Fatigue and daytime sleepiness in patients with myotonic dystrophy type 1: to lump or split?

Latent factors underlying the symptoms of adult-onset myotonic dystrophy type 1 during the clinical course

BACKGROUND

Myotonic dystrophy type 1 (DM1) is a multisystem genetic disorder that classically presents with symptoms associated with myotonia, early onset cataracts, and muscular weakness, although the presentation and pattern of disease progression is quite varied. Presenting symptoms are well documented among adults with DM1. However, less is known about the co-occurrence of symptoms over time. We aimed to use factor analysis to explore the correlation pattern of signs and symptoms (S/S) that emerged during the clinical course.

RESULTS

Clinical records of 228 individuals with adult onset DM1 were abstracted using the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) from a six-site cohort in the United States during an eight-year study period. Factor analysis was used to group the correlated S/S into latent factors. Three factors were identified. Group 1: 'Facial Weakness/Myotonia' includes the two most common S/S, as indicated by its name. Group 2: 'Skeletal Muscle Weakness' includes eight muscular S/S and is more frequently reported by males and those with older age at onset. Group 3: 'Gastrointestinal distress/Sleepiness' includes four non-muscular S/S and hand stiffness. The abstracted medical records reported that over 63% of individuals had S/S from all three groups. Associations of covariates with factor scores were also examined using linear regression. CTG repeat length was significantly positively associated with higher factor scores for all three factors.

CONCLUSIONS

This study identified three latent factors of S/S which accumulated during the clinical course of adult onset DM1.

Association between Reported Sleep Disorders and Behavioral Issues in Children with Myotonic Dystrophy Type 1-Results from a Retrospective Analysis in Italy

Background: Sleep disorders have been poorly described in congenital (CDM) and childhood (ChDM) myotonic dystrophy despite being highly burdensome. The aims of this study were to explore sleep disorders in a cohort of Italian CDM and ChDM and to assess their association with motor and respiratory function and disease-specific cognitive and behavioral assessments. Methods: This was an observational multicenter study. Reported sleep quality was assessed using the Pediatric Daytime Sleepiness Scale (PDSS) and Pediatric Sleep Questionnaire (PSQ). Sleep quality was correlated to motor function (6 min walk test, 6MWT and grip strength; pulmonary function (predicted Forced Vital Capacity%, FVC% pred.); executive function assessed by BRIEF-2; autism traits assessed by Autism Spectrum Screening Questionnaire (ASSQ) and Repetitive Behavior Scale-revised (RBS-R); Quality of life (PedsQL) and disease burden (Congenital Childhood Myotonic Dystrophy Health Index, CCMDHI). Results: Forty-six patients were included, 33 CDM and 13 ChDM, at a median age of 10.4 and 15.1 years. Daytime sleepiness and disrupted sleep were reported by 30% children, in both subgroups of CDM and ChDM. Daytime sleepiness correlated with autism traits in CDM (p < 0.05). Disrupted sleep correlated with poorer executive function (p = 0.04) and higher disease burden (p = 0.03). Conclusions: Sleep issues are a feature of both CDM and ChDM. They correlate with behavioral issues and impact on disease burden.

Common Characteristics Between Frailty and Myotonic Dystrophy Type 1: A Narrative Review

Myotonic dystrophy type 1 (DM1) is an inherited neuromuscular disorder often considered a model of accelerated aging due to the early appearance of certain age-related clinical manifestations and cellular and molecular aging markers. Frailty, a state of vulnerability related to aging, has been recently studied in neurological conditions but has received considerably less attention in neuromuscular disorders. This narrative review aims to describe 1) the common characteristics between Fried's frailty phenotype criteria (muscular weakness, slow gait speed, weight loss, exhaustion/fatigue, and low physical activity) and DM1, and 2) the psychological and social factors potentially contributing to frailty in DM1. This review gathered evidence suggesting that DM1 patients meet four of the five frailty phenotype criteria. Additionally, longitudinal studies report the deterioration of these criteria over time in DM1. Patients also exhibit psychological/cognitive and social factors that might contribute to frailty. Monitoring frailty criteria in the DM1 population could help to implement timely preventions and interventions to reduce the disease burden and severity of frailty symptoms.

267th ENMC International workshop: psychological interventions for improving quality of life in slowly progressive neuromuscular disorders

This workshop aimed to develop recommendations for psychological interventions to support people living with slowly progressive neuromuscular disorders (NMD). The workshop comprised clinicians, researchers, people living with NMD and their relatives. First, participants considered the key psychological challenges presented by NMD and the impact of NMD on relationships and mental health. Later, several psychological approaches for enhancing well-being in NMD were described. The results of randomised controlled trials of Cognitive Behaviour Therapy and Acceptance and Commitment Therapy for improving fatigue, quality of life, and mood in adults with NMD were examined. Then the group considered ways to adapt therapies for cognitive impairments or neurodevelopmental differences that occur in some NMD, alongside ways to support children and adolescents with NMD and their family members. Based on the evidence from randomised controlled trials, carefully conducted observational studies, and the coherence of these data with the experience of those living with NMD, the group recommends that psychological interventions should be embedded in the routine clinical care offered to people living with NMD.

[Sleep disorders and fatigue in patients with different forms of myotonic dystrophy type 1]

OBJECTIVE

To characterize sleep disorders in children and adults with different forms of myotonic dystrophy type 1 (DM1), to assess their impact on cognitive functions, excessive daytime sleepiness (EDS) and fatigue, to determine the relationship of EDS, fatigue, and sleep disorders with the quality of life of patients.

MATERIAL AND METHODS

The study included 48 adults and 9 children with confirmed DM1. Patients underwent an assessment of clinical and anamnestic data, neurological, cognitive status, severity of EDS, fatigue, quality of life according to international scales and questionnaires. Polysomnography was performed to identify sleep disorders.

