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Objective. To test the hypothesis that exposure to alcohol in breast milk affects infants' sleep and activity levels in the short term.Methods. Thirteen lactating women and their infants were tested on 2 days, separated by an interval of 1 week. On each testing day, the mother expressed 100 mL of milk, while a small, computerized movement detector called an actigraph was placed on the infant's left leg to monitor sleep and activity patterning. After the actigraph had been in place for ∼15 minutes, the infants ingested their mother's breast milk flavored with alcohol (32 mg) on one testing day and breast milk alone on the other. The infants' behaviors were monitored for the next 3.5 hours.Results. The infants spent significantly less time sleeping during the 3.5 hours after consuming the alcohol-flavored milk (78.2 minutes compared with 56.8 minutes after feeding alcohol in breast milk). This reduction was apparently attributable to a shortening in the longest sleeping bout (34.5 compared with 56.7 minutes for sleeping after breast milk alone) and the amount of time spent in active sleep (25.8 minutes compared with 44.2 minutes after breast milk alone); the decrease in active sleep was observed in all but 2 of the 13 infants tested.Conclusions. Although the mechanisms underlying the reduction in sleep remain to be elucidated, this study shows that short-term exposure to small amounts of alcohol in breast milk produces distinctive changes in the infant's sleep–wake patterning.

Postural Differences in Cardiac Dynamics during Quiet and Active Sleep in Low Birth Weight Infants † 74

Objectives: To examine the maturational changes in cardiac interbeat interval variability during quiet (QS) and active sleep (AS) in low birth weight (LBW) infants.

Objectives: The objectives of this study were to determine the effects of body position (supine vs prone) on cardiorespiratory activity during quiet and active sleep in growing low birth weight (LBW) infants.

To evaluate the effect of human milk on CNS functional development, we compared HR (RR intervals) an its spontaneous variability (HRV): high-, mid-, low-frequency bands as a function of sleep-wake states in HM and FF premature infants studied at 4 months. All were born AGAs and weighed 1000-1750 g. They were “healthy” and fully fed by 12 days of age, groups were matched by BW and GA. HM fed infants (n=16) showed longer RR intervals in all sleep-wake states, active sleep (AS), quiet sleep (QS), and wakefulness (W) relative to FF (n=20). HM fed presented higher HRV amplitude (milliseconds) relative to FF. Longer RR intervals and higher HRV amplitudes in all sleep states in BF infants, indicates a more mature pattern of CNS functional development. This phenomenon is observed at all frequency suggesting an effect in both sympathetic and parasympathetic autonomic nervous systems. We conclude that human milk favors the progression of CNS functional maturation. (Funded by USA NIH 22380 and Fondecyt 1930820). Table

It was investigated how postnatal development of cardiac control can be described by linear methods and by new application of non-linear methods of time series analysis.

The development of pathologic apnea, respiratory pauses, and periodic respiration was examined in 71 high-risk preterm infants, observed weekly. Respiration was recorded every 10 seconds; apnea length and periodic respiration were scored from a tape. All subjects had respiratory pauses, and 36 had pathologic apnea. The mean length of respiratory pauses was longer in quiet sleep, and the frequency of respiratory pauses was greater in active sleep. The mean length of respiratory pauses and probability of pathologic apnea in both sleep states and frequency of pauses in quiet sleep decreased with age. Sex, theophylline treatment, race, and length of mechanical ventilation affected the developmental trajectories of some apnea variables. Apnea in preterm infants cannot be considered a unitary phenomenon.

Summary During sleep, of ventilated newborns and young infants, spontaneous respiratory movements may occur, unrelated to the ventilation impulsions. The respiratory pattern is then classified as « active . On the contrary, the respiratory pattern is classified as « passive , when all respiratory movements are related to the ventilation insufflation. The factors which influence the dependence on the ventilator are studied in a group of 20 newborn and young infants. Prematurity, some biological data such as hyperoxia, hypocapnia, seem to favor this dependence. A rapid rate of ventilation (superior to 30/minute) is rarely related to an active respiration ; a slow rate of ventilation seems favor this respiratory pattern. It is clear that adaptation to artificial ventilation is better during quiet sleep than during active sleep. Some physiopathological considerations are developed.

Using an automated procedure for sleep recording, the sleep of 20 healthy full-term infants was monitored for 24-hour periods in the home once a week during the 1st to 5th weeks of life. A pressure-sensitive mattress, placed in the infant's crib, was used for recording analog signals from respiration and body movements. The motility signals were recorded on a single channel of a small Oxford 24-hour recorder. In the laboratory, the recorded signals were processed and computer scored for states using a pattern recognition program which employs a template matching procedure. For each 30-s epoch, the state was scored as either active sleep (AS), quiet sleep (QS), active-quiet transitional sleep (AQ), sleep-wake transition (TR), or wakefulness (WA). Significant individual differences were found for each state parameter. Significant developmental trends over weeks were found: AS decreased and QS increased as a function of changing bout lengths in these states. The number of state changes per hour was constant over the 5 weeks. State patterns obtained by this automated recording procedure did not differ from those obtained by direct behavioral observations. Diurnal differences in the state distributions for 12-hour day and night periods were found, with more wakefulness occurring during the daytime. The infants showed a significant linear increase in wakefulness during the daytime, while wakefulness during the night remained relatively stable across weeks. Even during periods when they were in the crib, the infants spent significantly more time awake during the daytime. These highly organized characteristics of infants' states were apparent from the earliest postnatal age despite variations in activities that typically occur in the home. The findings confirm the validity and potential usefulness of the sensor mattress recording procedure.

