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Biomedical subjects

E B Thoman

Publications and source records attributed to E B Thoman.

At least 37 records · Page 2Linked to original sources
PubMed1991

Sleep and apnea in the elderly: reliability and validity of 24-hour recordings in the home.

Two studies investigated the reliability and validity of measures of sleep and apnea using the home sleep monitoring system (HMS), which requires no instrumentation of the subject. From a pressure-sensitive pad on the subject's bed, signals from respiration and motility are recorded. These are scored for sleep and the occurrence of apneas, and the following measures are obtained: time in bed, total sleep time, number of awakenings from sleep, waking after sleep onset, sleep efficiency, and number of apneas. Overnight recordings of 14 adults were made concurrently with polysomnographic recordings in the New Haven Sleep Disorders Center. Significant agreement was found for each sleep measure and the apnea index. Four weekly 24-h recordings were made of eight elderly women, aged 62 to 90, in the home. There were significant individual differences and measurement reliability for each sleep measure and number of apneas. Some of the elderly showed highly episodic sleep patterns; and three of them showed high and variable apneas over the four weeks. These studies indicate the potential of the HMS for characterizing sleep in the elderly from nonintrusive, naturalistic observations in the home.

Adult↗
PubMed1991

Premature infants seek rhythmic stimulation, and the experience facilitates neurobehavioral development.

This was a clinical trials study of self-regulation of rhythmic stimulation in preterm infants. Infants were enrolled in three regional hospitals and followed in four outlying hospitals. Forty-five premature infants, 22 males and 23 females, enrolled at 29-33 weeks conceptional age (CA) received in the isolette either a "breathing" teddy bear (set to breathe at one-half the infant's quiet sleep respiration rate) or a nonbreathing bear. Using time-lapse videorecording at a 60:1 ratio, subjects were recorded for 3 days at the beginning of the Intervention period and again for 3 days, 2 weeks later. After discharge from the hospital, the sleep of the subjects was monitored in the home for a 24-hour period on weeks 1, 2, 3, 4, and 5 after expected date of birth (postterm). Infants with a breathing bear spent more time in contact with the bear, and increased their contact over the two weeks. Postterm, the "breathing bear babies" showed more quiet sleep and a greater increase in quiet sleep over weeks. The results indicate that premature infants ("prematures") are capable of organizing their motility to express a preference for rhythmic stimulation, and that the experience facilitates neurobehavioral development.

Acoustic Stimulation↗
PubMed1990

Sleeping and waking states in infants: a functional perspective.

There is little agreement on sleep-wake state categories for describing infants, nor is there agreement on how states are to be conceptualized. We propose General Systems Theory as a perspective for viewing behavioral states and for describing their function as a behavioral system within the infant's larger social system. In the social context, states provide communicative cues, mediate perception of caregiver stimuli, and modulate the infant's responses to those stimuli. Thus, states reflect the infant's CNS status and they are related in a complex, dynamic way to the developmental course of that status. A taxonomy of infants' behavioral states is described, composed of ten Primary States: Alert, Nonalert Waking, Fuss, Cry, Drowse, Daze, Sleep-Wake Transition, Active Sleep, Active-Quiet Transition, and Quiet Sleep. Using combinations of these states, a set of six Derived States is also defined. Results of naturalistic studies of infants' states are described to demonstrate for each of these states: reliability of measurement, evidence for concurrent and predictive validity, and unique intraperson correlation patterns. The findings support the usefulness of this state taxonomy for describing infants and for investigating the functions of state. Categorical and conceptual differences with the states as viewed by Wolff and Prechtl are discussed.

Humans↗
PubMed1989

Sleep cyclicity in infants during the earliest postnatal weeks.

