Report of the first Outcome Measures in Myotonic Dystrophy type 1 (OMMYD-1) international workshop

Periostin as a blood biomarker of muscle cell fibrosis, cardiomyopathy and disease severity in myotonic dystrophy type 1

BACKGROUND AND PURPOSE

Myotonic dystrophy type 1 (DM1) is the most common form of adult-onset muscular dystrophy and is caused by an repeat expansion [r(CUG)^exp] located in the 3' untranslated region of the DMPK gene. Symptoms include skeletal and cardiac muscle dysfunction and fibrosis. In DM1, there is a lack of established biomarkers in routine clinical practice. Thus, we aimed to identify a blood biomarker with relevance for DM1-pathophysiology and clinical presentation.

METHODS

We collected fibroblasts from 11, skeletal muscles from 27, and blood samples from 158 DM1 patients. Moreover, serum, cardiac, and skeletal muscle samples from DMSXL mice were included. We employed proteomics, immunostaining, qPCR and ELISA. Periostin level were correlated with CMRI-data available for some patients.

RESULTS

Our studies identified Periostin, a modulator of fibrosis, as a novel biomarker candidate for DM1: proteomic profiling of human fibroblasts and murine skeletal muscles showed significant dysregulation of Periostin. Immunostaining on skeletal and cardiac muscles from DM1 patients and DMSXL mice showed an extracellular increase of Periostin, indicating fibrosis. qPCR studies indicated increased POSTN expression in fibroblasts and muscle. Quantification of Periostin in blood samples from DMSXL mice and two large validation cohorts of DM1 patients showed decreased levels in animals and diseased individuals correlating with repeat expansion and disease severity and presence of cardiac symptoms identified by MRI. Analyses of longitudinal blood samples revealed no correlation with disease progression.

CONCLUSIONS

Periostin might serve as a novel stratification biomarker for DM1 correlating with disease severity, presence of cardiac malfunction and fibrosis.

Masseter muscle volume as a disease marker in adult-onset myotonic dystrophy type 1

The advent of clinical trials in myotonic dystrophy type 1 (DM1) necessitates the identification of reliable outcome measures to quantify different disease manifestations using minimal number of assessments. In this study, clinical correlations of mean masseter volume (mMV) were explored to evaluate its potential as a marker of muscle involvement in adult-onset DM1 patients. We utilised data from a preceding study, pertaining to 39 DM1 patients and 20 age-matched control participants. In this study participants had undergone MRI of the brain, completed various clinical outcome measures and had CTG repeats measured by small-pool PCR. Manual segmentation of masseter muscles was performed by a single rater to estimate mMV. The masseter muscle was atrophied in DM1 patients when compared to controls (p<0.001). Significant correlations were found between mMV and estimated progenitor allele length (p = 0.001), modal allele length (p = 0.003), disease duration (p = 0.009) and and the Muscle Impairment Rating Scale (p = 0.008). After correction for lean body mass, mMV was also inversely correlated with self-reported myotonia (p = 0.014). This study demonstrates that changes in mMV are sensitive in reflecting the underlying disease process. Quantitative MRI methods demonstrate that data concerning both central and peripheral disease could be acquired from MR brain imaging studies in DM1 patients.

Patient-Centered Core Impact Sets: What They are and Why We Need Them

A quote attributed to Mark Twain states, “What gets us into trouble is not what we don’t know. It’s what we know for sure that just ain’t so.” The growing focus on patient centricity has revealed a misalignment between what patients report as important to them about their disease and/or treatment, and the data collected in research and care. Decisions across healthcare are made using an evidence base most stakeholders acknowledge is inadequate. Patients might report that what is important to them are everyday life impacts, concepts that can be very different from the more typical clinical outcomes we often track. In this paper, we encourage expanding current thinking to all “impacts,” not only health outcomes, but also the other equally (and sometimes more important) concerns patients report as important to them. We propose that a patient-centered core impact set be developed for each disease or condition of interest, and/or subpopulation of patients. A patient-centered core impact set begins with gathering from patients and caregivers an inventory of all impacts disease and treatments have on a patient’s (and carers’ and families’) life. Then, through a formal prioritization process, a core set of impacts is derived, inclusive of but extending beyond relevant health outcomes. We offer several recommendations on how to move the goal of a patient-centered core impact set forward through collaboration, leadership, and establishment of a patient-centered core impact set development blueprint with supporting tools.

