Stability of temperament over the childhood years.

Temperament of 55 children was assessed annually using separate instruments for the years 4-7 and 8-11. Mothers made differential ratings of siblings, and the two questionnaires showed continuity and stability. There were consistently significant correlations with respect to individual differences over the full range of ages, and no evidence of variation across age or developmental change.

A comparative study of quiet sleep, active sleep, and waking on the first 2 days of life.

Direct behavioral observation and motility monitoring procedures provide reliable data, and both are appropriate for sleep/wake state measurements starting immediately after birth. Using these procedures, newborn rats, rabbits, and humans were found to have a greater amount of quiet sleep on the day of birth rather than 24 hr later. Changes in active sleep and wake were inconsistent across the 2 days. The quiet sleep findings are contrary to the developmental course which increases with age. The findings are interpreted as a temporary adaptive response to the stress of the birth process.

Sleep patterns in newborns and temperament at eight months: a preliminary study.

The sleep patterns of 41 full-term newborn infants were recorded continuously during the first 2 postnatal days. The recordings were made nonintrusively using the Motility Monitoring System while the infants were in the hospital. When the subjects were 8 months old, their mothers filled out the Infant Temperament Questionnaire, which yields scores on nine dimensions of temperament. There were four significant correlations between Day 1 sleep measures and later temperament dimensions; there were eight correlations on Day 2, hardly more than a chance number. The temperament scores were used to classify infants as having Easy, Intermediate, Difficult, or Most Difficult temperament. Profiles of sleep measures for the infants in the four groups differed significantly on Day 1, and the Most Difficult infants showed the most extreme values on all measures. Differences in the predictive findings from Day 1 and Day 2 were attributed to the greater influence of the stress of labor and delivery on the first postnatal day.

Sleep/wake states of preterm infants: stability, developmental change, diurnal variation, and relation with caregiving activity.

Using time-lapse video, we recorded the sleep/wake states of 95 preterm infants, born under 1500 g and cared for in three hospitals, for three 24-hr periods at 33 and 35 weeks conceptional age. The videotapes were scored in 5-min epochs for quiet sleep (QS); active sleep (AS); wakefulness (Wa); bout lengths of QS (QSBL), AS (ASBL), and waking (WaBL); nursing/caregiving periods (Crgv); bout lengths of Crgv (CrgvBL); and time out of the crib (OOC). The infants' sleep showed significant individual differences at each age, over age, and from day to nighttime. They showed developmental changes in QS, AS, Wa, and QSBL. QS and QSBL were positively related to caregiving time; ASBL was related to maternal age; and QS was related to gestational age and birth weight. Thus, very low birth weight preterm infants show marked stability and developmental change in the organization of the sleep/wake states from a very early age, and their states are related to demographic variables as well as temporal measures of caregiving.

Sleep rhythmicity in infants: index of stress or maturation.

The rhythmicity of bouts of quiet sleep (QS) was assessed, starting immediately after the baby's birth. The subjects were 58 healthy fullterm, single-birth, newborn infants, 26 females and 32 males. Using a non-intrusive recording procedure, their sleep was monitored for 24-h periods on the 1st and 2nd postnatal days in the hospital, then for 2 days in the home at 6 months. The cyclicity index permitted determination of the degree of periodicity as well as whether the recurrence of QS bouts showed significant periodicity. The number of subjects with significant cyclicity increased from 34% of the group on postnatal day 1 to 73% at 6 months; cyclicity scores (CS) increased from 0.71 to 0.86; and mean cycle length increased from 51 to 57 min. Infants with significant cyclicity on day 1 had lower mental scores at 6 months; but infants with significant cyclicity at 6 months had higher mental scores at 1 year. In addition, the infants with significant cyclicity on day 1 had lower birth weights and were born to younger mothers; but these relationships were also reversed at 6 months. Finally, cyclicity scores at 6 months were significantly correlated with 1-year mental scores, but the function of this relationship was quadratic. Thus, while significant cyclicity was found from the first postnatal day, the results suggest that regularity in QS cycles in the newborn period has negative implications for development, while such regularity at 6 months has positive implications-although excessive rigidity in rhythms at the later age, in terms of extremely high cyclicity scores, was also an indicator of developmental compromise.

Biological and behavioral correlates of quiet sleep respiration rates in infants.

