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Objective: The North Star Assessment for limb-girdle type muscular dystrophies (NSAD), a clinician-reported outcome measure (ClinRO) of motor performance, was initially developed and validated for use in dysferlinopathy, an autosomal recessive form of limb-girdle muscular dystrophy (LGMD R2/2B). Recent developments in treatments for limb-girdle muscular dystrophies (LGMD) have highlighted the urgent need for disease-specific ClinROs. The purpose of this study was to understand the ability of the NSAD to quantify motor function across the broad spectrum of LGMD phenotypes., Methods: Assessments of 130 individuals with LGMD evaluated by the physical therapy teams at Nationwide Children's Hospital and the John Walton Muscular Dystrophy Research Centre were included in the analysis. NSAD, 100-m timed test (100MTT), and Performance of Upper Limb 2.0 assessment data were collected. Psychometric analysis with Rasch measurement methods was used to examine the NSAD for suitability and robustness by determining the extent to which the observed data "fit" with predictions of those ratings from the Rasch model. The NSAD score was correlated with the 100MTT and Performance of Upper Limb 2.0 assessment scores for external construct validity., Results: The NSAD demonstrated a good spread of items covering a continuum of abilities across both individuals who had LGMD and were ambulatory and individuals who had LGMD and were weaker and nonambulatory. Items fit well with the construct measured, validating a summed total score. The NSAD had excellent interrater reliability [intraclass correlation coefficient (ICC) = 0.986, 95% CI = 0.981-0.991] and was highly correlated with the 100MTT walk/run velocity (Spearman rho correlation coefficient of rs(134) = .92)., Conclusion: Although LGMD subtypes may differ in age of onset, rate of progression, and patterns of muscle weakness, the overall impact of progressive muscle weakness on motor function is similar. The NSAD is a reliable and valid ClinRO of motor performance for individuals with LGMD and is suitable for use in clinical practice and research settings., Impact: Recent developments in potential pharmacological treatments for LGMD have highlighted the urgent need for disease-specific outcome measures. Validated and meaningful outcome measures are necessary to capture disease presentation, to inform expected rates of progression, and as endpoints for measuring the response to interventions in clinical trials. The NSAD, a scale of motor performance for both individuals who have LGMD and are ambulatory and those who are nonambulatory, is suitable for use in clinical and research settings., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Physical Therapy Association.)

Background: Valosin-containing protein (VCP) disease, caused by mutations in the VCP gene, results in myopathy, Paget's disease of bone (PBD) and frontotemporal dementia (FTD). Natural history and genotype-phenotype correlation data are limited. This study characterises patients with mutations in VCP gene and investigates genotype-phenotype correlations., Methods: Descriptive retrospective international study collecting clinical and genetic data of patients with mutations in the VCP gene., Results: Two hundred and fifty-five patients (70.0% males) were included in the study. Mean age was 56.8±9.6 years and mean age of onset 45.6±9.3 years. Mean diagnostic delay was 7.7±6 years. Symmetric lower limb weakness was reported in 50% at onset progressing to generalised muscle weakness. Other common symptoms were ventilatory insufficiency 40.3%, PDB 28.2%, dysautonomia 21.4% and FTD 14.3%. Fifty-seven genetic variants were identified, 18 of these no previously reported. c.464G>A (p.Arg155His) was the most frequent variant, identified in the 28%. Full time wheelchair users accounted for 19.1% with a median time from disease onset to been wheelchair user of 8.5 years. Variant c.463C>T (p.Arg155Cys) showed an earlier onset (37.8±7.6 year) and a higher frequency of axial and upper limb weakness, scapular winging and cognitive impairment. Forced vital capacity (FVC) below 50% was as risk factor for being full-time wheelchair user, while FVC <70% and being a full-time wheelchair user were associated with death., Conclusion: This study expands the knowledge on the phenotypic presentation, natural history, genotype-phenotype correlations and risk factors for disease progression of VCP disease and is useful to improve the care provided to patient with this complex disease., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