The aim of this study was to investigate the characteristics of mouth movements during behavioural states 1F (quiet sleep) and 2F (active sleep) in the near term human fetus. Thirty-six women participated. Fetal heart rate and fetal movements were recorded for 2 hours continuously. Videotapes with enclosed periods 1F and 2F were replayed to record fetal mouth movements in detail. During 1F, regular mouthing movements dominated (present in 74%), while jaw opening, yawn and grimace were only observed in 5 to 16% of the recordings. Tongue protrusion was not observed in 1F. In all 2F periods jaw opening was present (100%), while tongue protrusion, yawn and grimace were also frequently observed. Regular mouthing was observed in 2F in only two fetuses. For regular mouthing and sucking, onset-to-onset intervals of clusters, cluster duration, and number and frequency of movements within clusters were calculated. In all aspects the differences between these two types of movement were statistically significant. Within the clusters of regular mouthing a decline in the mouthing frequency was found. The data on fetal regular mouthing correspond with observations in the neonate.

1. 1. In appropriate surroundings young caimans (Caiman sclerops) exhibited behavioral sleep and shifted from alertness to sleep and vice versa within minutes. 2. 2. In all behavioral states there was beta-range EEG activity (20–22 c/sec; 5–10 μV). 3. 3. Alert animals showed dominant activity in alpha range (10–16 c/sec; 20–70 μV). 4. 4. In behavioral sleep dominant activity was in delta range (0.8–2.2 c/sec; 50–130 μV). 5. 5. In behavioral sleep, heart and respiratory rates and EMG activity were usually reduced. 6. 6. Active sleep was not seen, but designating periods of EEG high voltage, slow waves as “slow-wave sleep” seemed justified.

Summary Polygraphic recordings were used to study respiration and night sleep in 26 such children. These children, who were « at riskfor sudden and unexpected death, could be divided into two groups : near-miss (NM) (15 cases), and those who were brothers, sisters, or cousins of a child who had died suddenly and unexpectedly (8 cases), or had periodic respiration (RP) (3 cases). No significant differences were found between the groups in respiratory tests, except for a significantly lower RP rate in the NM group and an increase in number of isolated pauses. Sleep organization was similar in both groups, though there was a significantly higher rate of active sleep (SA) in the NM group more than 2 months old. The highest respiratory indices were noted in the extreme cases of a non-NM group (including 2 brothers of infants who had died unexpectedly). Treatment with Diphemanil methylsulfate (Prantal) reduced the number of SA and respiratory pauses of the NM infants less than 2 months old.

Most of the phasically occurring periods of rapid eye movements (REMs) of active sleep are accompanied by enhanced suppression of somatomotor activity; however, during some of the REM episodes there are muscular twitches and jerks. The membrane potential changes underlying these motor processes were examined by recording intracellularly from lumbar motoneurons in cats that were undrugged, unanesthetized and normally respiring. Summated hyperpolarizing potentials were evident during REM episodes in conjunction with a decrease in motoneuron excitability. During other episodes of REMs there occurred summated depolarizing potentials which occasionally produced action potentials. These depolarizing events were in most cases preceded by a brief period of hyperpolarization. Thus, it appears that there is inhibitory input to lumbar motoneurons during all REM periods of active sleep; in some episodes the simulataneous coactivation of excitatory input leads to depolarization of the membrane and action potential generation.

An automatic analysis of movements detected by the static charge sensitive bed (SCSB) was developed for the study of sleep and breathing disturbances (apnoeas) during sleep. Three signals on separate channels are analysed: one relating to body movements, one to respiratory movements and one to movements of the heart (ballistocardiogram). The analysis can be made on-line or from tape recordings. With a portable microcomputer the records and analyses can be carried out at home or on the ward without any professional personnel. The system can be preset to start and to end recording automatically. The subject just has to lie down. The automatic analysis of body movements on the basis of their amplitude and duration yields criteria for scoring of sleep into 'wakefulness,' 'quiet sleep' and 'active sleep.' A simple hypnogram and the statistics on the durations and proportions of these stages are printed. Simultaneous SCSB and polygraphic records were made on healthy subjects. Comparison of the two types of sleep scoring showed that the results agreed during 81% of the time. The amplitudes of the movements detected on the 3 channels are integrated in epochs and the results of this analysis are represented in a compressed graphic form which allows easy visualization of the overnight records. The pattern of 'respiratory movements' reveals whether the breathing has been regular, irregular or periodic.