Brief assessment of cognitive function in myotonic dystrophy: multicenter longitudinal study using computer-assisted evaluation

INTRODUCTION/AIMS

Myotonic dystrophy type 1 (DM1) is known to affect cognitive function, but the best methods to assess CNS involvement in multicenter studies have not been determined. This study's primary aim was to evaluate the potential of computerized cognitive tests to assess cognition in DM1.

METHODS

We conducted a prospective, longitudinal, observational study of 113 adults with DM1 at 6 sites. Psychomotor speed, attention, working memory, and executive functioning were assessed at baseline, 3-months and 12-months using computerized cognitive tests. Results were compared with assessments of muscle function and patient reported outcomes (PROs), including the Myotonic Dystrophy Health Index (MDHI) and EQ-5D-5L.

RESULTS

Based on intra-class correlation coefficients (ICCs), computerized cognitive tests had moderate to good reliability for psychomotor speed (0.76), attention (0.82), working memory speed (0.79), working memory accuracy (0.65), and executive functioning (0.87). Performance at baseline was lowest for working memory accuracy (p < 0.0001). Executive function performance improved from baseline to 3-months (p < 0.0001), without further changes over one year. There was a moderate correlation between poorer executive function and larger CTG repeat size (r = -0.433). There were some weak associations between PROs and cognitive performance.

DISCUSSION

Computerized tests of cognition are feasible in multicenter studies of DM1. Poor performance was exhibited in working memory, which may be a useful variable in clinical trials. Learning effects may have contributed to the improvement in executive functioning. The relationship between PROs and cognitive impairment in DM1 requires further study. This article is protected by copyright. All rights reserved.

Clinical Outcome Evaluations and CBT Response Prediction in Myotonic Dystrophy

BACKGROUND

The European OPTIMISTIC clinical trial has demonstrated a significant, yet heterogenous effect of Cognitive Behavioural Therapy (CBT) for Myotonic Dystrophy type 1 (DM1) patients. One of its remaining aims was the assessment of efficacy and adequacy of clinical outcome measures, including the relatively novel primary trial outcome, the DM1-Activ-c questionnaire.

OBJECTIVES

Assessment of the relationship between the Rasch-built DM1-Activ-c questionnaire and 26 commonly used clinical outcome measurements. Identification of variables associated with CBT response in DM1 patients.

METHODS

Retrospective analysis of the to date largest clinical trial in DM1 (OPTIMISTIC), comprising of 255 genetically confirmed DM1 patients randomized to either standard care or CBT with optionally graded exercise therapy. Correlations of 27 different outcome measures were calculated at baseline (cross-sectional) and of their respective intervention induced changes (longitudinal). Bootstrap enhanced Elastic-Net (BeEN) regression was validated and implemented to select variables associated with CBT response.

RESULTS

In cross-sectional data, DM1-Activ-c correlated significantly with the majority of other outcome measures, including Six Minute Walk Test and Myotonic Dystrophy Health Index. Fewer and weaker significant longitudinal correlations were observed. Nine variables potentially associated with CBT response were identified, including measures of disease severity, executive cognitive functioning and perceived social support.

CONCLUSIONS

The DM1-Activ-c questionnaire appears to be a well suited cross-sectional instrument to assess a variety of clinically relevant dimensions in DM1. Yet, apathy and experienced social support measures were less well captured. CBT response was heterogenous, requiring careful selection of outcome measures for different disease aspects.

Cerebral involvement and related aspects in myotonic dystrophy type 2

Myotonic dystrophy type 2 (DM2) is an autosomal dominant multisystemic disorder caused by CCTG repeats expansion in the first intron of the CNBP gene. In this review we focus on the brain involvement in DM2, including its pathogenic mechanisms, microstructural, macrostructural and functional brain changes, as well as the effects of all these impairments on patients' everyday life. We also try to understand how brain abnormalities in DM2 should be adequately measured and potentially treated. The most important pathogenetic mechanisms in DM2 are RNA gain-of-function and repeat-associated non-ATG (RAN) translation. One of the main neuroimaging findings in DM2 is the presence of diffuse periventricular white matter hyperintensity lesions (WMHLs). Brain atrophy has been described in DM2 patients, but it is not clear if it is mostly caused by a decrease of the white or gray matter volume. The most commonly reported specific cognitive symptoms in DM2 are dysexecutive syndrome, visuospatial and memory impairments. Fatigue, sleep-related disorders and pain are also frequent in DM2. The majority of key symptoms and signs in DM2 has a great influence on patients' daily lives, their psychological status, economic situation and quality of life.