The purpose of this study was to quantitate motor performance in 196 genetically confirmed steroid-naïve boys with Duchenne muscular dystrophy (DMD), to evaluate the test-retest reliability of measures of motor performance in young DMD boys, and to assess correlations among the different functional outcomes including timed tests. Boys aged 4-7 years were recruited in the FOR-DMD study, a comparative effectiveness study of different steroid regimens in DMD. Eligible boys had to be able to rise from the floor independently and to perform pulmonary function testing consistently. The boys were evaluated with standardized assessments at the screening and baseline visits at 32 sites in 5 countries (US, UK, Canada, Italy, Germany). Assessments included timed rise from floor, timed 10 m walk/run, six-minute walk distance, North Star Ambulatory Assessment (NSAA) and forced vital capacity (FVC). Mean age at baseline was 5.9 years (range 4.1-8.1 years). Test-retest reliability was high for functional assessments, regardless of time lag between assessments (up to 90 days) and for the majority of age groups. Correlations were strong among the functional measures and timed tests, less so with FVC. Physiotherapy measures are reliable in a young, steroid-naïve population and rise from floor velocity appears to be a sensitive measure of strength in this population., Competing Interests: Declaration of Competing Interests Anna G. Mayhew has participated in SAB meetings for Roche, Regenxbio, Summit, PTC and Biogen and performs Consultancy work (training physiotherapists for trial in DMD) for Roche, Pfizer, PTC, Summit, Sarepta, Lysogene, Italfarmaco, Amicus, Biogen and Avexis. Dionne Moat provides consultancy services for the following companies: ATOM International (covers consultancy services provided to Amicus Therapeutics Pty Ltd, Ascendis Pharma, Biomarin, Catabasis, Faraday, FibroGen, Genethon, Italfarmaco, NS Pharma, Pfizer, PTC Therapeutics, QED Therapeutics Ltd, Reveragen, Sarepta Therapeutics), outside the submitted work. Michael McDermott has been supported by a research grant from PTC Therapeutics, has received compensation for consulting from Fulcrum Therapeutics, Inc., and NeuroDerm, Ltd., and has served on Data and Safety Monitoring Boards (DSMBs) for AstraZeneca, Eli Lilly and Company, Catabasis Pharmaceuticals, Inc., Vaccinex, Inc., Cynapsus Therapeutics, Neurocrine Biosciences, Inc., Voyager Therapeutics, Prilenia Therapeutics Development, Ltd., ReveraGen BioPharma, Inc., and NS Pharma, Inc. Michelle Eagle is Managing Director at ATOM International Limited and is contracted with the following companies through ATOM: Amicus, Biomarin, Capricor, Catabasis, Denali, Dyne, Edgewise, Faraday, Fibrogen, Genethon, Italfarmaco, Lysogen, Modis, NSPharma, PTC, Sarepta, Solid, Referagen. Robert Griggs receives research support from the NIH, the Muscular Dystrophy Association, the Parent Project for Muscular Dystrophy, and from Sarepta Biopharma, PTC Therapeutics and Santhera Pharmaceuticals. He serves as a Consultant for Strongbridge and Stealth Pharmaceuticals. He is Chair of a DSMB for Solid Pharmaceuticals. He receives monies for editorial work from Elsevier as an Editor of Cecil Essentials and Cecil Textbook of Medicine. He serves as Chair of the Research Advisory Committee and is a Board Member of the American Brain Foundation. He is on the Executive Committee of the Muscle Study Group, which receives support for its activities from Pharmaceutical companies. Meredith K. James provides consultancy services for the following companies: ATOM International (covers consultancy services provided to Amicus Therapeutics Pty Ltd, Ascendis Pharma, Biomarin, Catabasis, Faraday, FibroGen, Genethon, Italfarmaco, NS Pharma, Pfizer, PTC Therapeutics, QED Therapeutics Ltd, Reveragen, Sarepta Therapeutics), outside the submitted work. MKJ has received payment for participation on advisory boards for F. Hoffman La Roche AG, PTC Therapeutics and fee support for PhD studies from the Jain Foundation, outside the submitted work. Robert Muni-Lofra has participated in the advisory board for Biogen and Roche and performs consultancy work (training physiotherapists for trial in DMD and SMA) for Roche, Pfizer, PTC, Summit, Sarepta, Italfarmaco, Amicus, Biogen and Avexis. Lindsey Pallant has performed consultancy work (workshops