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Background: Muscle pain is a common symptom in patients with neuromuscular disorders (NMD) and accounts for severely reduced quality of life. OBJECTIVE: This clinical study aimed to observe possible differences in pain prevalence among distinct NMDs and to determine whether the patients' nociceptive pain is influenced by gender, muscle strength and psychological factors and to examine potential pain-associated alterations in muscle properties., Methods: The cross-sectional study on nociceptive pain in various NMDs involved patient-reported outcomes, muscle strength evaluations (dynamometry and quick motor function test (QMFT)), nociceptive pain evaluations (muscular pressure pain threshold (PPT)), and non-invasive measurement of muscle stiffness, frequency, decrement, relaxation, and creep (myotonometry)., Results: Involving 81 NMD patients and a control group, the study found high variability in pain prevalence among the subgroups. Patients with DM2 and FSHD had significantly higher levels of pain prevalence compared to other examined NMD subgroups and the control group. Female gender, high fatigue levels (representing factors such as depression, anxiety, stress, and impairment of quality of life), and low QMFT scores (representing reduced muscle strength) showed an association with increased sensitivity to pressure pain in the arm and leg region. As assessed by myotonometry, less pain is experienced in neck muscles with a high muscle tone, high stiffness, and a short relaxation time highlighting the importance of intrinsic muscular tone for their pressure pain sensitivity., Conclusion: Individualized therapeutic concepts including psychological and physical approaches in the pain management of patients with NMDs, especially in women, should be considered. Further research in this field is necessary to gain a more detailed insight into the perception of muscle pain.

Neuromuscular disorders show extremely varied expressions of different symptoms and the involvement of muscles. Non-invasively, myotonia and muscle stiffness are challenging to measure objectively. Our study aims to test myotonia, elasticity, and stiffness in various neuromuscular diseases and to provide reference values for different neuromuscular disease groups using a novel handheld non-invasive myometer device MyotonPRO ® . We conducted a monocentric blinded cross-sectional study in patients with a set of distinct neuromuscular diseases (NCT04411732, date of registration June 2, 2020). Fifty-two patients in five groups and 21 healthy subjects were enrolled. We evaluated motor function (6-min walk test, handheld dynamometry, Medical Research Council (MRC) Scale) and used ultrasound imaging to assess muscle tissue (Heckmatt scale). We measured muscle stiffness, frequency, decrement, creep, or relaxation using myotonometry with the device MyotonPRO ® . Statistically, all values were calculated using the t test and Mann-Whitney U test. No differences were found in comparing the results of myotonometry between healthy and diseased probands. Furthermore, we did not find significant results in all five disease groups regarding myotonometry correlating with muscle strength or ultrasound imaging results. In summary, the myometer MyotonPRO ® could not identify significant differences between healthy individuals and neuromuscular patients in our patient collective. Additionally, this device could not distinguish between the five different groups of disorders displaying increased stiffness or decreased muscle tone due to muscle atrophy. In contrast, classic standard muscle tests could clearly decipher healthy controls and neuromuscular patients., (© 2023. The Author(s).)

Background and Aim: Physiotherapy has a key role in the symptomatic treatment of neuromuscular disorders (NMD). In the health care of adults with NMD, there may be intransparency of physiotherapy processes due, among other factors, to disciplinary interfaces. This study describes the current state of physiotherapeutic care for adults with NMD and examines the needs of physiotherapists in improving the quality of physiotherapeutic care., Methods: An online survey of physiotherapists in the city area of Munich was carried out using Lime Survey. The survey link was distributed in both inpatient and outpatient settings and with use of the snowball principle. The data on the closed and open questions were accordingly evaluated quantitatively descriptively and content-analytically., Results: A total of 137 physiotherapists participated in the online survey, and information from 124 survey participants was included in the analyses. 62.4% (n=58) of them were involved in the treatment of adults with NMD. The most common physiotherapy prescription was "Physiotherapy for the treatment of central movement disorders" (KG-ZNS) (82.9%; n=34). Home visits and assistive devices were ranked as the most effective interventions. 69.1% (n=56) of survey participants would like more information on NMD, primarily in the form of e-learning (24.0%; n=37) and professional articles (21.4%; n=33). In addition to the identified need for information, there were requests for more in-depth interprofessional communication and increased time resources in physiotherapeutic treatment., Conclusion: The wide range of physiotherapeutic measures applied pursues, among other things, the goal of helping patients maintain their independence and is considered to be of great benefit in the care of adult patients with NMD. It is important to address the identified desire and need for information expressed by physiotherapists on the subject of NMD in the preferred form by means of low-threshold offers. The interprofessional communication should be intensified and time-related aspects should be considered in the issuing of prescriptions as well as with regard to a possible blank prescription option in the future, in order to achieve positive effects in the physiotherapeutic care of adult patients with NMD., Competing Interests: Alle Autorinnen/Autoren geben keinen Interessenkonflikt zum Inhalt dieses Beitrags an., (Thieme. All rights reserved.)

Background: The possibilities in the field of molecular therapies of neuromuscular diseases have rapidly developed in recent years. First compounds are already available in clinical practice and numerous other substances are in advanced phases of clinical trials. This article gives an exemplary overview of the current state of clinical research in molecular therapies of neuromuscular diseases. It also gives a view into the near future of the clinical application, including the challenges., Discussion: Using Duchenne muscular dystrophy (DMD) and myotubular myopathy as examples, the principles of gene addition in monogenetic skeletal muscle diseases, which are already manifested in childhood are described. In addition to initial successes, the challenges and setbacks hindering the approval and regular clinical application of further compounds are demonstrated. Furthermore, the state of current clinical research in Becker-Kiener muscular dystrophy (BMD) and the numerous forms of limb-girdle muscular dystrophy (LGMD) are summarized. Numerous new therapeutic approaches and a corresponding outlook are also shown for facioscapulohumeral muscular dystrophy (FSHD), Pompe disease, and myotonic dystrophy., Conclusion: Clinical research in the field of molecular therapy of neuromuscular diseases is one of the pacesetters of modern precision medicine; however, challenges need to be seen, jointly addressed and overcome in the future., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Several types of molecular therapy have become a novel opportunity in the precision treatment of hereditary neuromuscular disorders. This cursive review of gene therapy in hereditary myopathies will focus on selected current phase 1 to 3 trials of common adult hereditary myopathies such as Becker muscular dystrophy, facioscapulohumeral muscular dystrophy, calpainopathy, and dysferlinopathy. The treatment options for Pompe disease serve as an example for hereditary metabolic myopathies., Competing Interests: Der Autor gibt keine Interessenkonflikte für den Inhalt der Übersicht an. Außerhalb der eingereichten Arbeit gibt der Autor Beratungshonorare von Argenx, Amicus, Astellas, Dyne, Sanofi und Taysha sowie Vortragshonorare von Alexion, Kedrion an., (Thieme. All rights reserved.)