Predictors of participation restriction over a 9-year period in adults with myotonic dystrophy type 1

PURPOSE

For slowly progressive neuromuscular disease, prognostic approach and long-term monitoring of participation is a crucial part of rehabilitation services. To improve the prognostic approach, professionals must identify individuals at risk of having higher participation restriction. This study aimed to identify personal and environmental predictors of participation restriction over nine years in adults with myotonic dystrophy type 1 (DM1).

METHODS

A secondary analysis of a longitudinal design comparing baseline with a follow-up nine years later was used with a multidimensional assessment of participation and personal and environmental factors. Based on theoretical models, multiple linear regressions were used.

RESULTS

One hundred and fourteen adults with DM1 were included in the study (63.2% women; 78.9% adult onset; mean (SD) age of 43.5 (10.4) years). When age, sex, phenotype, and education were controlled for, participation restriction was predicted by a longer time to stand and walk, lower grip strength, higher body mass index, absence of perceived impact of myotonia in daily living, use of adapted transportation from community services, and perception of obstacle in physical environment (p < 0.001, adjusted R² = 0.50).

CONCLUSIONS

The majority of predictors of participation restriction can be advantageously modified by rehabilitation and environmental changes, such as politics targeting community services provision or physical environment and services accessibility.Implications for rehabilitationPredictors could better inform rehabilitation professional to recognize individuals at risk of higher participation restriction over time and to target specific interventions based on a prognostic approach.Rehabilitation professionals could inform the people living with myotonic dystrophy type 1 and their relatives of the multifactorial nature of occurrence of participation restriction to diminish the "fatality" associated with a genetic progressive disorder.Predictors allow professionals to assess and intervene in the management of specific factors depending on the rehabilitation goal.Identifying individual with myotonic dystrophy with higher risk of participation restriction could help implement a long-term community based rehabilitation intervention plan targeting both personal and environmental factors.

Central Nervous System Involvement as Outcome Measure for Clinical Trials Efficacy in Myotonic Dystrophy Type 1

Increasing evidences indicate that in Myotonic Dystrophy type 1 (DM1 or Steinert disease), an autosomal dominant multisystem disorder caused by a (CTG)n expansion in DMPK gene on chromosome 19q13. 3, is the most common form of inherited muscular dystrophy in adult patients with a global prevalence of 1/8000, and involvement of the central nervous system can be included within the core clinical manifestations of the disease. Variable in its severity and progression rate over time, likely due to the underlying causative molecular mechanisms; this component of the clinical picture presents with high heterogeneity involving cognitive and behavioral alterations, but also sensory-motor neural integration, and in any case, significantly contributing to the disease burden projected to either specific functional neuropsychological domains or quality of life as a whole. Principle manifestations include alterations of the frontal lobe function, which is more prominent in patients with an early onset, such as in congenital and childhood onset forms, here associated with severe intellectual disabilities, speech and language delay and reduced IQ-values, while in adult onset DM1 cognitive and neuropsychological findings are usually not so severe. Different methods to assess central nervous system involvement in DM1 have then recently been developed, these ranging from more classical psychometric and cognitive functional instruments to sophisticated psycophysic, neurophysiologic and especially computerized neuroimaging techniques, in order to better characterize this disease component, at the same time underlining the opportunity to consider it a suitable marker on which measuring putative effectiveness of therapeutic interventions. This is the reason why, as outlined in the conclusive section of this review, the Authors are lead to wonder, perhaps in a provocative and even paradoxical way to arise the question, whether or not the myologist, by now the popular figure in charge to care of a patient with the DM1, needs to remain himself a neurologist to better appreciate, evaluate and speculate on this important aspect of Steinert disease.

Validation of the Italian version of the Charcot-Marie-Tooth disease Pediatric Scale

The Charcot-Marie-Tooth disease Pediatric Scale (CMTPedS) is a Rasch-built clinical outcome measure of disease severity. It is valid, reliable, and responsive to change for children and adolescents aged 3 to 20 years. The aim of this study was to translate and validate an Italian version of the CMTPedS using a validated framework of transcultural adaptation. The CMTPedS (Italian) was translated and culturally adapted from source into Italian by two experts in CMT with good English language proficiency. The two translations were reviewed by a panel of experts in CMT. The agreed provisional version was back translated into English by a professional translator. The definitive Italian version was developed during a consensus teleconference by the same panel. CMT patients were assessed with the final version of the outcome measure and a subset had a second assessment after 2 weeks to evaluate test-retest reliability. Seventeen patients with CMT aged 5 to 20 years (eight female) were evaluated with the CMTPedS (Italian), and test-retest was performed in three patients. The CMTPedS (Italian) showed a high test-retest reliability. No patient had difficulty in completing the scale. The instructions for the different items were clearly understood by clinicians and therefore the administration of the outcome measure was straight forward and easily understood by the children assessed. The CMTPedS (Italian) will be used for clinical follow-up and in clinical research studies in the Italian population. The data is fully comparable to that obtained from the English language version.

