Utility and Results from a Patient-Reported Online Survey in Myotonic Dystrophies Types 1 and 2.

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.

How to capture activities of daily living in myotonic dystrophy type 2?

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.

Utility of maximum inspiratory and expiratory pressures as a screening method for respiratory insufficiency in slowly progressive neuromuscular disorders.

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 r2 was found for MIP % predicted and forced vital capacity (FVC) % predicted. Manometry predicted abnormal FVC and forced expiratory volume 1 s (FEV1). MEP > 80 cmH2O 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.

Validation of Motor Outcome Measures in Myotonic Dystrophy Type 2.

Introduction: Myotonic dystrophy type 2 (DM2) lacks disease-specific, validated, motor outcome measures (OMs), and patients' reported outcomes (PROs). This represents a limit for the monitoring of disease progression and treatment response. Our aim was to identify the most appropriate OMs to be translated in clinical practice and clinical trials on DM2. This study has been registered on clinicaltrials.gov NCT03603171 (https://clinicaltrials.gov/ct2/show/NCT03603171). Methods: Sixty-six patients with genetically confirmed DM2 underwent a baseline and a follow-up visit after 1 year. The tested OMs included: hand opening time, pressure pain threshold (PPT), manual muscle testing (MMT), hand held dynamometry (HHD), scale for the assessment and rating of ataxia (SARA), quantitative motor function test (QMFT), gait stairs Gowers chair (GSGC), 30-s sit to stand test, functional index 2 (FI-2) and 6MWT. The PROs included DM1-Active-C, Rasch-built Pompe-specific activity scale (R-Pact), fatigue and daytime sleepiness (FDSS), brief pain inventory short form (BPI-sf), myotonia behavior scale (MBS), and the McGill pain questionnaire. Results: All patients completed the MBS and the results correlated well with the hand-opening time. The PPT showed a low reliability, no correlation with pain questionnaires, and did not differentiate patients with or without myalgia. Both muscle strength assessments, MMT and HHD, showed good construct validity. The QMFT showed an acceptable ceiling effect (14.5%), good convergent and differential validity and performed overall better than GSGC. The SARA score showed high flooring effect and is not useful in DM2. 6MWT proved a valid outcome measure in DM2. The 30-s sit to stand is a feasible test with good convergent validity, showing a flooring effect of 20% as it cannot be used in more severely affected patients. The FI-2 is time-consuming and has a high ceiling effect. At the 1-year visit the only assessments able to detect a worsening of DM2 were HHD, QMFT, and 6MWT, which are the most sensitive to change, and therefore clinically meaningful OMs in DM2. Conclusion: The clinical meaningful motor outcome measures that best depict the multifaceted phenotype of DM2 and its slow progression are MBS, MMT, or HHD (depending on the clinical setting), QMFT, and the 6MWT.

A systematic review on the definition of rhabdomyolysis.

BACKGROUND: Rhabdomyolysis (RML) is an interdisciplinary condition due to muscle cell injury followed by the release of cell components into circulation. Etiology of RML has a broad range; a serious complication is acute kidney injury (AKI). Despite its high relevance, there is no established formal definition for RML. OBJECTIVES: A systematic review, focusing on RML definition, providing a recommendation for clinicians. METHOD: Systematic literature research in PubMed and Embase (1968-07/2018). RESULTS: The database research presented 8136 articles in PubMed and 2151 in Embase. After screening, 614 papers were retained for statistical analysis. A retrospective study was the most used design (44%). A definition of RML was stated in 231 studies (37.6%), including a precise creatine kinase level (CK) cut-off most frequently (67.1%). In 53/231 (22.9%) studies the CK cut-off was > 5 × upper limit of normal (ULN), and in 64/231 (27.7%) studies > 1000 IU/L. Further components of definitions were elevated CK without specific thresholds, and clinical symptoms. Exclusion criteria referring to the definition of RML were established in 113 studies, including myocardial, renal, cerebral and neuromuscular characteristics. CONCLUSION: At present, we recommend a clinical syndrome of acute muscle weakness, myalgia, and muscle swelling combined with a CK cut-off value of > 1000 IU/L/ or CK > 5 × ULN for the standard definition of a mild RML. Additionally measured myoglobinuria and AKI indicate a severe type of RML. Exclusion criteria as well as the chronological sequence need to be considered for a conclusive RML definition.

