Factors Associated With Health-Related Quality of Life in Children With Duchenne Muscular Dystrophy

Decreased quality of life in Duchenne muscular disease patients related to functional neurological and cardiac impairment

In this prospective study involving 37 Duchenne muscular dystrophy (DMD) patients aged 8-18 years and older, we examined the impact of neurological and cardiac factors on quality of life (QoL). Our findings revealed a negative correlation between upper limb movement and overall mobility, self-service, and usual activities. Ambulatory and non-ambulatory DMD patients showed significant differences in mobility-related parameters. Cardiac evaluations demonstrated associations between mitral annular plane systolic excursion (MAPSE) and mobility-related aspects. The PEDSQL 3.0 neuromuscular model questionnaire further highlighted age-related and movement-related correlations with QoL. The loss of ambulatory status and reduced upper limb movement were negatively associated with QoL, while upper limb movement positively correlated with septal MAPSE. However, no significant associations were found between MAPSE and anxiety/depression. These findings underscore the multifaceted impact of DMD on QoL and emphasize the importance of considering both neurological and cardiac factors in comprehensive patient care.

Duchenne Muscular Dystrophy Fatigue Trajectories

INTRODUCTION

 Children with Duchenne muscular dystrophy (DMD) are at risk of experiencing fatigue that negatively impacts their health-related quality of life (HRQoL). This study aimed to assess the association between fatigue and HRQoL, by examining fatigue trajectories over 48 weeks, and assessing factors associated with these fatigue trajectories.

METHODS

 The study sample consisted of 173 DMD subjects enrolled in a 48-week-long phase 2 clinical trial (NCT00592553) for a novel therapeutic who were between the ages of 5 and 16 years.

RESULTS

 The results of regression modeling show baseline fatigue and baseline HRQoL (R 2 = 0. 54 for child self-report and 0.51 for parent proxy report) and change in fatigue and HRQoL over 48 weeks (R 2 = 0.47 for child self-report and 0.36 for parent proxy report) were significantly associated with one another. Three unique fatigue trajectories using Latent Class Growth Models were identified for child and parent proxy reported fatigue. The risk of being in the high fatigue group as compared to the low fatigue group increased by 24% with each year increase in age and also with decreasing walking distance, as reported by children and parent proxy, respectively.

CONCLUSION

 This study identified fatigue trajectories and risk factors associated with greater fatigue, helping clinicians and researchers identify the profile of fatigue in DMD children.

Pain and health-related quality of life in Duchenne muscular dystrophy: A multiple mediator analysis

OBJECTIVES

The objective was to investigate the serial mediating effects of daily activities, patient health communication, and disease-specific worry in the relationship between pain intensity and overall generic health-related quality of life (HRQOL) in pediatric patients with Duchenne muscular dystrophy from the patient perspective.

METHODS

Pain Intensity Item, Daily Activities Scale, Communication Scale and Worry Scale from Pediatric Quality of Life Inventory (PedsQL) Duchenne Muscular Dystrophy Module and PedsQL 4.0 Generic Core Scales were completed by 110 pediatric patients with Duchenne muscular dystrophy ages 8-17. A serial multiple mediator model analysis was conducted to test the hypothesized sequential mediating effects of daily activities, patient health communication, disease-specific worry as intervening variables in the association between the pain intensity predictor variable and overall generic HRQOL.

RESULTS

Pain predictive effects on overall generic HRQOL were serially mediated by daily activities, patient health communication, and disease-specific worry. In a predictive analytics model utilizing hierarchical multiple regression analysis with age demographic covariate, patient-reported pain intensity, daily activities, patient health communication, and disease-specific worry accounted for 47% of the variance in overall generic HRQOL (P < 0.001), representing a large effect size.

CONCLUSIONS

Pain intensity, daily activities, patient health communication, and disease-specific worry explain in part the mechanism of pain predictive effects on overall generic HRQOL in pediatric patients with Duchenne muscular dystrophy. Identifying the mediators of pain intensity on overall generic HRQOL from the patient perspective may inform targeted clinical interventions and future patient-centered clinical research to improve overall daily functioning.

