Development of the relationship between respiration rates and oxygenation in infants, and implications for cognitive competence

Date of Completion

January 2001


Psychology, Developmental|Psychology, Physiological




Four studies explore, from birth through the first year, the relationships between infants' respiration rate and blood oxygenation during the behavioral state of Quiet Sleep, and their scores on an assessment of mental and motor development. Results from the study described in Chapter 2 suggest a developmental advantage on the part of infants who breathe more slowly during Quiet Sleep between birth and 6 months; these infants had higher mental development scores when they reached 6 months and 1 year. Since the purpose of involuntary respiration during sleep is the maintenance of blood gas homeostasis, the results from this first study supported exploration of the relationship between respiration and blood oxygenation, as well as between oxygenation and mental and motor development. The results described in Chapter 3 support the use of pulse oximetry to record infant oxygenation, while Chapters 4 and 5 describe results from such recordings. The results described in Chapter 4 show that while respiration follows a slowing trend across development during Quiet Sleep from birth to 6 months, the average for blood oxygenation is a trend in the opposite direction. By 12 weeks, the strength of the inverse relationship between respiration and oxygenation in individuals is related to their mental development: infants who have slower respiration and higher oxygenation during Quiet Sleep also have higher mental development scores. Finally, the results from the study presented in Chapter 5 show that 6-month oxygenation recordings are associated with higher motor development scores, which are highly intercorrelated with mental development scores. ^ Sleep characteristics have long been known to have an influence on the development of waking behaviors and cognitive competence. Taken together, the studies presented here support the conclusion that the complex system of influences upon cognitive development through the first year should include respiratory rate and oxygenation during sleep. While research has focused upon the effects of respiratory disease upon development, the data presented here show for the first time that clinically normal variation in these physiologic variables may also be important predictors of development in normal, healthy infants from birth through at least the first postnatal year. ^