In the early premature, the EEG is mostly discontinuous. Discontinuity becomes limited to quiet sleep periods by the 36th week of conceptional age (CA). Temporal theta bursts, or the "sawtooth" pattern, come and go between 27 and 32 weeks' CA. Delta brushes attain their maximum about 32 to 34 weeks' CA and disappear about 40 to 44 weeks' CA. Frontal sharp transients have their peak occurrence at 35 or 36 weeks' CA and are still present at 44 to 48 weeks' CA. The background activity is essentially symmetric but transient patterns are less symmetric and frequently asynchronous. Lack of variability in the record is abnormal after 34 weeks' CA. Responses to isolated light flashes are prominent from very early prematurity through full-term. On the other hand, photic driving is frequent in early prematures (29-32 weeks' CA), but it then declines and is difficult to detect in the full-term neonate. Nonspecific responses to stimulation occur from early prematurity. Sleep--waking cycles are clearly discernible about 37 weeks' CA. Active sleep (rapid eye movement) goes from 60% at 34 weeks' CA to the 25% of adulthood at about 8 months of age. The EEG of the full-term newborn has four patterns, corresponding to three states: the low voltage irregular for wakefulness, high voltage slow and tracé alternant for quiet sleep, and the mixed for either wakefulness or active sleep.

Spontaneous startles have been reported to occur most frequently in quiet sleep, less frequently in active sleep and drowse, and relatively nonexistent in the waking states. These findings may be a result of a focus on infants whose prenatal histories reflect a restricted range of the conditions to which normal newborns are exposed. The present study examined the spontaneous startle behavior of 30 newborn infants characterized by high numbers of obstetric complications and by indicators of prenatal malnutrition, but within the range of normal, healthy newborns. In this sample, startles were not limited to the sleep and drowse states. Because individual differences in a number of neonatal behaviors have been related to autonomic nervous system (ANS) functioning, the different pattern of spontaneous startles observed in this sample may be related to the functional integrity of this system.

Changes in forehead skin blood flow during active and quiet sleep were determined in 16 healthy neonates using a recently developed semi-conductor laser Doppler flow meter with-out light conducting fibres. Measurements were carried out at a postnatal age varying from 5 hours to 7 days. The two sleep states could be distinguished in 17 recordings. The mean skin blood flow values during active sleep were significantly higher (p less than 0.01) than those during quiet sleep, the mean increase being 28.1%. The variability of the flow signal, expressed as the coefficient of variation, changed significantly from 23.1% during active sleep to 18.2% during quiet sleep.

We examined 55 infants on 119 occasions, from birth to 6 months, to obtain normal data and to establish guidelines for the management of oxygen-dependent infants with chronic lung disease. Transcutaneous oxygen tension (tcPo2) and saturation (tcSao2) were monitored during four states: awake, feeding, quiet sleep, and active sleep. Lowest values (mean +/- SD) for tcSao2 were recorded in all states during the first week of life: awake 96.2% +/- 2.6%, feeding 91.2% +/- 3.7%, quiet sleep 93.2% +/- 2.9%, and active sleep 92.1% +/- 2.9%. After the first week the results were affected by state rather than age, with differences observed between awake and feeding (P less than 0.0001), awake and asleep (P less than 0.00001), and quiet sleep and active sleep (P less than 0.001). The findings for tcPo2 were less consistent and probably affected by the characteristics of skin. In the first week, values were as follows: awake 83.5 +/- 10.1 mm Hg, feeding 73.4 +/- 10.1 mm Hg, quiet sleep 78.5 +/- 10.9 mm Hg, and active sleep 73.4 +/- 11.4 mm Hg. Subsequently, only the state effect remained, and significant differences existed between awake and feeding (P less than 0.0001) and awake and asleep (P less than 0.00001). We conclude that transcutaneous blood gas measurements are affected by state of the infant.

The sleep-wake pattern of healthy preterm infants under two different schedules of routine procedures was studied by 4-day polygraphic-recording. Group-I experienced the usual routine care conditions, Group-II remained less disturbed by means of time-coordination of the procedures. Group-II-infants were less awake, showed a higher percentage of active sleep and the undisturbed phases of active and quiet sleep were longer than in Group-I-infants. Routine procedures left Group-II-infants more often in an unchanged state than Group-I-infants, the latter exhibiting an arousal reaction more frequently. The unknown effect of sleep disturbances in preterm-infants demands a reduction and coordination of routine procedures as far as possible.

A distinctive pattern called premature temporal theta (PTθ) was studied in 436 infants, ranging in age from 24 to 46 weeks. The pattern is seen in early prematurity, maximizes at 29–31 weeks and then diminishes and disappears near term. Usually the pattern is found independently on both temporal areas, but with a right-sided preference. Patients without PTθ or with a significantly low amount had either neurological or non-neurological (medical) conditions. With age there is a tendency for an increase in frequency and a decrease in amplitude. Five different peaks in the amount of this pattern are seen at approximately every month. Unilateral PTθ tends to be seen in older babies, more often on the right side and with an abnormal EEG. An abnormal EEG is usually associated with a delay in both the appearance and disappearance of this wave form. PTθ is also associated mainly with REM or active sleep. A polynomial rather than an exponential or power function best describes these data with changes of age. PTθ may arise from the inferior temporal gyrus and/or especially the transverse gyrus.