RESULTS

Obstructive sleep apnea syndrome (OSAS) was found in 78% of children and 79.2% of adults. The severity of OSAS in adults, in contrast to children, was influenced by obesity (p<0.001), the severity of muscle weakness (p=0.033), especially the neck muscles (p=0.018). In patients with OSAS and nocturnal hypoxemia, an increase in the duration of the 1st stage of sleep (p=0.008) and in the microactivation index (p=0.005) was revealed. EDS and fatigue were present in 31 (64.6%) and 34 (70.8%) adults, respectively, in 9 (18.8%) they emerged at the onset of the disease. The greater severity of muscle symptoms, anxiety, depression contributed to increased fatigue in adults and the presence of obesity and type 2 diabetes mellitus contributed to EDS. Increased fatigue affects the quality of life to a greater extent than EDS and sleep disturbances.

CONCLUSION

OSAS, the development of which is facilitated by the presence of muscle weakness and obesity, is the leading syndrome among the spectrum of sleep disorders in all age groups. Cognitive and emotional impairments are not the result of sleep apnea, but rather develop because of a primary CNS lesion. The presence of increased fatigue reduced the quality of life of patients.

Excessive rest time during active phase is reliably detected in a mouse model of myotonic dystrophy type 1 using home cage monitoring

Myotonic dystrophy type 1 (DM1) is a dominantly inherited neuromuscular disease caused by the abnormal expansion of CTG-repeats in the 3'-untranslated region of the Dystrophia Myotonica Protein Kinase (DMPK) gene, characterized by multisystemic symptoms including muscle weakness, myotonia, cardio-respiratory problems, hypersomnia, cognitive dysfunction and behavioral abnormalities. Sleep-related disturbances are among the most reported symptoms that negatively affect the quality of life of patients and that are present in early and adult-onset forms of the disease. DMSXL mice carry a mutated human DMPK transgene containing >1,000 CTGrepeats, modeling an early onset, severe form of DM1. They exhibit a pathologic neuromuscular phenotype and also synaptic dysfunction resulting in neurological and behavioral deficits similar to those observed in patients. Additionally, they are underweight with a very high mortality within the first month after birth presenting several welfare issues. To specifically explore sleep/rest-related behaviors of this frail DM1 mouse model we used an automated home cage-based system that allows 24/7 monitoring of their activity non-invasively. We tested male and female DMSXL mice and their wild-type (WT) littermates in Digital Ventilated Cages (DVCR) assessing activity and rest parameters on day and night for 5 weeks. We demonstrated that DMSXL mice show reduced activity and regularity disruption index (RDI), higher percentage of zero activity per each hour and longer periods of rest during the active phase compared to WT. This novel rest-related phenotype in DMSXL mice, assessed unobtrusively, could be valuable to further explore mechanisms and potential therapeutic interventions to alleviate the very common symptom of excessive daytime sleepiness in DM1 patients.

Characteristics of myotonic dystrophy patients in the national registry of Japan

Myotonic dystrophies (DM) are inherited autosomal dominant disorders affecting multiple organs. Currently available therapeutics for DM are limited; therefore, a patient registry is essential for therapeutic development and success of clinical trials targeting the diseases. We have developed a nationwide DM registry in Japan under the Registry of Muscular Dystrophy (Remudy). The registration process was patient-initiated; however, physicians certified the clinical information. The dataset includes all Naarden and TREAT-NMD core datasets and additional items covering major DM clinical features. As of March 2020, we enrolled 976 patients with genetically confirmed DM. The majority (99.9%) of these patients had DM1, with 11.4% having the congenital form. However, 1 patient had DM2. Upon classifying 969 symptomatic DM1 patients based on their age at onset, an earlier onset was associated with a longer CTG repeat length. Myotonia was the most frequent symptom, followed by hand disability, fatigue, and daytime sleepiness. The frequency of hand disabilities, constipation, and visual disturbances was higher for patients with congenital DM. According to a multiple regression analysis of objective clinical measurements related to prognosis and activities of daily living, CTG repeat length strongly influenced the grip strength, forced vital capacity, and QRS time in an electrocardiogram. However, the grip strength was only modestly related to disease duration. This report will shed light on the Japanese national DM registry, which has recruited a significant number of patients. The registry will provide invaluable data for planning clinical trials and improving the standard of care for patients.

The actigraphic documentation of circadian sleep-wake rhythm dysregulation in myotonic dystrophy type 1

STUDY OBJECTIVES

The present study aimed at identifying the sleep-wake rhythm in patients with myotonic dystrophy type 1 (DM1) compared to healthy controls.

METHODS

Patients with genetic diagnosis of DM1 and healthy controls underwent a 7-day actigraphic recording and filled out a daily sleep diary to evaluate the sleep-wake rhythm. All participants underwent a physical and neurological examination to exclude conditions interfering with the sleep-wake cycle. Daytime activity, nocturnal sleep, and non-parametric circadian rhythm activity (NPCRA) were analysed.

RESULTS

Twenty-nine patients affected by DM1 were included in the present study and were compared to 16 controls. Considering nocturnal actigraphic data, DM1 patients showed a longer time in bed, sleep period time, actual sleep time, and sleep latency compared to controls. Central phase measurement was significantly longer in DM1 patients than controls. At NPCRA analysis patients showed a lower degree of regularity in the activity-rest pattern compared to controls. Moreover, DM1 patients showed reduced motor activity during daytime and a lower synchronization of the rest-activity rhythm than controls.

CONCLUSIONS

This study documented that patients with DM1 not only present the impairment of nocturnal sleep, but also show a dysregulation of the sleep-wake circadian rhythm; moreover, reduced amplitude of the circadian rhythmicity was also evident in comparison to controls, probably in relation to the reduced diurnal motor activity of patients. These findings add further evidence to the already documented sleep impairment and excessive daytime sleepiness in DM1 patients.

