Our results confirm the high prevalence of OSAS in children with DS. A significant number also have low baseline saturations, central apnoeas, and nocturnal hypoventilation. Contrary to popular belief, more than half of children with DS had satisfactory adherence to respiratory support.

Objective.To describe the respiratory trajectories and their correlation with motor function in an international paediatric cohort of patients with type 2 and non-ambulant type 3 spinal muscular atrophy (SMA).Methods.Eight-year retrospective observational study of patients in the iSMAc natural history study. We retrieved anthropometrics, forced vital capacity (FVC) absolute, FVC% predicted (FVC%P.), Non-Invasive ventilation (NIV) requirement. Hammersmith functional motor scale (HFMS) and Revised performance of upper limb (RULM) were correlated with respiratory function. We excluded patients in interventional clinical trials and on Nusinersen commercial therapy.Results.There were 437 patients with SMA: 348 type 2, 89 non-ambulant type 3. Mean age at first visit was 6.9(±4.4) and 11.1(±4) years. In SMA type 2 FVC%P declined by 4.2%/year from 5 to 13 years, followed by a slower decline (1.0%/year). In type 3 FVC%P declined by 6.3%/year between 8 and 13 years, followed by a slower decline (0.9%/year). 39% SMA type 2 and 9% type 3 required NIV at median age 5.0(1.8-16.6) and 15.1(13.8-16.3) years. 84% SMA type 2 and 80% type 3 had scoliosis, 54% and 46% required surgery, which did not significantly affect respiratory decline. FVC%P positively correlated with HFMS and RULM in both subtypes.Conclusions.In SMA type 2 and non-ambulant type 3 lung function declines differently, with a common levelling after age 13 years. Lung and motor function correlated in both subtypes. Our data further defines the milder SMA phenotypes and provides novel information to benchmark the long-term efficacy of new treatments for SMA.

Please cite this article as: Trucco F, Rosenthal M, Bush A, Tan H-L, The McGill score as a screening test for obstructive sleep disordered breathing in children with co-morbidities, Sleep Medicine,

Introduction/Aims Mutations amenable to skipping of specific exons have been associated with different motor progression in Duchenne muscular dystrophy (DMD). Less is known about their association with long‐term respiratory function. In this study we investigated the features of respiratory progression in four DMD genotypes relevant in ongoing exon‐skipping therapeutic strategies. Methods This was a retrospective longitudinal study including DMD children followed by the UK NorthStar Network and international AFM Network centers (May 2003 to October 2020). We included boys amenable to skip exons 44, 45, 51, or 53, who were older than 5 years of age and ambulant at first recorded visit. Subjects who were corticosteroid‐naive or enrolled in interventional clinical trials were excluded. The progression of respiratory function (absolute forced vital capacity [FVC] and calculated as percent predicted [FVC%]) was compared across the four subgroups (skip44, skip45, skip51, skip53). Results We included 142 boys in the study. Mean (standard deviation) age at first visit was 8.6 (2.5) years. Median follow‐up was 3 (range, 0.3‐8.3) years. In skip45 and skip51, FVC% declined linearly from the first recorded visit. From the age of 9 years, FVC% declined linearly in all genotypes. Skip44 had the slowest (2.7%/year) and skip51 the fastest (5.9%/year) annual FVC% decline. The absolute FVC increased progressively in skip44, skip45, and skip51. In skip53, FVC started declining from 14 years of age. Discussion The progression of respiratory dysfunction follows different patterns for specific genotype categories. This information is valuable for prognosis and for the evaluation of exon‐skipping therapies.

Background:The decline of respiratory function in Duchenne muscular dystrophy (DMD) is associated with sleep disordered breathing (SDB) and alteration of nocturnal gas exchange, first manifesting as nocturnal hypoventilation (NH). However, the correlation between pulmonary function measured by spirometry (PFT) and the onset of SDB with or without NH is unclear.Aim:To identify the prevalence and features of SDB and to investigate the relationship between lung function determined by forced vital capacity (FVC) and sleep abnormalities in a large paediatric DMD population.Methods:Retrospective, single-center cohort study. FVC% predicted (FVC%) was calculated using predicted equations from the Global Lung Function Initiative. NH was defined by transcutaneous (tc) CO2 >50 mmHg for >25% of total sleep time (TST); borderline NH by a mean tcCO2 between 45-50mmHg or tcCO2>50mmHg for ≤25% of TST; Clinically meaningful obstructive sleep apnea (OSA) by obstructive Apnea–Hypopnea Index >5. The sensitivity, specificity, positive and negative predictive value of FVC<50% to indicate presence of nocturnal hypoventilation were calculated.Results:134 patients underwent 284 sleep studies and 1222 PFT. Mean (SD) age at first and last sleep study was 12.9 (2.7) and 14.3 (2.6) years. Borderline NH (n=31) was detected in both ambulant and early-non ambulant subjects, while 100% of NH cases (n=14) were non-ambulant. NH was detected in 4/14 patients despite an FVC>50%. Seventeen/26 patients with OSA presented with concomitant NH or borderline NH. FVC<50% was associated with NH indicating a sensitivity and specificity of 73% and 86%, respectively. Positive and negative predictive value were 32% and 97% respectively. PFT showed a non-linear, sudden FVC% decline in 18% of cases.Conclusions:FVC% <50 was associated with NH in close to a third of patients. CO2 elevation can be associated with obstructive/pseudo-obstructive events and was also observed in early non-ambulant cases or in the presence of FVC>50%. These results are relevant for the clinical management of SDB.

ObjectiveRapid implementation of home sleep studies during the first UK COVID-19 ‘lockdown’—completion rates, family feedback and factors that predict success.DesignWe included all patients who had a sleep study conducted at home instead of as inpatient from 30 March 2020 to 30 June 2020. Studies with less than 4 hours of data for analysis were defined ‘unsuccessful’.Results137 patients were included. 96 underwent home respiratory polygraphy (HRP), median age 5.5 years. 41 had oxycapnography (O2/CO2), median age 5 years. 56% HRP and 83% O2/CO2 were successful. A diagnosis of autism predicted a lower success rate (29%) as did age under 5 years.ConclusionSwitching studies rapidly from an inpatient to a home environment is possible, but there are several challenges that include a higher failure rate in younger children and those with neurodevelopmental disorders.

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