This study was carried out on 57 normal infants: 22 full-term newborns, examined in the hospital laboratory, and 35 2-18-wk-old infants, examined in two resident nurseries. Polygraphic records, including 1-3 complete sleep cycles, were performed during the morning. The tracings were analyzed by 20-sec epochs. Three to 10% of active sleep states (AS) and 0.8-4% of quiet sleep states (QS) included greater than or equal to 3 sec respiratory pauses. There were minimal, non-significant differences between respiratory frequencies (RF) in total and in no-pause tracings. Our results confirmed that RF was higher in AS in all ages, when compared with QS (P less than 0.02). During the transition (TS) from one to another well-defined sleep state, the respiratory rate showed an intermediate level (AS greater than TS greater than QS): the transition from AS to QS showed progressive slowing of RF, while the transition from QS to AS occurred abruptly, with sudden acceleration of RF. There was a significant slowing of RF during the couse of QS, while the RF in AS was more variable without significant differences between the beginning, the middle and the end of AS state. In this material RF was higher in 2-5-wk and 6-10-wk age groups, compared to newborns and to 11-18-wk-old infants. At all ages, there was a high degree of correlation (P less than 0.01) between RF found in different sleep states for given individuals: some infants breathed more rapidly and other more slowly in all sleep states. A review of the literature showed that the differences between normal RF.

We named transient activity recorded from midline frontal area 'Fz theta/alpha bursts' and investigated their characteristics and clinical significance. Polygraphic examinations were carried out on a total of 155 infants from 35 to 46 weeks of postconceptional age. Fz theta/alpha bursts were recorded in 40 (36%) of 111 infants without neurological problems. Especially these bursts were found in 33 (55%) of 60 infants at 38-42 weeks of postconceptional age. They occurred in pre-term as well as in full-term newborns. Three hundred and sixty-two Fz theta/alpha bursts were recorded from 40 infants without neurological problems. Ninety-one percent of them were found in quiet sleep, and others in indeterminate sleep. None of them were recorded in active sleep. Fz theta/alpha bursts did not occur synchronously with frontal or temporal sharp transients. The incidence of Fz theta/alpha bursts in infants with abnormal neurological signs was lower than in control infants (4/44 vs. 37/73; P less than 0.01). The bursts were not detected in EEGs with moderately or more severely depressed background. One hundred and thirty-five infants were followed up for more than 12 months. Fz theta/alpha bursts were recorded in 38 (35%) of 109 infants with normal outcome, and in only 1 (4%) of 26 infants with abnormal outcome. Our results indicated that Fz theta/alpha bursts were of normal EEG components without pathological significance.

Kittens at 10, 20, and 40 days of age were made intermittently hypoxic in 10 or 7% oxygen chambers for either 3 or 8 days. Respiration, EKG, EEG, and neck and eye movements were recorded during hypoxia. Compared to 21% oxygen controls, hypoxic kittens had fewer and shorter epochs of active sleep, and longer epochs of quiet sleep. Some hypoxic kittens exhibited slow and labored respiration during quiet sleep and transitional epochs, which reversed during active sleep. Kittens that showed most pronounced respiratory changes or died had less active sleep than kittens that compensated adequately and survived. These results suggest that active sleep may be important for stimulation of respiration during infancy. Suppression of active sleep, augmentation of quiet sleep, or other disturbances to normal sleep-waking patterns during hypoxia, may increase the risk for hypoxic respiratory depression and death.

Long daytime EEG-polygraph recordings were obtained at 36, 38, and 40 weeks conceptional age, weekly thereafter for 12 weeks, and at 26 and 52 weeks post term in 5 infants born at 30–33 weeks gestation. The babies have developed normally for 18–38 months. All 74 EEGs were normal for age. Derived data were compared with similar data from 17 normal full-term infants. The trace alternant pattern disappeared earlier in the premature than in the control group (mean ages 21.4 vs. 33.4 days post term; P < 0.01). Rolandic sleep spindles appeared earlier in the premature group (mean ages 35.4 vs. 43.8 days; P < 0.05). There were no age differences between the groups with respect to (1) the shift from active sleep onset to quiet sleep onset, (2) active sleep and quiet sleep as percentages of total sleep time, or (3) disappearance of frontal sharp waves. Overall attainment of ‘infantile’ EEG sleep patterns occurred at 35–60 days post term (mean 43.8) for the premature group and at 27–66 days (mean 46.4) for the full-term group (difference not significant). These findings indicate that no significant errors will be made in clinical practice by applying the same maturational criteria to the post-term EEGs of prematures as to the EEGs of full-term infants.

Multiple-unit activity was recorded from residual neurons in the gigantocellular field (FTG) of the pontine reticular formation in young rats after extensive contralateral FTG lesions. Epochs of normal appearing active sleep continued to occur but were characterized by abnormally low FTG neuronal firing rates. In contrast, during epochs of active sleep with exaggerated motility, the FTG discharge frequencies approximated those observed during active wakefulness.

• The electrically elicited blink reflex (BR) was evaluated in 80 normal neonates and 12 neonates with neurologic abnormalities. In normal subjects, R1 and bilateral R2 responses were elicited both while awake and in a quiet sleep state. Whereas the R1 response was consistently elicited in the active sleep state, as well as while awake, the ipsilateral R2 response was markedly suppressed and the contralateral R2 response was almost absent. The BR in neonates with neurologic abnormalities showed the following variable results: normal, prolonged latency, or suppressed response at initial recording. Abnormal BRs were detected in most neonates with respiratory or sucking problems. While neonates in whom a suppressed response or prolonged latency persisted for over three months had a poor prognosis, those with normal BRs or early correction of the BR abnormality had almost normal development. The BR appears to be useful not only to evaluate brain-stem function in the neonatal period but also to predict subsequent outcome.

