CD46, CD55, and CD59 in 133 patients with MMN and 380 controls. We correlated each polymorphism to clinical parameters.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome.

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain.

Simulating progressive motor neuron degeneration and collateral reinnervation in motor neuron diseases using a dynamic muscle model based on human single motor unit recordings.

To simulate progressive motor neuron loss and collateral reinnervation in motor neuron diseases (MNDs) by developing a dynamic muscle model based on human single motor unit (MU) surface-electromyography (EMG) recordings.Single MU potentials recorded with high-density surface-EMG from thenar muscles formed the basic building blocks of the model. From the baseline MU pool innervating a muscle, progressive MU loss was simulated by removal of MUs, one-by-one.

Feasibility and tolerability of multimodal peripheral electrophysiological techniques in a cohort of patients with spinal muscular atrophy.

Objective: Electrophysiological techniques are emerging as an aid in identifying prognostic or therapeutic biomarkers in patients with spinal muscular atrophy (SMA), but electrophysiological assessments may be burdensome for patients. We, therefore, assessed feasibility and tolerability of multimodal peripheral non-invasive electrophysiological techniques in a cohort of patients with SMA.

Methods: We conducted a single center, longitudinal cohort study investigating the feasibility and tolerability of applying multimodal electrophysiological techniques to the median nerve unilaterally.

Multifocal motor neuropathy is not associated with altered innate immune responses to endotoxin.

Objective: Antibody- and complement-mediated peripheral nerve inflammation are central in the pathogenesis of MMN. Here, we studied innate immune responses to endotoxin in patients with MMN and controls to further our understanding of MMN risk factors and disease modifiers.

Methods: We stimulated whole blood of 52 patients with MMN and 24 controls with endotoxin and collected plasma.

Primary SARS-CoV-2 infection in patients with immune-mediated inflammatory diseases: long-term humoral immune responses and effects on disease activity.

Background: Patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressants (ISPs) may have impaired long-term humoral immune responses and increased disease activity after SARS-CoV-2 infection. We aimed to investigate long-term humoral immune responses against SARS-CoV-2 and increased disease activity after a primary SARS-CoV-2 infection in unvaccinated IMID patients on ISPs.

Methods: IMID patients on active treatment with ISPs and controls (i.

Longitudinal prospective cohort study to assess peripheral motor function with extensive electrophysiological techniques in patients with Spinal Muscular Atrophy (SMA): the SMA Motor Map protocol.

Background: Hereditary spinal muscular atrophy (SMA) is a motor neuron disorder with a wide range in severity in children and adults. Two therapies that alter splicing of the Survival Motor Neuron 2 (SMN2) gene, i.e.

Chronic inflammatory neuropathies and their impact on activities and participation.

Background: Chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) are inflammatory neuropathies that can lead to considerable limitations in daily activities and in social participation. However, systematic evaluation of these self-reported limitations is lacking in the currently available studies. Understanding the impact of these diagnoses on patients' life is important to optimize management strategies.

Randomized double-blind placebo-controlled crossover trial with pyridostigmine in spinal muscular atrophy types 2-4.

Hereditary proximal spinal muscular atrophy causes weakness and increased fatigability of repetitive motor functions. The neuromuscular junction is anatomically and functionally abnormal in patients with spinal muscular atrophy. Pharmacological improvement of neuromuscular transmission may therefore represent a promising additional treatment strategy.

Disease activity in patients with immune-mediated inflammatory diseases after SARS-CoV-2 vaccinations.

For patients with immune-mediated inflammatory diseases (IMIDs), concerns exist about increased disease activity after vaccination. We aimed to assess changes in disease activity after SARS-CoV-2 vaccination in patients with IMIDs, and determine risk factors for increased disease activity. In this substudy of a prospective observational cohort study (Target-to-B!), we included patients with IMIDs who received a SARS-CoV-2 vaccine.