Background and Purpose: Clinical outcome information on patients with neuromuscular diseases (NMDs) who have been infected with SARS-CoV-2 is limited. The aim of this study was to determine factors associated with the severity of COVID-19 outcomes in people with NMDs., Methods: Cases of NMD, of any age, and confirmed/presumptive COVID-19, submitted to the International Neuromuscular COVID-19 Registry up to 31 December 2021, were included. A mutually exclusive ordinal COVID-19 severity scale was defined as follows: (1) no hospitalization; (2) hospitalization without oxygenation; (3) hospitalization with ventilation/oxygenation; and (4) death. Multivariable ordinal logistic regression analyses were used to estimate odds ratios (ORs) for severe outcome, adjusting for age, sex, race/ethnicity, NMD, comorbidities, baseline functional status (modified Rankin scale [mRS]), use of immunosuppressive/immunomodulatory medication, and pandemic calendar period., Results: Of 315 patients from 13 countries (mean age 50.3 [±17.7] years, 154 [48.9%] female), 175 (55.5%) were not hospitalized, 27 (8.6%) were hospitalized without supplemental oxygen, 91 (28.9%) were hospitalized with ventilation/supplemental oxygen, and 22 (7%) died. Higher odds of severe COVID-19 outcomes were observed for: age ≥50 years (50-64 years: OR 2.4, 95% confidence interval [CI] 1.33-4.31; >64 years: OR 4.16, 95% CI 2.12-8.15; both vs. <50 years); non-White race/ethnicity (OR 1.81, 95% CI 1.07-3.06; vs. White); mRS moderately severe/severe disability (OR 3.02, 95% CI 1.6-5.69; vs. no/slight/moderate disability); history of respiratory dysfunction (OR 3.16, 95% CI 1.79-5.58); obesity (OR 2.24, 95% CI 1.18-4.25); ≥3 comorbidities (OR 3.2, 95% CI 1.76-5.83; vs. ≤2; if comorbidity count used instead of specific comorbidities); glucocorticoid treatment (OR 2.33, 95% CI 1.14-4.78); and Guillain-Barré syndrome (OR 3.1, 95% CI 1.35-7.13; vs. mitochondrial disease)., Conclusions: Among people with NMDs, there is a differential risk of COVID-19 outcomes according to demographic and clinical characteristics. These findings could be used to develop tailored management strategies and evidence-based recommendations for NMD patients., (© 2022 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Background: Telemedicine (TM) contributes to bridge the gap between healthcare facilities and patients' homes with neuromuscular disease (NMD) because of mobility issues. However, its deployment is limited due to difficulties evaluating subtle neurological signs such as mild weakness or sensory deficits. The COVID-19 pandemic has disrupted healthcare delivery worldwide, necessitating rapid measures implementation by health care providers (HCPs) to protect patients from acquiring SARS-CoV-2 while maintaining the best care and treatment., Objectives: Given the challenges faced by remote healthcare assistance of NMD patients, we aim to evaluate the use of TM in NMD during the COVID-19 pandemic., Methods: Based on the Model for Assessment-of-Telemedicine-Applications (MAST), we conducted a survey amongst clinicians of the ERN EURO NMD (European-Reference-Network-for-Rare-Neuromuscular-Diseases)., Results: Based on 42 responses over 76 expected ones, our results show that the COVID-19 pandemic significantly increased the number of HCPs using TM (from 60% to 100%). The TM types most used during the COVID-19 period are teleconsultation and consultation by phone, particularly in the context of symptoms worsening in NMD patients with COVID-19 infection. Most European HCPs were satisfied when using TM but as a complementary option to physical consultations. Many responses addressed the issue of technical aspects needing improvement, particularly for elderly patients who need caregivers' assistance for accessing the TM platform., Conclusions: TM has been essential during COVID-19, but its use still presents some limitations for NMD patients with cognitive deficits or for first-time diagnosis. Thus, TM should be used as complement to, rather than substitute, for face-to-face consultations.

The main pathologies in the muscles of patients with neuromuscular diseases (NMD) are fatty infiltration and edema. Recently, quantitative magnetic resonance (MR) imaging for determination of the MR biomarkers proton density fat fraction (PDFF) and water T 2 (T 2w ) has been advanced. Biophysical effects or pathology can have different effects on MR biomarkers. Thus, for heterogeneously affected muscles, the routinely performed mean or median value analyses of MR biomarkers are questionable. Our work presents a voxel-based histogram analysis of PDFF and T 2w images to point out potential quantification errors. In 12 patients with NMD, chemical-shift encoding-based water-fat imaging for PDFF and T 2 mapping with spectral adiabatic inversion recovery (SPAIR) for T 2w determination was performed. Segmentation of nine thigh muscles was performed bilaterally (n = 216). PDFF and T 2 maps were coregistered. A voxel-based comparison of PDFF and T 2w showed a decreased T 2w with increasing PDFF. Mean T 2w and mean T 2w without fatty voxels (PDFF < 10%) show good agreement, whereas standard deviation (σ) T 2w and σ T 2w without fatty voxels show increasing difference with increasing values of σ. Thereby two subgroups can be observed, referring to muscles in which the exclusion of fatty voxels has a negligible influence versus muscles in which a strong dependency of the T 2w value distribution on the exclusion of fatty voxels is present. Because of the two opposite effects that influence T 2w in a voxel, namely, (i) a pathophysiologically increased water mobility leading to T 2w elevation, and (ii) a dependency of T 2w on the PDFF leading to decreased T 2w , the T 2w distribution within a muscle might be heterogenous and the routine mean or median analysis can lead to a misinterpretation of the muscle health. It was concluded that muscle T 2w mean values can wrongly suggest healthy muscle tissue. A deeper analysis of the underlying value distribution is necessary. Therefore, a quantitative analysis of T 2w histograms is a potential alternative., (© 2022 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.)

Background: Sarcopenia is the age-related loss of muscle mass and strength. Undiagnosed late-onset neuromuscular disorders need to be considered in the differential diagnosis of sarcopenia., Aim: Based on emblematic case reports and current neuromuscular diagnostic guidelines for three common late-onset neuromuscular disorders, a differential diagnostic approach for geriatric patients presenting with a sarcopenic phenotype is given., Methods: Patients over 65 years of age with sarcopenia, amyotrophic lateral sclerosis, inclusion body myositis and myotonic dystrophy type 2 were recruited. All patients were assessed for sarcopenia based on the revised European consensus definition. Patients with neuromuscular diseases were diagnosed according to the revised El Escorial criteria and the European neuromuscular centre criteria. Phenotypes and diagnostic criteria for all patients were summarized including their specific histopathological findings., Results: All patients with neuromuscular diseases were positively screened for sarcopenia and classified as severe sarcopenic by means of assessment. The clinical phenotype, the evolution pattern of weakness and muscle atrophy combined with laboratory finding including electromyography could unquestionably distinguish the diseases., Discussion: Neuromuscular disorders can manifest beyond the age of 65 years and misdiagnosed as sarcopenia. The most common diseases are inclusion body myositis, amyotrophic lateral sclerosis and myotonic dystrophy type 2. A diagnostic work-up for neuromuscular diseases ensures their correct diagnosis by clinical-, electrophysiological, histopathological, and genetic work-up., Conclusions: In geriatric patients with a focal or asymmetrical muscular weakness and atrophy, sarcopenia assessment should be extended with patient's history of disease course. Furthermore, concomitant diseases, analysis of serum creatine kinase, electrophysiological examination, and in selected patients muscle biopsy and gene analysis is needed to rule out a late-onset neuromuscular disorder.

Apart from disorders and diseases of the peripheral nerves, symptoms and disorders of the musculature and the neuromuscular transmission have also been described in association with coronavirus disease 2019 (COVID-19). In the second part of our review we provide an overview about frequently reported symptoms, such as myalgia as well as defined disorders, such as rhabdomyolysis, myositis, myasthenia and intensive care unit (ICU)-acquired weakness, which have been described during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections or COVID-19.Furthermore, the criteria for a causality, such as association strength, plausibility, time course, and experimental evidence for a causal association that should be applied for the COVID-19-asssociated neuromuscular conditions described in the two parts of the review are discussed. At present, in addition to anosmia, which is also known in the lay press, myalgia in particular as a nonspecific symptom are frequent sequelae of a symptomatic SARS-CoV‑2 infection. Other neuromuscular complications seem to be principally plausible (considering the pathogenesis) but apparently rare consequences of a SARS-CoV‑2 infection. Prospective or cohort studies are necessary to confirm a causality and assess the risk.

