Children with spinal muscular atrophy (SMA) type 1 showed abnormal polysomnography parameters and needed ventilation despite nusinersen treatment, according to a new study published in the journal Pediatric Pulmonology. This suggests these patients should regularly be monitored with polysomnography.

“Understanding the respiratory disease trajectory of children undergoing treatment with nusinersen will inform decision-making regarding optimal timing of ventilatory support initiation,” Lena Xiao, MD, and colleagues wrote.

Even though nusinersen treatment improves disease trajectory in patients with SMA, objective data on the outcomes of polysomnography, the relationship between motor scores and respiratory parameters, the dependence on respiratory assistance, and healthcare utilization in patients with SMA treated with nusinersen were not fully clear.

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Here, a team of researchers from Canada conducted a retrospective observational study in 11 children with SMA type 1 being treated with nusinersen between October 2016 and February 2021.

The children were diagnosed with the disease between ages 2.8 and 5 months and had a diagnostic polysomnogram after the initiation of nusinersen treatment at a median of 9.4 months. Nusinersen was initiated when children were between 3.4 and 7.6 months old, at which time 8 of them had respiratory symptoms. 

The polysomnography data showed a median central apnea-hypopnea index of 4.1 and an obstructive apnea-hypopnea index of 2.2 events per hour. 

The researchers reported an inverse relationship between the patients’ motor scores and their central apnea-hypopnea indices. “All children required ventilatory support at the end of the study period,” they said.

SMA type 1 is the most severe and most common type of SMA in which symptoms usually appear within the first 6 months of life. They include low muscle tone, and breathing and swallowing difficulties. Patients need respiratory assistance to help with breathing difficulties. 


Xiao L, Chiang J, Castro-Codesal M, et al. Respiratory characteristics in children with spinal muscular atrophy type 1 receiving nusinersen. Pediatr Pulmonol. Published online October 3, 2022. doi:10.1002/ppul.26173