Early Sleep Patterns of Premature Infants Are Differentially Related to Later Developmental Disabilities

Abstract

The sleep states and wakefulness of 100 prematurely born infants were recorded for 24-hour periods in the home when the infants were 1, 2, 3, 4, and 5 weeks postterm. Sleep monitoring was accomplished using the Home Monitoring System: analog signals from respiration and body movement are recorded while the infant is on a pressure sensitive crib pad. The signals are computer scored and visually edited in 30-second epochs for quiet sleep, active-quiet transitional sleep, active sleep, sleep-wake transition, and waking. At 3 years of age, the babies were classified into one of four groups: those who were normal and those with neurodevelopmental, physical, or minor mental problems. Assignment to groups was based on Bayley Scales administered at one year, biannual questionnaires throughout the 3 years, and a home visit at 3 years. Individual state measures differentiated the abnormal outcome groups from the normal one, and profiles of state parameters were unique for each outcome group. Profile measures gave greater prediction for individuals than did clinical risk factors. The findings indicate that specific forms of later disabilities in premature infants are expressed in differential organization of sleep states during the early postterm period.