NobleBlocks

Bradley Hospital

Hospital / health systemEast Providence, Rhode Island, United States

Research output, citation impact, and the most-cited recent papers from Bradley Hospital (United States). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
1.8K
Citations
163.5K
h-index
174
i10-index
1.8K
Also known as
Bradley Hospital

Top-cited papers from Bradley Hospital

Meta-Analysis of Quantitative Sleep Parameters From Childhood to Old Age in Healthy Individuals: Developing Normative Sleep Values Across the Human Lifespan
Maurice M. Ohayon, Mary A. Carskadon, Christian Guilleminault, Michael V. Vitiello
2004· SLEEP3.3Kdoi:10.1093/sleep/27.7.1255

OBJECTIVES: The purposes of this study were to identify age-related changes in objectively recorded sleep patterns across the human life span in healthy individuals and to clarify whether sleep latency and percentages of stage 1, stage 2, and rapid eye movement (REM) sleep significantly change with age. DESIGN: Review of literature of articles published between 1960 and 2003 in peer-reviewed journals and meta-analysis. PARTICIPANTS: 65 studies representing 3,577 subjects aged 5 years to 102 years. MEASUREMENT: The research reports included in this meta-analysis met the following criteria: (1) included nonclinical participants aged 5 years or older; (2) included measures of sleep characteristics by "all night" polysomnography or actigraphy on sleep latency, sleep efficiency, total sleep time, stage 1 sleep, stage 2 sleep, slow-wave sleep, REM sleep, REM latency, or minutes awake after sleep onset; (3) included numeric presentation of the data; and (4) were published between 1960 and 2003 in peer-reviewed journals. RESULTS: In children and adolescents, total sleep time decreased with age only in studies performed on school days. Percentage of slow-wave sleep was significantly negatively correlated with age. Percentages of stage 2 and REM sleep significantly changed with age. In adults, total sleep time, sleep efficiency, percentage of slow-wave sleep, percentage of REM sleep, and REM latency all significantly decreased with age, while sleep latency, percentage of stage 1 sleep, percentage of stage 2 sleep, and wake after sleep onset significantly increased with age. However, only sleep efficiency continued to significantly decrease after 60 years of age. The magnitudes of the effect sizes noted changed depending on whether or not studied participants were screened for mental disorders, organic diseases, use of drug or alcohol, obstructive sleep apnea syndrome, or other sleep disorders. CONCLUSIONS: In adults, it appeared that sleep latency, percentages of stage 1 and stage 2 significantly increased with age while percentage of REM sleep decreased. However, effect sizes for the different sleep parameters were greatly modified by the quality of subject screening, diminishing or even masking age associations with different sleep parameters. The number of studies that examined the evolution of sleep parameters with age are scant among school-aged children, adolescents, and middle-aged adults. There are also very few studies that examined the effect of race on polysomnographic sleep parameters.

Emotion Regulation as a Scientific Construct: Methodological Challenges and Directions for Child Development Research
Pamela M. Cole, Sarah E. Martin, Tracy A. Dennis
2004· Child Development2.0Kdoi:10.1111/j.1467-8624.2004.00673.x

Emotion regulation has emerged as a popular topic, but there is doubt about its viability as a scientific construct. This article identifies conceptual and methodological challenges in this area of study and describes exemplar studies that provide a substantive basis for inferring emotion regulation. On the basis of those studies, 4 methods are described that provide compelling evidence for emotion regulation: independent measurement of activated emotion and purported regulatory processes; analysis of temporal relations; measurement across contrasting conditions; and multiple, convergent measures. By offering this perspective, this article aims to engage thoughtful debate and critical analysis, with the goal of increasing methodological rigor and advancing an understanding of emotion regulation as a scientific construct.

