Sleep-disordered breathing in spinal muscular atrophy types 1 and 2

Objective: Our aim was to assess the respiratory pattern during sleep in patients affected by spinal muscular atrophy types 1 and 2 and to compare their apnea-hypopnea indices with those of controls. Design: All consecutively referred patients underwent polysomnography. Sleep stages were defined as either wake, quiet sleep (OS), or active sleep (AS). As measures of thoracoabdominal coordination, we measured: phase angle during QS and AS (Ph Angle OS and AS), phase relation during inspiration and expiration during QS and AS: (Ph RIB QS, Ph RIB AS, Ph REB QS; Ph REB AS) and the apnea-hypopnea index. Results: The 14 consecutively referred infants and small children (age, 11.7 +/- 11.4 mos) showed a higher apnea-hypopnea index (P < 0.001), Ph Angle QS (P < 0.001), Ph Angle AS (P < 0.001), Ph RIB QS (P < 0.001), Ph RIB AS (P < 0.001), Ph REB OS (P < 0.001), and Ph REB AS (P < 0.001) compared with 28 healthy controls (age, 10.1 +/- 8.9 mos). Conclusions: Patients affected by types 1 and 2 spinal muscular atrophy had significantly higher apnea-hypopnea indices than controls. Thoracoabdominal asynchrony was present during the inspiratory and expiratory phases in both quiet and active sleep. Measures of thoracoabdominal coordination may be useful for the evaluation and monitoring of therapeutic interventions for these patients.