Dataset Information

Revised North Star Ambulatory Assessment for Young Boys with Duchenne Muscular Dystrophy.

ABSTRACT: The advent of therapeutic approaches for Duchenne muscular dystrophy (DMD) has highlighted the need to identify reliable outcome measures for young boys with DMD. The aim of this study was to develop a revised version of the North Star Ambulatory Assessment (NSAA) suitable for boys between the age of 3 and 5 years by identifying age appropriate items and revising the scoring system accordingly. Using the scale in 171 controls between the age of 2.9 and 4.8 years, we identified items that were appropriate at different age points. An item was defined as age appropriate if it was completed, achieving a full score, by at least 85% of the typically developing boys at that age. At 3 years (±3months) there were only 8 items that were age appropriate, at 3 years and 6 months there were 13 items while by the age of 4 years all 17 items were appropriate. A revised version of the scale was developed with items ordered according to the age when they could be reliably performed. The application of the revised version of the scale to data collected in young DMD boys showed that very few of the DMD boys were able to complete with a full score all the age appropriate items. In conclusion, our study suggests that a revised version of the NSAA can be used in boys from the age of 3 years to obtain information on how young DMD boys acquire new abilities and how this correlates with their peers.

SUBMITTER: Mercuri E

PROVIDER: S-EPMC4975396 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Revised North Star Ambulatory Assessment for Young Boys with Duchenne Muscular Dystrophy.

Mercuri Eugenio E Coratti Giorgia G Messina Sonia S Ricotti Valeria V Baranello Giovanni G D'Amico Adele A Pera Maria Carmela MC Albamonte Emilio E Sivo Serena S Mazzone Elena Stacy ES Arnoldi Maria Teresa MT Fanelli Lavinia L De Sanctis Roberto R Romeo Domenico M DM Vita Gian Luca GL Battini Roberta R Bertini Enrico E Muntoni Francesco F Pane Marika M

PloS one 20160805 8

The advent of therapeutic approaches for Duchenne muscular dystrophy (DMD) has highlighted the need to identify reliable outcome measures for young boys with DMD. The aim of this study was to develop a revised version of the North Star Ambulatory Assessment (NSAA) suitable for boys between the age of 3 and 5 years by identifying age appropriate items and revising the scoring system accordingly. Using the scale in 171 controls between the age of 2.9 and 4.8 years, we identified items that were ap ...[more]

PMID: 27494024

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Project description:Functional variability among boys with Duchenne muscular dystrophy (DMD) is well recognised and complicates interpretation of clinical studies. We hypothesised that boys with DMD could be clustered into groups sharing similar trajectories of ambulatory function over time, as measured by the North Star Ambulatory Assessment (NSAA) total score. We also explored associations with other variables such as age, functional abilities, and genotype. Using the NorthStar Clinical Network database, 395 patients with >1 NSAA assessment were identified. We utilised latent class trajectory analysis of longitudinal NSAA scores, which produced evidence for at least four clusters of boys sharing similar trajectories versus age in decreasing order of clinical severity: 25% of the boys were in cluster 1 (NSAA falling to ? 5 at age ~10y), 35% were in cluster 2 (NSAA ? 5 ~12y), 21% in were cluster 3 (NSAA? 5 ~14y), and 19% in cluster 4 (NSAA > 5 up to 15y). Mean ages at diagnosis of DMD were similar across clusters (4.2, 3.9, 4.3, and 4.8y, respectively). However, at the first NSAA assessment, a significant (p<0.05) association was observed between earlier declining clusters and younger age, worse NSAA, slower rise from supine, slower 10 metre walk/run times, and younger age of steroid initiation. In order to assess the probability of observing complete loss of function for individual NSAA items, we examined the proportion of patients who shifted from a score of 1 or 2 at baseline to a score of 0. We also assessed the probability of gain of function using the inverse assessment and stratified the probability of deterioration, improvement-or static behavior-by age ranges and using baseline functional status. Using this tool, our study provides a comprehensive assessment of the NSAA in a large population of patients with DMD and, for the first time, describes discrete clusters of disease progression; this will be invaluable for future DMD clinical trial design and interpretation of findings.

Project description:BackgroundStride Velocity 95th Centile (SV95C) is the first wearable device-derived clinical outcome assessment (COA) to receive European Medicines Agency (EMA) qualification as a primary endpoint in ambulant patients with Duchenne muscular dystrophy (DMD) aged ≥4 years.ObjectiveTo compare SV95C-in its first-ever clinical trial application as a secondary endpoint-with established motor function COAs used in the trial (Four-Stair Climb [4SC] velocity, North Star Ambulatory Assessment [NSAA], and Six-Minute Walk Distance [6MWD]).MethodsSV95C was a secondary endpoint in a subset (n = 47) of participants in the SPITFIRE/WN40227 trial of taldefgrobep alfa, which was discontinued due to lack of clinical benefit. Participants in the ≤48-week SV95C sub-study were 6-11 years old and received corticosteroids for ≥6 months pre-treatment. Pearson correlations were used to compare SV95C with the other COAs. Responsiveness and changes over time were respectively assessed via standardized response means (SRMs) based on absolute changes and mixed models for repeated measures.ResultsSV95C change at Week 24 was -0.07 m/s, with limited variability (standard deviation: 0.16, n = 27). The SRM for SV95C indicated moderate responsiveness to clinical change at the earliest timepoint (Week 12, n = 46), while those of the other COAs did not indicate moderate responsiveness until Week 36 (6MWD, n = 33) or Week 48 (4SC velocity, n = 20; NSAA total score, n = 20). Baseline correlations between SV95C and other COAs were strong (r = 0.611-0.695). Correlations between SV95C change from baseline to Week 48 and changes in other COAs were moderate to strong (r = 0.443-0.678).∥.ConclusionsOverall, SV95C demonstrated sensitivity to ambulatory decline over short intervals, low variability, and correlation with established COAs. Although the negative trial precluded demonstration of SV95C's sensitivity to drug effect, these findings support the continued use of SV95C in DMD clinical trials.