Over-the-Air Deep Learning Based Radio Signal Classification
Timothy J. O’Shea, Tamoghna Roy, T. Charles Clancy
2018· IEEE Journal of Selected Topics in Signal Processing1.5Kdoi:10.1109/jstsp.2018.2797022

We conduct an in depth study on the performance of deep learning based radio signal classification for radio communications signals. We consider a rigorous baseline method using higher order moments and strong boosted gradient tree classification, and compare performance between the two approaches across a range of configurations and channel impairments. We consider the effects of carrier frequency offset, symbol rate, and multipath fading in simulation, and conduct over-the-air measurement of radio classification performance in the lab using software radios, and we compare performance and training strategies for both. Finally, we conclude with a discussion of remaining problems, and design considerations for using such techniques.

Activity-Based Sleep-Wake Identification: An Empirical Test of Methodological Issues
Avi Sadeh, Melinda S. Sharkey, Mary A. Carskadon
1994· SLEEP1.5Kdoi:10.1093/sleep/17.3.201

The effects of actigraph placement and device sensitivity on actigraphic automatic sleep-wake scoring were assessed using concomitant polysomnographic and wrist actigraphic data from dominant and nondominant hands of 20 adults and 16 adolescents during 1 laboratory night. Although activity levels differed between dominant and nondominant wrists during periods of sleep (F = 4.57; p < 0.05) and wake (F = 15.5; p < 0.0005), resulting sleep-wake scoring algorithms were essentially the same and were equally explanatory (R2 = 0.64; p < 0.0001). When the sleep-wake scoring algorithm derived from the nondominant hand was used to score the nondominant data for sleep-wake, overall agreement rates with polysomnography scoring ranged between 91 and 93% for the calibration and validation samples. Results obtained with the same algorithm for the dominant-wrist data were within the same range. Agreement for sleep scoring was consistently higher than for wake scoring. Statistical manipulation of activity levels before applying the scoring algorithm indicated that this algorithm is quite robust toward moderate changes in activity level. Use of "twin-wrist actigraphy" enables identification of artifacts that may result from breathing-related motions.

Emotion regulation among school-age children: The development and validation of a new criterion Q-sort scale.
Ann Shields, Dante Cicchetti
1997· Developmental Psychology1.4Kdoi:10.1037/0012-1649.33.6.906

To foster the study of emotion regulation beyond infancy and toddlerhood, a new criterion Q-sort was constructed. In Study 1, Q-scales for emotion regulation and autonomy were developed, and analyses supported their discriminant validity. Study 2 further explored the construct validity of the Emotion Regulation Q-Scale within a sample of 143 maltreated and 80 impoverished children, aged 6 to 12 years. A multitrait-multimethod matrix and confirmatory factor analyses indicated impressive convergence among the Emotion Regulation Q-Scale and established measures of affect regulation. This new scale also was discriminable from measures of related constructs, including Q-sort assessments of ego resiliency. The use of this new measure was further supported by its ability to distinguish between maltreated and comparison children and between groups of well-regulated versus dysregulated children.

Association between Puberty and Delayed Phase Preference
Mary A. Carskadon, Cecilia Vieira, Christine Acebo
1993· SLEEP1.2Kdoi:10.1093/sleep/16.3.258

Many teenagers go to bed and wake up significantly later than younger children, a developmental progression thought to reflect adolescent psychosocial processes. To determine whether biological processes may underlie a delay of phase preference in adolescents, 183 sixth-grade boys and 275 sixth-grade girls completed questionnaires for morningness/eveningness (M/E) and pubertal status. School environment and birth order were also evaluated. A significant relationship of pubertal status to M/E was found in girls, with a similar though nonsignificant trend in boys. No relationship between M/E and psychosocial factors was found. These data support involvement of a biological factor in the adolescent phase preference delay and indicate that our current understanding of adolescent sleep patterns may need revision.

