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Maturation of respiration in prematures and young infants. Neuropadiatriie 3: 294-304 (1972). Changes in respiratory patterns were studied in prematures from 30 wks. oonceptional age to 8 mons. past term and in full term infants between 40 wks. conceptional age (and 8 tnons. past term. Regular respiration was found to increase greatly after 36 wks. concepuional >aige, while very little periodic breathing or lapnea were seen after this age. Irregular respiration accounted foir 5O°/o of each 2-3 hr. record, until 8 months past term, when it was less. In addition, the maturaioional increase in regular respiration was concurrent with increases in the simultaneous presence of other indicators of nervous system inhibition, specifically, the absence of eye and body movements.It is argued that these maturational changes could not be adequately explained by current theories. A model of the development of respiratory control is proposed, based on the concept that the neuronal complexity of interaction at each brain level increases at the same time that the hierarchical locus of control moves upward and the interaction between all brain levels becomes more complex.

SUMMARY Suggestions that rapid eye movement (REM) sleep is ontogenetically primitive and observations of the behaviour of premature infants led to an attempt to trace the development of sleep in human infants from the premature period to three months after the expected date of delivery. Three sleep states were established, Quiet Sleep, Active Sleep (REM sleep), and Transitional Sleep, for the categorization of each 20 second interval of sleep during lengthy electroence‐phalographic and polygraphic recordings. Criteria regarding observed movements, eye movements, respiratory pattern, heart rate, chin electromyogram, and the EEG were used for a visual analysis of the tracings, with the specification that only four of the six criteria had to be met for classification of a 20 second interval as one sleep state or another. A second analysis, by means of computer sorting, was more rigid in that each 20 second interval had to meet all three criteria regarding observed movement, respiratory pattern, and eye movements. The other criteria were omitted. The second stricter analysis yielded a greater percentage of intervals that could not be called Active or Quiet Sleep and were, therefore, classified as Transitional Sleep, especially below 35 weeks gestational age. This finding/supports the concept that the sleep states of the more premature infants are less well defined and that the simultaneous occurrence of all the necessary criteria, particularly in Active 5jileep, is rarer than at later ages. Both analyses showed that the amount of Quiet Sleep increases as the infant matures, from 10 per cent at 31–32 weeks gestational age to roughly 50 per cent at 3 months past term. Conversely, Active Sleep decreases with maturation, the exact amount depending on the method of categorization. When the records were analysed visually, Active Sleep was found to constitute 68 per cent of the total sleep at 33–34 weeks gestational age and diminished to 36 per cent at 3 months; with computer sorting the comparable figures were 45 per cent and 25 per cent. Nevertheless, the figures for premature infants at term and 3 months were similar to those for full‐term infants at the same ages. The ill‐defined nature of the Active Sleep state in the early gestational ages and its subsequent delineation and diminution in amount amplify previous characterizations of this sleep state as a neurophysiologically primitive state and predecessor of the later stage during which dreaming occurs. RÉSUMÉ EAtats de sommeil chez les prématurés On a suggéré que le sommeil avec mouvements rapides des yeux (REM) est primitif ontogénétiquement; ceci, ajoutéà des observations du comportement des prématurés, nous a amenéà tenter de tracer le développement du sommeil chez les nouveaux‐nés humains depuis la période prématurée jusqu'à trois mois après la date prévue de l'accouchement. Trois états de sommeil ont étéétablis: Sommeil Tranquille, Sommeil Actif (Sommeil REM), et Sommeil Transitoire; pour la caractérisation de chacun d'entre eux on a étudié des intervalles de 20...

An autocorrelation technique was used to determine the periodicity underlying successive recurrences of specific sleep states (Quiet Sleep and Active Sleep). Groups of short (2-3 hr)polygraphic records and individual all-night recordings were analyzed. Active Sleep and Quiet Sleep periodicities at 32 weeks conceptional age were 12 min. At 36 weeks, 40 weeks (term), and 1, 3, and 8 months, the periodicity of both Active and Quiet Sleep was consistently in the 40-60 min range. At all ages, the cycle time of one state was consistently longer than the other. The appearance of clear periodicities underlying both states and the similarity of the periodicities found in 36 week records to those found in much older infants' records indicate that this biological rhythm is basic to human CNS functioning. The Index of Rhythmicity values in these records and other investigators' data suggest that this rhythm reaches a mature form by 36 weeks postconception.

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