This study is aimed at assessing untoward effects of physiologic jaundice on apparently well babies 1 month after jaundice was cleared. Two measures of neonatal physiologic jaundice were correlated with 15 behavioral measures, taken from 37 low-risk Black preterm infants tested at expected date of birth. The behavioral measures evaluated visual function, motor function, affect, and central nervous system integrity. Higher bilirubin values were associated with poorer visual function, quicker cessation of distress in response to social intervention, and longer periods of active sleep. The pattern of the results was similar when the effects of health risks other than jaundice were statistically controlled. The results support the hypothesis that even physiologic jaundice is associated with individual differences in the behavioral outcome of preterm infants.

Home recorded videotapes of all-night sleep were obtained for 32 2-month-old and 38 9-month-old infants. Changes in the proportionate amounts of time spent in active sleep, quiet sleep, wakefulness, and out of the crib were significantly related to age. Sleep-cycle lengths did not change with age, but the state relationships within sleep cycles showed maturational effects. Temporal patterning of sleep states was present by 9 months. Time-lapse video recording of sleep provides an opportunity for nonobtrusive monitoring of sleep longitudinally in normal and pathological infants.

Sixty polygraphic records were made: 16 in newborns and 44 in infants aged from 1 to 25 weeks. 1. 1. The stage of development of the central nervous system is better defined by criteria such as spindle maturation or skin potential response (SPR) distribution according to stages of sleep, than by chronological age; SPR prevalence during “quiet” sleep (“adult” distribution) is not apparent before 12 weeks of age. Classification according to the presence or absence of spindles during quiet sleep shows that: (a) in the group without spindles (1–6 weeks old), SPRs are more numerous during “active” sleep than in newborns; (b) in the group with sporadic spindles (3–11 weeks old) the SPR mean frequency is about the same in “active” and in “quiet” sleep; (c) SPR prevalence during “quiet” NREM sleep (“adult” distribution) appears clearly in the group with spindles present throughout “quiet” sleep (10–25 weeks old). On the contrary, no relation was found between SPR distribution and the mode of onset of sleep. 2. 2. “Active” REM sleep seems to mature earlier than “quiet” NREM sleep. Our studies show that, in active sleep, SPRs increase significantly during the 1st month of life; after that, their frequency does not change any more. On the contrary, SPRs in quiet sleep increase throughout the whole period studied. This increase is also parallel to sleep spindle maturation. 3. 3. During transitional periods SPR frequency is between that of active and that of quiet sleep. There is no significant difference between SPR frequency during the first and the second sleep cycles.

The effects of ad libitum access to a pacifier on the behavioral state and motor activity of preterm infants have been compared with those observed in full-term neonates. Regardless of maturity, nonnutritive sucking (NNS) decreases the amount of time spent in active states and increases that spent in quiescent states, lengthens the longest state bout, and decreases the frequency of state transitions. NNS also reduces overall motor activity as well as that during Active Sleep. Provided such ad libitum sucking opportunity, preterm infants thus appear to derive no less benefit from NNS than do term neonates. This result contrasts with an earlier finding that preterms are less soothed by NNA than are term infants.

A procedure is described for continuous monitoring of sleep states and wakefulness of infants in the home, with no intervention required for the recording. The infant's motility patterns produced by respiration and body movements are recorded from a pressure-sensitive mattress in the crib onto a single channel of a small 24-h analog recorder. In this way, signals produced by the naturally occurring states are obtained during all portions of the day when the infant is in the crib. Later, in the laboratory, the signals are analyzed by computer, using a pattern recognition program with a template-matching procedure that scores the data every 30 s for Active Sleep, Quiet Sleep, Active-Quiet Transition Sleep, Sleep-Wake Transition, and Wakefulness. Computer-scored records for 2-h recordings of 10 infants were compared with direct behavioral state observations that were made at the same time as the mattress recording. The results confirmed the validity of the computer scoring procedure, both when templates were obtained from each infant's observation and when a standard set of templates from one infant were used for scoring the data from all other subjects.

Summary In 10 artificially ventilated babies, we found significant relationships between the degree of dependence on the ventilator and sleep states. Respiration was more active, more autonomous in active sleep (AS), and on the contrary more passive, more dependent on the ventilator in quiet sleep (QS). In 3 babies, continuous recording of transcutaneous PtcO2 showed a higher level during wakefulness and AS with active respiration, compared to QS with passive respiration.

The human neonate normally spends nearly 2/3 of its time asleep, and of this time ca 2/3 are spent in active sleep (AS). The present study was designed to investigate the temporal organisation and behavioural composition of this state. The hypothesis was put forward that the amount of facial behaviour that could be observed at any point in time during AS was representative of the neonate's general state of activation, and that the degree of activation varied with cyclic regularity. To test this, the facial behaviour of 8 normal neonates was filmed, and the films observed repeatedly. All activity occurring in three facial regions was registered and the resultant behavioural sequences analysed. It was found that facial behaviour tended to occur in bursts, and the median activity-quiescence cycle length was about 9 seconds. The amount of facial behaviour tended to wax and wane in a compound rhythm, and the lengths of the activity cycles involved could be predicted from a geometric function model. The results were compared with the evidence for cyclic behavioural activity found by previous investigators, and several explanatory models were examined. It is proposed that the activity cycles observed here are related to the rhythmicity observed in other behavioural states of the human infant.