Update on Cardiovascular Implantable Electronic Device Infections and Their Management
Larry M. Baddour, Andrew E. Epstein, Christopher C. Erickson, Bradley P. Knight +4 more
2010· Circulation1.0Kdoi:10.1161/circulationaha.109.192665

Despite improvements in cardiovascular implantable electronic device (CIED) design, application of timely infection control practices, and administration of antibiotic prophylaxis at the time of device placement, CIED infections continue to occur and can be life-threatening. This has prompted the study of all aspects of CIED infections. Recognizing the recent advances in our understanding of the epidemiology, risk factors, microbiology, management, and prevention of CIED infections, the American Heart Association commissioned this scientific statement to educate clinicians about CIED infections, provide explicit recommendations for the care of patients with suspected or established CIED infections, and highlight areas of needed research.

Age-Related Changes in 1/<i>f</i>Neural Electrophysiological Noise
Bradley Voytek, Mark Kramer, John Case, Kyle Q. Lepage +3 more
2015· Journal of Neuroscience858doi:10.1523/jneurosci.2332-14.2015

Aging is associated with performance decrements across multiple cognitive domains. The neural noise hypothesis, a dominant view of the basis of this decline, posits that aging is accompanied by an increase in spontaneous, noisy baseline neural activity. Here we analyze data from two different groups of human subjects: intracranial electrocorticography from 15 participants over a 38 year age range (15-53 years) and scalp EEG data from healthy younger (20-30 years) and older (60-70 years) adults to test the neural noise hypothesis from a 1/f noise perspective. Many natural phenomena, including electrophysiology, are characterized by 1/f noise. The defining characteristic of 1/f is that the power of the signal frequency content decreases rapidly as a function of the frequency (f) itself. The slope of this decay, the noise exponent (χ), is often <-1 for electrophysiological data and has been shown to approach white noise (defined as χ = 0) with increasing task difficulty. We observed, in both electrophysiological datasets, that aging is associated with a flatter (more noisy) 1/f power spectral density, even at rest, and that visual cortical 1/f noise statistically mediates age-related impairments in visual working memory. These results provide electrophysiological support for the neural noise hypothesis of aging. Significance statement: Understanding the neurobiological origins of age-related cognitive decline is of critical scientific, medical, and public health importance, especially considering the rapid aging of the world's population. We find, in two separate human studies, that 1/f electrophysiological noise increases with aging. In addition, we observe that this age-related 1/f noise statistically mediates age-related working memory decline. These results significantly add to this understanding and contextualize a long-standing problem in cognition by encapsulating age-related cognitive decline within a neurocomputational model of 1/f noise-induced deficits in neural communication.

Regulation of Adolescent Sleep: Implications for Behavior
Mary A. Carskadon, Christine Acebo, Oskar G. Jenni
2004· Annals of the New York Academy of Sciences800doi:10.1196/annals.1308.032

Adolescent development is accompanied by profound changes in the timing and amounts of sleep and wakefulness. Many aspects of these changes result from altered psychosocial and life-style circumstances that accompany adolescence. The maturation of biological processes regulating sleep/wake systems, however, may be strongly related to the sleep timing and amount during adolescence-either as "compelling" or "permissive" factors. The two-process model of sleep regulation posits a fundamental sleep-wake homeostatic process (process S) working in concert with the circadian biological timing system (process C) as the primary intrinsic regulatory factors. How do these systems change during adolescence? We present data from adolescent participants examining EEG markers of sleep homeostasis to evaluate whether process S shows maturational changes permissive of altered sleep patterns across puberty. Our data indicate that certain aspects of the homeostatic system are unchanged from late childhood to young adulthood, while other features change in a manner that is permissive of later bedtimes in older adolescents. We also show alterations of the circadian timing system indicating a possible circadian substrate for later adolescent sleep timing. The circadian parameters we have assessed include phase, period, melatonin secretory pattern, light sensitivity, and phase relationships, all of which show evidence of changes during pubertal development with potential to alter sleep patterns substantially. However the changes are mediated-whether through process S, process C, or by a combination-many adolescents have too little sleep at the wrong circadian phase. This pattern is associated with increased risks for excessive sleepiness, difficulty with mood regulation, impaired academic performance, learning difficulties, school tardiness and absenteeism, and accidents and injuries.