and training physiotherapists in trials for DMD) for PTC and Sarepta. Katy Eichinger has received personal compensation for serving on advisory boards and/or as a consultant for Ionis, Biogen, Acceleron, Fulcrum, Avidity, PTC and the Myotonic Dystrophy Foundation. Dr. Eichinger has received personal compensation for serving as a speaker from Cure SMA, FSH Society, and Ology. She has received research/grant support from the CMTA. Heather McMurchie has received financial support from PTC and Biogen to access and provide training. Marina DiMarco attended a World Muscle Society conference sponsored by PTC Therapeutics and is a Consultant Physiotherapist presenting at PTC workshops. Lindsay N. Alfano provides consultancy services through ATOM International, Ltd for the following companies: Amicus Therapeutics Pty Ltd, Catabasis, Genethon, Italfarmaco, NS Pharma, Pfizer, PTC Therapeutics); reports royalties and other support from Sarepta Therapeutics; royalties for licensed technologies; other support from Novartis Gene Therapies; advisory board for Biogen. Linda P. Lowes provides consultancy services through ATOM International, Ltd for the following companies: Amicus Therapeutics Pty Ltd, Catabasis, Genethon, Italfarmaco, NS Pharma, Pfizer, PTC Therapeutics); reports royalties and other support from Sarepta Therapeutics; royalties for licensed technologies; other support from Novartis Gene Therapies; advisory board for Biogen. Amy Pasternak has participated in advisory boards for Roche, Biogen, Avexis, Scholar Rock and Audentes. Victoria Kern has received an honorarium from the MDA USA for a presentation. Cheryl Scholtes has sat on advisor panels for Biogen Canada and Roche Canada, and has been provided education on behalf of Biogen Canada and Roche Canada. Catherine Lacroix has acted as a consultant and advisory board participant to Biogen. Katherine Kundrat has participated in an advisory board for Biogen. Michela Guglieri is the study chair for a ReveraGen study. MG has research collaborations with ReveraGen and Sarepta. MG is (has been over the past 5 years) PI for clinical trials sponsored by Pfizer, Italfarmaco, Santhera, ReveraGen, Dynacure, Roche, PTC, Summit. MG has been participating in advisory boards for Pfizer, NS Pharma, Dyne (consultancies through Newcastle University). MG has performed consultancy work (speaker) for Sarepta. Declarations of interest: none for remaining authors, (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Valosin-containing protein (VCP) associated multisystem proteinopathy (MSP) is a rare inherited disorder that may result in multisystem involvement of varying phenotypes including inclusion body myopathy, Paget's disease of bone (PDB), frontotemporal dementia (FTD), parkinsonism, and amyotrophic lateral sclerosis (ALS), among others. An international multidisciplinary consortium of 40+ experts in neuromuscular disease, dementia, movement disorders, psychology, cardiology, pulmonology, physical therapy, occupational therapy, speech and language pathology, nutrition, genetics, integrative medicine, and endocrinology were convened by the patient advocacy organization, Cure VCP Disease, in December 2020 to develop a standard of care for this heterogeneous and under-diagnosed disease. To achieve this goal, working groups collaborated to generate expert consensus recommendations in 10 key areas: genetic diagnosis, myopathy, FTD, PDB, ALS, Charcot Marie Tooth disease (CMT), parkinsonism, cardiomyopathy, pulmonology, supportive therapies, nutrition and supplements, and mental health. In April 2021, facilitated discussion of each working group's conclusions with consensus building techniques enabled final agreement on the proposed standard of care for VCP patients. Timely referral to a specialty neuromuscular center is recommended to aid in efficient diagnosis of VCP MSP via single-gene testing in the case of a known familial VCP variant, or multi-gene panel sequencing in undifferentiated cases. Additionally, regular and ongoing multidisciplinary team follow up is essential for proactive screening and management of secondary complications. The goal of our consortium is to raise awareness of VCP MSP, expedite the time to accurate diagnosis, define gaps and inequities in patient care, initiate appropriate pharmacotherapies and supportive therapies for optimal management, and elevate the recommended best practices guidelines for multidisciplinary care internationally., (© 2022. The Author(s).)