The aim of this study was to assess whether different cut-offs of maximum inspiratory and/or expiratory pressure (MIP/MEP) are valuable screening parameters to detect restrictive respiratory insufficiency. Spirometry, MIP, MEP and capillary blood gas analysis were obtained from patients with confirmed neuromuscular disorders. We calculated regression analysis, sensitivity, specificity and predictive values. We enrolled 29 patients with myotonic dystrophy type 1 (DM1), 19 with late-onset Pompe disease (LOPD), and 24 with spinal muscular atrophy type 3. Moderate to high reduction in manometry was exclusively found in LOPD and DM1 patients. Significant associations were found between manometry and spirometry. Highest adjusted r 2 was found for MIP % predicted and forced vital capacity (FVC) % predicted. Manometry predicted abnormal FVC and forced expiratory volume 1 s (FEV1). MEP > 80 cmH 2 O predicted normal FVC and FEV1, regardless of cut-off values. MIP and MEP did not positively predict alterations in capillary blood gas analysis. Disease-specific cut-offs of manometry did not increase the prediction rate of patients with abnormal FVC and FEV1. Predicted values should be calculated for a more comprehensive interpretation of manometry results. MIP and MEP can serve as a screening parameter for patients with neuromuscular disorders, but parallel testing of both MIP and MEP needs to be performed to increase the positive prediction probability across disease groups., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Muscle water T 2 (T 2w ) has been proposed as a biomarker to monitor disease activity and therapy effectiveness in patients with neuromuscular diseases (NMD). Multi-echo spin-echo (MESE) is known to be affected by fatty infiltration. A T 2 -prepared 3D turbo spin echo (TSE) is an alternative method for T 2 mapping, but has been only applied in healthy muscles., Purpose: To examine the performance of T 2 -prepared 3D TSE in combination with spectral adiabatic inversion recovery (SPAIR) in measuring T 2w in fatty infiltrated muscles based on simulations and in vivo measurements in thigh muscles of patients with NMD., Study Type: Prospective., Subjects: One healthy volunteer, 34 NMD patients., Field Strength/sequence: T 2 -prepared stimulated echo acquisition mode (STEAM) magnetic resonance spectroscopy (MRS), SPAIR STEAM MRS, and SPAIR T 2 -prepared STEAM MRS were performed in the subcutaneous fat of a healthy volunteer's thigh. T 2 mapping based on SPAIR 2D MESE and SPAIR T 2 -prepared 3D TSE was performed in the NMD patients' thigh region. Multi-TE STEAM MRS was performed for measuring a reference T 2w at different thigh locations., Assessment: The behavior of the fat spectrum in the SPAIR T 2 -prepared 3D TSE was simulated using Bloch simulations. The in vivo T 2 results of the imaging methods were compared to the in vivo T 2w MRS results., Statistical Tests: Pearson correlation coefficient with slope and intercept, relative error., Results: The simulated T 2 for the SPAIR T 2 -prepared 3D TSE sequence remained constant within a relative error of not more than 4% up to a fat fraction of 80%. In vivo T 2 values of SPAIR T 2 -prepared 3D TSE were in good agreement with the T 2w values of STEAM MRS (R = 0.86; slope = 1.12; intercept = -1.41 ms). In vivo T 2 values of SPAIR 2D MESE showed large deviations from the T 2w values of STEAM MRS (R = 0.14; slope = 0.32; intercept = 38.83 ms)., Data Conclusion: The proposed SPAIR T 2 -prepared 3D TSE shows reduced sensitivity to fatty infiltration for T 2w mapping in the thigh muscles of NMD patients., Level of Evidence: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:1727-1736., (© 2019 The Authors. Journal of Magnetic Resonance Imaging published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.)

Quantitative imaging techniques are emerging in the field of magnetic resonance imaging of neuromuscular diseases (NMD). T 2 of water (T 2w ) is considered an important imaging marker to assess acute and chronic alterations of the muscle fibers, being generally interpreted as an indicator for "disease activity" in the muscle tissue. To validate the accuracy and robustness of quantitative imaging methods, 1 H magnetic resonance spectroscopy (MRS) can be used as a gold standard. The purpose of the present work was to investigate T 2w of remaining muscle tissue in regions of higher proton density fat fraction (PDFF) in 40 patients with defined NMD using multi-TE single-voxel 1 H MRS. Patients underwent MR measurements on a 3 T system to perform a multi-TE single-voxel stimulated echo acquisition method (STEAM) MRS (TE = 11/15/20/25(/35) ms) in regions of healthy, edematous and fatty thigh muscle tissue. Muscle regions for MRS were selected based on T 2 -weighted water and fat images of a two-echo 2D Dixon TSE. MRS results were confined to regions with qualitatively defined remaining muscle tissue without edema and high fat content, based on visual grading of the imaging data. The results showed decreased T 2w values with increasing PDFF with R 2  = 0.45 (p < 10 -3 ) (linear fit) and with R 2  = 0.51 (exponential fit). The observed dependence of T 2w on PDFF should be considered when using T 2w as a marker in NMD imaging and when performing single-voxel MRS for T 2w in regions enclosing edematous, nonedematous and fatty infiltrated muscle tissue., (© 2019 John Wiley & Sons, Ltd.)

Introduction: The system of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (cas) is a new technology that allows easier manipulation of the genome. Its potential to edit genes opened a new door in treatment development for incurable neurological monogenic diseases (NMGDs). The aim of this systematic review was to summarise the findings on the current development of CRISPR-cas for therapeutic purposes in the most frequent NMGDs and provide critical assessment., Methods and Data Acquisition: We searched the MEDLINE and EMBASE databases, looking for original studies on the use of CRISPR-cas to edit pathogenic variants in models of the most frequent NMGDs, until end of 2017. We included all the studies that met the following criteria: 1. Peer-reviewed study report with explicitly described experimental designs; 2. In vitro, ex vivo, or in vivo study using human or other animal biological systems (including cells, tissues, organs, organisms); 3. focusing on CRISPR as the gene-editing method of choice; and 5. featured at least one NMGD., Results: We obtained 404 papers from MEDLINE and 513 from EMBASE. After removing the duplicates, we screened 490 papers by title and abstract and assessed them for eligibility. After reading 50 full-text papers, we finally selected 42 for the review., Discussion: Here we give a systematic summary on the preclinical development of CRISPR-cas for therapeutic purposes in NMGDs. Furthermore, we address the clinical interpretability of the findings, giving a comprehensive overview of the current state of the art. Duchenne's muscular dystrophy (DMD) paves the way forward, with 26 out of 42 studies reporting different strategies on DMD gene editing in different models of the disease. Most of the strategies aimed for permanent exon skipping by deletion with CRISPR-cas. Successful silencing of the mHTT gene with CRISPR-cas led to successful reversal of the neurotoxic effects in the striatum of mouse models of Huntington's disease. Many other strategies have been explored, including epigenetic regulation of gene expression, in cellular and animal models of: myotonic dystrophy, Fraxile X syndrome, ataxias, and other less frequent dystrophies. Still, before even considering the clinical application of CRISPR-cas, three major bottlenecks need to be addressed: efficacy, safety, and delivery of the systems. This requires a collaborative approach in the research community, while having ethical considerations in mind., Competing Interests: The authors have declared that no competing interests exist.

Objective: The assessment of fatty infiltration and edema in the musculature of patients with neuromuscular diseases (NMDs) typically requires the separate performance of T1-weighted and fat-suppressed T2-weighted sequences. T2-weighted Dixon turbo spin echo (TSE) enables the generation of T2-weighted fat- and water-separated images, which can be used to assess both pathologies simultaneously. The present study examines the diagnostic performance of T2-weighted Dixon TSE compared with the standard sequences in 10 patients with NMDs and 10 healthy subjects., Methods: Whole-body magnetic resonance imaging was performed including T1-weighted Dixon fast field echo, T2-weighted short-tau inversion recovery, and T2-weighted Dixon TSE. Fatty infiltration and intramuscular edema were rated by 2 radiologists using visual semiquantitative rating scales. To assess intermethod and interrater agreement, weighted Cohen's κ coefficients were calculated., Results: The ratings of fatty infiltration showed high intermethod and high interrater agreement (T1-weighted Dixon fast field echo vs T2-weighted Dixon TSE fat image). The evaluation of edematous changes showed high intermethod and good interrater agreement (T2-weighted short-tau inversion recovery vs T2-weighted Dixon TSE water image)., Conclusions: T2-weighted Dixon TSE imaging is an alternative for accelerated simultaneous grading of whole-body skeletal muscle fat infiltration and edema in patients with NMDs.

