Effect of Lung Volume Recruitment on Pulmonary Function in Progressive Childhood-Onset Neuromuscular Disease: A Systematic Review

Performance of upper limb entry item to predict forced vital capacity in dysferlin-deficient limb girdle muscular dystrophy

Dysferlin-deficient limb girdle muscular dystrophy (LGMD R2), also referred to as dysferlinopathy, can be associated with respiratory muscle weakness as the disease progresses. Clinical practice guidelines recommend biennial lung function assessments in patients with dysferlinopathy to screen for respiratory impairment. However, lack of universal access to spirometry equipment and trained specialists makes regular monitoring challenging. This study investigated the use of the Performance of Upper Limb (PUL) clinical scale entry item as a low-cost screening tool to identify patients with dysferlinopathy at risk of respiratory impairment. Using data from 193 patients from the Jain Foundation's International Clinical Outcomes Study, modelling identified a significant positive relationship between the PUL entry item and forced vital capacity (FVC). Eighty-eight percent of patients with the lowest PUL entry item score of 1 presented with FVC % predicted values of <60 %, suggestive of respiratory impairment. By contrast, only 10 % of the remainder of the cohort (PUL entry item of 2 or more) had an FVC of <60 %. This relationship also held true when accounting for ambulatory status, age, and sex as possible confounding factors. In summary, our results suggest that the PUL entry item could be implemented in clinical practice to screen for respiratory impairment where spirometry is not readily available.

Understanding the experiences of lung volume recruitment among boys with Duchenne muscular dystrophy: A multicenter qualitative study

BACKGROUND

Despite recommendations for regular lung volume recruitment (LVR) use in clinical practice guidelines for children with neuromuscular disease, adherence to LVR is poor. We aimed to describe the experience of LVR by boys with Duchenne muscular dystrophy (DMD), their families, and healthcare providers (HCPs), as well as to identify the barriers and facilitators to LVR use.

METHODS

This multicenter, qualitative study evaluated boys with DMD (n = 11) who used twice-daily LVR as part of a randomized controlled trial, as well as their parents (n = 11), and HCPs involved in the clinical use of LVR (n = 9). Semistructured interviews were conducted to identify participants' understanding of LVR therapy and their beliefs, barriers and facilitators to its use. Thematic analysis was conducted using an inductive approach. A subanalysis compared adherent and nonadherent children.

RESULTS

Seven themes were identified related to participants' beliefs and experiences with LVR: emotional impact, adaptation to LVR, perceived benefits of LVR, routine, family engagement, clinical resources, and equipment-related factors. Strategies to improve adherence were also identified, including education, reinforcement and demonstration of LVR benefit, as well as clinician support. There were no thematic differences between adherent and nonadherent children.

DISCUSSION

Despite the benefits of LVR and positive experiences with it by many families, there remain barriers to adherence to treatment. HCPs need to balance the need for early introduction to give families time to adapt to LVR while ensuring that the benefit of LVR outweighs the burden. Clinician support is important for family engagement.

Combination Therapy with Nusinersen and Onasemnogene Abeparvovec-xioi in Spinal Muscular Atrophy Type I

Background: Spinal muscular atrophy (SMA) is a neuromuscular progressive disease, characterized by decreased amounts of survival motor neuron (SMN) protein, due to an autosomal recessive genetic defect. Despite recent research, there is still no cure. Nusinersen, an antisense oligonucleotide acting on the SMN2 gene, is intrathecally administered all life long, while onasemnogene abeparvovec-xioi, a gene therapy, is administered intravenously only once. Both therapies have proven efficacy, with best outcomes obtained when administered presymptomatically. In recent years, disease-modifying therapies such as nusinersen and onasemnogene abeparvovec-xioi have changed the natural history of SMA. Methods: We observed seven SMA type I patients, who received both therapies. We compared their motor function trajectories, ventilation hours and cough assist sessions to a control group of patients who received one therapy, in order to investigate whether combination therapy may be more effective than a single intervention alone. Results: Patients who received both therapies, compared to the monotherapy cohort, had the same motor function trajectory. Moreover, it was observed that the evolution of motor function was better in the 6 months following the first therapy than in the first 6 months after adding the second treatment. Conclusions: Our results suggest that early treatment is more important than combined therapy.