Prevalence of Neuropsychiatric Disorders in Duchenne and Becker Muscular Dystrophies: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate the prevalence of neuropsychiatric disorders, including autism spectrum disorders (ASDs), attention-deficit hyperactivity disorder (ADHD), depression, anxiety disorders, and obsessive-compulsive disorder (OCD), in populations with Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD).

DATA SOURCES

MEDLINE (via PubMed), Scopus, Web of Science, and Cochrane Library from inception to November 2021.

STUDY SELECTION

Observational studies of individuals with DMD or BMD that estimated the prevalence of ASDs, ADHD, depression, anxiety disorders, and OCD in each population.

DATA EXTRACTION

A random-effects meta-analysis was performed on each outcome and each population (ie, DMD, BMD).

DATA SYNTHESIS

Twenty-three studies were included in the meta-analysis. In DMD, there was a prevalence of 7.0% of ASDs, 18.0% of ADHD, 11.0% of depression, 24.0% of anxiety disorders, and 12.0% of OCD. Furthermore, in BMD, there was a prevalence of 6.0% of ASDs, 28.0% of ADHD, 7.0% of depression, 25.0% of anxiety disorders, and 7.0% of OCD.

CONCLUSIONS

The prevalence of these neuropsychiatric disorders is higher among patients with DMD or BMD than among the general population, and the presence of these disorders may negatively influence optimal medical management.

Objective and subjective measures of sleep in men with Muscular Dystrophy

Purpose

Despite poor sleep quality being recognised in Duchenne Muscular Dystrophy, reports from milder forms of Muscular Dystrophy (MD), and accompanied associations with quality of life (QoL), pain and fatigue, remain limited however.

Methods

Adult males (n = 15 Beckers MD (BMD), n = 12 Limb-Girdle MD (LGMD), n = 12 Fascioscapulohumeral (FSHD), n = 14 non-MD (CTRL)) completed assessments of body composition (Bio-electrical impedance), sleep (7-day 24-hour tri-axial accelerometer, Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index, QoL (SF36-v2), pain (Visual analogue scale), fatigue (Modified Fatigue Index Scale) and functional assessments (Brookes and Vignos).

Results

FSHD and BMD reported worse sleep than CTRL on the PSQI. FSHD scored worse than CTRL on the Insomnia Severity Index (P<0.05). 25–63% and 50–81% of adults with MD reported poor sleep quality using the Insomnia Severity Index and PSQI, respectively. Accelerometery identified no difference in sleep quality between groups. Associations were identified between sleep measures (PSQI global and insomnia severity) with mental or physical QoL in LGMD, BMD and FSHD. Multiple regression identified associations between sleep impairment and fatigue severity (all MDs), body composition (BMD & LGMD), upper and lower limb function (LGMD, FSHD) and age (FSHD).

Conclusions

25–81% of men with MD, depending on classification, experience sleep impairment, using self-report sleep measures. Whilst BMD and FSHD showed worse sleep outcomes than CTRL, no group difference was observed between LGMD and CTRL, however all groups showed associations with sleep impairment and higher levels of fatigue. These findings, and associations with measures of health and wellbeing, highlight an area for further research which could impact QoL in adults with MD.

Development of a New Quality of Life Measure for Duchenne Muscular Dystrophy Using Mixed Methods: The DMD-QoL

Objective

Based on concerns about existing patient-reported outcome measures (PROMs) for assessing quality of life (QoL) in Duchenne muscular dystrophy (DMD), we describe the mixed methods development of a new QoL PROM for use in boys and men with DMD: the DMD-QoL.

Methods

The DMD-QoL was developed in 3 stages. First, draft items were generated from 18 semistructured qualitative interviews with boys and men with DMD, analyzed using framework analysis. Second, cognitive debriefing interviews with patients (n = 10), clinicians (n = 8), and patients' parents (n = 10) were undertaken, and a reduced item set was selected and refined. Third, psychometric data on the draft items from a cross-sectional online survey (n = 102) and stakeholder input from patients and patients' parents were used to produce the final questionnaire. Patient and public involvement and engagement was embedded throughout the process.