Background: Duchenne muscular dystrophy (DMD) is a rare, X-linked, fatal, degenerative neuromuscular disease caused by DMD gene mutations. A relationship between exon skipping and dystrophin production in exon 51-amenable patients treated with eteplirsen (EXONDYS 51®) is established. Once-weekly eteplirsen significantly increased dystrophin, with slower decline in ambulatory function compared to baseline. Long-term treatment with eteplirsen leads to accumulation of dystrophin over time and observed functional benefits in patients with DMD., Objective: Compare long-term ambulatory function in eteplirsen-treated patients versus controls., Methods: Study 201/202 included 12 eteplirsen-treated patients assessed twice/year for ambulatory function over 4 years. Ambulatory evaluations (6-minute walk test [6MWT], loss of ambulation, and North Star Ambulatory Assessment [NSAA]) were compared with matched controls from Italian Telethon and Leuven registries., Results: At Years 3 and 4, eteplirsen-treated patients demonstrated markedly greater mean 6MWT than controls (difference in change from baseline of 132 m [95%CI (29, 235), p = 0.015] at Year 3 and 159 m [95%CI (66, 253), p = 0.002] at Year 4). At Year 4, a significantly greater proportion of eteplirsen-treated patients were still ambulant versus controls (10/12 vs 3/11; p = 0.020). At Year 3, eteplirsen-treated patients demonstrated milder NSAA decline versus controls (difference in change from baseline of 2.6, 95%CI [-6, 11]), however, the difference was not statistically significant; Year 4 control NSAA data were not available., Conclusion: In this retrospective matched control study, eteplirsen treatment resulted in attenuation of ambulatory decline over a 4-year observation period, supporting long-term benefit in patients with DMD.

Background: Advances in treatment for Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA) hold promise for children with these disorders. Accurate genetic diagnosis, early in the disease process, will allow these treatments to be most effective. Newborn screening (NBS) for SMA has been recommended in the United States, and a pilot DMD NBS program is underway in Hangzhou, China., Data Sources: A PubMed search, limited to the past 5 years, was conducted to identify: (1) therapeutic advancements for DMD/SMA approved by the United States Food and Drug Administration or the European Medicine Agency and (2) The status of NBS for DMD/SMA., Results: We review the current state of approved treatments for DMD/SMA. We present recommendations regarding the future of NBS for these diseases, with a focus on the outcomes and challenges of SMA NBS in New York, USA, and the DMD NBS pilot program in Hangzhou, China., Conclusions: Approved treatments for DMD and SMA may change the natural history of these diseases. Long-term studies of these treatments are underway. To avoid the known diagnostic delay associated with these disorders and provide optimal effectiveness of these treatments, early identification of patients through NBS will be necessary. Establishing comprehensive follow-up plans for positively identified patients will need to be in place for NBS programs to be successful.

This analysis aims to describe the outcomes of two nonambulatory patients with Duchenne muscular dystrophy (DMD) who participated in two clinical studies. The two consecutive trials of eteplirsen (studies 201 and 202) were conducted in patients with DMD (N = 12) and confirmed genetic mutations amenable to exon 51 skipping.In study 201, 12 patients were randomized to receive once-weekly, double-blind intravenous infusions of eteplirsen 30 or 50 mg/kg or placebo for 24 weeks; patients then received open-label eteplirsen during weeks 25 through 28. All 12 patients continued onto open-label extension study 202 and received long-term treatment with eteplirsen. We compared cardiac, pulmonary, and upper limb function and dystrophin production in the nonambulatory twin patients versus the 10 ambulatory patients through 240 combined treatment weeks.Ten study patients remained ambulatory through both studies, while the identical twin patients both experienced early, rapid loss of ambulation. The twin patients had greater disease severity at baseline (6-minute walk test [6MWT], 330 and 256 m) versus the other patients (n = 10; 6MWT range, 341-418 m). They maintained cardiac and upper limb function through combined week 240, with outcomes similar to those of the patients who remained ambulatory. Dystrophin production was confirmed following eteplirsen treatment.Despite the loss of ambulation, other markers of disease progression remained relatively stable in the eteplirsen-treated twin patients and were similar to those of the ambulatory patients.

