Polysomnography findings in pediatric spinal muscular atrophy types 1-3

Sleep disordered breathing (SDB) causes sleep disturbance and daytime symptoms in children with neuromuscular disorders. Although polysomnography (PSG) findings are well described in many neuromuscular disorders, there are limited reports from children with spinal muscular atrophy (SMA). The aim of this study was to determine the sleep architecture and breathing characteristics and non-invasive ventilation (NIV) use in our pediatric SMA cohort.

We conducted a cross-sectional cohort study of all children with SMA in Queensland, Australia. Children were Nusinersen naïve and had a full diagnostic PSG in 2018. The PSG was scored and reported by a single pediatric sleep physician in accordance with American Academy of Sleep Medicine Criteria (2012).

In sum, 31 children (18 males), Six with Type 1, 16 with Type 2 and nine with Type 3, aged 0.25-18.8 years old were studied. SDB was seen in each SMA type and was more pronounced during rapid eye movement (REM) sleep. Type 1: all patients exhibited SDB, three (50%) with central sleep apnea (CSA) and three (50%) with mixed disease. Type 2: five (31%) had CSA, one (6%) mixed disease, seven (44%) had early SDB and three (19%) had normal sleep breathing. Type 3: four (44%) children had CSA and five had early SDB. No child exhibited obstructive sleep apnea (OSA) alone.Starting NIV significantly reduced mean total PSG Apnea-Hypopnea Index (AHI) scores from a grouped mean of 15.4 events per hour (SD ± 14.6; 95% CI 6.1-24.7) to 4.0 events per hour (SD ± 4.2, 95% CI 1.2-6.5, p = 0.01).

SDB is common in children with SMA and was present in all types. CSA was the most common disorder; with mixed SDB also present in type 1 and 2 SMA.