To assess the distribution of body motility according to sleep states and age, we performed polygraphic tracings in 39 normal premature and full-term infants during the neonatal period, grouped according to conceptional age in weeks (wCA): 31-34, 35-36, 37-38, and 39-41 wCA. Movements of the upper and lower limbs (UL, LL) were recorded using piezo-electric crystals. Time passed with movements (TWM) was automatically measured at an accuracy of 0.01 seconds. Sleep states were defined according to EEG and REMs criteria. We did not find any significant difference when TWM was compared between age-groups before the 38 wCA, on both UL and LL. TWM decreases significantly after 39 wCA (p less than 0.01). In all infants studied TWM was significantly higher in active sleep (AS) than in quiet sleep (QS). TWM in indeterminate sleep (IS) was usually similar to that in AS. The prevalence of body motility during AS compared to QS further confirms the observation of differences in the control of physiological variables according to sleep states as early as 31 wCA (the lower limit of our study).

Quiet sleep (QS) was correlated with a different set of constitutional variables from those associated with active sleep (AS), in a sample of 69 species of mammals. The time spent in quiet sleep was negatively correlated with body size and basal metabolic rate. The latter relationship remained even after controlling for the effects of body weight. Neither the total time spent in active sleep, nor active sleep as a percentage of total sleep time was significantly correlated with body weight or metabolic rate. Altricial species spend more time in active sleep than do precocial species. The time between the onset of successive episodes of active sleep, the AS-QS cycle length, was positively correlated with body weight. For their body sizes, species that live in temperate regions have shorter AS-QS cycles than those living in tropical or sub-tropical regions. Correlations between patterns of sleep and adult brain weight probably result from the confounding effects of body weight. These findings were used to evaluate several explanations for interspecific differences in patterns of sleep among mammals.

In 44 children aged from 1 week to 6 months, 70 polygraph records were performed. The day tracings were carried out in the nursery in the child's normal environment. They lasted from 1 to 3 sleep cycles. As well as classical EEG developmental data, some new or rarely described in the literature data are pointed out. The onset of sleep is frequently difficult to define precisely. EEG slowing sometimes begin the eye open. Up to 12 weeks, the mode of onset of sleep (defined by the sole criterion of rapide eye movements) is variable: some babies fall asleep in active (AS), the other in quiet sleep (QS). After 12 weeks of age, all children fall asleep in quiet sleep. The early appearance on the median line of the fiqures characteristic of stages of maturity is striking. Vertex sharp waves and spindles appear in QS from 3 weeks with marked interindividual variation. The rhythmic vertex-occipital sharp figures ("saw-tooth" waves) of AS appear after 5 weeks and become well defined from 11 weeks. Several weeks later these characteristic figures spread to the central and posterior areas of the two hemispheres. Quiet sleep and active sleep in babies before 6 months of age are not similar to the slow wave and paradoxical sleep of the adult. Some behavioural parameters, such as body and eye movements permit to oppose the 2 states of sleep as they do in adult. On the contrary, the EEG morphology and certain other variables present some differences compared to the adult.

In this study we identified consistent characteristics of the sleep-wake state of newborn infants. Forty-one normal, full-term infants were observed in a warmer–skin temperature maintained at 36.1°C–located in a sound-attenuated room for 1 hr during 2 successive mid-feeding periods. The infant's state was recorded on a check-list every 10 sec using the following categories for sleep and wakefulness: Quiet Sleep A, Quiet Sleep B, Active Sleep Without REM, Active Sleep With REM, Active Sleep With Dense REM, Drowsy, Alert Inactivity, Waking Activity, Fussing, Crying, and Indefinite State. Immediately following the completion of each observation, the 2 observers made independent judgments of the degree of organization shown by the infant, using a 6-point scale. Over the two 1-hr observations, only Quiet Sleep A, Quiet Sleep B, and Crying showed any consistency. Active Sleep as typically defined showed no consistency whatsoever. However, 2 of the 3 components of Active Sleep were significantly reliable measures for the 2 observations; in sleeping infants all 3 components of active sleep showed high reliability. These results indicate that Active Sleep may be a composite of at least 3 meaningful categories. To look at overall state organization in the neonate, including both sleep and wake states, we considered Active Sleep as 3 separate states and then combined the resulting 11 behavioral states into derived clusters such that each combination of states showed a test-retest reliability above .52. With these 5 state clusters we viewed each infant's state behaviors in terms of a profile depicting the percent of time spent in each state cluster. We found a close association between these profiles and the subjective judgments of sleep-wake state organization made by the observers. The results clearly indicate that a 1-hr observation provides reliable information on individual sleep-wake states in the newborn.

