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Biomedical subjects

C Acebo

Publications and source records attributed to C Acebo.

At least 19 recordsLinked to original sources
PubMed2001

Effects of acute sleep restriction on behavior, sustained attention, and response inhibition in children.

This study examined the effects of acute sleep restriction on the day-time behavior and performance of healthy children and adolescents. 82 participants (8 to 15 years of age) completed 5 nights of baseline sleep and were randomly assigned to Optimized (10 hr.) or Restricted (4 hr.) sleep for an overnight lab visit. Behavior, performance, and sleepiness were assessed the following day. Sleep restriction was associated with shorter daytime sleep latency, increased subjective sleepiness, and increased sleepy and inattentive behaviors but was not associated with increased hyperactive-impulsive behavior or impaired performance on tests of response inhibition and sustained attention. Results are discussed in terms of current theories regarding effects of inadequate or disturbed sleep among children and adolescents.

Adolescent↗
PubMed2001

Extended nights, sleep loss, and recovery sleep in adolescents.

In summary, this study of sleep in adolescents on an atypical schedule of 18-hour nights showed marked but not unanticipated differences in sleep as function of prior sleep deprivation. Unanticipated was the evidence of "recovery" sleep in adolescents who not only were not sleep deprived, but who had been on a sleep "optimizing" schedule and had been awake for only 10 hours. Extended sleep beginning about 4 hours in advance of entrained sleep onset phase was not associated with a return of SWS, a finding coinciding with predictions from studies in adults. Finally, this study provides an indication that the homeostatic sleep/wake process becomes less robust or sleep responsive during adolescent development, a phenomenon that may influence the delay of sleep common in adolescents.

Adolescent↗
PubMed1999

Estimating sleep patterns with activity monitoring in children and adolescents: how many nights are necessary for reliable measures?

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.

Adolescent↗
PubMed1999

Intrinsic circadian period of adolescent humans measured in conditions of forced desynchrony.

Circadian timing was assessed with forced desynchrony (FD) in 10 healthy adolescents (five boys, five girls; mean age 13.7 years). Following 10 days of entrainment to a fixed light-dark (LD) schedule at home, participants were studied under dim light (<20 lux) in the laboratory. A 28-h schedule (FD) was imposed for 12 x 28-h cycles. Saliva was collected at 30- or 60-min intervals throughout; core temperature was measured in constant routines (CR) before and after FD. Intrinsic circadian period was estimated by linear regression using temperature minimum from CRs and dim-light salivary melatonin onsets and offsets from FD. Average intrinsic circadian period for core temperature (n = 7) was 24.30+/-0.20, for melatonin onset was 24.33+/-0.21, and for melatonin offset was 24.35+/-0.21. Intrinsic circadian period in every adolescent was greater than 24 h.

Adolescent↗
PubMed1998

Adolescent sleep patterns, circadian timing, and sleepiness at a transition to early school days.

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.

Adolescent↗
PubMed1998

Parental report of sleep problems in children with attentional and learning disorders.

This study examined whether parents of children diagnosed with neurodevelopmental disorders (n = 79) report greater sleep-related problems in their offspring than do parents of normal community-based children (n = 86) on a research questionnaire developed to assess sleep and breathing problems, sleepiness, and behavioral problems. Clinical subgroups included: attention deficit/hyperactivity disorder (ADHD) (n = 43), learning disabilities (LD) (n = 11), and combined ADHD/LD (n = 25). Analyses revealed that parents of children with neurodevelopmental disorders report greater problems along all three dimensions than parents of normal control children. Sleep-related difficulties were reported at the same frequency across all three clinical subgroups. No significant difference between clinical and control groups was noted, however, in the reported length of sleep on weeknights. These preliminary findings suggest that sleep-related problems need to be routinely reviewed as part of the clinical evaluation of neurodevelopmental problems, because they may contribute to and/or exacerbate the behavioral manifestation of these disorders.

Analysis of Variance↗
PubMed1997

Effects of menopause and nasal occlusion on breathing during sleep.