Assessment of self-reported and objective daytime sleepiness in adult-onset myotonic dystrophy type 1

STUDY OBJECTIVES

Excessive daytime sleepiness (EDS) in myotonic dystrophy type 1 (DM1) is mostly of central origin but it may coexist with sleep-related breathing disorders. However, there is no consensus on the sleep protocols to be used, assessments vary and only a minority of patients are regularly tested or are on treatment for EDS. Our study presents data on self-reported and objective EDS in adult-onset DM1.

METHODS

63 adult-onset DM1 patients were subjected to EDS-sleep assessments (polysomnography, PSG; Multiple Sleep Latency Test, MSLT; Epworth Sleepiness Scale, ESS. Correlation coefficients were computed to assess the relationship between sleep and sleepiness test results, fatigue, quality of life.

RESULTS

33% and 48% of patients had EDS based respectively on the ESS and the MSLT with a low concordance between these tests (k = 0.19). Thirteen patients (20%) displayed 2 or more sleep-onset REM periods on MSLT. Patients having EDS by MSLT had a shorter disease duration (p<0.05), higher total sleep time, sleep efficiency and lower WASO (Wake After Sleep Onset) on PSG. Patients with self-reported EDS reported significantly higher fatigue score compared to patients without EDS (p<0.05). No other difference was found in demographic, clinical and respiratory features.

CONCLUSIONS

EDS test results are contradictory making treatment options difficult. Combining quantitative tests and self-reported scales may facilitate physicians in planning EDS care with patients and families.

Noninvasive Home Mechanical Ventilation in Adult Myotonic Dystrophy Type 1: A Systematic Review

INTRODUCTION

Chronic hypercapnic respiratory failure induces considerable morbidity and mortality in patients with myotonic dystrophy type 1 (DM1). This study systematically reviews the effects of noninvasive home mechanical ventilation (HMV) on gas exchange, quality of life, survival, and compliance in DM1 patients.

METHODS

A systematic Medline and Embase search was performed (January 1995 to January 2020). Records were screened for eligibility criteria, data were extracted from included studies, and risk of bias was assessed. We present findings mainly using a narrative synthesis.

RESULTS

Twenty-eight relevant full-text articles were screened for eligibility criteria. Nine studies were included. Randomized controlled trials were not found. Studies had either an observational (n = 8) or interventional (n = 1) design. In the pooled data analysis, HMV showed to improve mean oxygen saturation with 4.8% and decreased mean carbon dioxide values with 3 mm Hg. Compliance varied widely between studies, from no use to more than 12 h per day. Quality of life was not studied extensively, but some studies reported positive effects of HMV on symptoms of chronic respiratory failure. HMV may improve survival in DM1 patients with chronic hypercapnic respiratory failure.

CONCLUSION

This review shows that HMV can improve gas exchange and relieve symptoms with a possible survival benefit in DM1 patients with chronic hypercapnic respiratory failure. Future studies should focus on developing strategies to optimize the timing of HMV initiation and to promote compliance.

Responsiveness of Daytime Sleepiness and Fatigue Scales in Myotonic Dystrophy Type 1

Daytime sleepiness and fatigue are prominent symptoms of myotonic dystrophy type 1 (DM1) that can be amenable to treatment in the context of randomized controlled trials. No study has yet documented whether self-reported measures of daytime sleepiness and fatigue can detect change over time and the meaning of this change. The aim was to explore indicators of responsiveness to change and interpretability for the Daytime Sleepiness Scale and the Fatigue Severity Scale in 115 DM1 prospectively followed patients. Results suggest that these two self-reported questionnaires are sufficiently sensitive to detect changes beyond expected measurement error over time in this population.

Pain in adult myotonic dystrophy type 1: relation to function and gender

Background

Pain is prevalent in myotonic dystrophy 1 (DM1). This study investigated whether CTG repeat size, disease duration, BMI and motor and psychological function were related to pain in adult patients with DM1, and if there were gender differences regarding intensity and location of pain.

Method

Cross-sectional design. Pain was investigated in 50 genetically confirmed DM1 patients by combining clinical assessment and self-reports of pain intensity and locations. Pain scoring results were related to CTG size, disease duration, muscle strength, walking capacity measured by 6-min walk test, activity of daily life by Katz ADL Index, respiratory function by Forced Vital Capacity and BMI. In addition, the degree of reported pain was related to Quality of life measured by WHOQOL-BREF; fatigue was measured by Fatigue severity scale; psychological functions were measured by Beck Depression Inventory, Beck Anxiety Inventory, IQ and Autism spectrum Quotient.

Results

Pain was reported in 84% of the patients and was significantly correlated with CTG size (r = 0.28 p = 0.050), disease duration (r = 0.38 p = 0.007), quality of life (r = − 0.37 p = 0.009), fatigue (r = 0.33 p = 0.02) and forced vital capacity (r = − 0.51, p = 0.005). Significant gender differences, with higher scores for females, were documented. In male subjects the number of pain locations was significantly correlated with quality of life and the autism quotient. In females, pain intensity was significantly correlated with activity, respiratory function and BMI.

Conclusions

Pain in DM1 was prevalent, with a strong association to lung function and other aspects of the disease. Significant gender differences were present for pain intensity and number of pain locations. How pain was related to other symptoms differed between male and female subjects. Our findings highlight the importance of assessments of pain in DM1 patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02124-9.

Consensus-Based Care Recommendations for Pulmonologists Treating Adults with Myotonic Dystrophy Type 1

PURPOSE OF REVIEW

Myotonic dystrophy type 1 (DM1) is a severe, progressive genetic disease that affects approximately 1 in 2,500 individuals globally [Ashizawa et al.: Neurol Clin Pract 2018;8(6):507-20]. In patients with DM1, respiratory muscle weakness frequently evolves, leading to respiratory failure as the main cause of death in this patient population, followed by cardiac complications [de Die-Smulders et al.: Brain 1998;121(Pt 8):1557-63], [Mathieu et al.: Neurology 1999;52(8):1658-62], [Groh et al.: Muscle Nerve 2011;43(5):648-51]. This paper provides a more detailed outline on the diagnostic and management protocols, which can guide pulmonologists who may not have experience with DM1 or who are not part of a neuromuscular multidisciplinary clinic. A group of neuromuscular experts in DM1 including pulmonologists, respiratory physiotherapists and sleep specialists discussed respiratory testing and management at baseline and during follow-up visits, based on their clinical experience with patients with DM1. The details are presented in this report.