Validity of the Mini-BESTest in adults with myotonic dystrophy type 1

INTRODUCTION

Myotonic dystrophy type 1 (DM1) is a multisystemic neuromuscular disease that causes balance problems. The objective of this study was to assess the construct validity of the Mini-BESTest among adults with DM1.

METHODS

Fifty-nine individuals with late-onset or adult phenotypes of DM1 were recruited. Participants performed the Mini-BESTest, 10-Meter Walk Test (10mWT), 6-Minute Walk Test (6MWT), and Timed Up & Go (TUG) and were questioned on their tendency to lose balance and whether they fell in the past month.

RESULTS

Scores on the Mini-BESTest were significantly different between phenotypes and CTG repeat numbers (P < .02). Significant correlations were found with the 10mWT, 6MWT, and the TUG (r = 0.77-0.84; P < .001). A cutoff score of 21.5 was found to identify fallers with 90% posttest accuracy.

DISCUSSION

The Mini-BESTest demonstrates evidence of construct validity when assessing balance in the DM1 population.

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.

Myotonic dystrophy type 1 accompanied with normal pressure hydrocephalus: a case report and literature review

Background

Myotonic dystrophy type 1 (DM1) is the most common disease that can cause muscle weakness and atrophy among adults. Normal pressure hydrocephalus (NPH) is characterized by the triad of gait disturbance, cognitive impairment and urinary incontinence. The association between DM1 and NPH is extremely rare. We report a Chinese female patient with DM1 in association with NPH.

Case presentation

The patient presented with a history of 3-year of walking instability and cognitive impairment. Her brain MRI showed ventriculomegaly with normal cerebrospinal fluid (CSF) pressure and the CSF tap-test was positive, which indicated the diagnosis of probable NPH. DM1 was confirmed by genetic testing.

Conclusions

Four patients with DM1-NPH association were found before. The association between NPH and DM1 may not be just a coincidence, NPH may occur in DM1 later in life and it is vital to recognize the association as a shunt surgery may improve patients’ quality of life.

Analysis of the functional capacity outcome measures for myotonic dystrophy

Objectives

Defining clinically relevant outcome measures for myotonic dystrophy type 1 (DM1) that can be valid and feasible for different phenotypes has proven problematic. The Outcome Measures for Myotonic Dystrophy (OMMYD) group proposed a battery of functional outcomes: 6‐minute walk test, 30 seconds sit and stand test, timed 10 m walk test, timed 10 m walk/run test, and nine‐hole peg test. This, however, required a large‐scale investigation,

Methods

A cohort of 213 patients enrolled in the natural history study, PhenoDM1, was analyzed in cross‐sectional analysis and subsequently 98 patients were followed for longitudinal analysis. We aimed to assess: (1) feasibility and best practice; (2) intra‐session reliability; (3) validity; and (4) behavior over time, of these tests.

Results

OMMYD outcomes proved feasible as 96% of the participants completed at least one trial for all tests and more than half (n = 113) performed all three trials of each test. Body mass index and disease severity associate with functional capacity. There was a significant difference between the first and second trials of each test. There was a moderate to strong correlation between these functional outcomes and muscle strength, disease severity and patient‐reported outcomes. All outcomes after 1 year detected a change in functional capacity except the nine‐hole peg test.

Conclusions

These tests can be used as a battery of outcomes or independently based on the shown overlapping psychometric features and strong cross‐correlations. Due to the large and heterogeneous sample of this study, these results can serve as reference values for future studies.

Age-related cognitive decline in myotonic dystrophy type 1: An 11-year longitudinal follow-up study

Background

Myotonic dystrophy type 1 (DM1) is an inherited multi‐systemic disease involving the central nervous system (CNS) and is consequently characterized by a range of cognitive impairments. However, whether this cognitive profile progresses over time is still a matter of debate. The aim of this study was to longitudinally assess a DM1 sample, in order to compare, for the first time, this progression with that of a control group. Clinical and socio‐demographic predictive factors potentially implicated in this possible decline are analysed.