Prevalence of sleep-disordered breathing (SDB) is reported to increase in menopausal women. We examined response to a nocturnal respiratory challenge (nasal occlusion) during overnight polysomnography in 31 women (45 to 55 yr). Thirteen were premenopausal, four perimenopausal, and 14 postmenopausal by history and hormonal assay. Nasal occlusion increased the apnea hypopnea index (AHI) (occlusion mean = 6.6 +/- 8.0 versus baseline mean = 1.6 +/- 2.6, p < 0.01) and arousal index (occlusion mean = 35.1 +/- 20.1 versus baseline mean = 20.7 +/- 11.6, p < 0.001), but did not change the oxygen saturation nadir in those with respiratory events (occlusion mean = 91.8 +/- 4.2 versus baseline mean = 92.0 +/- 11.6). Menopausal groups did not differ on AHI, arousal index, or oxygen saturation nadir in either condition. Key variables were compared between occlusion responders (n = 11) and nonresponders (n = 20). Responders and nonresponders were not distinguished by age, menopausal status, nor several cephalometric or anthropometric variables. Body mass index (31.1 +/- 8.5 versus 24.3 +/- 3.4, p < 0.003), neck circumference (34.0 +/- 2.5 versus 32.5 +/- 1.7 cm, p < 0.05), and mandibular-hyoid distance (18.5 +/- 3.8 versus 14.5 +/- 5.7 mm, p < 0.05) were greater in responders. These findings suggest hormonal factors may be less important than weight and facial morphology in midlife development of SDB in women.

Anthropometry↗
PubMed1997

An approach to studying circadian rhythms of adolescent humans.

The "long nights" protocol was designed to evaluate sleep processes and circadian rhythm parameters in young humans. A total of 19 children (10 boys, ages 11.2 to 14.1 years [mean = 12.7 +/- 1.0], and 9 girls, ages 12.2 to 14.4 years [mean = 13.1 +/- 0.7]) took part in the study. Sleep/wake initially was assessed at home using actigraphy and diary for 1 week on each child's self-selected schedule followed by an 8-night fixed light-dark (LD) condition, while sleeping from 22:00 to 08:00 h and wearing an eye mask to exclude as much light as possible. Phase measurements included 4-night mean actigraphically estimated sleep onset and offset as well as 1-night dim light salivary melatonin onset (DLSMO) phase at the end of each condition. Subjects then lived in the laboratory for 6 consecutive cycles: Day 1 LD = 14:10 h, lights out 22:00 to 08:00 h; Days 2-4 LD = 6:18 h, lights out 18:00 to 12:00 h; Days 5-6 = constant routine in continuous dim light (about 20 lux); Night 6 = 14 h recovery sleep. Phase markers (sleep onset, sleep offset, DLSMO) were significantly less dispersed after the fixed LD as compared to the self-selected condition, indicating efficacy of the LD protocol. Phase markers were correlated at the self-selected assessment (sleep onset vs. sleep offset r = .72; DLSMO vs. sleep onset r = .82; DLSMO vs. sleep offset r = .76) but not on the fixed schedule, probably due to restricted range. The constant routine provided additional phase markers, melatonin offset and midphase. Offset phase of melatonin secretion was significantly correlated with age (r = .62) and Tanner stage (r = .62). In conclusion, these preliminary data indicate a relationship between adolescent development and circadian phase. Thus, the long nights protocol is a feasible way in which to assess circadian parameters in young humans as well as to examine intrinsic sleep processes.

Adolescent↗
PubMed1996

The effects of regularizing sleep-wake schedules on daytime sleepiness.

The present study evaluated the differential effects of two manipulations of sleep-wake schedules on daily subjective ratings of daytime sleepiness of college undergraduate students. Two experimental conditions were compared: a sleep only group and a regularity group. Subjects in both conditions were given a lower limit for total sleep time (7.5 hours). Subjects in the regularity group received an additional instruction to keep a regular sleep schedule. The study was longitudinal and prospective. Following a baseline period (12 days), the experimental conditions were introduced. The experimental phase lasted 4 weeks and overall compliance was good. A follow-up phase (1 week) began 5 weeks past termination of the experimental phase. The findings indicated that when nocturnal sleep is not deprived, regularization of sleep-wake schedules is associated with reduced reported sleepiness. Subjects in the regular schedule condition reported greater and longer lasting improvements in alertness compared with subjects in the sleep only condition and reported improved sleep efficiency.