Adolescent Sleep Patterns, Circadian Timing, and Sleepiness at a Transition to Early School Days
Mary A. Carskadon, Amy R. Wolfson, Christine Acebo, Orna Tzischinsky +1 more
1998· SLEEP771doi:10.1093/sleep/21.8.871

STUDY OBJECTIVES: This study examined effects on adolescent sleep patterns, sleepiness, and circadian phase of a school transition requiring an earlier start. DESIGN AND SETTING: Adolescents were evaluated in 9th and 10th grades; school start time in 9th grade was 0825 and in 10th grade was 0720. Assessments at each point included 2 weeks of actigraphy and sleep diaries at home, followed by a 22-hour laboratory evaluation, including evening saliva samples every 30 minutes in dim light for determination of dim-light salivary melatonin onset phase (DLSMO), overnight sleep monitoring, and multiple sleep latency test (MSLT). PARTICIPANTS: Twenty-five females and 15 males, ages 14 to 16.2 were enrolled; 32 completed the study in 9th grade and 26 completed in 10th grade. INTERVENTIONS: Participants kept their own schedules, except that laboratory nights were scheduled based upon school-night sleep patterns. MEASUREMENTS AND RESULTS: According to actigraphy, students woke earlier on school days in 10th than in 9th grade, but they did not go to sleep earlier and they slept less. DLSMO phase was later in 10th grade (mean = 2102) than 9th grade (mean = 2024). Sleep latency on MSLT overall was shorter in 10th (mean = 8.5 minutes) than in 9th (mean = 11.4 minutes), particularly on the first test of the morning at 0830 (5.1 vs 10.9 minutes). Two REM episodes on MSLT occurred in 16% of participants in 10th grade; one REM episode occurred in 48%. When those with REM sleep on one or both morning MSLTs (n = 11) were compared to those without morning REM, significant differences included shorter sleep latency on the first test, less slow wave sleep the night before, and later DLSMO phase in those who had morning REM. CONCLUSIONS: Early start time was associated with significant sleep deprivation and daytime sleepiness. The occurrence of REM sleep on MSLT indicates that clinicians should exercise caution in interpreting MSLT REM sleep in adolescents evaluated on their "usual" schedules. Psychosocial influences and changes in bioregulatory systems controlling sleep may limit teenagers' capacities to make adequate adjustments to an early school schedule.

Estimating Sleep Patterns with Activity Monitoring in Children and Adolescents: How Many Nights Are Necessary for Reliable Measures?
Christine Acebo, Avi Sadeh, Ronald Seifer, Orna Tzischinsky +3 more
1999· SLEEP727doi:10.1093/sleep/22.1.95

STUDY OBJECTIVES: This study provides estimates of reliability for aggregated values from 1 to 7 recording nights for five commonly used actigraphic measures of sleep patterns, reliability as a function of night type (weeknight or weekend night), and stability of measures over several months. DESIGN AND SETTING: Data are from three studies that obtained 7 nights of actigraph data (using Mini Motionlogger actigraphs and associated validated algorithms [ASA]) on children and adolescents living at home on self-selected sleep-wake schedules. PARTICIPANTS: Participants were 169 children aged 12-60 months, and 55 adolescents aged 11-16 years. MEASUREMENTS AND RESULTS: Up to 28% of weekly recordings may be unacceptable for analysis in young participants because of illness, technical problems, and participant noncompliance; studies aiming to collect 5 nights of actigraph data should record for at least 1 full week. Reliability estimates for values aggregated over any 5 nights were adequate (> or = .70) for sleep start time, wake minutes, and sleep efficiency. Measures of sleep minutes and sleep period were less reliable and may require 7 or more nights for estimates of stable individual differences. Reliability for 1- or 2-night aggregates were poor for all measures. We found significant and high correlations between summer and fall session measures for all five variables when weekend nights were included. CONCLUSIONS: Five or more nights of usable recordings are required to obtain reliable actigraph measures of sleep for children and adolescents.