Method

Seventy‐five DM1 patients with childhood, juvenile, adult, and late‐onset, and 54 control participants were re‐assessed in an 11‐year follow‐up with a comprehensive neuropsychological battery. The analyses employed were mixed ANOVA for repeated measures to test intergroup comparisons over time and multiple linear regression for predictive variable analysis.

Results

Myotonic dystrophy type 1 patients significantly worsened in visuospatial/visuoconstructive abilities and visual memory compared with controls. Multiple linear regression revealed that progression of cognitive impairment measured by copy of the Rey–Osterrieth complex figure was predicted by muscular impairment, whilst on the block design test age predicted the change with a cut‐off at 31 years of age.

Discussion

A domain‐specific progressive cognitive decline was found in DM1, with visuospatial/visuoconstructive abilities showing the greatest vulnerability to the passage of time. In addition to important clinical implications, these results suggest the need for the scientific community to delve deeper into the potential mechanisms underlying early cognitive decline in this population.

Outcome Measures for Central Nervous System Evaluation in Myotonic Dystrophy Type 1 May Be Confounded by Deficits in Motor Function or Insight

Background: Central nervous system involvement in myotonic dystrophy type 1 (DM1) is associated with cognitive deficits, impaired social performance and excessive somnolence, which greatly impact quality of life. With the advent of clinical trials in DM1, there is a pressing need to identify outcome measures for quantification of central symptoms that are feasible and valid. In this context, we sought to evaluate neuropsychological and self-reported measures currently recommended by expert consensus, with particular reference to their specificity for central nervous system involvement in a moderate-sized DM1 cohort.

Methods: Forty-five adults with DM1 and 20 controls completed neuropsychology assessments and symptom questionnaires. Those without contraindication also underwent MRI brain, from which global gray matter volume and white matter lesion volume were quantified. CTG repeat was measured by small pool PCR, and was screened for the presence of variant repeat sequences.

Results: The neuropsychology test battery was well tolerated and detected impairment across various domains in the DM1 group vs. controls. Large effect sizes in the Stroop and Trail Making Tests were however attenuated by correction for basic speed, which could be influenced by dysarthria and upper limb weakness, respectively. Low mood was strongly associated with increased self-reporting of central symptoms, including cognitive impairment. Conversely, self-reported cognitive impairment did not generally predict poorer performance in neuropsychology assessments, and there was a trend toward greater self-reporting of low mood and cognitive problems in those with milder white matter change on MRI. Global gray matter volume correlated with performance in several neuropsychology assessments in a multivariate model with age and sex, while white matter lesion volume was associated with executive dysfunction reported by a proxy. Screening for variant repeats was positive in three individuals, who reported mild muscle symptoms.

Conclusions: Identification of outcome measures with good specificity for brain involvement in DM1 is challenging, since complex cognitive assessments may be compromised by peripheral muscle weakness and self-reported questionnaires may be influenced by mood and insight. This highlights the need for further large, longitudinal studies to identify and validate objective measures, which may include imaging biomarkers and cognitive measures not influenced by motor speed.

Neuropsychological and Psychological Functioning Aspects in Myotonic Dystrophy Type 1 Patients in Italy

Introduction: Myotonic Dystrophy Type 1 (DM1) is an autosomal dominant genetic illness, characterized by a progressive loss of strength. Important deficits in cognitive functioning and a significant prevalence of psychiatric disorders have been previously reported.

Methods:A neuropsychological and psychological assessment was carried out in 31 DM1 patients (61% males) in order to measure the cognitive functioning and explore their personality profiles. The MMSE Mini-Mental State Examination, Frontal Assessment Battery (FAB), ENB-2 Battery assessing memory (short term, long term and working memory), integration capacities, visual-spatial ability, attention (selective, divided, shifting/switching) executive functions, praxis, discrimination and logic capabilities and psychopathology Symptom Check List 90-R (SCL-90-R) were administered. The neuropsychological and psychological evaluation of DM1 patients was carried out taking into consideration the clinical parameters (CTG repeat, age at onset, disease duration, Muscular Impairment Rate Scale (MIRS), Medical Research Council Scale (MRC) and the Epworth Sleepiness Scales (EPS)).