The sleep and respiration of 88 infants were recorded for 24-h periods on the first 2 postnatal days and again at 6 months. The recordings were made with the Motility Monitoring System, which does not require instrumentation of the infants. Quiet sleep respiration rates (QSRR) increased over the first 2 days (mean = 42.2, SD = 1.0 and mean = 44.5, SD = 1.1, respectively), then decreased by 6 months (mean = 25.3, SD = 0.5); females showed lower QSRR on the first 2 days, infants delivered vaginally showed lower QSRR at 6 months; by 6 months QSRR was significantly higher during the day than at night; and significant individual differences across age and from day to nighttime were found at each age. Delivery mode, maternal age and education, and mental scores at 6 and 12 months were negatively related to QSRR at 6 months. Taken together, these data suggest a developmental advantage of slower QSRR and evidence for the role of the higher central nervous centers in the regulation of QSRR.

A procedure for withdrawal of sleep medication in elderly women who have been long-term users.

A program for withdrawal of sedative/hypnotic medication was investigated in elderly women, ages 64 to 91. The sleep cycles of 10 drug withdrawal (DW) and 10 non-drug withdrawal (N-DW) subjects were monitored for a 24-hour period for 5 successive weeks, using a nonintrusive recording procedure. The first 2 baseline weeks were followed by 1 week of half-dose, then 2 weeks of full withdrawal for the DW group. The results indicated no demonstrable effect on sleep, sleep complaints, levels of depression, or daytime sleepiness on the DW group. The conclusion is that the procedure of withdrawal from sleep medication over a 2-week period, combined with the use of a substitute pill to maintain the ritual of nightly pill-taking, is appropriate and effective for long-term elderly users.

Infants' earliest sleep/wake organization differs as a function of delivery mode.

The sleep/wake states of newborn infants were investigated as as a function of vaginal and C-section delivery. The subjects were 51 normal full-term infants: 26 vaginally delivered, 12 delivered by emergency C-section, and 13 delivered by elective C-section. Their sleep states and wakefulness were continuously recorded from the time of birth throughout their stay in the hospital, that is, the first 2 postnatal days for the vaginally delivered infants and 5 days for the C-section infants. Sleep was recorded using the automated Motility Monitoring System, which permits 24-hr recordings without instrumentation of the subject. During the 1st postnatal day, both C-section groups showed state patterns that differed significantly from those of the vaginally delivered infants. Analyses for single states indicated that both C-section groups had significantly less active sleep, and the elective group had more wake and more sleep--wake transition than the vaginal group. The two C-section groups did not differ significantly on any measure. Only the vaginally delivered infants showed significant day/night differences during the first 2 days, with more wakefulness, shorter mean sleep periods and shorter longest-sleep periods during the daytime on both days. The results of this study indicate that the earliest postnatal sleep patterns differ and the diurnal sleep rhythm is disrupted as a result of surgical delivery.

The effects of evening light exposure on the sleep of elderly women expressing sleep complaints.

In order to address the typical phase advanced, disturbed sleep of the elderly, additional evening light was provided to elderly women by means of a "visor" which provides 2000 lux to each eye. The subjects wore the light visor for 30 min in the evening. The subjects were 10 community-residing women over the age of 65 (mean = 79.4 years; range, 67-87 years). Sleep was recorded in the home for 28 successive 24-hr periods: 7 days pretreatment, 14 days while using the light visor, and 7 days posttreatment. Thus, each subject served as her own control. Sleep was recorded using the Home Monitoring System (HMS), a nonintrusive procedure which does not require instrumentation of the subject. The subjects showed significant changes during and even after the intervention: there was a significant decrease in sleep latency over weeks, and a significant increase in sleep time and sleep efficiency. The subjects also reported less fatigue during treatment. The results suggest that additional light, provided for as little as 0.5 hr in the evening and at only 2000 lux, increases the amount of nighttime sleep and improves the quality of sleep in older women.

Snoring, nightmares, and morning headaches in elderly women: a preliminary study.

Self-reported snoring in 37 females aged 65-94 years was assessed and the relationships between snoring and sleep characteristics, respiratory events, depression scores, sleep complaints and self-reported health problems were investigated. Sleep was recorded for two 24-h periods in the home on successive weeks, using the Home Monitoring System. Snoring was positively correlated with the frequency of nightmares and morning headaches; and nightmares and morning headaches were significantly correlated. Snoring was also significantly and positively correlated with the number of brief wakings during sleep, and was positively correlated with weight. While these relationships are ones that have previously indicated risk status, snoring was not related to respiratory events, sleep complaints, or other health problems. Snoring, nightmares and headaches each showed a significant, negative correlation with age, but this is a finding that cannot be readily interpreted from a cross-sectional study. Replication of this study with a larger sample, studied longitudinally, is required to confirm a significance of the snoring/nightmares/headaches constellation for aging women.