RECENT FINDINGS

Myotonic recruited 66 international clinicians experienced in the treatment of people living with DM1 to develop and publish consensus-based care recommendations targeting all body systems affected by this disease [Ashizawa et al.: Neurol Clin Pract. 2018;8(6):507-20]. Myotonic then worked with 12 international respiratory therapists, pulmonologists and neurologists with long-standing experience in DM respiratory care to develop consensus-based care recommendations for pulmonologists using a methodology called the Single Text Procedure. This process generated a 7-page document that provides detailed respiratory care recommendations for the management of patients living with DM1. This consensus is completely based on expert opinion and not backed up by empirical evidence due to limited clinical care data available for respiratory care management in DM patients. Nevertheless, we believe it is of relevance for professionals treating adults with myotonic dystrophy because it addresses practical issues related to respiratory management and care, which have been adapted to meet the specific issues in patients with DM1.

SUMMARY

The resulting recommendations are intended to improve respiratory care for the most vulnerable of DM1 patients and lower the risk of untoward respiratory complications and mortality by providing pulmonologist who are less experienced with DM1 with practical indications on which tests and when to perform them, adapting the general respiratory knowledge to specific issues related to this multiorgan disease.

Health-Related Quality of Life in Patients with Adult-Onset Myotonic Dystrophy Type 1: A Systematic Review

Background

Adult-onset myotonic dystrophy type 1 (DM1) is a chronic, multisystem disorder that leads to disability and premature death.

Objectives

The objective of our study was to conduct a systematic literature review of the health-related quality of life (HRQoL) of patients with DM1.

Methods

We searched Embase, Web of Science, and PubMed for English language full-text articles reporting results from studies of HRQoL in patients with adult-onset DM1 published between 1 January 2000 and 21 February 2018. We excluded reviews, editorials, and studies reporting results for a sample with fewer than five patients (to allow for meaningful inference).

Results

The search identified 266 unique publications. Of these, 231 were excluded following title and abstract screening and 16 after full-text review, leaving 19 articles for data synthesis. We found 15 articles measuring the HRQoL of patients with adult-onset DM1 using the 36-Item Short Form Health Survey (SF-36), six using the Individualized Neuromuscular Quality of Life Questionnaire (INQoL), and one using Cantril’s Ladder. Available evidence shows that patient HRQoL is impaired in DM1, mainly due to compromised physical health, but also reveals that substantial heterogeneity exists in estimates across studies.

Conclusions

HRQoL in adult-onset DM1 has been extensively studied using the SF-36 and the INQoL, but current estimates are inconclusive, and little is known of the impact of the disease as measured using other instruments. Our data synthesis should help characterize the patient burden of DM1 and inform future studies of HRQoL in this indication.

Electronic supplementary material

The online version of this article (10.1007/s40271-019-00357-y) contains supplementary material, which is available to authorized users.

Screening for early symptoms of respiratory involvement in myotonic dystrophy type 1 using the Respicheck questionnaire

Symptoms of respiratory involvement are frequently present but overlooked by patients with Myotonic Dystrophy type 1 (DM1). A respiratory symptom checklist was designed to test whether a DM-specifically designed checklist to detect symptoms of respiratory involvement (The Respicheck Questionnaire) could help patients be more aware of their respiratory problems, if any, and help clinicians in identifying potential candidates for intervention. The Respicheck questionnaire was administered to 58 consecutive adult-onset patients with genetically determined DM1 who did not complain of respiratory involvement per history at enrollment. Based on respiratory function test results patients were divided into 3 groups: A, (n = 17) having no signs of respiratory involvement; B (n = 13), patients having borderline results on respiratory assessments and having no need for respiratory intervention; C, (n = 28) patients having respiratory impairment requiring intervention. Respiratory test results and Respicheck scores were analyzed. Respicheck total score and subscales correlated positively with global respiratory impairment. Respicheck appears to be able to discriminate between patients having a higher level of respiratory dysfunction from those having a lower risk of respiratory involvement. This might allow to better target efforts and resources in respiratory management in DM1.

Predicting daytime sleepiness and fatigue: a 9-year prospective study in myotonic dystrophy type 1

OBJECTIVE

Daytime sleepiness and fatigue are prominent symptoms of myotonic dystrophy type I (DM1) that exact a heavy toll on patients' quality of life, but information is scarce on their predictive factors. This study aimed to determine factors that may influence levels of daytime sleepiness and fatigue in a large cohort of DM1 patients followed for 9 years.

METHODS

This study included 115 patients with DM1 at baseline (Time 1, T1) and at Time 2 (T2) who were questioned for daytime sleepiness, fatigue, history of depression, psychological distress, pain, hypothyroidism, and sleep habits. Also, their muscular impairment and intellectual quotient were evaluated. Regression models were used to identify correlates of daytime sleepiness and fatigue while controlling for time effect.

RESULTS

Both daytime sleepiness and fatigue increased between T1 and T2, but their rate of change are higher when CTG repeat number is higher (p < 0.05). Also, higher psychological distress level is associated with higher daytime sleepiness and fatigue levels both at T1 and T2 (p < 0.01). Moreover, patients with a history of depression report higher daytime sleepiness levels both at T1 and T2 (p < 0.05). In addition, patients with higher fatigue levels both at T1 and T2 have more severe muscular impairment (p < 0.01) and report a longer habitual sleep duration (p < 0.05). Finally, a higher BMI and a history of hypothyroidism predict higher daytime sleepiness levels at T2 (p < 0.05).

CONCLUSION

This study identified potentially modifiable risk factors of future daytime sleepiness and fatigue in DM1 patients, including BMI, psychological distress, hypothyroidism, and sleep habits.