Objective: To assess the ability of functional measures to detect disease progression in dysferlinopathy over 6 months and 1 year., Methods: One hundred ninety-three patients with dysferlinopathy were recruited to the Jain Foundation's International Clinical Outcome Study for Dysferlinopathy. Baseline, 6-month, and 1-year assessments included adapted North Star Ambulatory Assessment (a-NSAA), Motor Function Measure (MFM-20), timed function tests, 6-minute walk test (6MWT), Brooke scale, Jebsen test, manual muscle testing, and hand-held dynamometry. Patients also completed the ACTIVLIM questionnaire. Change in each measure over 6 months and 1 year was calculated and compared between disease severity (ambulant [mild, moderate, or severe based on a-NSAA score] or nonambulant [unable to complete a 10-meter walk]) and clinical diagnosis., Results: The functional a-NSAA test was the most sensitive to deterioration for ambulant patients overall. The a-NSAA score was the most sensitive test in the mild and moderate groups, while the 6MWT was most sensitive in the severe group. The 10-meter walk test was the only test showing significant change across all ambulant severity groups. In nonambulant patients, the MFM domain 3, wrist flexion strength, and pinch grip were most sensitive. Progression rates did not differ by clinical diagnosis. Power calculations determined that 46 moderately affected patients are required to determine clinical effectiveness for a hypothetical 1-year clinical trial based on the a-NSAA as a clinical endpoint., Conclusion: Certain functional outcome measures can detect changes over 6 months and 1 year in dysferlinopathy and potentially be useful in monitoring progression in clinical trials., Clinicaltrialsgov Identifier: NCT01676077., (Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Background: Spinal muscular atrophy type 1 (SMA1) is a progressive, monogenic motor neuron disease with an onset during infancy that results in failure to achieve motor milestones and in death or the need for mechanical ventilation by 2 years of age. We studied functional replacement of the mutated gene encoding survival motor neuron 1 (SMN1) in this disease., Methods: Fifteen patients with SMA1 received a single dose of intravenous adeno-associated virus serotype 9 carrying SMN complementary DNA encoding the missing SMN protein. Three of the patients received a low dose (6.7×10 13 vg per kilogram of body weight), and 12 received a high dose (2.0×10 14 vg per kilogram). The primary outcome was safety. The secondary outcome was the time until death or the need for permanent ventilatory assistance. In exploratory analyses, we compared scores on the CHOP INTEND (Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders) scale of motor function (ranging from 0 to 64, with higher scores indicating better function) in the two cohorts and motor milestones in the high-dose cohort with scores in studies of the natural history of the disease (historical cohorts)., Results: As of the data cutoff on August 7, 2017, all 15 patients were alive and event-free at 20 months of age, as compared with a rate of survival of 8% in a historical cohort. In the high-dose cohort, a rapid increase from baseline in the score on the CHOP INTEND scale followed gene delivery, with an increase of 9.8 points at 1 month and 15.4 points at 3 months, as compared with a decline in this score in a historical cohort. Of the 12 patients who had received the high dose, 11 sat unassisted, 9 rolled over, 11 fed orally and could speak, and 2 walked independently. Elevated serum aminotransferase levels occurred in 4 patients and were attenuated by prednisolone., Conclusions: In patients with SMA1, a single intravenous infusion of adeno-associated viral vector containing DNA coding for SMN resulted in longer survival, superior achievement of motor milestones, and better motor function than in historical cohorts. Further studies are necessary to confirm the safety and efficacy of this gene therapy. (Funded by AveXis and others; ClinicalTrials.gov number, NCT02122952 .).