Results: Regarding psychopathology 19.4% of patients scored a moderate or high level of symptoms intensity index (GSI), 12.9% reported a high number of symptoms (PST) and 16.1% reported a high intensity level of the perceived symptoms (PSDI). Fatigue and daytime sleepiness resulted as being associated with higher levels of psychoticism (PSY). Only 1 patient reported a severe impairment in the spatial and temporal orientation, memory, language, praxis, attention and calculation. Longer disease duration was also associated with cognitive impairment evaluated through ENB-2 (p < 0.05).

Discussions and Conclusions:There are indications of the utility of neuropsychological and psychological screening and support for these patients and their families due to the link between disease duration and cognitive performances. A proposal of a clinical protocol, with an illustration of a clinical case report of a family is presented.

Eight years after an international workshop on myotonic dystrophy patient registries: case study of a global collaboration for a rare disease

BACKGROUND

Myotonic Dystrophy is the most common form of muscular dystrophy in adults, affecting an estimated 10 per 100,000 people. It is a multisystemic disorder affecting multiple generations with increasing severity. There are currently no licenced therapies to reverse, slow down or cure its symptoms. In 2009 TREAT-NMD (a global alliance with the mission of improving trial readiness for neuromuscular diseases) and the Marigold Foundation held a workshop of key opinion leaders to agree a minimal dataset for patient registries in myotonic dystrophy. Eight years after this workshop, we surveyed 22 registries collecting information on myotonic dystrophy patients to assess the proliferation and utility the dataset agreed in 2009. These registries represent over 10,000 myotonic dystrophy patients worldwide (Europe, North America, Asia and Oceania).

RESULTS

The registries use a variety of data collection methods (e.g. online patient surveys or clinician led) and have a variety of budgets (from being run by volunteers to annual budgets over €200,000). All registries collect at least some of the originally agreed data items, and a number of additional items have been suggested in particular items on cognitive impact.

CONCLUSIONS

The community should consider how to maximise this collective resource in future therapeutic programmes.

Ankle Strength Impairments in Myotonic Dystrophy Type 1: A Five-Year Follow-up

BACKGROUND

In Myotonic Dystrophy type 1 (DM1) patients, ankle muscles are affected early and this impairment is reported to be a good biological marker for longitudinal studies.

OBJECTIVE

To characterize the ankle dorsiflexion (DF) and eversion (EV) maximal isometric muscle strength changes in adult DM1 patients over 5 years using a standardized handheld dynamometer protocol and the Myoankle method, compare the changes measured with both methods and to the standard error of measurement, and verify the relationship between ankle muscle strength and gait performance.

METHODS

The maximal isometric muscle strength of ankle DF and EV in DM1 patients from Quebec and Lyon was assessed at baseline, 18, 36 and 60 months using a handheld dynamometer (HHD) protocol and the MyoAnkle method.

RESULTS

There was a decrease of torque in DF/EV of 36.0% /31.3% and 27.7% /35.5% for the Quebec and Lyon cohorts respectively (p≤0.01), but not in a linear way. In most cases (82.5%), the changes observed were greater than the standard error of measurement. DF torque measures taken by the two methods (HHD and MyoAnkle) were highly correlated (rp = 0.97-0.98, p < 0.001).

CONCLUSION

Muscle strength ankle impairments are clinically meaningful in DM1 and can be accurately monitored using quantitative testing to measure the efficacy of therapeutic trials.

Cognitive impairment and quality of life in patients with myotonic dystrophy type 1

INTRODUCTION

This study sought to clarify whether specific cognitive abilities are impaired in patients with myotonic dystrophy type 1 (DM1) as well as to investigate the relationships among quality of life (QoL), cognitive function, and psychological factors.

METHODS

Sixty patients with DM1 were evaluated on cognitive functioning (abstract reasoning, attention/working memory, executive function, processing speed, and visuoconstructive ability), apathy, depression, excessive daytime sleepiness, fatigue, and QoL. QoL was assessed by 2 domains of the Muscular Dystrophy Quality of Life Scale (Psychosocial Relationships and Physical Functioning and Health).

RESULTS

More than half of the patients exhibited cognitive impairment in attention/working memory, executive function, processing speed, and visuoconstructive ability. The Psychosocial Relationships factor was associated with processing speed, attention/working memory, and apathy, whereas depression and fatigue were associated with 2 QoL domains.