Disease burden of myotonic dystrophy type 1

OBJECTIVE

The objective of this cross-sectional, observational study was to investigate the disease burden of myotonic dystrophy type 1 (DM1), a disabling muscle disorder.

METHODS

Adults with DM1 were recruited as part of the PhenoDM1 study from Newcastle University (Newcastle upon Tyne, UK). Disease burden data were recorded through the Individualized Neuromuscular Quality of Life (INQoL) questionnaire. Results were examined by sex and clinical variables [e.g. the six-minute walk test (6MWT), the Mini Mental State Examination, and estimated progenitor and modal allele CTG repeat length].

RESULTS

Our sample consisted of 60 patients with DM1 (mean age: 45 years; 45% female). Muscle weakness and fatigue constituted the two most common disease manifestations, reported by 93% and 90% of patients, respectively, followed by muscle locking (73%). Most patients (> 55%) reported feeling anxious/worried, depressed, frustrated, and/or having low confidence/self-esteem, 23% and 33% indicated substantial impairment of daily and leisure activities, respectively, and 47% did not work as a consequence of the disease. Estimated progenitor CTG length corrected by age correlated surprisingly well with INQoL scores. Differences by sex were generally minor.

CONCLUSION

We show that DM1 is associated with a substantial disease burden resulting in impairment across many different domains of patients' lives, emphasizing the need for a holistic approach to medical management. Our results also show that the INQoL records relevant information about patients with DM1, but that further investigation of the psychometric properties of the scale is needed for meaningful interpretation of instrument scores.

Perceived fatigue in myotonic dystrophy type 1: a case-control study

Background

The aim of this study was to explore perceived fatigue, experienced functional limitations due to fatigue and clinical correlates in patients with Myotonic Dystrophy type 1 (DM1).

Methods

In total, 32 consecutive patients with DM1 (14 women and 18 men) and 30 sex, age and education matched healthy control subjects participated. Perceived fatigue was rated on the Fatigue Impact Scale (FIS). Patients also completed a set of assessments aimed to characterize CTG-repeat size, muscle impairment, depression and cognitive functions. Non-parametric analysis were performed as appropriate, including Mann-Whitney U-test and Spearman correlation test.

Results

DM1 patients had higher FIS total score than healthy controls, suggesting higher fatigue levels. More specifically, DM1 patients scored higher on the FIS physical and psychosocial subscales than controls but not on the FIS cognitive scale. Scores on fatigue correlated significantly with muscle impairment and depression.

Conclusions

Perceived fatigue is significantly more common in patients with DM1 than in healthy controls. Higher ratings on depression and muscle impairment were associated with the condition. This indicates that both depression and muscle impairment may contribute to the experience of fatigue in DM1.

Health-related quality of life and its correlates in Japanese patients with myotonic dystrophy type 1

PURPOSE

Myotonic dystrophy type 1 (DM1) is a common form of muscular dystrophy that presents with a variety of symptoms that can affect patients' quality of life (QoL). Despite the importance of clarifying patients' subjective experience in both physical and psychosocial aspects for improved symptom management, there is lack of evidence concerning QoL of patients with DM1 in Japan.

PATIENTS AND METHODS

A cross-sectional study was performed with 51 DM1 patients who completed questionnaires that measured health-related QoL (HRQoL), depression, and daytime sleepiness. Activities of daily living, body mass index (BMI), and genetic information were also collected, together with general demographic information. Correlation analyses using these variables were performed. Furthermore, regression analysis was utilized to assess the relationship that HRQoL, depression, and daytime sleepiness scores have with other variables.

RESULTS

Physical component summary (PCS) score was affected by the disease more than the mental component summary (MCS) score among study participants. Moderate correlation was observed between PCS and depression, PCS and Barthel index, and depression and daytime sleepiness. Regression analysis revealed that age, sex, cytosine-thymine-guanine repeats, and BMI did not predict the aforementioned dependent variables.

CONCLUSION

DM1 symptoms influenced physical component scores more than mental component scores, although the state of physical wellness seemed to affect patients' mood. Explaining the QoL of these patients only using biologic and genetic characteristics was not sufficient. We conclude that social and psychological aspects of these patients' lives and the nature of adjustments made by patients due to DM1 to require further examination in order to improve the standard of care.

Relationships between Lower Limb Muscle Strength Impairments and Physical Limitations in DM1

BACKGROUND

Although adult and late-onset DM1 phenotypes DM1 present distinct lower limb weaknesses portraits, resulting physical limitations have never been described separately for each phenotype.

OBJECTIVE

To characterize the lower limb weaknesses and physical limitations among the DM1 adult and late-onset phenotypes separately and to document the contribution of weaknesses on mobility to optimize the management of this population.

METHODS

The strength of four muscle groups among 198 participants was quantified. Participants were categorized according to the severity of their muscular involvement using the Muscular Impairment Rating Scale (MIRS). Physical limitations were assessed using the Timed up-and-go (TUG), Berg Balance Scale (BBS) and 10 meters comfortable walking speed (10MWT). Multiple linear regressions were performed to identify the contribution of each muscle group to the mobility tests scores.

RESULTS

Late-onset demonstrated less weakness and physical limitations (p < 0.001 - 0.002) than the adult phenotype, but 21.9-47.5% of participants with this phenotype showed mobility scores below reference values. Physical limitations were observed in the first two MIRS grades (37.5-42.1% of the participants) for the TUG and 10MWT. Ankle dorsiflexors and knee extensors were the two muscle groups that showed the strongest relationships with mobility scores.

CONCLUSION

Although less impaired, the late-onset phenotype shows significant lower limb muscle weakness associated with physical limitations. The surprising presence of quantitative lower limb muscle weakness in the first two MIRS grades needs to be considered when using this scale. Both ankle dorsiflexors and knee extensors appear to be good indicators of physical limitations in DM1.