Evidence for the Validity of a Sleep Habits Survey for Adolescents
Amy R. Wolfson, Mary A. Carskadon, Christine Acebo, Ronald Seifer +3 more
2003· SLEEP682doi:10.1093/sleep/26.2.213

STUDY OBJECTIVES: To examine the validity of self-reported survey estimates of sleep patterns in adolescents through a comparison of retrospective survey descriptions of usual school- and weekend-night sleep habits with diary-reported sleep patterns and actigraphically estimated sleep behaviors over a subsequent week. DESIGN AND SETTING: High school students completed a Sleep Habits Survey about the previous 2 weeks and then wore an actigraph (AMI, Ardsley, NY) for 8 days while keeping a daily sleep diary. Matched-pair t tests assessed average differences between survey and diary reports and between survey and actigraph estimates. Pearson correlations assessed the extent to which survey reports were in agreement with diary reports and actigraphy estimates. PARTICIPANTS: 302 high school students (196 girls, 106 boys) in grades 9-12 from five high schools. RESULTS: School-night survey total sleep times and wake times did not differ from sleep amounts reported in the diary or estimated by actigraphy; survey bedtimes were slightly earlier. On weekends, survey total sleep times and wake times were longer and later, respectively, than estimated with actigraphy and reported on diaries. Moreover, school- and weekend-night survey variables were significantly correlated both with diary and actigraphy variables. Strengths of the associations were consistently greater for school-night variables than the corresponding weekend-night variables. CONCLUSIONS: The findings support the validity of the Sleep Habits Survey estimates in comparison with diary and actigraphy. Strengths and limitations for survey measures of high school students' usual sleep/wake patterns are discussed.

An update on adolescent sleep: New evidence informing the perfect storm model<sup>☆</sup>
Stephanie J. Crowley, Amy R. Wolfson, Leila Tarokh, Mary A. Carskadon
2018· Journal of Adolescence636doi:10.1016/j.adolescence.2018.06.001

The maturation of sleep regulatory systems during adolescence in combination with psychosocial and societal pressures culminate in a "Perfect Storm" of short and ill-timed sleep and the associated consequences for many youngsters. This model, first described by Carskadon in 2011, guides our current thinking of adolescent sleep behavior. Since the original description, the field has moved forward with remarkable pace, and this review aims to summarize recent progress and describe how this new work informs our understanding of sleep regulation and sleep behavior during this developmental time frame.

Common and distinct patterns of grey-matter volume alteration in major depression and bipolar disorder: evidence from voxel-based meta-analysis
Toby Wise, Joaquim Raduà, Esther Via, Narcı́s Cardoner +4 more
2016· Molecular Psychiatry617doi:10.1038/mp.2016.72

Finding robust brain substrates of mood disorders is an important target for research. The degree to which major depression (MDD) and bipolar disorder (BD) are associated with common and/or distinct patterns of volumetric changes is nevertheless unclear. Furthermore, the extant literature is heterogeneous with respect to the nature of these changes. We report a meta-analysis of voxel-based morphometry (VBM) studies in MDD and BD. We identified studies published up to January 2015 that compared grey matter in MDD (50 data sets including 4101 individuals) and BD (36 data sets including 2407 individuals) using whole-brain VBM. We used statistical maps from the studies included where available and reported peak coordinates otherwise. Group comparisons and conjunction analyses identified regions in which the disorders showed common and distinct patterns of volumetric alteration. Both disorders were associated with lower grey-matter volume relative to healthy individuals in a number of areas. Conjunction analysis showed smaller volumes in both disorders in clusters in the dorsomedial and ventromedial prefrontal cortex, including the anterior cingulate cortex and bilateral insula. Group comparisons indicated that findings of smaller grey-matter volumes relative to controls in the right dorsolateral prefrontal cortex and left hippocampus, along with cerebellar, temporal and parietal regions were more substantial in major depression. These results suggest that MDD and BD are characterised by both common and distinct patterns of grey-matter volume changes. This combination of differences and similarities has the potential to inform the development of diagnostic biomarkers for these conditions.