DISCUSSION

Our study identified specific cognitive impairments in DM1. Specific cognitive functions and psychological factors may be potential contributors to QoL. Muscle Nerve 57: 742-748, 2018.

Traduction française de l’échelle Charcot-Marie-Tooth Disease Pediatric Scale

Cet article présente le processus de traduction en français du Charcot-Marie-Tooth Disease Pediatric Scale (CMTPedS), le seul outil de mesure validé évaluant la sévérité de la maladie chez les enfants atteints de CMT. Le processus de traduction utilisé s’inspire des lignes directrices de la Food and Drug Administration (FDA). La version préliminaire francophone du CMTPedS a été testée auprès de 14 enfants atteints. Les résultats de l’application démontrent que la passation a été bien tolérée par les enfants et s’est avérée conviviale pour les cliniciens. La disponibilité de cet outil en français semble prometteuse pour le suivi des enfants atteints et la réalisation d’essais clinique.

Further evidence for the reliability and validity of the Fatigue and Daytime Sleepiness Scale

BACKGROUND

Myotonic dystrophy type 1 (DM1) is an inherited neuromuscular disease causing, among other symptoms, fatigue and excessive daytime sleepiness, which are frequently undifferentiated by patients and/or clinicians. The Fatigue and Daytime Sleepiness Scale (FDSS) has been devised to measure these two overlapping symptoms as a single clinical entity.

OBJECTIVE

To further examine the reliability and the construct validity of the FDSS in patients with DM1.

METHODS

The scale was administered to 48 DM1 patients on two occasions at a 2week-interval. Intra-rater reliability and internal consistency were established by calculating the intraclass correlation coefficient (ICC) and Cronbach's alpha, respectively. Construct validity was assessed by using the known-group method. More precisely, the mean FDSS score of patients with and without subjective complaints of fatigue and/or sleepiness was compared.

RESULTS

The FDSS showed good intra-rater reliability (ICC=0.83) and acceptable internal consistency (Cronbach's alpha =0.6). Also, the FDSS was able to distinguish between patients who had fatigue and sleepiness complaints from those who did not (mean FDSS score of 10.6 vs 8.0, p=0.01), suggesting good construct validity.

CONCLUSION

Overall, the present study supports the continued use of the FDSS as a reliable and valid instrument to measure fatigue and daytime sleepiness in patients with DM1 for either clinical or research purposes.

Functional impairment in patients with myotonic dystrophy type 1 can be assessed by an ataxia rating scale (SARA)

Myotonic dystrophy type 1 (DM1) is not characterised by ataxia per se; however, DM1 and ataxia patients show similar disturbances in movement coordination often experiencing walking and balance difficulties, although caused by different underlying pathologies. This study aims to investigate the use of a scale previously described for the assessment and rating of ataxia (SARA) with the hypothesis that it could have utility in DM1 patients as a measure of disease severity and risk of falling. Data from 54 DM1 patients were pulled from the PHENO-DM1 natural history study for analysis. Mean SARA score in the DM1 population was 5.45 relative to the maximum score of eight. A flooring effect (score 0) was observed in mild cases within the sample. Inter-rater and test–retest reliability was high with intraclass coefficients (ICC) of 0.983 and 1.00, respectively. Internal consistency was acceptable as indicated by a Cronbach’s alpha of 0.761. Component analysis revealed two principle components. SARA correlated with: (1) all measures of muscle function tested, including quantitative muscle testing of ankle dorsiflexion (r = −0.584*), the 6 min walk test (r = −0.739*), 10 m walk test (r = 0.741*), and the nine hole peg test (r = 0.602*) and (2) measures of disease severity/burden, such as MIRS (r = 0.718*), MDHI (r = 0.483*), and DM1-Activ (r = −0.749*) (*p < 0.001). The SARA score was predicted by an interaction between modal CTG repeat length and age at sampling (r = 0.678, p = 0.003). A score of eight or above predicted the use of a walking aid with a sensitivity of 100% and a specificity of 85.7%. We suggest that further research is warranted to ascertain whether SARA or components of SARA are useful outcome measures for clinical trials in DM1. As a tool, it can be used for gathering information about disease severity/burden and helping to identify patients in need of a walking aid, and can potentially be applied in both research and healthcare settings.