Quality of life in adult patients with limb-girdle muscular dystrophies

Although limb-girdle muscular dystrophies (LGMD) can cause permanent disability, to date there are no studies that examined quality of life (QoL) in these patients. Our aim was to evaluate QoL in patients with LGMD, and to identify the most significant predictors of QoL. The study comprised 46 patients with diagnosis of limb-girdle muscular weakness. QoL in patients was evaluated using two scales-SF-36 questionnaire and the Individualized Neuromuscular Quality of Life questionnaire (INQoL). Following scales were also applied: Epworth Sleepiness Scale (ESS), Hamilton Scale for Depression (HamD), and Krupp's Fatigue Severity Scale (FSS). Mean SF-36 score was 52.4 ± 23.5, and physical composite score was worse than mental. Total INQoL score was 46.1 ± 20.4, with worst results obtained for weakness, fatigue and independence, while social relationships and emotions showed better results. Significant predictors of worse SF-36 score in LGMD patients were higher fatigue level (β = - 0.470, p < 0.01) and use of assistive device (β = - 0.245, p < 0.05). Significant predictors of worse INQoL score were higher fatigue level (β = 0.514, p < 0.01) and presence of cardiomyopathy (β = - 0.385, p < 0.01). It is of special interest that some of the identified factors that correlated with worse QoL in LGMD patients were amenable to treatment.

French translation and cross-cultural adaptation of The Myotonic Dystrophy Health Index

INTRODUCTION

Validation studies of disease-specific instruments for myotonic dystrophy type-1 (DM1) are required prior to their global use in clinical trials involving different cultures and countries. Here we translate and culturally adapt the Myotonic Dystrophy Health Index (MDHI), a disease-specific patient-reported outcome (PRO) measure, for a French DM1 population.

METHODS

Using the International Society for Pharmacoeconomics and Outcomes Research Task Force method for translation and adaptation of PRO questionnaires, we created a French translation of the MDHI. We subsequently tested this instrument in a cohort of French-speaking patients with DM1.

RESULTS

The MDHI was forward and back translated and modified by consensus to create the most compatible translation. Cognitive interviews were conducted with 5 patients with DM1 to ensure the usability and understanding of the translation.

DISCUSSION

The French version of the MDHI is an optimal translation of the original instrument that is acceptable to native patients and ready for clinical trial use. Muscle Nerve 57: 686-689, 2018.

Myotonic Dystrophies: State of the Art of New Therapeutic Developments for the CNS

Myotonic dystrophies are multisystemic diseases characterized not only by muscle and heart dysfunction but also by CNS alteration. They are now recognized as brain diseases affecting newborns and children for myotonic dystrophy type 1 and adults for both myotonic dystrophy type 1 and type 2. In the past two decades, much progress has been made in understanding the mechanisms underlying the DM symptoms allowing development of new molecular therapeutic tools with the ultimate aim of curing the disease. This review describes the state of the art for the characterization of CNS related symptoms, the development of molecular strategies to target the CNS as well as the available tools for screening and testing new possible treatments.

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.

Clinical efficacy of Rong-Yang-Jyh-Gan-Tang on patients with chronic hepatitis C: A double-blinded randomized placebo-controlled crossover study

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) has been widely used by the Chinese population for treatment of chronic hepatitis. However, the efficacy of TCM for patients with chronic hepatitis has not been confirmed, mostly due to the lack of available scientific parameters such as serum viral load to evaluate treatment response.

AIM OF THE STUDY

We evaluated the efficacy of Rong-Yang-Jyh-Gan-Tang (RYJGT, composed of Long-Dan-Xie-Gan-Tang, Jia-Wei-Xia-Yao-San, Dan-Shen, and Hou-Po) on patients with chronic hepatitis C.

MATERIALS AND METHODS

Thirty-six patients with chronic hepatitis C who had no response to or had contraindications to interferon-ribavirin therapy were randomly allocated to receive RYJGT 15g/day or placebo for 12 weeks. After a 2-week washout period, patients were crossed over to receive placebo or RYJGT for another 12 weeks. Evaluation parameters included liver biochemistries, serum HCVRNA, side effects of RYJGT/placebo, and TCM symptoms.

RESULTS

Of the patients who had 12-week RYJGT treatment, 51.7% had decreased serum HCVRNA levels, whereas only 25.8% patients had decreased levels in the placebo group (p=0.036). TCM patterns of "Damp-Heat" and "Liver Qi Depression" had significantly improved after RYJGT treatment in comparison with the placebo. Logistic analyses showed that RYJGT treatment, and pre-treatment values of TCM symptoms of "Damp-Heat" and "Liver Qi Depression", were statistically significant factors in predicting the decrease in serum HCVRNA.

CONCLUSION

Chronic hepatitis C patients who received a 12-week RYJGT treatment had significantly higher HCVRNA decrease ratio, and improved TCM symptoms of "Damp-Heat" and "Liver Qi Depression", than those who received the placebo. Our results require further larger scale clinical trials.

Psychological characteristics of patients with myotonic dystrophy type 1

OBJECTIVES

Myotonic dystrophy type 1 (DM1) is the most common adult-onset muscular dystrophy. It is associated with motor symptoms but patients also display non-motor symptoms such as particular personality traits. Studies have reported mixed results about personality characteristics which may be attributable to small sample sizes, different disease severity of groups studied, and use of different questionnaires or method. This study aimed to describe the psychological characteristics of a large cohort of patients with DM1, to characterize those at risk of developing a psychiatric disorder, and to compare characteristics between two DM1 phenotypes, a mild and more severe adult-onset phenotype.

METHODS

Two hundred patients with DM1 (152 adult-onset; 48 mild) were asked to complete questionnaires assessing personality traits, psychological symptoms, self-esteem, and suicidal risk. Neurological and neuropsychological assessments were performed to compare personality characteristics to clinical and cognitive measures.