Developmental care does not alter sleep and development of premature infants.

OBJECTIVE: The Neonatal Individualized Developmental Care Program (NIDCAP) for very low birth weight (VLBW) preterm infants has been suggested by Als et al to improve several medical outcome variables such as time on ventilator, time to nipple feed, the duration of hospital stay, better behavioral performance on Assessment of Preterm Infants' Behavior (APIB), and improved neurodevelopmental outcomes. We have tested the hypothesis of whether the infants who had received NIDCAP would show advanced sleep-wake pattern, behavioral, and neurodevelopmental outcome. METHODS: Thirty-five VLBW infants were randomly assigned to receive NIDCAP or routine infant care. The goals for NIDCAP intervention were to enhance comfort and stability and to reduce stress and agitation for the preterm infants by: a) altering the environment by decreasing excess light and noise in the neonatal intensive care unit (NICU) and by using covers over the incubators and cribs; b) use of positioning aids such as boundary supports, nests, and buntings to promote a balance of flexion and extension postures; c) modification of direct hands-on caregiving to maximize preparation of infants for, tolerance of, and facilitation of recovery from interventions; d) promotion of self-regulatory behaviors such as holding on, grasping, and sucking; e) attention to the readiness for and the ability to take oral feedings; and f) involving parents in the care of their infants as much as possible. The infants' sleep was recorded at 36 weeks postconceptional age (PCA) and at 3 months corrected age (CA) using the Motility Monitoring System (MMS), an automated, nonintrusive procedure for determining sleep state from movement and respiration patterns. Behavioral and developmental outcome was assessed by the Neurobehavioral Assessment of the Preterm Infant (NAPI) at 36 weeks PCA, the APIB at 42 weeks PCA, and by the Bayley Scales of Infant Development (BSID) at 4, 12, and 24 months CA. RESULTS: Sleep developmental measures at 3 months CA showed a clear developmental change compared with 36 weeks PCA. These include: increased amount of quiet sleep, reduced active sleep and indeterminate sleep, decreased arousal, and transitions during sleep. Longest sleep period at night showed a clear developmental effect (increased) when comparing nighttime sleep pattern of infants at 3 months with those at 36 weeks of age. Day-night rhythm of sleep-wake increased significantly from 36 weeks PCA to 3 months CA. However, neither of these sleep developmental changes showed any significant effects of NIDCAP intervention. Although all APIB measures showed better organized behavior in NIDCAP patients, neither NAPI nor Bayley showed any developmental advantages for the intervention group. The neurodevelopmental outcome measured by the Bayley at 4, 12, and 24 months CA showed 64% of the NIDCAP intervention group at the lowest possible score compared with 33% of the control group. These findings could not be explained by the occurrence of intraventricular hemorrhage or the socioeconomic status of the parents, which showed no significant group effect. CONCLUSION: The results of this study, including measures of sleep maturation and neurodevelopmental outcome up to 2 years of age did not demonstrate that the NIDCAP intervention results in increased maturity or development. Buehler et al (Pediatrics. 1995;96:923-932) have reported that premature infants (N = 12; mean gestational age 32 weeks, mean birth weight 1700 g) who received developmental care compared with a similar group of infants who received routine care showed better organized behavioral performance on an APIB assessment at 42 weeks PCA. None of the medical outcome measures were significantly different in this study. Although our APIB results are in agreement, the results of the NAPI, the Bayley and sleep measures do not show an increase in neurodevelopmental maturation. In the earlier report by Als et al (Journal of the American Medical Associatio

Sleep rhythmicity in premature infants: implications for development status.