A role for cannabinoids in the treatment of myotonia? Report of compassionate use in a small cohort of patients.

BACKGROUND: The symptomatic treatment of myotonia and myalgia in patients with dystrophic and non-dystrophic myotonias is often not satisfactory. Some patients anecdotally report symptoms' relief through consumption of cannabis. METHODS: A combination of cannabidiol and tetrahydrocannabinol (CBD/THC) was prescribed as compassionate use to six patients (four patients with myotonic dystrophy types 1 and 2, and 2 patients with CLCN1-myotonia) with therapy-resistant myotonia and myalgia. CBD/THC oil was administered on a low dose in the first 2 weeks and adjusted to a higher dose in the following 2 weeks. Myotonia behaviour scale (MBS), hand-opening time, visual analogue scales (VAS) for myalgia and myotonia, and fatigue and daytime sleepiness severity scale (FSS, ESS) were performed weekly to monitor treatment response. RESULTS: All patients reported an improvement of myotonia especially in weeks 3 and 4 of treatment: MBS improved of at least 2 points in all patients, the hand-opening time variously improved in 5 out of 6 patients. Chronic myalgia was reported by both DM2 patients at baseline, one of them experienced a significant improvement of myalgia under treatment. Some gastrointestinal complaints, as abdominal pain and diarrhoea, improved in 3 patients; however, 4 out of 6 patients reported new-onset constipation. No other relevant side effect was noticed. CONCLUSIONS: These first empirical results suggest a potentially beneficial role of CBD/THC in alleviating myotonia and should encourage further research in this field including a randomized-controlled trial on larger cohorts.

Safety and Treatment Effects of Nusinersen in Longstanding Adult 5q-SMA Type 3 - A Prospective Observational Study.

OBJECTIVE: Spinal muscular atrophy (SMA) is a progressive autosomal recessive motor neuron disease caused by loss of the SMN1 gene. Based on randomized clinical trials in children with SMA type 1 and 2, Nusinersen has been approved as the first treatment for all types of SMA, including adults with SMA type 3. METHODS: We evaluated the safety and treatment effects of Nusinersen in longstanding adult 5q-SMA type 3. Patients were treated with intrathecal loading doses at day 1, 14, 28 and 63, followed by maintenance dose every four months up to 300 days. We monitored the patients within SMArtCARE, a prospective open-label outcome study for disease progression, side effects and treatment efficacy, encompassing clinical examination including MRC sum score, vital capacity in sitting position (VC, VC % pred.), ALS Functional Rating Scale (ALS-FRS), 6-Minute-Walk-Test (6MWT), Revised Upper Limb Module (RULM), and Hammersmith Functional Rating Scale (HFMSE). We also measured biomarkers in the spinal fluid (phosphorylated neurofilament heavy chain pNFH, neuron-specific enolase NSE, proteins, ß-Amyloid 1-40, ß-Amyloid 1-42, tau and phospho-tau) and creatine kinase (CK). Assessments were performed at baseline, day 63 (V4), day 180 (V5) and day 300 (V6). For statistical analysis, we compared baseline to V4, V5 and V6, using the paired sample t-test. When there were significant differences, we added cohen's d and effect size r for evaluation of clinical meaningfulness. RESULTS: 19 patients were included, 17 of them have completed the observation period of 10 months (day 300, V6). Patients were aged 18 to 59 years with disease duration ranging from 6 to 53 years. Except for the 6MWT, the RULM and the peak cough flow, there were no relevant significant changes in all functional outcome assessments at V4, V5 or V6, compared to baseline. For the 6MWT, there was a statistically significant improvement at visit 5 and at visit 6. RULM-score increased significantly at V6, and peak cough flow at visit 5. In biomarker studies, there was a significant decline in NSE and pTAU as well as a slight increase in proteins. In safety analysis, overall, Nusinersen applications were well tolerated. Eleven patients reported adverse events that were related to the study procedures, comprising back pain in seven patients and post-lumbar-puncture headache following intrathecal administration in four patients. Post-lumbar-puncture headache was reported in three females and one male, in total eleven times of 108 punctures (10%). No serious adverse events occurred. CONCLUSIONS: This prospective observational study indicates a mild treatment effect in adults with long-standing SMA3 after 10 months of treatment with Nusinersen, which had never occurred in the natural history of the disease. In our cohort, the most significant outcome measures were the 6MWT with statistically significant changes after day 180 and day 300, RULM after day 300 and peak cough flow after day 180.