Respiratory muscle strength is a proven predictor of long-term outcome of neuromuscular disease (NMD), including amyotrophic lateral sclerosis, Duchenne muscular dystrophy, and spinal muscular atrophy. Maximal inspiratory pressure (MIP), a sensitive measure of respiratory muscle strength, one of several useful tests of respiratory muscle strength, is gaining interest as a therapeutic clinical trial endpoint for NMD. In this comprehensive review we investigate the use of MIP as a measure of respiratory muscle strength in clinical trials of therapeutics targeting respiratory muscle, examine the correlation of MIP with survival, quality of life, and other measures of pulmonary function, and outline the role of MIP as a clinically significantly meaningful outcome measure. Our analysis supports the utility of MIP for the early evaluation of respiratory muscle strength, especially of the diaphragm, in patients with NMD and as a surrogate endpoint in clinical trials of therapies for NMD.

Little is known about pain associated with temporomandibular disorders (TMD) in neuromuscular diseases. Inpatients (N = 134) with neuromuscular disorder diagnoses were given questionnaires to estimate pain localization and intensity. Research Diagnostic Criteria for Temporomandibular Disorders and the Temporomandibular Index (TMI) were utilized to assess TMD. Pain was reported by 116 patients (86%). Legs (52%) and arms (33%) were the most common locations for pain localization, but the highest Pearson correlations (TMI vs. perceived pain) appeared for pain located in the trunk and arms (0.861, P < 0.01). No correlation between TMI and diagnosis group existed except for "acquired myopathy" and "miscellaneous neuromuscular diseases." These results suggest that the degree of TMD does not correlate with pain according to disease, although common mechanisms might be responsible for pain development in specific body regions connected with TMD. Most important, higher levels of TMD are associated with higher levels of perceived pain.

Background: The minimal clinically important difference (MCID) is the smallest change in outcome that physicians or patients would consider meaningful and is relevant when evaluating disease progression or the efficacy of interventions. Studies of patients with late-onset Pompe disease (LOPD) have used the 6-min walk distance (6MWD) as an endpoint to assess motor function. However, an MCID for 6MWD (% predicted and meters) has yet to be established in LOPD. The objective of the study was to derive 6MWD MCID (% predicted and meters) with different analysis methods and for subgroups of different disease severity for LOPD. Methods: Data from the PROPEL trial were used to calculate 6MWD MCID in the overall PROPEL population and subgroups of baseline severity as assessed by walking distance and body mass index (BMI), using anchor- and distribution-based approaches. Results: The 6MWD MCIDs varied widely, depending on the method and subgroup, ranging from 2.27%-8.11% predicted for the overall LOPD population (23.7 m-57.2 m). For patients with baseline 6MWD < 150 m, MCIDs ranged from -0.74%-3.37% (-2.1 m-11.3 m). MCIDs increased with distance walked at baseline until a plateau was reached. For BMI subgroups, the MCIDs were generally lowest in obese patients. Conclusion: Our analysis shows that MCID depends on the chosen method and disease severity. The findings suggest that applying a single MCID to all patients can be misleading; consequently, a range of possible MCIDs should be considered. This may also be highly relevant for other neuromuscular diseases. This study provides a range of 6MWD MCIDs for LOPD, with lower MCIDs for more severe patients. [ABSTRACT FROM AUTHOR]

Background: Causal therapies are not yet available for most neuromuscular diseases. Additionally, data on the use of complementary or alternative therapies (CAM) in patients groups with a variety of different neuromuscular diseases are rare. This retrospective cross-sectional study aims to record the frequency of use and satisfaction of conventional therapies and complementary or alternative medicine (CAM) in patients with neuromuscular disorders in order to compare them afterwards. Methods: Patients from the University of Leipzig (Department and Outpatient Department of Neurology), the Friedrich-Baur-Institute (Department of Neurology), the Hoher Meißner Clinic (Department of Neurology) and the German Society for Muscular Diseases (DGM e.V.) were included. The focus of this study has been on patients with chronic neuromuscular diseases. Our data are based on standardised questionnaires in analogue form from three German neuromuscular centres and in digital form from the official website of the German Society for Muscular Diseases. Therapy satisfaction was assessed with the Patient Evaluation of Global Response (PEGR) ranking scale (very satisfactory + 2 to very unsatisfactory − 2). Results: Of 192 questionnaires analysed, the most common diagnoses were spinal muscular atrophy (n = 42; 21.9%), muscular dystrophies (n = 41; 21.4%) and myotonic dystrophies (n = 38; 19.8%). More than half (n = 112; 58.3%) used both conventional and CAM treatments. Physiotherapy (n = 165) was used most frequently within all treatments with conventional manual (PEGR 1.25, p = 0.013; CI 95%) and aquatic therapy (PEGR 1.3, p = 0.038) showing significantly higher satisfaction compared to therapy on training equipment. Less-used therapies such as psychotherapy (n = 53; PEGR 1.2) were also satisfactory. Within CAM, massages (n = 96) were the most reported and meditation (PEGR 1.5) was best rated. Massage therapy was significantly more satisfactory than progressive muscle relaxation (p = 0.003) and chiropractic treatment (p = 0.036). Chiropractic treatment (PEGR − 0.1) was rated most negatively. No significant differences were found between the group of conventional therapies and CAM users regarding social and disease-dependent factors. Conclusions: Treatment with conventional therapy (manual, aquatic therapy) and some CAM therapies can be recommended if adequately indicated. [ABSTRACT FROM AUTHOR]

The obituary published in the European Journal of Neurology honors the life and contributions of Professor Dr. med. Stephan Zierz (1954–2024), a renowned figure in the fields of neurology and neuromuscular medicine. Throughout his career, Zierz made significant advancements in research, particularly in neuromuscular disorders, and was recognized with prestigious awards for his work. He was also known for his dedication to teaching, having authored over 350 scientific reports and monographs. Zierz's legacy in European and international neuromuscular medicine continues to inspire future generations. [Extracted from the article]

The main pathologies in the muscles of patients with neuromuscular diseases (NMD) are fatty infiltration and edema. Recently, quantitative magnetic resonance (MR) imaging for determination of the MR biomarkers proton density fat fraction (PDFF) and water T2 (T2w) has been advanced. Biophysical effects or pathology can have different effects on MR biomarkers. Thus, for heterogeneously affected muscles, the routinely performed mean or median value analyses of MR biomarkers are questionable. Our work presents a voxel‐based histogram analysis of PDFF and T2w images to point out potential quantification errors. In 12 patients with NMD, chemical‐shift encoding‐based water‐fat imaging for PDFF and T2 mapping with spectral adiabatic inversion recovery (SPAIR) for T2w determination was performed. Segmentation of nine thigh muscles was performed bilaterally (n = 216). PDFF and T2 maps were coregistered. A voxel‐based comparison of PDFF and T2w showed a decreased T2w with increasing PDFF. Mean T2w and mean T2wwithout fatty voxels (PDFF < 10%) show good agreement, whereas standard deviation (σ) T2w and σ T2wwithout fatty voxels show increasing difference with increasing values of σ. Thereby two subgroups can be observed, referring to muscles in which the exclusion of fatty voxels has a negligible influence versus muscles in which a strong dependency of the T2w value distribution on the exclusion of fatty voxels is present. Because of the two opposite effects that influence T2w in a voxel, namely, (i) a pathophysiologically increased water mobility leading to T2w elevation, and (ii) a dependency of T2w on the PDFF leading to decreased T2w, the T2w distribution within a muscle might be heterogenous and the routine mean or median analysis can lead to a misinterpretation of the muscle health. It was concluded that muscle T2w mean values can wrongly suggest healthy muscle tissue. A deeper analysis of the underlying value distribution is necessary. Therefore, a quantitative analysis of T2w histograms is a potential alternative. [ABSTRACT FROM AUTHOR]