Project description:BackgroundDuchenne muscular dystrophy (DMD) is the most common muscular dystrophy in the pediatric population. The manifestations of this disease include progressive muscle weakness, gait dysfunction, and motor impairment, leading to a loss of ambulation by the age of 13 years. Molecular diagnosis is the standard diagnostic tool for DMD. This study aimed to investigate disease progression and genetic patterns in Iranian ambulant boys and to find the correlation between genotypes and motor function phenotypes.MethodsThis study was performed on 152 DMD patients. Clinical history, including the disease phenotype, steroid therapy, and the North Star Ambulatory Assessment (NSAA) score, was taken for all the patients. Molecular diagnoses were confirmed by multiplex ligation-dependent probe amplification and next-generation sequencing tests.ResultsA total of 152 Iranian DMD patients were examined in this study. The mean age at the time of disease onset was 4.04 ± 2.00 years, and the mean age at diagnosis was 5.05 ± 2.08 years. The mean age of ambulation loss was 10.9 years. Contracture was reported in 38.9% of cases. In terms of age, the mean total NSAA score showed a peak at 4 years of age, with a mean NSAA score of 24. Annual changes in the NSAA score were determined for all cases, based on the mutation type and exon site. Deletion mutation was found in 79.1% of cases, duplication in 6.8%, nonsense in 12.8%, and splice site in 1.4%. The most common single exon deletion was exon 44 (5.3%), and the most common multiexon deletions were attributed to exons 45-50 and exons 45-52 (4.6%). The results did not indicate any correlation between the mutation type and age at the time of disease onset, loss of ambulation age, and wheelchair dependence; however, a significant association was found between contracture and mutation type. The results showed a significant difference in the NSAA score between the deletion and nonsense groups at the age of 3 years (P = 0.04). No significant correlation was found between the phenotype and exon site. Overall, 91.1% of the study population had a history of corticosteroid use, and 54.1% showed compliance with rehabilitation therapy.ConclusionThis study demonstrated the phenotypes and mutational features of Iranian DMD boys and provided information regarding the natural motor history of the disease, disease progression, diagnosis, and status of DMD management in Iran. The present findings can promote the development of clinical trials and future advanced molecular therapies in Iran.

Project description:Background and objectivesDuchenne muscular dystrophy (DMD) is a paediatric neuromuscular disorder caused by mutations in the dystrophin gene. Geneotype-phenotype associations have been examined in glucocorticoid treated boys, but there are few data on the young glucocorticoid-naïve DMD population. A sample of young glucocorticoid-naïve DMD boys is described and genotype-phenotype associations are investigated.MethodsScreening and baseline data were collected for all the participants in the Finding the Optimum Corticosteroid Regime for Duchenne Muscular Dystrophy (FOR-DMD)study, an international, multi-centre, randomized, double-blind, clinical trial comparing three glucocorticoid regimens in glucocorticoid-naïve, genetically confirmed boys with DMD between 4 and <8 years of age.ResultsOne hundred and ninety-six boys were recruited. The meanage at randomization (+ standard deviation) was 5.8+ 1.0 years. The predominant mutation type was out of frame deletions 67.4%, (130/193) of which 68.5% (89/130) were amenable to exon skipping. The most frequent mutations were deletions amenable to exon 51 skipping 13.0% (25/193). Stop codon mutations accounted for 10.4% (20/193).The mean age at first parental concerns was 29.8 + 18.7 months, the mean age at genetic diagnosis was 53.9 + 21.9 months and the mean diagnostic delay was 25.9 + 18.2 months. The mean diagnostic delay for boys diagnosed following an incidental finding of isolated hyperCKemia (n=19) was 6.4 + 7.4 months. The mean ages at independent walking and talking in sentences were 17.1 + 4.2 and 29.0 + 10.7 months, respectively. Median height percentiles were below the 25th percentile regardless of age group. No genotype-phenotype associations were identified expect for boys with an exon 8 skippable deletions who had better performance on time to walk/run 10 meters (p=0.02)compared to boys with deletions not amenable to skipping.DiscussionThis study describes clinical and genetic characteristics of a sample of young glucocorticoid-naïve boys with DMD. A low threshold for CK testing can lead to an earlier diagnosis. Motor and speech delay were common presenting symptoms.The effects of low, pre-treatment height on growth and adults height requires further study. These findings may promote earlier recognition of DMD and inform study design for future clinical trials.

Dataset Information

Revised North Star Ambulatory Assessment for Young Boys with Duchenne Muscular Dystrophy.

Publications

Revised North Star Ambulatory Assessment for Young Boys with Duchenne Muscular Dystrophy.

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