Safety and efficacy of short- and long-term inspiratory muscle training in late-onset Pompe disease (LOPD): a pilot study.

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.

How to Interpret Abnormal Findings of Spirometry and Manometry in Myotonic Dystrophies?

BACKGROUND/AIM: Pulmonary function tests are used for screening respiratory insufficiency in patients with myotonic dystrophy (DM). We analysed the agreement between two different approaches in assessment of abnormal findings of forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP), in DM patients. METHODS: We used Cohen's κ- and Bangdiwala's B- statistic to compare the agreement between different cut-off values recommended by experts (ENMC) and the cut-off values based on the reference range (RR). We further analysed their sensitivity (Sn) and specificity (Sp) in detecting symptoms associated with respiratory insufficiency. RESULTS: The observed agreement was: 1) for FVC: κ= -0.002, B = 0.406; 2) for FEV1: κ= 0.944, B = 0.946; 3) for MIP: κ= 0.625, B = 0.674; and 4) for MEP: κ= 0.241, B = 0.373. Overall, RR cut-off values showed higher sensitivity, whereas the ENMC values showed higher specificity in detecting symptoms of respiratory involvement. CONCLUSIONS: The two approaches showed perfect agreement in assessment of FEV1, substantial agreement for MIP, and weak agreement for FVC and MEP. RR is an established method of assessment for spirometry and should be favoured because it takes variability within the population into account. Further development and validation of regression equations for RR calculations of predicted maximal respiratory pressures, with corresponding lower limits of normal, is required.The B statistic is more robust in assessing agreement between two diagnostic methods, resolving the issue of the κ paradox.

The effect of process variables on the degradation and physical properties of spray dried insulin intended for inhalation.

The aim of this study was to investigate the effect of process variables on the degradation and physical properties of spray dried insulin intended for inhalation. A 2(4) full factorial experimentally designed study was performed to investigate the influence of the following independent spray drying variables: feed flow rate, nozzle gas flow rate, inlet air temperature and aspirator capacity (drying gas flow rate). Human insulin (biosynthetic and Ph.Eur. quality) was dissolved in distilled water to concentrations of 5 mg/ml. The solutions were spray dried in a Mini Spray Dryer Büchi and the dry powders produced were characterized by high performance liquid chromatography, size exclusion chromatography, laser diffraction, thermo gravimetric analysis, scanning electron microscopy and weighing. The degradation of insulin was found to be affected mainly by the process variables that determine the outlet air temperature, i.e.: inlet air temperature, aspirator capacity and feed flow rate. The outlet air temperature should be kept below 120 degrees C to avoid degradation. A statistical optimization of the spray drying variables was performed, and found to recommend an experiment with an outlet air temperature of 61+/-4 degrees C. This experiment ought to generate a yield of 54+/-7% by weight of particles with a mass median diameter 2.9+/-0.4 microm, moisture content 3.9+/-0.5% by weight, content of high molecular weight proteins 0.3+/-0.1% by area, A-21 desamido insulin 0.3+/-0.05% by area and other insulin related compounds 0.3+/-0.1% by area.