Background: Muscle water T2 (T2w ) has been proposed as a biomarker to monitor disease activity and therapy effectiveness in patients with neuromuscular diseases (NMD). Multi-echo spin-echo (MESE) is known to be affected by fatty infiltration. A T2 -prepared 3D turbo spin echo (TSE) is an alternative method for T2 mapping, but has been only applied in healthy muscles.Purpose: To examine the performance of T2 -prepared 3D TSE in combination with spectral adiabatic inversion recovery (SPAIR) in measuring T2w in fatty infiltrated muscles based on simulations and in vivo measurements in thigh muscles of patients with NMD.Study Type: Prospective.Subjects: One healthy volunteer, 34 NMD patients.Field Strength/sequence: T2 -prepared stimulated echo acquisition mode (STEAM) magnetic resonance spectroscopy (MRS), SPAIR STEAM MRS, and SPAIR T2 -prepared STEAM MRS were performed in the subcutaneous fat of a healthy volunteer's thigh. T2 mapping based on SPAIR 2D MESE and SPAIR T2 -prepared 3D TSE was performed in the NMD patients' thigh region. Multi-TE STEAM MRS was performed for measuring a reference T2w at different thigh locations.Assessment: The behavior of the fat spectrum in the SPAIR T2 -prepared 3D TSE was simulated using Bloch simulations. The in vivo T2 results of the imaging methods were compared to the in vivo T2w MRS results.Statistical Tests: Pearson correlation coefficient with slope and intercept, relative error.Results: The simulated T2 for the SPAIR T2 -prepared 3D TSE sequence remained constant within a relative error of not more than 4% up to a fat fraction of 80%. In vivo T2 values of SPAIR T2 -prepared 3D TSE were in good agreement with the T2w values of STEAM MRS (R = 0.86; slope = 1.12; intercept = -1.41 ms). In vivo T2 values of SPAIR 2D MESE showed large deviations from the T2w values of STEAM MRS (R = 0.14; slope = 0.32; intercept = 38.83 ms).Data Conclusion: The proposed SPAIR T2 -prepared 3D TSE shows reduced sensitivity to fatty infiltration for T2w mapping in the thigh muscles of NMD patients.Level Of Evidence: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:1727-1736. [ABSTRACT FROM AUTHOR]

Introduction: Myotonic dystrophies (DMs) are the most frequent autosomal dominant neuromuscular disorders in adults. Our objective was to evaluate the utility of an online survey in a rare disease as well as to assess and compare the onset and the progression of clinical symptoms in patients with myotonic dystrophy types 1 (DM1) and 2 (DM2). Methods: We conducted a patient's reported online survey assessing demographics, disease-related symptoms (age of onset, first symptom, time of diagnosis, current symptoms, inheritance, and family history) combined with capturing current symptoms by validated questionnaires. The questionnaire consisted of open, closed, single- and multiple-choice questions. Multiple answers were possible in some cases. Patients with genetically confirmed DM1 or DM2 who were registered in the German DM registry or the Deutsche Gesellschaft für Muskelkranke e.V. – Diagnostic Group for DMs were invited to participate in this online survey. We calculated descriptive and exploratory analysis, where applicable. Results: Out of 677 data sets from respondents, 394 were suitable for final analysis, containing completed questionnaires from 207 DM1 (56% female) and 187 DM2 patients (71% female). The median age of onset was 28 years for DM1 and 35 years for DM2. Muscular symptoms were most frequently reported as the first symptom. The onset of myotonia was earlier than the onset of muscle weakness in both DM1 and DM2. Forty-four percent of patients with DM1 and one-third of patients with DM2 indicated muscle weakness as the first symptom. Patients with DM1 were significantly younger when experiencing muscle weakness as first symptom. Fatigue was only mentioned by a small fraction of patients as a first symptom but increased significantly in the course of the disease. There was no statistically significant difference in the incidence of cataracts, cardiac symptoms, and gastrointestinal symptoms between DM1 and DM2. Falls were reported almost equally in both groups, and most of the patients reported 2–3 falls within the past year. Discussion: Overall, as our results are consistent with the results of clinical studies and online registries, it can be assumed that this type of systematic gathering of data from patients with rare diseases is useful and provides realistic and appropriate results. Due to the nature of online surveys and the absence of an assessor, some uncertainty remains. Furthermore, survey frauds cannot be completely excluded. An additional clinical assessment could confirm the given information and will improve the utility and validity of reported symptoms participants provide in online surveys. Therefore, we recommend a combination of data collecting by online surveys and clinical assessments. [ABSTRACT FROM AUTHOR]

Background: Pompe disease is a rare, severe neuromuscular disease with high mortality and substantial clinical and humanistic burden. However, the economic burden of Pompe disease and the health economic value of its treatments are not well understood. The objectives of this systematic review were to characterize the health economic evidence on Pompe disease, including healthcare resource use and costs (direct and indirect), health utilities, and the cost-effectiveness of current treatments used to manage patients with Pompe disease. Methods: A systematic search of MEDLINE® and Embase® was performed to retrieve publications on the health economics of Pompe disease. Publications were screened according to predefined criteria, extracted, and quality assessed using the Newcastle–Ottawa Scale. Data were narratively synthesized. Results: Eight publications evaluated patients with infantile-onset Pompe disease (IOPD) (two studies), late-onset Pompe disease (LOPD) (four studies), or both (two studies). In IOPD, total cost of supportive therapy (excluding treatment) was €32,871 (equivalent to US$41,667 when adjusted for currency and inflation to 2017 US dollars) over a life expectancy of 0.4 years. In adult LOPD, the average annual cost per patient of supportive therapy was €22,475 (adjusted $28,489). Resource use in LOPD was high, with nursing home admissions accounting for 19% of annual direct medical costs. Health economic evaluations estimating incremental costs per quality-adjusted life year (QALY) gained with enzyme-replacement therapy (ERT) versus supportive therapy ranged from £109,991 (adjusted, $186,851) per QALY gained in Columbia to €1,043,868 (adjusted, $1,323,207) in the Netherlands. Discussion: Despite a full systematic literature search, only eight relevant publications were identified, most of which were of relatively poor quality. However, a significant economic burden of Pompe disease on patients, families, healthcare systems, and society was found, with the majority of costs driven by the only currently approved treatment, ERT. Health economic evaluations of ERT versus supportive therapy vary significantly, with the majority well above willingness-to-pay thresholds. New therapies and approaches to care are needed to address the persistent and lifelong economic burden of Pompe disease and the large incremental cost-effectiveness ratios observed. [ABSTRACT FROM AUTHOR]