Cyclicity within sleep was investigated in 20 fullterm infants who were monitored in the home for 24-hour periods when they were 2-5 weeks old. Using a pressure sensitive mattress in the crib, analog signals from the baby's respiration and body movements were computer scored for: Quiet Sleep, Active Sleep, Active-Quiet Transitional Sleep, Sleep-Wake Transition, and Wakefulness. Sleep episodes with at least four recurrences of Quiet Sleep were analyzed for cyclicity. Significant cyclicity of Quiet Sleep was found in 49 of the 55 sleep episodes analyzed. The mean Quiet Sleep recurrence period was 63.2 minutes. Eighteen of the 20 infants exhibited cyclicity on one or more weeks. Thus, sleep during the neonatal period is generally characterized by the presence of cyclicity. Cyclicity was not related to other parameters of the sleep cycle, but was correlated with stability of state patterning over weeks. The results provide new evidence for neurobehavioral competence of the neonate in terms of sleep organization.

Aging↗
PubMed1988

Infants at risk for sudden infant death syndrome (SIDS): differential prediction for three siblings of SIDS infants.

The outcome for three siblings of SIDS (SSIDS) infants was predicted, using as a risk model the sleep and respiratory characteristics of a SIDS victim studied extensively during the neonatal period. The SIDS infant had shown unstable state organization and deviant respiration patterns, including a deficit of brief apneic pauses. Like the SIDS infant, the SSIDS infants and a group of 16 normal infants were observed in the home for 7-hr periods when they were 2, 3, 4, and 5 weeks old. Two of the infants showed normal sleep and respiratory characteristics, and they were predicted to develop without respiratory dysfunction. In contrast, the third infant showed a pattern of deviancies similar to the SIDS infant; and at 4 months, she had prolonged apneic episodes, requiring resuscitation on two occasions. The findings are consistent with the notion of subtle central nervous system (CNS) dysfunction in SIDS risk infants from the time of birth.

Arousal↗
PubMed1987

Behavioral states of premature infants: implications for neural and behavioral development.

Nine premature and 28 full-term infants were observed in their homes for 7 hr when they were 2, 3, 4, and 5 weeks post-term, and the sleeping and waking states displayed by these infants were compared. For these comparisons, the observation day was divided into two mutually exclusive contexts: times when the baby was alone and times when the baby was with the mother. The premature infants spent more time alone (mean of 5.4 hr a day) than the full-terms (4.6 hr). Over the total 7-hr day, the premature infants spent more time in alert, nonalert waking activity, and sleep-wake transition than the full-terms, and they spent less time in drowse and total sleep. These results clearly indicate that, at the same post-term ages, the sleep-wake states of premature infants differ markedly from those of full-terms. Four states showed significant Group X Context interactions indicating that state differences between premature and full-term infants were also a function of the context in which the infants were observed. For example, the prematures exhibited more fuss or cry and more drowse when alone; whereas the full-terms exhibited more of these states when with their mothers. This finding of context-related differences between prematures and full-terms has implications for the conflicting reports in the literature, as heretofore the states of prematures and full-terms have been compared from observations made in a single situation. The results indicate that prematures exhibit significant commonality in their neurobehavioral development through the early post-term period despite heterogeneity among them in their exposure to prenatal, perinatal, and early postnatal stresses.

Arousal↗
PubMed1987

The sleeping and waking states of infants: correlations across time and person.

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 intra-person 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.(ABSTRACT TRUNCATED AT 250 WORDS)

Child Behavior↗
PubMed1987

Computer scoring of motility patterns for states of sleep and wakefulness: human 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.

Beds↗
PubMed1986

Self-regulation of stimulation by premature infants.

Premature babies are capable of seeking contact with a source of rhythmic stimulation that reflects their own breathing rhythm. Optional stimulation, in the form of a "breathing" stuffed bear, was made available to premature infants, 32 to 35 weeks' gestational age. The bear's breathing rate was matched to that of each individual infant during quiet sleep. Other infants were exposed to a bear that did not breathe, and some infants were not exposed to a bear. All infants were monitored continuously using time-lapse video. After 2 to 3 weeks' exposure, those infants with a breathing bear showed significantly more contact with their head, body, or limbs than either of the control groups (for the no-bear group, contact with the area that would have been occupied by the bear was determined to describe the contact that might have been expected by chance). In addition, the infants given the opportunity to self-regulate their stimulation showed greater amounts of quiet sleep than the other two groups.