Results

From an initial draft of 47 items, a revised set of 27 items was produced at stage 2, and this set was further refined at stage 3 to generate the DMD-QoL, a 14-item QoL PROM. The DMD-QoL is designed for use from 7 years of age by proxy report and from 10 years of age by self-report or proxy report. The final measure showed good psychometric properties.

Conclusion

The DMD-QoL is a new 14-item QoL PROM for boys and men with DMD, with demonstrable content and face validity.

The Canadian Neuromuscular Disease Registry 2010-2019: A Decade of Facilitating Clinical Research Througha Nationwide, Pan-NeuromuscularDisease Registry

We report the recruitment activities and outcomes of a multi-disease neuromuscular patient registry in Canada. The Canadian Neuromuscular Disease Registry (CNDR) registers individuals across Canada with a confirmed diagnosis of a neuromuscular disease. Diagnosis and contact information are collected across all diseases and detailed prospective data is collected for 5 specific diseases: Amyotrophic Lateral Sclerosis (ALS), Duchenne Muscular Dystrophy (DMD), Myotonic Dystrophy (DM), Limb Girdle Muscular Dystrophy (LGMD), and Spinal Muscular Atrophy (SMA). Since 2010, the CNDR has registered 4306 patients (1154 pediatric and 3148 adult) with 91 different neuromuscular diagnoses and has facilitated 125 projects (73 academic, 3 not-for-profit, 3 government, and 46 commercial) using registry data. In conclusion, the CNDR is an effective and productive pan-neuromuscular registry that has successfully facilitated a substantial number of studies over the past 10 years.

Measuring quality of life in Duchenne muscular dystrophy: a systematic review of the content and structural validity of commonly used instruments

Duchenne muscular dystrophy (DMD) is an inherited X-linked neuromuscular disorder. A number of questionnaires are available to assess quality of life in DMD, but there are concerns about their validity. This systematic review aimed to appraise critically the content and structural validity of quality of life instruments for DMD. Five databases (EMBASE, MEDLINE, CINAHL, PsycINFO, and Cochrane Library) were searched, with supplementary searches in Google Scholar. We included articles with evidence on the content and/or structural validity of quality of life instruments in DMD, and/or instrument development. Evidence was evaluated against the Consensus-based Standards for the selection of health Measurement INstruments (COSMIN) criteria. Fifty five articles featured a questionnaire assessing quality of life in DMD. Forty instruments were extracted and 26 underwent assessment. Forty-one articles contained evidence on content or structural validity (including 37 development papers). Most instruments demonstrated low quality evidence and unsatisfactory or inconsistent validity in DMD, with the majority not featuring direct validation studies in this population. Only KIDSCREEN received an adequate rating for instrument design and a satisfactory result for content validity based on its development, yet, like the majority of PROMs, the measure has not been directly validated for use in DMD. Further research is needed on the validity of quality of life instruments in DMD, including content and structural validity studies in this population.

The impact of long-term ventilator-use on health-related quality of life and the mental health of children with neuromuscular diseases and their families: need for a revised perspective?

Background

Life extension by medical interventions and health-related quality of life (HRQOL) are sometimes conflicting aspects of medical care. Long-term ventilation in children with neuromuscular disease is a well-established life-extending procedure and often at the center of this conflict. HRQOL and the mental health of affected children and their families become even more important in respect to emerging therapies in neuromuscular diseases with longer life-expectancy of treated patients and considerable costs of medical treatment.

Methods

We performed a questionnaire survey in a total of forty-three families of children with neuromuscular disease treated in the University Medical Center Hamburg-Eppendorf and the Children’s Hospital Altona. We evaluated self- and proxy-reported HRQOL and mental health outcomes of affected children and their parents using validated and age-appropriate instruments.

Results

Compared to normative data, children with neuromuscular diseases and their families experienced a lower HRQOL and mental health. However, there was no additional negative influence on the overall HRQOL by ventilator use.

Conclusions

As ventilator use was not responsible for the reduction of HRQOL and mental health our data contributes an important aspect to the discussion about life-prolonging procedures, in particular mechanical ventilation, in severly disabled patients.