Variations in sleep-waking states at puberty in the female rat were studied. Waking time increased due to a lengthening of the mean duration of waking episodes. Decreases in quiet and active sleep resulted from reductions in the number of episodes of each of these states. Probabilities of transition from one state to another were also affected at puberty. Precocious induction of puberty resulted in similar changes in sleep-waking states compared to those at spontaneous puberty. However, these alterations in sleep-waking patterns occurred primarily during the light period at precocious puberty and during the dark period when puberty occurred spontaneusly.

Study of the sleeping and waking states of infants was extended to the time domain by analyzing their temporal covariation over a 4-week interval using the intraperson correlation coefficient. As a methodological question, inter-person and intra-person correlation matrices were compared. Twenty-eight fullterm, normal infants were observed in the home weekly from 2 to 5 weeks of age. Over each 7-hour observation, the following states were recorded every 10 seconds: Alert, Non-Alert Waking Activity, Fussing, Crying, Daze, Drowse, Sleep-Wake Transition, Active Sleep, Quiet Sleep, and Unclassified Sleep (sleep during periods of the day when a mother was holding her baby). Data were obtained in two social contexts: when the baby was with the mother and when alone. Significant individual differences were found for each of the states in both social contexts. When the baby was alone, there were a greater number of intra-person correlations than inter-person correlations. All correlations between the waking states and Active Sleep or Quiet Sleep were negative, suggesting the hypothesis that the underlying neurobiological mechanisms may allow a degree of substitution among coupled sleep and wake states. This is an extension of the original hypothesis by Roffwarg, Muzio, and Dement. There were fewer systematic relationships among the states when the babies were with their mother in comparison with periods when they were alone. It was concluded that: (1) an intra-person analysis is the appropriate one for examining state as a process which occurs over time within individuals; (2) for some conditions an inter-person analysis may be substituted for the intra-person analysis; (3) mother-infant interactions account for the reduced number of state associations when the infant is with its mother; and (4) examination of the full range of sleeping and waking states is required for an understanding of the states as a behavioral system.

Vasotocin was recently reported to increase the neonatal amount of active sleep in kittens. In this study we examined the effects of arginine vasotocin (vasotocin), given intraperitoneally and at a wide dose range, on the sleep-wake behavior of 7-day-old and 14-day-old rat pups using a static charge sensitive recording system. It increased the percentage of quiet state relative to total sleep time at the doses of 0.01–1.0 ng/g of body weight but did not affect it at the dose of 0.001 ng/g. The percentage of active sleep was decreased by doses of 0.01–10.0 ng/g. The increase in the amount of quiet state and the concurrent suppression of active sleep lasted for 6 hours. Wakefulness was slightly increased at 10 ng/g of vasotocin. These findings indicate that, in contrast to the reports on kittens, in newborn rats peripheral administration of vasotocin increases the amount of quiet state relative to total sleep time and decreases that of active sleep.

All-night polygraphic recordings of 25 normal infants were carried out to describe the early development of sleep-waking-state sequencing. Each minute of the 12-h recordings was coded into quiet sleep, active sleep, or waking states. These data were then transformed into a binary series and subjected to spectral analysis using the fast Fourier transform for determination of periodicity of each state. Spectral estimates of sleep- and waking-state periodicities displayed a high variance early in life, but by 3 to 4 months of age, there was a principal rhythm approximating 1 cycle/h in the active and quiet sleep states. The average frequency for the quiet and active sleep states increased significantly from 0.87 to 1.07 cycles/h during this 6-month period. These data offer evidence that the establishment of the periodic organization of sleep states requires 4 months to develop in the normal infant.

Predictions from two theories which attempt to explain the function of active sleep (AS) were tested on 144 rats. Total sleep deprived, activity control, stationary control, active steep deprived, large pedestal control, or homecage control conditions were imposed on 30-day and 90-day-old subjects for 5 days. Open-field (OF) and startle response measures and adrenal and body weights permitted examination of changes in emotionality. Increases in OF activity and decreases in defecation in this paradigm are attributed primarily to AS deprivation, while reductions in quiet sleep may account for elevated startle responsivity in totally deprived subjects. Limited support for the Ontogenetic hypothesis is found in the treatment by age effect for OF activity, but the P-hypothesis prediction of increased emotionality in AS deprived subjects is contradicted by our data.

Evaluation of fetal movements revealed a striking difference of motor activity during assumed quiet sleep and active sleep in the fetus. Furthermore motor activity was found to be enhanced in post-term fetuses. Consequences for the methods of fetal acceleration determination (FAD) and daily fetal movement count (DFMC) are discussed.

Summary: Continuous measurements of minute ventilation (vI), oxygen consumption (vO2), heart rate (HR), activity, and temperature were made in eleven low birth weight infants during the interval between feedings. Significant increases in vI, vO2, and HR were noted between quiet and active sleep. (vI Active − vI Quiet/vI Quiet) × 100 = 18.4% vO2 Active − vO2 Quiet/vO2 Quiet) × 100 = 10.1% and HRActive − HRQuiet/HRQuiet) × 100 = 6.4%. Significant differences were also noted within epochs of the same state of sleep: mean slope vI versus time in epoch (t) = −156 ml/kg·min/hr, vO2 versus t. = 1.49 ml/kg·min/hr and HR versus t = −15.0 beats/min/hr. Differences between successive epochs of the same state of sleep were also observed: vI, +5.9 to 46.6%; vO2, 4.7 to 24.6%; HR, 1.0 to 9.7%. These differences were related to the length of time after feeding. These data indicate that steady state conditions do not occur in growing low birth weight infants and that the design of studies of respiration and metabolism in these infants should include continuous assessment of the state of sleep or activity and time after feeding to ensure that experimental and control periods are truly comparable. Speculation: The significant variability in minute ventilation, oxygen consumption, and heart rate which occurs spontaneously in low birth weight infants secondary to changes in activity and postprandial interval must be acknowledged in the design of clinical research. It is probable that these factors influence not only mean levels of metabolic and respiratory activity but also the sensitivity to experimental stimuli such as hypoxia, hypercarbia, and drugs.