Adolescent Changes in the Homeostatic and Circadian Regulation of Sleep
Megan Hastings Hagenauer, J.I. Perryman, Theresa M. Lee, Mary A. Carskadon
2009· Developmental Neuroscience571doi:10.1159/000216538

Sleep deprivation among adolescents is epidemic. We argue that this sleep deprivation is due in part to pubertal changes in the homeostatic and circadian regulation of sleep. These changes promote a delayed sleep phase that is exacerbated by evening light exposure and incompatible with aspects of modern society, notably early school start times. In this review of human and animal literature, we demonstrate that delayed sleep phase during puberty is likely a common phenomenon in mammals, not specific to human adolescents, and we provide insight into the mechanisms underlying this phenomenon.

Ensuring Comprehensive Care and Support for Transgender and Gender-Diverse Children and Adolescents
Jason Rafferty, SECTION ON LESBIAN, GAY, BISEXUAL, AND TRANSGENDER HEALTH AND WELLNESS, Michael W. Yogman, Rebecca Baum +4 more
2018· PEDIATRICS569doi:10.1542/peds.2018-2162

As a traditionally underserved population that faces numerous health disparities, youth who identify as transgender and gender diverse (TGD) and their families are increasingly presenting to pediatric providers for education, care, and referrals. The need for more formal training, standardized treatment, and research on safety and medical outcomes often leaves providers feeling ill equipped to support and care for patients that identify as TGD and families. In this policy statement, we review relevant concepts and challenges and provide suggestions for pediatric providers that are focused on promoting the health and positive development of youth that identify as TGD while eliminating discrimination and stigma.

Patterns of sleep and sleepiness in adolescents.
Mary A. Carskadon
1990· PubMed556

Most studies of adolescent sleep habits show a pattern of decreasing total sleep time, a tendency to delay the timing of sleep, and an increased level of daytime sleepiness. Laboratory tests have shown that adolescents do not have a decreased need for sleep but probably need more sleep than prepubertally. A number of factors affect the development of adolescent sleep patterns. Puberty itself imposes a burden of increased daytime sleepiness with no change in nocturnal sleep. Parental involvement in setting bedtimes wanes, though they become increasingly involved in waking teenagers in the mornings. Curfews and school schedules also affect adolescent sleep patterns, seen most commonly as imposing earlier rise times as the school day begins earlier during the adolescent years. Part-time employment has a significant impact on the sleep patterns of teenagers: those who work more than 20 h each week sleep less, go to bed later, are more sleepy, and drink more caffeine and alcohol. Development of circadian rhythms may also play a role in the phase delay teenagers commonly experience. The primary conclusion is that many adolescents do not get enough sleep. The consequences of the chronic pattern of insufficient sleep are daytime sleepiness, vulnerability to catastrophic accidents, mood and behavior problems, increased vulnerability to drugs and alcohol, and development of major disorders of the sleep/wake cycle. Educational programs hold the promise of improving teenagers' sleep patterns through informing youngsters, parents, and pediatricians about proper sleep hygiene and the risks of poor sleep habits.

The Relationship Between Reported Sleep Quality and Sleep Hygiene in Italian and American Adolescents
Monique K. LeBourgeois, Flavia Giannotti, Flavia Cortesi, Amy R. Wolfson +1 more
2005· PEDIATRICS486doi:10.1542/peds.2004-0815h