RESULTS

Patients with DM1 globally showed personality traits and psychological symptoms in the average range compared to normative data, with normal levels of self-esteem and suicidal ideation. However, 27% of patients were found to be at high risk of developing a psychiatric disorder. Moreover, psychological traits differed across phenotypes, with the most severe phenotype tending to show more severe psychological symptoms. The presence of higher phobic anxiety and lower self-esteem was associated with lower education, a higher number of CTG repeats, more severe muscular impairment, and lower cognitive functioning (P < 0.001).

CONCLUSIONS

Different phenotypes should thus be taken into account in clinical settings for individual management of patients and optimizing therapeutic success.

Comparisons of intellectual capacities between mild and classic adult-onset phenotypes of myotonic dystrophy type 1 (DM1)

Background

Myotonic dystrophy type 1 (DM1) is an autosomal dominant genetic multisystem disorder and the commonest adult-onset form of muscular dystrophy. DM1 results from the expansion of an unstable trinucleotide cytosine-thymine-guanine (CTG) repeat mutation. CTG repeats in DM1 patients can range from 50 to several thousands, with a tendency toward increased repeats with successive generations (anticipation). Associated findings can include involvements in almost every systems, including the brain, and cognitive abnormalities occur in the large majority of patients. The objectives are to describe and compare the intellectual abilities of a large sample of DM1 patients with mild and classic adult-onset phenotypes, to estimate the validity of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) in DM1 patients with muscular weakness, and to appraise the relationship of intelligence quotient (IQ) to CTG repeat length, age at onset of symptoms, and disease duration.

Methods

A seven-subtest WAIS-R was administered to 37 mild and 151 classic adult-onset DM1 patients to measure their Full-Scale (FSIQ), Verbal (VIQ) and Performance IQ (PIQ). To control for potential bias due to muscular weakness, Standard Progressive Matrices (SPM), a motor-independent test of intelligence, were also completed.

Results

Total mean FSIQ was 82.6 corresponding to low average IQ, and 82% were below an average intelligence. Mild DM1 patients had a higher mean FSIQ (U=88.7 vs 81.1, p<0.001), VIQ (U=87.8 vs 82.3, p=0.001), and PIQ (U=94.8 vs 83.6, p<0.001) than classic adult-onset DM1 patients. In both mild and classic adult-onset patients, all subtests mean scaled scores were below the normative sample mean. FSIQ also strongly correlate with SPM (r_s=0.67, p<0.001), indicating that low intelligence scores are not a consequence of motor impairment. FSIQ scores decreased with both the increase of (CTG)n (r_s=−0.41, p<0.001) and disease duration (r_s=−0.26, p=0.003).

Conclusions

Results show that intellectual impairment is an extremely common and important feature in DM1, not only among the classic adult-onset patients but also among the least severe forms of DM1, with low IQ scores compared to general reference population. Health care providers involved in the follow-up of these patients should be aware of their intellectual capacities and should adapt their interventions accordingly.

Prevalence of Lifestyle Risk Factors in Myotonic Dystrophy Type 1

Background:

The prevalence of unhealthy lifestyle habits such as smoking has seldom been described in neuromuscular disorders, including myotonic dystrophy type 1 (DM1). However, it is essential to document the unhealthy lifestyle habits as they can exacerbate existing impairments and disabilities. The objectives are: 1) To determine the prevalence of risk factors among individuals with DM1; 2) To compare the prevalence among classic and mild phenotypes.

Method:

A survey was done on a sample of two-hundred (200) patients with DM1 as part of a larger study. Lifestyle risk factors included being overweight or obese, tobacco smoking, illicit drug use, excessive alcohol consumption and physical inactivity. A registered nurse administered the validated public health survey. Categorization of risk factors were based on national standards and compared with provincial and regional prevalences.

Results:

50% of DM1 patients were overweight or obese, 23.6% were regular smokers, and 76% were physically inactive. Except for overweight and obesity, significant differences were observed between patients with classic and mild phenotypes for all the other lifestyle risk factors: those with the classic phenotype being more often regular smokers, consuming more often illicit drugs and being less physically active.

Conclusions:

The results of this study will provide guidance for the development of better adapted and focussed health promotion interventions in the future.

Significant impact of behavioral and cognitive impairment on quality of life in patients with myotonic dystrophy type 1

OBJECTIVE

To assess an impact of cognitive and behavioral impairment on QoL in a larger cohort of patients with DM1.

METHODS

Sixty six genetically confirmed DM1 patients (22 with juvenile (jDM1) and 44 with adult form (aDM1) of the disease) were recruited. Following behavioral tests were used: Hamilton scales for depression and anxiety (HamD and HamA), Daytime Sleepiness Scale (DSS), and Krupp's Fatigue Severity Scale (FSS). Patients also underwent detailed classic neuropsychological investigation and Cambridge Neuropsychological Test Automated Battery (CANTAB). Individualized Neuromuscular Quality of Life questionnaire (INQoL) was used as a measure of QoL.

RESULTS

Patients with jDM1 scored lower than aDM1 patients regarding total INQoL score and all INQoL subdomains, except for myotonia. Significant predictors of total INQoL score in patients with jDM1 were severity of fatigue (β=+0.60, p<0.01) and percentage of correct responses on Spatial Recognition Memory test from CANTAB that measures visuospatial abilities (β=-0.38, p<0.05). The most important predictors of total INQoL score in patients with aDM1 were severity of fatigue (β=+0.36, p<0.05) and level of education (β=-0.29, p<0.05).

CONCLUSION

Our results showed clear influence of different central manifestations on QoL in patients with both aDM1 and jDM1.

Transcranial sonography in patients with myotonic dystrophy type 1

INTRODUCTION

In this study we analyzed transcranial sonography (TCS) in patients with myotonic dystrophy type 1 (DM1).

METHODS

This cross-sectional study included 66 DM1 patients and 55 matched healthy controls (HCs). Echogenicity of the brainstem raphe (BR) and substantia nigra (SN) and third ventricle width (DTV) were assessed by TCS.