Background: Myositis-associated antibodies (MAA) and myositis-specific antibodies (MSA) are detected in patients with idiopathic inflammatory myopathies (IIM); their role as diagnostic biomarkers is however still debated. The aim of our study was to assess the utility of MAA/MSA assessed by new line immunoassays in detecting myositis among neuromuscular patients. Methods: We retrospectively analysed sera samples obtained from patients tested for myositis antibodies with the "Euroline: Autoimmune Inflammatory Myopathies 16Ag" and "myositis profile 3" kits (Mi-2, TIF1γ, MDA5, NXP2, SAE1, Jo-1, SRP, PL-7/12, EJ, OJ, Ro-52, Ku, PM-Scl75/100). First symptom, CK, EMG, muscle biopsy and diagnosis were also analysed. Using logistic regression analysis, two diagnostic models were built to evaluate the diagnostic power of MAA/MSA in distinguishing myositis patients from controls and other myopathies. Results: 1229 patients were identified. 141 patients had a bioptic confirmed IIM; other diagnoses included: myopathy (n = 357), other neuromuscular diseases (n = 144) and no neuromuscular diseases (n = 587). The specificity was 95% for MSA and 89% for MAA, the sensitivity 20% and 22%, respectively. MAA showed no use in differentiating myositis patients from controls, whereas MSA had limited effect (OR = 5.165), compared to other variables as EMG (OR = 47.755) or CK > 2000 U/L (OR = 45.307). MSA were, however, the most useful parameter differentiating IIM from non-IIM patients (OR = 7.259), better than CK > 2000 U/L (OR = 4.033) and MAA (OR = 2.737). Conclusions: Line immunoassays for myositis antibodies show high specificity but low sensitivity. Their usefulness as diagnostic biomarkers widely depends on the clinical settings. Our study suggests that MSA/MAA should be used for confirmatory and differential diagnosis rather than for screening purposes in inflammatory myopathies. [ABSTRACT FROM AUTHOR]

Background: In patients with late-onset Pompe disease, progressive respiratory muscle weakness with predominantly diaphragmatic involvement is a frequent finding at later stages of the disease. Respiratory muscle training (RMT) is an established therapy option for patients with several neuromuscular disorders including Duchenne muscular dystrophy. Forced voluntary muscle contractions of inspiration and/or expiration muscles enhance ventilation by increasing respiratory coordination, endurance, and strength. Efficacy of RMT in LOPD is rarely examined, and the clinical studies performed are difficult to compare because of different training programs and protocols. This impedes a useful statement and recommendation about the safety and efficacy of respiratory muscle training.Methods: We conducted a monocentric unblinded single-arm pilot study in patients with LOPD to evaluate the safety and efficacy of inspiratory muscle training (IMT). The primary objective was to determine the efficacy of a 6-week repetitive IMT with a gradual increase of inspiratory resistance, measured by MIP (maximum inspiratory pressure) in the upright position. For statistical analysis, we used an A-B-C single subject design. The 6-week training-period A was followed by a 6-week non-training period B and an optional training period of 40 weeks in period C. The total study duration for the periods A, B and C was 52 weeks. Throughout the study, spirometry assessments (FCV, FEV1) and measurements of respiratory strength (MIP, MEP) were performed at defined time points, as well as capillary oximetry and capnometry, motor function test and patient's questionnaires for quality of life and dyspnea, measured by St. George's Respiratory Questionnaire (SGRQ) and MMRC-Dyspnea scale. For the cross-sectional comparison, a paired two-sided t test, and for the longitudinal comparison, a two-sample, two-sided t test were used. When data were not normally distributed, a Wilcoxon-Mann-Whitney test was added. Finally, the annual decline in FVC and FEV1 before and after IMT was compared.Findings: 11 subjects were included in this pilot study. Overall, IMT was well tolerated. In four subjects, a total of six adverse events related to the study procedures were noticed. Training compliance was excellent in the first weeks of training, but declined continuously in the extension period. There was a significant increase in our primary outcome measure MIP within the 6-week period of frequent IMT with a mean of 15.7% (p =0.024; d =0.402). A significant increase was also seen after week 52 by a mean of + 26.4% (mean + 13.4 cmH2O, p =0.001, d =0.636). In the 6-week non-training interim-period (period B), the values remained stable, and there was no clinically meaningful decline in secondary outcome measures. The increase in MIP did not have any effect on secondary outcome measures like spirometry tests (FVC, FEV1), capillary blood gas analysis, motor function tests, patient's perceived quality of life or any significant change in dyspnea score.Conclusions: Frequent IMT improves MIP and thereby stabilizes and decelerates the decline of the diaphragm strength. The gradual increase of inspiratory resistance is well tolerated without any increase of side effects, as long as IMT is supervised and resistance is individually adjusted to the patient's perceived grade of exhaustion. Although we could not detect a significant impact on secondary outcome measures, IMT should be offered to all LOPD patients, especially to those who demonstrate a progressive decline in respiratory muscle function or are unable to receive ERT. [ABSTRACT FROM AUTHOR]

Background: Humanistic burden considers the impact of an illness on a patient's health-related quality of life (HRQoL), activities of daily living (ADL), caregiver health, and caregiver QoL. Humanistic burden also considers treatment satisfaction and adherence to treatment regimens. Pompe disease is an autosomal recessive, progressive, multisystemic neuromuscular disease. Approval of enzyme-replacement therapy (ERT) markedly improved prognosis for patients, but considerable morbidity and a substantial humanistic burden remain. This article characterizes the humanistic burden of Pompe disease through a systematic literature review.Methods: A systematic search of MEDLINE® and Embase® with back-referencing and supplementary literature searches was performed to retrieve data from interventional and non-interventional studies on the humanistic burden of Pompe disease. Publications were screened according to predefined criteria, extracted, and assessed for quality. Extracted data were narratively synthesized.Results: No publications on the humanistic burden of infantile-onset Pompe disease (IOPD) were identified. As such, of 17 publications included here, all are in patients with late-onset Pompe disease (LOPD). Thirteen publications were initiated after approval of ERT, two were initiated before, and two overlapped the approval of ERT. The review shows that LOPD patients have a significantly lower HRQoL than the general population, even if treated with ERT. On transitioning to ERT, treatment was associated with improvement in the physical component score of the SF-36 and fatigue, although the SF-36 mental component score remained stable. Physical HRQoL remained below population norms after 4 years of ERT. Significantly more ERT-treated patients reported pain than controls, and bodily pain worsened in later years following ERT initiation. Treatment-naïve LOPD patients had significantly poorer ADL functioning compared with the general population, although ERT stabilized deteriorating functioning impairment. ERT studies showed caregivers provide 17.7 h/week informal care on average. Fifty percent, 40% and <20% of caregivers reported mental health, physical health, and financial/relational problems, respectively. In ERT-naïve patients, wheelchair use and home ventilatory support was associated with lower physical HRQoL and ADL functioning. In ERT-treated patients, key factors predicting worse HRQoL and ADL functioning were higher respiratory distress, poorer sleep quality, greater pain, and more fatigue.Conclusions: Pompe disease has a substantial humanistic burden, with strong inter-relationships among and between humanistic burden parameters and clinical progression. [ABSTRACT FROM AUTHOR]

Myotonic dystrophies type 1 (DM1) and type 2 (DM2) are neuromuscular diseases, caused by accumulation of CUG and CCUG RNAs in toxic aggregates. Here we report that the increased stability of the mutant RNAs in both types of DMis caused by deficiency of RNA helicase p68. We have identified p68 by studying CCUG-binding proteins associated with degradation of the mutant CCUG repeats. Protein levels of p68 are reduced in DM1 and DM2 biopsied skeletal muscle. Delivery of p68 in DM1/2 cells causes degradation of the mutant RNAs, whereas delivery of p68 in skeletal muscle of DM1 mouse model reduces skeletal muscle myopathy and atrophy. Our study shows that correction of p68 may reduce toxicity of the mutant RNAs in DM1 and in DM2. [ABSTRACT FROM AUTHOR]