Fatigue in adults with spinal muscular atrophy under treatment with nusinersen

5q-Associated spinal muscular atrophy is a hereditary neuromuscular disease leading to progressive muscle weakness in which fatigue occurs and affects quality of life. Treatment with the antisense oligonucleotide nusinersen has been shown to improve motor function. Fatigue can be measured within the Fatigue Severity Scale (FSS). FSS is a self-reported questionnaire consisting of nine items to quantify fatigue severity within the last week. Higher values indicating a higher severity. Using the FSS, fatigue was measured in 28 adult patients, subdivided into ambulatory and non-ambulatory, suffering from a genetically confirmed 5q-SMA under treatment with nusinersen in accordance with the label. Correlations were performed among FSS and motor scales, 6-minute walk test (6MWT) and Hammersmiths Functional Motor Scale Expanded (HFMSE). Evaluation was performed prior to treatment initiation and after 6 and 10 months. The mean FSS score for all 28 patients at baseline was 4.61 ± 1.44. After 6 months mean FSS score significantly reduced to 3.92 ± 1.35. After 10 months mean FSS score had not differed from baseline, 3.84 ± 1.25. A moderate negative correlation of the difference of FSS and 6MWT after 6 months compared to baseline conditions was measured. Nusinersen reduces fatigue as measured by the FSS in adult patients with 5q-SMA transiently after initiation of treatment. There was no reduction of FSS 10 months after the beginning of treatment when compared to baseline.

Mobile arm supports in Duchenne muscular dystrophy: a pilot study of user experience and outcomes

PURPOSE

This pilot study examined whether two different types of non-powered mobile arm supports (MAS) enhanced upper limb function and independence with activities of daily living (ADLs) in people with Duchenne muscular dystrophy (DMD).

METHOD

A mixed methods cross-sectional design was used. Participants were four males with DMD, aged 16 to 20 years (M = 18.25 years). Two participants were current MAS users, and two had previously used MAS. To explore experiences of MAS use, semi-structured interviews were undertaken, then transcribed verbatim and analysed thematically. To measure the impact of MAS on arm function and ADLs, participants using MAS completed the Performance of the Upper Limb (PUL) and the DMD Upper Limb Patient Reported Outcome Measure with and without MAS. Participants no longer using MAS only completed the PUL without MAS.

RESULTS

MAS enhanced upper limb function and independence with ADLs in three of four participants. Eating and drinking was most often positively impacted by MAS. Access to informal support for MAS set-up, and ongoing input from a clinician or assistive technology (AT) supplier with MAS expertise, were important enablers to successful MAS use. Barriers to use included inadequate upper limb strength, interference of MAS with wheelchair controls, and AT funding delays.

CONCLUSION

MAS should be considered by individuals with DMD and clinicians working with them as the disease progresses and strength declines. Potential barriers to MAS use need to be addressed to ensure maximum utility. AT funding delays must also be minimized to avoid impact on outcomes of people with DMD.Implications for RehabilitationIndividuals with DMD, and clinicians working with them, may consider MAS to aid achievement of functional goals as the disease progresses and upper limb function declines.Both objective and subjective outcome measures should be used when evaluating the effectiveness of MAS.Consideration should be given to the potential interference of MAS with wheelchair controls and the availability of informal or paid supports (e.g., family, support workers, teachers) to aid MAS use.Efficient and timely funding of MAS is required, as delays may negatively impact outcomes for people with progressive neurological conditions, such as DMD.

Fatigue in young people with Duchenne muscular dystrophy

AIM

To describe fatigue in Duchenne muscular dystrophy (DMD) from patients' and parents' perspectives and to explore risk factors for fatigue in children and adolescents with DMD.

METHOD

A multicentre, cross-sectional study design was used. Seventy-one patients (all males; median age 12y, age range 5-17y) identified via the Canadian Neuromuscular Disease Registry, and their parents completed questionnaires. Subjective fatigue was assessed using the Pediatric Quality of Life Inventory Multidimensional Fatigue Scale by child self-report and parent proxy-report.

