Motility and arousal in near miss sudden infant death syndrome.

Developmental sleep patterns were compared in infants at known risk for "near-miss" sudden infant death syndrome and age-matched normal infants. Near-miss SIDS infants had significant differences suggestive of a temporary developmental delay. They retained rapid eye movement (REM) sleep at neonatal proportions, and stage 2 non-REM sleep appeared later. They also had a significantly increased apnea index. Twenty-four-hour recordings of sleep and respiratory patterns in near-miss SIDS infants from 3 weeks through 6 months of age showed a significant reduction in number of body movements in REM, non-REM, and total sleep time and in percentage of movement time at 3 weeks through 3 months of age. These findings can be used to address the role of arousal threshold in infants at risk for SIDS.