In the first study, researchers evaluated 256 full-term and preterm infants at one year of age with a standardized test that measured physical and mental development. The infants were part of the multi-center Collaborative Home Infant Monitoring Evaluation (CHIME) study. The CHIME study sought to identify factors that could put infants at risk for sudden infant death syndrome (SIDS). Participants included healthy infants as well as those at increased risk of SIDS because they had a history of prematurity, a life-threatening event during sleep, or a sibling who had died from SIDS. The infants' breathing, heart rates, and blood oxygen levels were monitored electronically at home for the first 4-6 months of age.

The researchers found that infants who totaled more than five episodes of abnormally slowed heart rate or apnea during the period they were monitored scored lower on the mental development test at one year of age than did infants who experienced fewer or no such episodes. The episodes were often associated with drops in oxygen levels. The lower mental development scores persisted even after data were adjusted to correct for other factors known to affect mental development in preterm infants. The study also found that full-term infants who experienced the abnormal episodes scored lower on the tests than did other full term infants, according to Hunt, the lead author, who conducted the research while at the Medical College of Ohio in Toledo.

The second study involved 205 children at 5 years of age. Researchers at Boston University School of Medicine compared neurocognitive function and behavior of 61 children with SDB symptoms to 144 children without symptoms. Symptoms of SDB, as reported by parents, included frequent snoring; heavy, loud, or noisy breathing duri
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7-Oct-2004