RESULTS

Patients with DMD across ages and disease stages experienced greater fatigue compared to typically developing controls from published data. Sleep disturbance symptoms were associated with greater fatigue by child self-report (ρ=-0.42; p=0.003) and parent proxy-report (ρ=-0.51; p<0.001). Depressive symptoms were associated with greater fatigue by child self-report (ρ=-0.46; p<0.001) and parent proxy-report (ρ=-0.45; p<0.001). Lower functional ability was associated with greater fatigue by parent proxy-report (ρ=0.26; p=0.03). Physical activity level, and musculoskeletal, respiratory, and cardiac function were not associated with fatigue.

INTERPRETATION

In paediatric DMD, sleep disturbance symptoms and depressive symptoms are potentially modifiable factors associated with fatigue, warranting additional investigation to facilitate the development of therapeutic strategies to reduce fatigue.

WHAT THIS PAPER ADDS

Fatigue is a major issue in paediatric Duchenne muscular dystrophy (DMD) across ages and disease stages. Sleep disturbance and depressive symptoms are significantly associated with fatigue in paediatric DMD.

Association Between Health-Related Quality of Life and Motor Function in Ambulant and Nonambulant Duchenne Muscular Dystrophy Patients

This cross-sectional study assessed health-related quality of life (HRQOL) in ambulant and nonambulant patients with Duchenne muscular dystrophy, and explored the association between health-related quality of life and clinically assessed motor function. The Pediatric Quality of Life Inventory (PedsQL) Generic Core Scale and PedsQL Neuromuscular module were completed by 34 parent-child dyads. Association between PedsQL scores and overall motor abilities and the transfers and standing posture domain measured by the Motor Function Measure were examined. Child self-reported and parent proxy-reported mean PedsQL scores for children with Duchenne muscular dystrophy were lower than those for healthy children for the physical and psychosocial health-related quality of life. Fifty-six percent of patients reported clinically impaired psychosocial health-related quality of life scores. Several aspects of the generic and disease-specific health-related quality of life in patients with Duchenne muscular dystrophy were positively associated to overall motor function and transfers and standing posture domain. Associations remained stable when adjusted for age and corticosteroid use. The Motor Function Measure is clinically meaningful in the context of a patient's day-to-day life.

Instruments for the Assessment of Behavioral and Psychosocial Functioning in Duchenne and Becker Muscular Dystrophy; a Systematic Review of the Literature

Objective

This systematic review aims to provide an overview of instruments used to assess behavioral and psychosocial functioning of patients with Duchenne and Becker muscular dystrophy, as well as to review the psychometric properties and applicability of these instruments.

Methods

Five databases (Embase, Psyc.info, ERIC, Pubmed/Medline, and Cochrane) were searched from inception to June, 2018. Potential articles were rated by two independent reviewers. A predefined PROSPERO form (CRD42017074518) was used to extract data from included articles.

Results

Sixty-one instruments were used in 54 studies. The Child Behavior Checklist is commonly used, but it lacks disease specific psychometric information. Sixteen instruments that contained disease specific psychometric information were included for final evaluation. The results displayed three instruments that are potentially valid for screening of psychosocial problems: The Psychosocial Adjustment and Role Skills Scale 3rd edition, the Pediatric Quality of Life Inventory Generic module, and the Life Satisfaction Index for Adolescents with Duchenne muscular dystrophy. Appropriate instruments for screening of behavioral problems may be: the Strengths and Difficulties Questionnaire, the Generalized Anxiety Disorder-7 item questionnaire, and the Patient Health Questionnaire-9 item questionnaire.

Conclusions

Further research on psychometric properties of screening instruments is crucial to ascertain a gold standard for clinical and research purposes. Meanwhile, for definite diagnostics purposes we recommend a multimethod, multisource, multisetting assessment in this high-risk population.

Producing a preference-based quality of life measure for people with Duchenne muscular dystrophy: a mixed-methods study protocol

INTRODUCTION

Preference-based measures (PBMs) of health-related quality of life (HRQoL) are used to generate quality-adjusted life years, which are necessary for cost-effectiveness evaluations of health interventions via cost-utility analysis. These measures of health can be generic (ie, pandiagnostic) or condition specific. No condition-specific PBM of HRQoL in Duchenne muscular dystrophy (DMD) exists, yet there are concerns that standard generic measures lack the specificity to assess aspects of HRQoL that are especially important to people with DMD. This study has been designed to produce a condition-specific PBM of HRQoL in DMD.