Adaptation, Physiological↗
PubMed1985

Theophylline affects sleep-wake state development in premature infants.

This study investigated the prolonged effects on state behavior of theophylline administered to infants for apnea of prematurity. There were three groups: Four premature infants who had received theophylline in the preterm period, five premature infants who had not received theophylline, and twenty-eight normal fullterm infants. The Theophylline infants had been off the drug for at least one month prior to the beginning of the study. Sleep-wake states were observed in the home for seven-hour periods when all infants were the same corrected ages: two, three, four and five weeks post-term. Data from the portion of the day that the infants were alone were analysed for this study. The state organization of the Theophylline group differed significantly from those of the other groups. They exhibited more non-alert waking activity, more alert, more drowse or transition, and less active sleep than did the Non-Theophylline and Fullterm infants. The state distributions of the latter two groups did not differ. On the basis of similarities between the results of this study and of a previous animal study, it was concluded that theophylline altered the normal development of state organization in premature infants. These effects persisted long after the drug had cleared the body.

Female↗
PubMed1983

Organization of sleeping and waking states in infants: consistency across contexts.

The sleep and waking states of infants are described from direct behavioral observations made in the home for a 7-hour period on weeks 2, 3, 4, and 5. States were analyzed separately for two contexts: infant alone and infant with the mother. States analyzed included Alert, Waking (Non-Alert) Activity, Fussing or Crying, Drowse or Sleep-Wake Transition, Active Sleep, Quiet Sleep, and Unclassified Sleep. Individual state profiles for each context were obtained for each week. A quantitative measure of profile consistency over weeks was calculated as an index of stability of state organization. Infants showed considerable range in state stability over weeks. State stability when alone was significantly correlated with state stability when with the mother (r = .67), even though there were differences in sleep-wake distributions and in level of stimulation in these contexts. These findings demonstrate within-individual consistency in CNS control of behavioral states, across sleep and wakefulness and throughout the diverse activities of the caretaking environment.

Central Nervous System↗
PubMed1983

Comparisons of behavioral, motoric and electrical criteria for assessment of sleep-wake states in the rabbit.

Each of the sleep and wake states of animals are characterized by specific patterns of behavioral, motoric, and electrophysiological activity. The purpose of this study was to determine the amount of agreement among these three patterns. Sleep-wake behavior of two adult rabbits was observed for 4 continuous hours by an experienced judge. At the same time, a single-channel analog recording of motility and an analog recording of the electrical activity of the hippocampus were obtained. Each recording was scored by assigning a state category to each 10-second epoch. The three descriptions were then compared for agreement using the 10-second epoch as the unit of statistical analysis. There was a mean agreement of 85.12% between the techniques of direct observation and judgment of motility recordings. A mean agreement of 95.64% was obtained when comparing the hippocampal recordings and those of direct observation; the hippocampal and motility recordings had a mean agreement of 85.38%. The high correlations among the three different procedures support the hypothesis that state is a construct representing a set of underlying neurophysiological properties of the organism which express themselves in a similar and invariant manner via behavior, motility, and electrical brain activity.

Animals↗
PubMed1983

Periodic and non-periodic sleep apnea in premature and fullterm infants.

The sleep states of nine premature infants were observed and concomitant respiration recordings were obtained at 37 and 41 weeks conceptional age. 19 fullterm infants were also studied at 41 weeks conceptional age. Between 37 and 41 weeks significant decreases occurred in the premature infants' percentage of periodic apnea, rate of apnea in active sleep-REM, and length of the longest apneic episode. The premature and fullterm infants at 41 weeks did not differ in the frequency of apneic episodes, but the premature group had shorter episodes. These results provide additional evidence for the difference between premature and fullterm infants in central nervous system organization.

Age Factors↗
PubMed1983

Infant crying and stability in the mother-infant relationship: a systems analysis.