Ultradian and diurnal rhythms in premature infants were investigated by assessing cyclicity of quiet sleep (QS) and the diurnal distribution of this cyclicity. The sleep of 49 preterm infants was recorded in the hospital for three successive 24-hour periods at 36 weeks conceptional age (CA), and 42 of the infants were recorded in the home for two 24-hour periods when they were 6 months old. Sleep was recorded nonintrusively by means of the motility monitoring system, which does not require instrumentation of the subject. Cyclicity was assessed using a procedure that permits assessment of significance as well as degree of cyclicity. Twenty of the 49 infants at the preterm age and 37 of the 42 infants at 6 months had sleep episodes with significant cyclicity. Mean cyclicity scores increased from 0.61 to 0.81 over age, but the cycle length of approximately 60 minutes did not change. There was no evidence for individual consistency across the two ages in any of the sleep or cyclicity measures. Evidence for diurnal differences was present from the preterm period. At both ages, there were far more analyzable sleep episodes and higher cyclicity at night. At the preterm period, cyclicity measures were negatively related to indices of advanced perinatal status as well as 6-month mental scores; at 6 months, the cyclicity measures were positively related to perinatal measures as well as mental scores. These results indicate the necessity for different interpretations of periodicity at the preterm and later age.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of infant crying in the early mother-infant dialogue.

This study examines the communicative role of crying by assessing the ability of infants to indicate different degrees of distress in different social circumstances. Behaviors of mother-infant pairs were observed in the home for 7-h periods when the infants were 2, 3, 4, and 5 wk old; and three weekly observations were made when the infants were 1 yr old. A Cry Responsiveness Index (CRI) was derived to quantify the degree to which a baby cried differentially during each observation. This statistic showed significant individual differences. The CRI scores were correlated with maternal measures during the early weeks and negatively correlated with "mother ignore" at one year. The CRI scores were unrelated to the total amount of crying. The results indicate that responsive infants have responsive mothers--or conversely, that responsive mothers have responsive infants. Thus, cry responsiveness is not a function of infant behavior alone but is inherently an expression of the dynamics of the mother-infant interactional system.

The breathing bear: effects on respiration in premature infants.

The sleep states and the regularity of quiet sleep (QS) respiration were investigated in premature infants who were provided a "breathing" teddy bear. The bear (BrBr) is a source of optional rhythmic stimulation that reflects the breathing rate of the individual infant it is with. At 33 weeks CA, 19 premature infants were given a BrBr and 17 were given a nonbreathing bear (N-BrBr). At 35 weeks CA, and again at 45 weeks CA, a 1-2-h interfeed motility recording was obtained. These analog signals were scored for active sleep, QS, and wakefulness; and each 10-s epoch of QS was judged for regularity of respiration using a four-point rating scale. At 35 weeks, the BrBr babies showed slower and more regular respiration during QS. At 45 weeks, the BrBr babies showed more QS and less active sleep. At both ages, only the BrBr babies showed a correlation between respiratory regulatory and the amount of QS. The findings suggest facilitation of neurobehavioral development as well as entrainment from optional stimulation, which reflects one of the infant's own biological rhythms.

Ultradian and diurnal cyclicity in the sleep states of newborn infants during the first two postnatal days.

OBJECTIVE: The purpose of this study was to investigate both ultradian and diurnal cyclicity in the sleep states of newborn fullterm infants during the first 2 postnatal days. METHODS: The sleep of 31 healthy newborn infants was recorded continuously throughout the first 2 postnatal days, starting immediately after birth, using an automated Motility Monitoring System (MMS). The MMS consists of a pressure sensitive mattress pad connected to an amplifier and a small 24-h analog recorder. A single channel of analog signals produced by the infant's respiration and body movements was recorded and then scored in 30-s epochs for Active Sleep. Quiet Sleep, Active-Quiet Transition, Sleep-Wake Transition, and Wake. DATA ANALYSES: The 48 h of recording were divided into successive 12-h periods from 07:00 h to 19:00 h (day) and 19:00 h to 07:00 h (night), and all measures were derived for each day and night period. Both cross-sectional and repeated measures analyses were used because all babies were not represented in all day/night periods. RESULTS: Day/night differences in state variables: On both days, there was greater Wakefulness, shorter Quiet Sleep Bout Lengths, shorter Mean Sleep Periods and shorter Longest Sleep Periods during the daytime. On day 1 only, there was less Quiet Sleep, shorter Quiet Sleep Bout Lengths and more Sleep-Wake Transition during the daytime. On day 2, repeated measures analyses revealed two additional day/night differences: less Quiet Sleep and more Sleep-Wake Transition during the daytime. Day/night differences in Quiet Sleep cyclicity: 28 sleep periods met the criteria for analysis of Quiet Sleep cyclicity, and only six of these occurred during the daytime. Seventeen of 28 analyzable sleep periods showed significant Quiet Sleep cyclicity. Only two of these occurred during the daytime. CONCLUSIONS: Contrary to the prevailing view of developing sleep rhythms, the results of this study suggest that newborn infants exhibit both ultradian ad diurnal cyclicity in their sleep patterns from the earliest postnatal period.