METHODS AND ANALYSIS

This mixed-methods study proceeds through three stages. In the first stage (concept elicitation), semistructured interviews will be conducted with boys and men diagnosed with DMD, and analysed with framework to produce a draft health state descriptive system for HRQoL in DMD. In the second stage (refining the descriptive system), patients, clinicians and primary caregivers of people with DMD will assess the face validity of the descriptive system. This will be followed by a quantitative survey on a larger sample of patients, which will be analysed with psychometric analyses to produce a refined descriptive system. In the third stage (valuation and econometric modelling), an online discrete choice experiment with duration will be administered to a general public sample to generate utility values for the new measure.

ETHICS AND DISSEMINATION

This study has received ethical approval from the National Health Service (REC reference: 18/SW/0055). The primary output of this research will be a condition-specific PBM (or 'bolt-on' to an existing generic PBM) in people with DMD and an associated value set. Results will be disseminated through international conferences and open-access journals.

A review of quality of life themes in Duchenne muscular dystrophy for patients and carers

Duchenne Muscular Dystrophy (DMD) is a severe, life-limiting and incurable condition. However, studies estimating quality of life and those measuring actual quality of life in people living with DMD vary considerably. This discrepancy indicates potential difficulties with assessing quality of life using common generic quality of life instruments in this rare and unique population. This study sought to document the range of themes relevant to quality of life for people with DMD by examining the published literature and additionally to investigate the themes that are relevant to quality of life for carers and the wider family. Eligible studies for the review were primary studies of any study design that reported outcomes or themes relevant to quality of life for either people with DMD, their families, or both. A review of studies identified from searching medical bibliographic sources between 2010 and 2016 found 45 relevant published studies. A thematic framework is proposed to categorise the themes identified into: i. physical; ii. psychological; iii. Social; iv. well-being domains. A final "other" domain was included to encompass themes identified from the literature that are not covered by commonly used quality of life instruments. The rich variety of themes identified from the review highlights that DMD has a complex quality of life profile which is not currently captured by standard quality of life tools that are commonly employed in the healthcare setting. The findings also highlight that the resulting impact on the quality of life of carers and wider family of people with DMD requires consideration.

Parents' perceptions of power wheelchair prescription for children with a neuromuscular disorder: a scoping review

Purpose: To conduct a scoping review of the published evidence on parents' perceptions of power wheelchair prescription for children with a neuromuscular disorder and clinicians' influence on timely wheelchair implementation.Method: Nine electronic databases and reference lists of all retrieved full-text articles were searched up to March 2017. Eligibility criteria included (1) at least one child participant with a neuromuscular disorder, (2) power wheelchair as an intervention, and (3) qualitative, quantitative or mixed methods parent-reported outcomes related to power wheelchair equipment.Results: None of the 67 eligible studies examined parental perceptions of wheelchair prescription as a primary aim, and only 10 studies included children with a neuromuscular disorder. Parents reported their own emotional responses including grief and loss, emphasis on their child's walking and lack of accessibility as key barriers to power wheelchair prescription. Clinicians' perspectives on walking and powered mobility influenced parental decision-making regarding power wheelchair use for their child.Conclusion: Parents' experiences of initial wheelchair prescription have not been explored in existing literature. Clinicians' understanding of the benefits of power wheelchair equipment, particularly in the context of progression of neuromuscular disorders, is critical to facilitating timely wheelchair prescription with children. Condition-specific evidence is urgently needed to inform and support multidisciplinary management of children and their families.Implications for RehabilitationIt is important that rehabilitation professionals recognize parental barriers to initial power wheelchair prescription, such as strong emotional responses, an emphasis on their child's walking and lack of access.Clinicians' perspectives on walking and powered mobility may influence parental decision-making regarding engagement in power wheelchair prescription and rehabilitation.It is critical that clinicians are aware of and actively educate families regarding the benefits of powered mobility to facilitate timely prescription and support physical and psychological adjustment.