RESULTS

BR hypoechogenicity was more common in DM1 patients than in HCs (37.7% vs. 7.8%, P < 0.01). Patients with depression or fatigue were more likely to have BR hypoechogenicity (80.0% vs. 29.4%, P < 0.01 and 51.9% vs. 24.2%, P < 0.05, respectively). Both hypoechogenicity and hyperechogenicity of SN were more frequent in DM1 patients than in controls (26.2% vs. 10.9% and 13.1% vs. 1.8%, respectively, P < 0.01). DTV was increased in DM1 patients compared with HCs (6.0 ± 1.4 vs. 4.9 ± 0.9 mm, P < 0.01).

CONCLUSION

TCS can offer new insight into structural changes of several cerebral areas in patients with DM1.

Sleep-Wake Cycle and Daytime Sleepiness in the Myotonic Dystrophies

Myotonic dystrophy is the most common type of muscular dystrophy in adults and is characterized by progressive myopathy, myotonia, and multiorgan involvement. Two genetically distinct entities have been identified, myotonic dystrophy type 1 (DM1 or Steinert's Disease) and myotonic dystrophy type 2 (DM2). Myotonic dystrophies are strongly associated with sleep dysfunction. Sleep disturbances in DM1 are common and include sleep-disordered breathing (SDB), periodic limb movements (PLMS), central hypersomnia, and REM sleep dysregulation (high REM density and narcoleptic-like phenotype). Interestingly, drowsiness in DM1 seems to be due to a central dysfunction of sleep-wake regulation more than SDB. To date, little is known regarding the occurrence of sleep disorders in DM2. SDB (obstructive and central apnoea), REM sleep without atonia, and restless legs syndrome have been described. Further polysomnographic, controlled studies are strongly needed, particularly in DM2, in order to clarify the role of sleep disorders in the myotonic dystrophies.

Clinical, psychosocial, and central correlates of quality of life in myotonic dystrophy type 1 patients

AIMS

To identify sociodemographic, clinical, and central correlates of health-related quality of life (HRQoL) in DM1 patients.

METHODS

200 DM1 patients had assessments of muscular impairment, CTG repeats, and intelligence. Validated instruments were used to assess sociodemographic and clinical factors as well as social support, social participation, daytime sleepiness, fatigue, personality, mood, and quality of life. Regression analysis was used to identify correlates of SF-36 physical and mental component summary scores.

RESULTS

Patients scored lower on all SF-36 physical health subscales compared with normative data but did not differ with respect to mental health function. Regression analysis revealed that psychological distress, fatigue, severe muscular impairment, emotional stability, not having worked within the last 12 months, and lower intellectual quotient were associated with lower scores in physical health function. Moreover, neuroticism, daytime sleepiness, dissatisfaction with social participation, and lower conscientiousness were associated with lower scores in mental health function.

CONCLUSION

DM1 has an impact on SF-36 physical summary scores but not on mental summary scores. Factors such as fatigue, daytime sleepiness, psychological distress, unemployment, and social participation dissatisfaction that significantly affect HRQoL in DM1 are amenable to treatment and psychosocial interventions, namely by providing care that integrate health, social, and community services.

Daytime sleepiness and myotonic dystrophy

Myotonic dystrophy type 1 (DM1) represents the 1 chronic neuromuscular disease with the most prominent sleep disorders, including excessive daytime sleepiness (EDS), sleep apneas, periodic leg movements during sleep, and rapid eye movement sleep dysregulation. The large majority of DM1 patients complain about EDS, which may have a deleterious impact on work, domestic responsibilities, social life, and quality of life. Here, we review the extant literature and report that studies are largely supportive of the view that DM1-related EDS is primarily caused by a central dysfunction of sleep regulation rather than by sleep-related disordered breathing (SRDB) or sleep fragmentation. The pathogenesis of EDS in DM1 still remains unclear but several arguments favor a model in which brain/brainstem nuclear accumulations of toxic expanded DM protein kinase (DMPK) gene are responsible for aberrant genes expression in modifying alternative splicing. Regarding management, early recognition, and treatment of SRDB with nocturnal noninvasive mechanical ventilation is first mandatory. However, despite its appropriate management, EDS often persists and may require a psychostimulant but no consensus has been yet established. Further studies are needed to clarify the discrepancies between daytime sleepiness/fatigue complaints and subjective/objective measurement of daytime sleepiness, the role of cognitive impairment and apathy in this relationship, and its reversibility with appropriate management.

Myotonic dystrophy type 1, daytime sleepiness and REM sleep dysregulation

Myotonic dystrophy type 1 (DM1), or Steinert's disease, is the most common adult-onset form of muscular dystrophy. DM1 also constitutes the neuromuscular condition with the most significant sleep disorders including excessive daytime sleepiness (EDS), central and obstructive sleep apneas, restless legs syndrome (RLS), periodic leg movements in wake (PLMW) and periodic leg movements in sleep (PLMS) as well as nocturnal and diurnal rapid eye movement (REM) sleep dysregulation. EDS is the most frequent non-muscular complaint in DM1, being present in about 70-80% of patients. Different phenotypes of sleep-related problems may mimic several sleep disorders, including idiopathic hypersomnia, narcolepsy without cataplexy, sleep apnea syndrome, and periodic leg movement disorder. Subjective and objective daytime sleepiness may be associated with the degree of muscular impairment. However, available evidence suggests that DM1-related EDS is primarily caused by a central dysfunction of sleep regulation rather than by sleep fragmentation, sleep-related respiratory events or periodic leg movements. EDS also tends to persist despite successful treatment of sleep-disordered breathing in DM1 patients. As EDS clearly impacts on physical and social functioning of DM1 patients, studies are needed to identify the best appropriate tools to identify hypersomnia, and clarify the indications for polysomnography (PSG) and multiple sleep latency test (MSLT) in DM1. In addition, further structured trials of assisted nocturnal ventilation and randomized trials of central nervous system (CNS) stimulant drugs in large samples of DM1 patients are required to optimally treat patients affected by this progressive, incurable condition.