Stability and instability of sleep in older persons recorded in the home.

Using a nonintrusive procedure for sleep monitoring, four 24-hour recordings of 40 independently living women, 65-94 years, were made during a 3-month period. Although the subjects distributed their sleep over much of the day, all measures showed significant reliability: with four recordings, reliabilities (r44 values) were > 0.70; and with only one recording, reliabilities (r11) were > 0.40 [r11 for the respiratory disturbance index (RDI) was lower but still significant]. Within-individual variability over recordings was low for total sleep time (TST), sleep (S), and sleep efficiency (SE) and high for sleep latency (SL) and RDI. The mean TST was 7.6 hours, which is not markedly different from that of younger adults. Within the age range studied, there was no relationship between age and any of the variables, including the amount of within-individual variability. These results, using the Home Monitoring System (HMS), indicate that both stability and instability of sleep parameters characterize the sleep of older women. The nature of specific forms of individual variability needs to be explored as possible indices of aging as distinct from indications of neurobiological abnormalities.

Infant sleep during the first postnatal day: an opportunity for assessment of vulnerability.

OBJECTIVE: The purpose of this study was to describe the sleep of newborns throughout the first 48 postnatal hours and to relate their earliest sleep characteristics to developmental status at 6 months. METHODS: The sleep of 36 healthy newborns was recorded continuously throughout the first two postnatal days, starting immediately after birth, using an automated Motility Monitoring System. The Motility Monitoring System consists of a pressure-sensitive mattress pad connected to an amplifier and a small 24-hour analog recorder. A single channel of analog signals produced by the newborn's respiration and motility is continuously recorded onto a 60-minute cassette tape. The signals are digitized and scored, in 30-second epochs, for Active Sleep, Quiet Sleep, Active-Quiet Transition, Sleep-Wake Transition, and Wake. In addition to the percent of time spent in each state, the Mean Bout Length of Active Sleep, Mean Bout Length of Quiet Sleep, Mean Sleep Period, Longest Sleep Period, and Arousals in Quiet Sleep were also measured. RESULTS: On postnatal day 1, four measures were significantly related to 6-month Bayley mental scores: Mean Sleep Period, Longest Sleep Period, Sleep-Wake Transition, and Arousals in Quiet Sleep; and two measures were significantly related to Bayley motor scores: Mean Sleep Period and Sleep-Wake Transition. On postnatal day 2, none of the measures were related to mental scores, while two measures were related to the motor scores: Quiet Sleep and Mean Bout Length of Quiet Sleep. CONCLUSIONS: The results suggest that the newborn's sleep characteristics during the first postnatal day provide uniquely sensitive indices of later neurobehavioral function.

Reliability and validity of computer scoring of behavioral sleep-wake states in rats and rabbits.

Previous studies in human infants, rabbits, and rats have shown that states of sleep and wakefulness can be reliably identified from motility signals produced by respiration and body movement. Thoman has described a computer-scoring algorithm for automated scoring of behavioral states from motility signals in human infants. In the present studies, we report the use of the computer scoring program with motility signals obtained from electronic activity monitors. In the newborn rabbit, computer classification of the data into behavioral states agreed with visual scoring of the motility signals. In infant and adult rats, computer scoring across the entire age range was validated against direct behavioral observations, video-taped observations, and visual scoring of the motility signal. This procedure permits prolonged recordings of freely moving animals and eliminates the need for an observer to be present.

Infant-parent co-sleeping in an evolutionary perspective: implications for understanding infant sleep development and the sudden infant death syndrome.

Evidence suggests that infant-parent co-sleeping represents the species-wide pattern of sleep in which human infant physiology evolved. The hypothesis evaluated in this manuscript is that the co-sleeping environment may foster development of optimal sleep patterning in infants and confer other benefits, including reducing the risk of the sudden infant death syndrome (SIDS). These postulations by McKenna are considered from different perspectives by the coauthors. Using evolutionary, cross-species, crosscultural, physiological and behavioral data, our objective was to present a conceptual framework for assessing the developmental consequences of solitary sleeping and infant-parent co-sleeping.

Early sleep patterns of premature infants are differentially related to later developmental disabilities.

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.