Background: We report on a patient with genetically confirmed overlapping diagnoses of CMT1A and FSHD. This case adds to the increasing number of unique patients presenting with atypical phenotypes, particularly in FSHD. Even if a mutation in one disease gene has been found, further genetic testing might be warranted in cases with unusual clinical presentation. Case presentation: The reported 53 years old male patient suffered from walking difficulties and foot deformities first noticed at age 20. Later on, he developed scapuloperoneal and truncal muscle weakness, along with atrophy of the intrinsic hand and foot muscles, pes cavus, claw toes and a distal symmetric hypoesthesia. Motor nerve conduction velocities were reduced to 20 m/s in the upper extremities, and not educible in the lower extremities, sensory nerve conduction velocities were not attainable. Electromyography showed both, myopathic and neurogenic changes. A muscle biopsy taken from the tibialis anterior muscle showed a mild myopathy with some neurogenic findings and hypertrophic type 1 fibers. Whole-body muscle MRI revealed severe changes in the lower leg muscles, tibialis anterior and gastrocnemius muscles were highly replaced by fatty tissue. Additionally, fatty degeneration of shoulder girdle and straight back muscles, and atrophy of dorsal upper leg muscles were seen. Taken together, the presenting features suggested both, a neuropathy and a myopathy. Patient's family history suggested an autosomal dominant inheritance. Molecular testing revealed both, a hereditary motor and sensory neuropathy type 1A (HMSN1A, also called Charcot-Marie-Tooth neuropathy 1A, CMT1A) due to a PMP22 gene duplication and facioscapulohumeral muscular dystrophy (FSHD) due to a partial deletion of the D4Z4 locus (19 kb). Conclusion: Molecular testing in hereditary neuromuscular disorders has led to the identification of an increasing number of atypical phenotypes. Nevertheless, finding the right diagnosis is crucial for the patient in order to obtain adequate medical care and appropriate genetic counseling, especially in the background of arising curative therapies. [ABSTRACT FROM AUTHOR]

Myasthenia gravis (MG) is an autoimmune disorder characterized by a defect in synaptic transmission at the neuromuscular junction causing fluctuating muscle weakness with a decremental response to repetitive nerve stimulation or altered jitter in single-fiber electromyography (EMG). Approximately 80% of all myasthenia gravis patients have autoantibodies against the nicotinic acetylcholine receptor in their serum. Autoantibodies against the tyrosine kinase muscle-specific kinase (MuSK) are responsible for 5-10% of all myasthenia gravis cases. The autoimmune target in the remaining cases is unknown. Recently, low-density lipoprotein receptor-related protein 4 (LRP4) has been identified as the agrin receptor. LRP4 interacts with agrin, and the binding of agrin activates MuSK, which leads to the formation of most if not all postsynaptic specializations, including aggregates containing acetylcholine receptors (AChRs) in the junctional plasma membrane. In the present study we tested if autoantibodies against LRP4 are detectable in patients with myasthenia gravis. To this end we analyzed 13 sera from patients with generalized myasthenia gravis but without antibodies against AChR or MuSK. The results showed that 12 out of 13 antisera from double-seronegative MG patients bound to proteins concentrated at the neuromuscular junction of adult mouse skeletal muscle and that approximately 50% of the tested sera specifically bound to HEK293 cells transfected with human LRP4. Moreover, 4 out of these 13 sera inhibited agrin-induced aggregation of AChRs in cultured myotubes by more than 50%, suggesting a pathogenic role regarding the dysfunction of the neuromuscular endplate. These results indicate that LRP4 is a novel target for autoantibodies and is a diagnostic marker in seronegative MG patients. [ABSTRACT FROM AUTHOR]

Abstract: We report seven patients with immune-mediated rippling muscle disease (iRMD) and AChR-antibody positive myasthenia gravis (MG) without germline caveolin-3 gene mutations. We describe the follow-up of two patients and the clinical features of five new patients (1 female, 4 male, aged 32 to 69 years). These presented with significant generalized, exercise-induced and electrically-silent muscle rippling with myalgia, combined with generalized MG. In two of the seven patients, MG appeared before iRMD. Mediastinal imaging excluded thymic alterations in all, although two had other coincident tumours. Myalgia and rippling were aggravated by acetylcholinesterase-inhibitor treatment. Generalized MG and iRMD were successfully treated with plasma exchange, steroids and azathioprine in the two patients followed long-term. Muscle morphology of five patients showed a minimal myopathic pattern with rare lymphohistiocytic infiltration. In four patients, sarcolemmal caveolin-3, and dysferlin immunofluorescence staining was moderately reduced in a mosaic pattern, but caveolin-3 protein on Western blots was clearly reduced only in two. Notably, electron microscopy showed that caveolae were almost completely lost at the sarcolemma in the three biopsies examined but not in endothelium. Antibodies targeting high molecular weight muscle proteins, likely associated with the neuromuscular endplate and sarcolemma, were found in the iRMD patients but also in age-matched MG patients without iRMD. Since the generalized MG and iRMD improved with immunosuppressive treatments, it is likely that both are caused by autoantibodies, but the target for pathogenic antibodies in iRMD requires further study. [Copyright &y& Elsevier]

Objectives: Muscle pain is a frequent concomitant symptom in a variety of neuromuscular disease and the most prominent findings in myofascial pain syndrome, as well as in fibromyalgia syndrome. Findings: Negligible awareness has been focused on pain characteristics in neuromuscular disorders. In the group of inflammatory myopathies, in dermatomyositis, the highest frequency of permanent muscle pain is complained in the shoulder girdle and thigh, and upper anus and legs. Pain quality is reported to be muscle-aching in the majority of patients, but additional different pain characteristics have been documented, including deep, gripping, dull, bright, sharp and superficial. Here small free nerve endings are connected to small blood vessels that show an upregulation of substance P and calcitonine gene related peptide as signs of an increased nociceptive input. Some forms of metabolic myopathies, especially glycogenolytic defects, are characterized by symptoms of stamina, painful contractures with exercise, cramps, and myoglobinuna. Pain expression in McArdle patients with chronic myalgia has frequently the features of functional muscle pain, or fibromyalgia syndrome. Depletion of high-energy phosphates like phosphocreatine and adenosine triphosphate during exercise may contribute to the pathogenesis. In degenerative myopathies, only a few disorders are investigated for pain pattern, but affected patients clearly present with muscle pain in myotonic dystrophies, facioscapulohumeral muscular dystrophy, other rare degenerative myopathies, and the peculiar rippling muscle disease. Most prevalent but still underrecognized as cause of muscle pain is the myofascial pain syndrome. Conclusion: The pathogenetic background of many type of muscle pain is still uncertain. Free nerve endings, substance P and adenosine triphosphate and tissue acidosis seem to be the player in muscle pain. [ABSTRACT FROM AUTHOR]

(1) Background and Purpose: The skeletal muscles of patients suffering from neuromuscular diseases (NMD) are affected by atrophy, hypertrophy, fatty infiltration, and edematous changes. Magnetic resonance imaging (MRI) is an important tool for diagnosis and monitoring. Concerning fatty infiltration, T1-weighted or T2-weighted DIXON turbo spin echo (TSE) sequences enable a qualitative assessment of muscle involvement. To achieve higher comparability, semi-quantitative grading scales, such as the four-point Mercuri scale, are commonly applied. However, the evaluation remains investigator-dependent. Therefore, effort is being invested to develop quantitative MRI techniques for determination of imaging markers such as the proton density fat fraction (PDFF). The present work aims to assess the diagnostic value of PDFF in correlation to Mercuri grading and clinically determined muscle strength in patients with myotonic dystrophy type 2 (DM2), limb girdle muscular dystrophy type 2A (LGMD2A), and adult Pompe disease. (2) Methods: T2-weighted two-dimensional (2D) DIXON TSE and chemical shift encoding-based water-fat MRI were acquired in 13 patients (DM2: n = 5; LGMD2A: n = 5; Pompe disease: n = 3). Nine different thigh muscles were rated in all patients according to the Mercuri grading and segmented to extract PDFF values. Muscle strength was assessed according to the British Medical Research Council (BMRC) scale. For correlation analyses between Mercuri grading, muscle strength, and PDFF, the Spearman correlation coefficient (rs) was computed. (3) Results: Mean PDFF values ranged from 7% to 37% in adults with Pompe disease and DM2 and up to 79% in LGMD2A patients. In all three groups, a strong correlation of the Mercuri grading and PDFF values was observed for almost all muscles (rs > 0.70, p < 0.05). PDFF values correlated significantly to muscle strength for muscle groups responsible for knee flexion (rs = −0.80, p < 0.01). (4) Conclusion: In the small, investigated patient cohort, PDFF offers similar diagnostic precision as the clinically established Mercuri grading. Based on these preliminary data, PDFF could be further considered as an MRI-based biomarker in the assessment of fatty infiltration of muscle tissue in NMD. Further studies with larger patient cohorts are needed to advance PDFF as an MRI-based biomarker in NMD, with advantages such as its greater dynamic range, enabling the assessment of subtler changes, the amplified objectivity, and the potential of direct correlation to muscle function for selected muscles. [ABSTRACT FROM AUTHOR]