The Canadian Neuromuscular Disease Registry: Connecting patients to national and international research opportunities

Introduction

Patient registries serve an important role in rare disease research, particularly for the recruitment and planning of clinical trials. The Canadian Neuromuscular Disease Registry was established with the primary objective of improving the future for neuromuscular (NM) patients through the enablement and support of research into potential treatments.

Methods

In this report, we discuss design and utilization of the Canadian Neuromuscular Disease Registry with special reference to the paediatric cohort currently enrolled in the registry.

Results

As of July 25, 2017, there are 658 paediatric participants enrolled in the registry, 249 are dystrophinopathies (229 are Duchenne muscular dystrophy), 57 are myotonic dystrophy participants, 98 spinal muscular atrophy participants and 65 are limb girdle muscular dystrophy. A total of 175 patients have another NM diagnosis. The registry has facilitated 20 clinical trial inquiries, 5 mail-out survey studies and 5 other studies in the paediatric population.

Discussion

The strengths of the registry are discussed. The registry has proven to be an invaluable tool to NM disease research and has increased Canada's visibility as a competitive location for the conduct of clinical trials for NM therapies.

Dynamic arm study: quantitative description of upper extremity function and activity of boys and men with duchenne muscular dystrophy

Background

Therapeutic management of upper extremity (UE) function of boys and men with Duchenne Muscular Dystrophy (DMD) requires sensitive and objective assessment. Therefore, we aimed to measure physiologic UE function of healthy subjects and DMD patients in different disease stages, and to evaluate the relation between these physiologic measures and functional UE scales.

Methods

Twenty-three DMD patients and twenty healthy controls (7–23 years) participated in this explorative case–control study. Maximal muscle torque, maximal and normalized surface electromyography (sEMG) amplitudes, muscle thickness, echogenicity and maximal passive and active joint angles were measured. At activity level, Brooke upper extremity rating scale and the Performance of Upper Limb (PUL) scale were used.

Results

Outcome measures related to proximal UE function could discriminate between disease stages. Increased normalized sEMG amplitudes were found in patients, even in early disease stages. Maximal active joint angles showed the strongest relation to Brooke scale (R² = 0.88) and PUL scale (R² = 0.85).

Conclusions

The decline of muscle functions precedes the decline in performance of UE activities, and therefore may play a role in early detection of UE limitations. Increased sEMG levels demonstrate that DMD patients use more of their muscle capacity compared to healthy subjects, to perform daily activities. This might result in increased fatigability. Active maximal joint angles are highly related to functional scales, so preserving the ability to use the full range of motion is important for the performance of daily activities. Close monitoring of active joint angles could therefore help in starting interventions that minimize functional UE decline in DMD patients timely.

Predictors of Health-Related Quality of Life in boys with Duchenne muscular dystrophy from six European countries

Duchenne muscular dystrophy (DMD) is a progressive, genetically determined neuromuscular disease that affects males and leads to severe physical disability in early teenage years. Over the last decades, patient-reported outcomes such as Health-Related Quality of Life (HRQoL) gained great interest in clinical research. However, little is known about factors affecting HRQoL in boys with DMD. Data from the multi-center CARE-NMD project of boys with DMD from six European countries collected between 2011 and 2012 were analyzed (8-17 years old; n = 321). HRQoL was measured using the KIDSCREEN-10 index, the Pediatric Quality of Life Inventory (PedsQL) and the Neuromuscular Module of the PedsQL (NMM). Linear regression models served to examine influences of socio-demographic, disease- and treatment-specific as well as participation- and environment-related factors on overall and disease-specific HRQoL. Proportions of explained variance varied across models using different outcomes (18-34%). Overall HRQoL according to the KIDSCREEN-10 index was associated with household income, the frequency of attending a clinic with specialized staff, the number of days spent outside home, and the attitude of the local community, but no significant association with age occurred. Overall HRQoL according to the generic PedsQL and disease-specific HRQoL were both positively associated with age and influenced by the country of residence, the disease stage, number of days spent outside home, and the attitude of the local community. Our results may be relevant for clinical practice and planning interventions for this population, but should be confirmed by future research. Further questions for future studies on boys with DMD are proposed.