Timed walking tests are often used to measure function in boys with Duchenne muscular dystrophy (DMD). Our objective was to evaluate the 100 meter timed test (100m), a fixed distance test of maximal performance, for use in DMD. To this end, we sought to establish normative 100m performance in healthy controls, compare DMD performance to controls, and evaluate the reliability of 100m. Seventy-two boys with DMD (18 steroid-naïve, 54 on steroids) and 599 controls (4-14 years) completed the 100m as speedily as possible on a 25-meter track. Repeat testing was completed between 1 and 42 days later and again at 1 year in a subgroup of 96 control boys. Additionally 35 DMD boys were followed longitudinally (5-19 months). Descriptive statistics are presented by age and cohort. There was a significant difference in performance between groups (p < 0.01). Age and body mass index (BMI) significantly influenced 100m (p < 0.0001) in the control cohort. Test-retest reliability was excellent for both cohorts (ICC > 0.90, p < 0.001). Normative data can be used to determine percent-predicted 100m times to quantify the severity of running impairment in children with a motor deficit. Performance of 100m follows the natural history established by other outcome measures in DMD., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Sporadic inclusion body myositis, a variant of inflammatory myopathy, has features distinct from polymyositis/dermatomyositis. The disease affects men more than women, most commonly after age 50. Clinical features include weakness of the quadriceps, finger flexors, ankle dorsiflexors, and dysphagia. The distribution of weakness is similar to Becker muscular dystrophy, where we previously reported improvement following intramuscular injection of an isoform of follistatin (FS344) by AAV1. For this clinical trial, rAAV1.CMV.huFS344, 6 × 10 11 vg/kg, was delivered to the quadriceps muscles of both legs of six sporadic inclusion body myositis subjects. The primary outcome for this trial was distance traveled for the 6-min walk test. The protocol included an exercise regimen for each participant. Performance, annualized to a median 1-year change, improved +56.0 m/year for treated subjects compared to a decline of -25.8 m/year (p = 0.01) in untreated subjects (n = 8), matched for age, gender, and baseline measures. Four of the six treated subjects showed increases ranging from 58-153 m, whereas two were minimally improved (5-23 m). Treatment effects included decreased fibrosis and improved regeneration. These findings show promise for follistatin gene therapy for mild to moderately affected, ambulatory sporadic inclusion body myositis patients. More advanced disease with discernible muscle loss poses challenges., (Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)

Introduction: Therapeutic trials in Duchenne muscular dystrophy (DMD) often exclude non-ambulatory individuals. Here we establish optimal and reliable assessments in a multicenter trial., Methods: Non-ambulatory boys/men with DMD (N = 91; 16.7 ± 4.5 years of age) were assessed by trained clinical evaluators. Feasibility (percentage completing task) and reliability [intraclass correlation coefficients (ICCs) between morning and afternoon tests] were measured., Results: Forced vital capacity (FVC), assessed in all subjects, showed a mean of 47.8 ± 22% predicted (ICC 0.98). Brooke Upper Extremity Functional Rating (Brooke) and Egen Klassifikation (EK) scales in 100% of subjects showed ICCs ranging from 0.93 to 0.99. Manual muscle testing, range of motion, 9-hole peg test, and Jebsen-Taylor Hand Function Test (JHFT) demonstrated varied feasibility (99% to 70%), with ICCs ranging from 0.99 to 0.64. We found beneficial effects of different forms of corticosteroids for the Brooke scale, percent predicted FVC, and hand and finger strength., Conclusions: Reliable assessment of non-ambulatory boys/men with DMD is possible. Clinical trials will have to consider corticosteroid use., (© 2014 Wiley Periodicals, Inc.)

Therapeutic trials in Duchenne Muscular Dystrophy (DMD) exclude young boys because traditional outcome measures rely on cooperation. The Bayley III Scales of Infant and Toddler Development (Bayley III) have been validated in developing children and those with developmental disorders but have not been studied in DMD. Expanded Hammersmith Functional Motor Scale (HFMSE) and North Star Ambulatory Assessment (NSAA) may also be useful in this young DMD population. Clinical evaluators from the MDA-DMD Clinical Research Network were trained in these assessment tools. Infants and boys with DMD (n = 24; 1.9 ± 0.7 years) were assessed. The mean Bayley III motor composite score was low (82.8 ± 8; p ≤ .0001) (normal = 100 ± 15). Mean gross motor and fine motor function scaled scores were low (both p ≤ .0001). The mean cognitive comprehensive (p=.0002), receptive language (p ≤ .0001), and expressive language (p = .0001) were also low compared to normal children. Age was negatively associated with Bayley III gross motor (r = -0.44; p = .02) but not with fine motor, cognitive, or language scores. HFMSE (n=23) showed a mean score of 31 ± 13. NSAA (n = 18 boys; 2.2 ± 0.4 years) showed a mean score of 12 ± 5. Outcome assessments of young boys with DMD are feasible and in this multicenter study were best demonstrated using the Bayley III., (Copyright © 2013 Elsevier B.V. All rights reserved.)