Presents an overview of a study which examined whether resistance exercise performed regularly as a countermeasure to progressive atrophy with 12 weeks of strict bed rest would support expression of one or more isoforms of nitric oxide synthases (NOS), thereby maintaining normal skeletal muscle functions during immobilization in clinical settings or in human spaceflight. Effect of resistance exercise on myofiber cross-sectional areas in vastus lateralis and soleus muscle biopsies; Results of the analysis of the effects of exercise on the cellular and subcellular distribution of NOS isoforms; Relative proportions of NOS 1 to 3 protein levels.

Quantitative imaging techniques are emerging in the field of magnetic resonance imaging of neuromuscular diseases (NMD). T2 of water (T2w) is considered an important imaging marker to assess acute and chronic alterations of the muscle fibers, being generally interpreted as an indicator for "disease activity" in the muscle tissue. To validate the accuracy and robustness of quantitative imaging methods, 1H magnetic resonance spectroscopy (MRS) can be used as a gold standard. The purpose of the present work was to investigate T2w of remaining muscle tissue in regions of higher proton density fat fraction (PDFF) in 40 patients with defined NMD using multi‐TE single‐voxel 1H MRS. Patients underwent MR measurements on a 3 T system to perform a multi‐TE single‐voxel stimulated echo acquisition method (STEAM) MRS (TE = 11/15/20/25(/35) ms) in regions of healthy, edematous and fatty thigh muscle tissue. Muscle regions for MRS were selected based on T2‐weighted water and fat images of a two‐echo 2D Dixon TSE. MRS results were confined to regions with qualitatively defined remaining muscle tissue without edema and high fat content, based on visual grading of the imaging data. The results showed decreased T2w values with increasing PDFF with R2 = 0.45 (p < 10−3) (linear fit) and with R2 = 0.51 (exponential fit). The observed dependence of T2w on PDFF should be considered when using T2w as a marker in NMD imaging and when performing single‐voxel MRS for T2w in regions enclosing edematous, nonedematous and fatty infiltrated muscle tissue. [ABSTRACT FROM AUTHOR]

Abstract: Mutations in CAV3 gene encoding the protein caveolin-3 are associated with autosomal dominant limb girdle muscular dystrophy 1C, rippling muscle disease, hyperCKemia, distal myopathy, hypertrophic cardiomyopathy and rare autosomal recessive limb girdle muscular dystrophy phenotypes. In a 57-year-old patient with asymmetric limb girdle weakness, we detected a novel homozygous intronic mutation (IVS1+2T>C) of the CAV3 gene. This is the first splicing mutation reported for CAV3. These findings add to the clinical and genetic variability of CAV3 mutations. [Copyright &y& Elsevier]

• Myotonic dystrophy type 2 lacks validated questionnaires for ADLs. • DM1-Activ-c and R-PAct proved to be valid measures of ADLs in DM2. • R-PAct, performed better than DM1-Activ-c in DM2 patients. Myotonic dystrophy type 2 (DM2) lacks validated patients´ reported outcomes (PROs). This represents a limit for monitoring disease progression and perceived efficacy of symptomatic treatments. Our aim was to investigate whether PROs for activities of daily living designed for other neuromuscular diseases could be used in DM2. Sixty-six DM2 patients completed the following PROs: DM1-Activ-c, Rasch-built Pompe-specific activity (R-PAct) scale, McGill-pain questionnaire, fatigue and daytime sleepiness scale and Beck depression inventory (BDI-II). Clinical data and motor outcome measures (6-minutes walking test - 6MWT, manual muscle testing, quick motor function test and myotonia behavior scale) were collected as well. Patients underwent one visit at baseline and one after 10 months. Ceiling/flooring effects, criterion validity and discriminant validity were calculated. DM1-activ-c and R-PAct showed acceptable ceiling effects despite being built for myotonic dystrophy type 1 and Pompe disease, respectively. The difficulty hierarchy of the single items was better preserved in R-PAct than in DM1-Activ-c. Both tests showed excellent criterion validity highly correlating with 6MWT, quick motor function test, myalgia and disease duration. They could partially discriminate patients with different disability grades. These results suggest that DM1-Activ-c, slightly better than R-PAct, might be adopted for monitoring activities of daily living also in DM2, at least until disease-specific PROs will be available. [ABSTRACT FROM AUTHOR]

Tubular aggregates in human muscle biopsies have been reported to occur in a variety of acquired and hereditary neuromuscular conditions since 1964. Recently mutations in the gene encoding the main calcium sensor in the sarcoplasmic reticulum, stromal interaction molecule 1 (STIM1), have been identified as a cause of autosomal dominant tubular aggregate myopathy. We studied a German family with tubular aggregate myopathy and defined cellular consequences of altered STIM1 function. Both patients in our family had early progressive myopathy with proximal paresis of arm and leg muscles, scapular winging, ventilatory failure, joint contractures and external ophthalmoplegia. One patient had a well-documented disease course over 50 years. Sequencing of the STIM1 gene revealed a previously unreported missense mutation (c.242G>A; p.Gly81Asp) located in the first calcium binding EF domain. Functional characterization of the new STIM1 mutation by calcium imaging revealed that calcium influx was significantly increased in primary myoblasts of the index patient compared to controls pointing at a severe alteration of intracellular calcium homeostasis. This new family widens the spectrum of STIM1 -associated myopathies to a more severe phenotype. [ABSTRACT FROM AUTHOR]

Abstract: Mutations in the nebulin gene are the main cause of autosomal recessive nemaline myopathy, with clinical presentations ranging from mild to severe disease. We have previously reported a nonspecific distal myopathy caused by homozygous missense mutations in the nebulin gene in six Finnish patients from four different families. Here we describe three non-Finnish patients in two unrelated families with distal nemaline myopathy caused by four different compound heterozygous nebulin mutations, only one of which is a missense mutation. One of the mutations has previously been identified in one family with the severe form of nemaline myopathy. We conclude that nemaline myopathy and distal myopathy caused by nebulin mutations form a clinical and histological continuum. Nemaline myopathy should be considered as a differential diagnosis in patients presenting with an early-onset predominantly distal myopathy. [Copyright &y& Elsevier]

Abstract: Limb girdle muscular dystrophy type 2L (LGMD2L) is an adult-onset slowly progressive muscular dystrophy associated with recessive mutations in the ANO5 gene. We analysed the muscle MRI pattern in a cohort of 25 LGMD2L patients in order to understand the extent and progression of muscle pathology in LGM2L and assess if muscle MRI might help in the diagnostic work-up of these patients. Our results showed a homogeneous pattern of muscle pathology on muscle MRI, with a predominant involvement of the posterior compartment muscles in both the thighs and calves. The muscles of the anterior compartments in the leg together with the sartorius and gracilis muscles were best preserved, which partially overlaps with patterns observed for other recessive LGMDs. Muscle MRI therefore does not appear to be as useful in the diagnostic work up of LGMD2L as for other neuromuscular diseases, such as Bethlem myopathy or myofibrillar myopathy. [Copyright &y& Elsevier]