97 Electroencephalographic Determination of Conceptional Age

Abstract

Order could not be made of the constantly changing electroencephalogram (EEG) in infants until its relation to the shifting states of sleep was understood. Recording of heart rate, respirations, eye movements, and bodily movements with EEGs makes it possible to define specific levels of states of sleep and arousal. Recordings of 2 ½ to 3 hours between feedings insures sampling of several sleep states. We have defined the following states of sleep: 1. Quiet Sleep—regular respiration and no eye or body movements; 2. Active Sleep—irregular respirations, eye movements and intermittent small movements of the body. 14 full term infants, 17 premature infants and 5 small for dates infants have been studied. The EEG patterns characteristic for Quiet Sleep and Active Sleep have been identified at 32, 36 and 40 weeks conceptional age. The EEG maturation of the premature infants was followed by matching their EEGs taken at 2 to 4-week intervals with premature infants born at various gestational ages and fullterm infants. Similarly, the small for dates babies' EEGs were matched with the EEGs of prematures compatible with their birth weights and with their reported gestational age. In 4 babies with birth weights of 1840, 1850, 1860 and 2030 gm, and reported gestational ages of 39 or more weeks, the EEG patterns in Active and Quiet Sleep matched those of fullterm infants. One infant with a birth weight of 1275, and a reported gestational age of 36 weeks, had EEG patterns expected for this gestational or conceptional age. The EEG can be used to identify the gestational or conceptional age of infants if specific states of sleep are identified during the EEG recording. (APS)