Sleep architecture in infants with spinal muscular atrophy type 1

Objective: Few reports on sleep patterns of patients with spinal muscular atrophy type 1 (SMA1) have been published and none on sleep microstructure. The aim of this study was to analyze sleep architecture and microstructure in a group of infants with SMA1, compared with age- and sex-matched controls. Methods: Twelve SMA1 patients (six males, mean age 5.9 months) and 10 controls (five males, mean age 4.8 months) underwent full polysomnography to evaluate their sleep architecture and microstructure by means of the cyclic alternating pattern (CAP). Results: Compared with control children, SMA1 patients showed increased sleep latency and apnea/hypopnea index. CAP analysis revealed a significant increase in the percentage of A1 CAP subtypes, a reduction of that of A3 subtypes and of A2 and A3 indexes (number/h), indicating a dysfunction of the arousal system in these patients. Conclusion: The results indicate the presence of an abnormality of sleep microstructure in SMA1 patients, characterized by a reduction of A2 and A3 CAP subtypes. We hypothesize that SMA1 patients have reduced arousability during non-rapid eye movement sleep, which could be interpreted as additional evidence of central nervous system involvement in this disease. © 2014 Elsevier B.V. All rights reserved.