Mother-infant interaction was studied using a general systems theory framework. 20 mother-infant pairs were observed in their home for a 7-hour period when the infants were 2, 3, 4, and 5 weeks of age. A measurement procedure was devised to assess, for each pair, the consistency over weeks in their allocation of time to 4 interactional contexts that make up the day: feeding, changing or bathing, social attention, and baby alone. The measure was called an Interactional Stability Score. Construct validity for this measure was investigated based on our hypothesis that high interactional stability would be strongly linked to low levels of crying during social attention. This hypothesis was confirmed. The results are interpreted within a general systems theory perspective--namely, that this measure of interactional stability is an empirical indicator of the degree of equilibrium within the relationship, at the level of patterning of interactional contexts. High stability scores represent consistency in allocation of time to the 4 contexts over weeks and not a rigidity in sequencing of these contexts, and thus appeared to reflect a dynamic process of mutual constraints on the behaviors of both partners.

Child Development↗
PubMed1982

Intense rapid eye movements during active sleep: an index of neurobehavioral instability.

Rapid Eye Movement (REM) Storms, intense REM bursts during Active Sleep (or REM Sleep), were investigated as an expression of the neural mechanisms involved in overall control of the sleep and waking states. Twenty normal full-term infants were observed in their homes for a 7-hr period when they were 2, 3, 4, and 5 weeks old. Sleep and waking states, and co-occurring behaviors of the mother, were recorded at 10-sec intervals throughout the observation day. During each 10-sec epoch of Active Sleep a rating was made of the infant's rapid eye movements, as follows: No REM, Light REMs, Moderate REMs, or intense REMs (REM Storms). REM Storm rates were related to a measure of stability in the distribution of the sleep and wake states over weeks, derived separately for time the infant was alone and for time the infant was with its mother. REM Storm rates were negatively correlated with state stability in each of these contexts. The results demonstrated a commonality between the incidence of REM Storms and overall sleep-wake state regulation.

Brain Damage, Chronic↗
PubMed1982

Effects of theophylline on behavioral state development in the newborn rabbit.

On Day 1 of life (Day 0 = birth), the sleep-wake behavioral states of rabbits were measured for 2 hr, after which half the animals received 10 mg/kg of theophylline by intubation (N = 16), whereas the remainder received normal saline (N = 17). Behavioral states were then measured on Days 2, 3, 5, 7, 15, 20, 30 and 40. Theophylline sharply reduced active sleep starting on Day 2 and continuing through Day 20. The development of quiet sleep was delayed for 10 days in the drug-treated group. Paralleling the loss of active sleep was a major increase in wake between Days 2 to 20. The drug also affected the intermediate states of sleep-wake transition and active-quiet sleep transition. The data raise major questions about the safety of a drug widely used in the newborn intensive care setting.

Aging↗
PubMed1982

Periodic apnea in the full-term infant: individual consistency, sex differences, and state specificity.

The occurrence of periodic apnea (apnea during periodic breathing) was studied in 27 normal, full-term infants during the first five weeks of life. The rate and mean length of apnea were analyzed both with respect to sleep state and with respect to respiratory pattern, ie, periodic vs nonperiodic breathing. The rate of apnea was found to vary according to sleep state and the pattern of breathing. The highest apnea rates were nonperiodic apneas in active sleep. Periodic apnea rates were relatively low in both active and quiet sleep; however, this type of apnea was consistently observed from weeks 2 through 5. The proportion of apneas that are periodic is much higher in quiet sleep than in active sleep. Rates of periodic and nonperiodic apnea were more consistently correlated in active sleep than in quiet sleep. The mean length of periodic apnea was found to be significantly greater than the mean length of nonperiodic apnea in both sleep states, a difference that reflected a greater positive skew in the distribution of the nonperiodic apnea lengths. This variation in length between periodic and nonperiodic apnea explains, in part, the increased mean length in quiet sleep compared with active sleep. There were significant individual differences over weeks in both forms of apnea in active sleep and in quiet sleep. Female infants were observed to have higher rates of nonperiodic apnea than male infants in active sleep, although no significant differences in the distribution of lengths were obtained.

Female↗