Frontal sharp waves (encoches pointues frontales) identified by Monod (1960) were studied in 110 neonates and infants. Three pattern were described: typical, related and degraded. They were recorded in all subjects, the reason why the frequency of each pattern varied was discussed. Pathological states did not increase the occurrence of those frontal sharp waves since most of them were recorded in children either normal or suffering from a minor pathology. Incidence of maturation seemed to be probable since the highest proportion of frontal sharp waves occurred in infants whose gestational and legal age were respectively greater than 43 weeks and between 20 and 40 days at the time of investigation. Typical and degraded forms were predominant in transitional period towards quiet sleep; they were less numerous during falling asleep in active sleep and totally absent during active sleep following quiet sleep. This could suggest that the two states of active sleep are different in nature.

1. The confounding effects of undernourishment and body cooling, resulting from maternal separation, were investigated by separating food and warmth deprivation. Rat pups aged 3–16 d were deprived of food for alternate 24-h periods by removal from the lactating mother. Some of the pups were placed with a foster mother, who kept them warm, whereas others were put in an empty cage at 22° which resulted in a sharp drop in body temperature.2. Pups which were kept warm showed great fluctuations in weight between periods of starvation and feeding. The cooled pups lost less weight during deprivation but also recovered less on refeeding.3. The resultant growth rate was much lower in non-fostered (i.e. cooled) than in fostered pups.4. Up to the age of 8 d, cooled pups failed to raise their body temperature above that of the surroundings and did not digest the milk in their stomachs. Although, thereafter, they were able to raise their temperature to 26° and to digest stomach contents, the extra energy expended resulted in more severe growth restriction.5. One-third of the pups died at 16 d but the rest were quickly rehabilitated by ad lib. feeding and showed a normal growth rate, although they remained smaller than the controls.6. The development of nipples, hair, eye opening and vaginal opening was related more to chronological age than to weight.7. A side effect of cooling was an almost complete abolition of active (REM) sleep, which is normally very high in infants; a slight rebound increase in active sleep was seen at 21 d. Direct as well as side effects of cooling may thus be responsible for some of the observed consequences of maternal separation.

Wakefulness and sleep states were determined from a single-channel analog recording of motility, including body movements and respiration. The subjects were normal infants ranging from 2 days to 4 months of age. First, one observer recorded behavioral states; at the same time respiration and motility was recorded from a pressure sensor under the baby. Subsequently, 4 judges used only the motility recordings to identify wakefulness and states of active, quiet, and active-quiet transitional sleep, for each successive 30-sec epoch. Inter-judge reliability ranged from a mean of 74.9 to 93.1 percent, assessed separately for each individual subject. Judge-observer validity was assessed over all subjects with agreement of r =0.90 for active sleep and r =0.92 for quiet sleep, and complete agreement on the occurrence and relative amount of wakefulness. Judge-observer validity was also assessed based on exact epoch-by-epoch agreement for each subject. Over the total observation agreement ranged from 70.3 to 89.0 percent, from 67.0 to 87.6 percent for active sleep, and from 59.3 to 93.0 percent for quiet sleep. Motility recording makes it possible to study the sequencing of states in infants during prolonged observational periods without instrumentation of the baby for the purpose of making the observations.

Summary The authors report the results of 16 sleep EEGs carried out on 5 infants said to have survived the syndrome of sudden infant death (near-miss group) and 5 controls. The recordings were performed at 1.5 months, 3 months and 4.5 months, times when the risk of sudden death is maximum. The EEG appearance and the organization of sleep patterns have been studied in both groups. The various states of wakefulness, and the modalities of sleep and waking were subjected to statistical analysis with respect to age. The study showed no significant difference between the percentages of different states of wakefulness in the control and ‘near-miss’ group, but there were more sleep onsets in active sleep (REM) in this group compared with the controls and there were fewer waking periods, although when they occurred these were more prolonged.

Periodicities in physiological activity were examined in young female rats prior to and at puberty. At least three distinct periodicities in these data were observed: (i) light: dark differences in the occurrence of wakefulness (W) and quiet sleep (QS); (ii) a 90-min cycle between behavioral sleep and wakefulness; and (iii) a 10 to 20-min rhythm possibly reflecting an active sleep cycle. These periodicities included changes in EEG and EMG amplitude, somatic activity, heart rate, and variability in heart rate. The changes in sleep-waking states at puberty (either spontaneous or precociously induced) did not result in any marked changes in either the 10 to 20-min or 90-min rhythms.