OBJECTIVE: The purpose of the study was to examine the relationship between self-reported sleep quality and sleep hygiene in Italian and American adolescents and to assess whether sleep-hygiene practices mediate the relationship between culture and sleep quality. METHODS: Two nonprobability samples were collected from public schools in Rome, Italy, and Hattiesburg, Mississippi. Students completed the following self-report measures: Adolescent Sleep-Wake Scale, Adolescent Sleep Hygiene Scale, Pubertal Developmental Scale, and Morningness/Eveningness Scale. RESULTS: The final sample included 776 Italian and 572 American adolescents 12 to 17 years old. Italian adolescents reported much better sleep hygiene and substantially better sleep quality than American adolescents. A moderate-to-strong linear relationship was found between sleep hygiene and sleep quality in both samples. Separate hierarchical multiple regression analyses were performed on both samples. Demographic and individual characteristics explained a significant proportion of the variance in sleep quality (Italians: 18%; Americans: 25%), and the addition of sleep-hygiene domains explained significantly more variance in sleep quality (Italians: 17%; Americans: 16%). A final hierarchical multiple regression analysis with both samples combined showed that culture (Italy versus United States) only explained 0.8% of the variance in sleep quality after controlling for sleep hygiene and all other variables. CONCLUSIONS: Cross-cultural differences in sleep quality, for the most part, were due to differences in sleep-hygiene practices. Sleep hygiene is an important predictor of sleep quality in Italian and American adolescents, thus supporting the implementation and evaluation of educational programs on good sleep-hygiene practices.

Homeostatic Sleep Regulation in Adolescents
Oskar G. Jenni, Peter Achermann, Mary A. Carskadon
2005· SLEEP467doi:10.1093/sleep/28.11.1446

STUDY OBJECTIVES: To examine the effects of total sleep deprivation on adolescent sleep and the sleep electroencephalogram (EEG) and to study aspects of sleep homeostasis. DESIGN: Subjects were studied during baseline and recovery sleep after 36 hours of wakefulness. SETTING: Four-bed sleep research laboratory. PARTICIPANTS: Seven prepubertal or early pubertal children (pubertal stage Tanner 1 or 2 = Tanner 1/2; mean age 11.9 years, SD +/- 0.8, 2 boys) and 6 mature adolescents (Tanner 5; 14.2 years, +/- 1.4, 2 boys). INTERVENTIONS: Thirty-six hours of sleep deprivation. MEASUREMENTS: All-night polysomnography was performed. EEG power spectra (C3/A2) were calculated using a Fast Fourier transform routine. RESULTS: In both groups, sleep latency was shorter, sleep efficiency was higher, non-rapid eye movement (NREM) sleep stage 4 was increased, and waking after sleep onset was reduced in recovery relative to baseline sleep. Spectral power of the NREM sleep EEG was enhanced after sleep deprivation in the low-frequency range (1.6-3.6 Hz in Tanner 1/2; 0.8-6.0 Hz in Tanner 5) and reduced in the sigma range (11-15 Hz). Sleep deprivation resulted in a stronger increase of slow-wave activity (EEG power 0.6-4.6 Hz, marker for sleep homeostatic pressure) in Tanner 5 (39% above baseline) than in Tanner 1/2 adolescents (18% above baseline). Sleep homeostasis was modeled according to the two-process model of sleep regulation. The build-up of homeostatic sleep pressure during wakefulness was slower in Tanner 5 adolescents (time constant of exponential saturating function 15.4 +/- 2.5 hours) compared with Tanner 1/2 children (8.9 +/- 1.2 hours). In contrast, the decline of the homeostatic process was similar in both groups. CONCLUSION: Maturational changes of homeostatic sleep regulation are permissive of the sleep phase delay in the course of adolescence.

Children's Sleep: An Interplay Between Culture and Biology
Oskar G. Jenni, Bonnie B. O’Connor
2005· PEDIATRICS464doi:10.1542/peds.2004-0815b

Pediatricians provide a major source of knowledge for parents about children's behavior and development, although their advice is largely based on their own cultural values and beliefs in interaction with their personal and clinical experience. This review presents cross-cultural aspects of children's sleep behavior in industrialized and complex modern societies and provides a basis for understanding dimensions and mechanisms of cultural differences. We submit that it is the interaction between culture and biology that establishes behavioral and developmental norms and expectations regarding normal and problematic children's sleep. Pediatricians need to recognize the cultural environment in which children live and be knowledgeable about how cultural beliefs and values of both families and physicians interact with the needs and biological characteristics of individual children.