Five-year study of quality of life in myotonic dystrophy

Background - Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy in adults. There is a complete lack of studies that assessed quality of life (QoL) trajectory during time in DM1 cohorts. Aim - To analyze changes of QoL in patients with DM1 during a 5-year follow-up period and to assess responsiveness of the SF-36 questionnaire. Patients and Method - At the baseline, this study comprised 84 DM1 patients, of whom 62 were retested after the mean period of 64.2 ± 3.9 months. Severity of muscular weakness was assessed using the Muscular Impairment Rating Scale (MIRS). Patients completed Serbian version of the SF-36 questionnaire as a measure of health-related QoL. Results - After 5 years, MIRS score of our DM1 patients showed significant progression of 0.5 grade (P < 0.01). All mental subdomains, role physical, and total SF-36 scores significantly improved after 5 years (P < 0.01). Unexpectedly, worsening of muscular weakness from mild to severe was in association with improvement of QoL. Conclusion - QoL improved in our cohort of DM1 patients during a 5-year period despite the progression of the disease. SF-36 should be used with caution as a patient-reported outcome measure in DM1 clinical trials.

Cognitive decline over time in adults with myotonic dystrophy type 1: A 9-year longitudinal study

Myotonic dystrophy type 1 (DM1) is an inherited neuromuscular disease with multisystemic involvement including the central nervous system. The evolution of the cognitive profile is a matter of debate, whether an eventual decline could be global or process-specific. Study aims are to describe, compare and document the clinical relevance of the progression of cognitive abilities in DM1 patients with adult and late-onset phenotypes. A total of 115 DM1 patients (90 adult; 25 late-onset) were assessed twice within a 9-year period on cognitive abilities (language, memory, visual attention, processing speed, visuoconstructive abilities and executive functions) and intellectual functioning (WAIS-R 7). A significant worsening over time was observed for verbal memory, visual attention, and processing speed. The progression in cognitive scores correlated with age and disease duration, but not with nCTG, muscular impairment nor education at baseline. Intellectual functioning remained stable. The rate of decline was higher among the late-onset phenotype than in the adult phenotype. Results showed that executive functions, language, and visual memory are impaired earlier in adult life, while verbal memory, visual attention, and processing speed decline later. Globally, results suggest an early and accelerated normal ageing process. This longitudinal study was based on the largest sample and the longest time period studied to date. These findings are highly relevant for clinical practice and genetic counselling.

Lower limb muscle impairment in myotonic dystrophy type 1: the need for better guidelines

In myotonic dystrophy type 1 (DM1), leg muscle weakness is a major impairment. There are challenges to obtaining a clear portrait of muscle strength impairment. A systematic literature review was conducted on lower limb strength impairment in late-onset and adult phenotypes to document variables which affect strength measurement. Thirty-two articles were reviewed using the COSMIN guidelines. Only a third of the studies described a reproducible protocol. Only 2 muscle groups have documented reliability for quantitative muscle testing and only 1 total score for manual muscle testing. Variables affecting muscle strength impairment are not described in most studies. This review illustrates the variability in muscle strength assessment in relation to DM1 characteristics and the questionable validity of the results with regard to undocumented methodological properties. There is therefore a clear need to adopt a consensus on the use of a standardized muscle strength assessment protocol.

Tractography reveals diffuse white matter abnormalities in Myotonic Dystrophy Type 1

Cerebral involvement in Myotonic Dystrophy Type 1 (DM1) is well-established but not well characterized. This study applied new Diffusion Tensor Imaging (DTI) tractography to characterize white matter disturbance in adults with DM1. Forty-five participants with DM1 and 44 control participants had MRIs on a Siemens 3T TIM Trio scanner. Data were processed with TRActs Constrained by UnderLying Anatomy (TRACULA) and 7 tracts were evaluated. Bilateral disturbances in white matter integrity were seen in all tracts in participants with DM1 compared to controls. There were no right-left hemisphere differences. The resulting DTI metrics were correlated with cognitive functioning, particularly working memory and processing speed. Motor speed was not significantly correlated with white matter microstructural integrity and, thus, was not the core explanation for the working memory and processing speed findings. White matter integrity was correlated with important clinical variables including the muscular impairment rating scale (MIRS). CTG repeat length was moderately associated with white matter status in corticospinal tract and cingulum. Sleepiness (Epworth Sleepiness Scale) was moderately associated with white matter status in the superior longitudinal fasciculus and cingulum. Overall, the results add to an emerging literature showing widespread white matter disturbances in both early-onset and adult-onset DM1. Results suggest that further investigation of white matter pathology is warranted in DM1 and that non-invasive measures such as DTI have a potentially important clinical value in characterizing the status of individuals with DM1.