Adolescent↗
PubMed1996

Sleep, breathing, and cephalometrics in older children and young adults. Part I -- Normative values.

STUDY OBJECTIVES: Aims were (1) to provide normative values for sleep and sleep-related breathing variables and physical features (cephalometrics, body mass index [BMI], and tonsillar size) in older children/adolescents and young adults, (2) to describe sex and age group differences, and (3) to evaluate relationships between physical features and sleep-related breathing variables. DESIGN: Standard polysomnographic variables describing sleep and breathing were measured during a single night. Cephalometric measures were obtained from a standing lateral skull radiograph. SUBJECTS: Normal, healthy boys (n=23; mean age=13.3+/-2.1 years), girls (n=22; mean age =13.8+/-1.8 years), men (n=23; mean age=22.2+/-1.5 years), and women (n=24; mean age=22.4+/-1.8 years) with BMI less than 27 were evaluated. RESULTS: Sleep variables showed age group and sex differences consistent with published norms. Slow-wave sleep and rapid eye movement (REM) latency declined with age; transient arousals increased with age. Sleep-related breathing variables showed few changes related to age group or sex; small but statistically significant sex differences were found for arterial oxygen saturation nadir (lower in male subjects) and respiration disturbance index in non-REM sleep (greater in male subjects). Differences in cephalometric measures largely reflected normal growth and expected sex differences. No significant relationships between sleep-related breathing variables and physical findings were observed. CONCLUSIONS: These data provide well-controlled normative values for sleep, breathing, and cephalometrics in a group of normal older children, adolescents, and young adults. The data provide useful reference points for patients of these ages in whom sleep apnea is suspected, particularly since such clinical studies are normally based on first-night polysomnography. Furthermore, these values represent developmentally appropriate grouping of the data.

Adolescent↗
PubMed1996

Sleep, breathing, and cephalometrics in older children and young adults. Part II -- Response to nasal occlusion.

STUDY OBJECTIVES: We postulated that nasal occlusion would provide a challenge enabling us to assess factors predisposing development of sleep apnea in older children/adolescents and young adults. Factors of interest included sex, age, body mass index (BMI), tonsillar hypertrophy, and cephalometric measurements. DESIGN: Sleep and breathing variables were examined and compared for four groups of subjects between one baseline night and one night of nasal occlusion in a sleep research laboratory. SUBJECTS: Healthy, normal boys (n=23, mean age=13.3+/-2.1 years), girls (n=22, mean age=13.8+/-1.8 years), men (n=23, mean age=22.2+/-1.5 years), and women (n=24, mean age=22.4+/-1.8 years) were studied. MEASUREMENTS AND RESULTS: The following sleep and sleep-related breathing measures showed significant increases in all four groups from baseline to occlusion: percentage of stage 1, number of transient arousals, transient arousal index, apnea index, respiratory disturbance index (RDI), and mean apnea length. No significant relationships were found between occlusion-night RDI and tonsillar size, cephalometric variables, or BMI, either singly or in combination. CONCLUSIONS: Subjects' responses to nasal occlusion varied: most demonstrated a minimal and clinically insignificant increase in RDI; few showed a marked increase in RDI. Significant increases of sleep fragmentation -- even in the absence of frankly disturbed breathing -- indicate that nasal occlusion may secondarily affect waking function if prolonged over a series of nights.

Adolescent↗
PubMed1995

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.

Adolescent↗
PubMed1995

Case study: sleep and aggressive behavior in a blind, retarded adolescent. A concomitant schedule disorder?

Blind people are prone to suffer from sleep-wake schedule disorders. This report describes 2 months of monitoring of sleep patterns and aggressive behaviors in a totally blind, severely retarded adolescent boy, hospitalized in a psychiatric hospital. The documented sleep-wake patterns seem to portray a sleep-wake schedule disorder with a monthly periodicity. Aggressive behaviors seem to echo the same periodicity, suggesting that a common or linked biobehavioral timing mechanism may underlie both sleep and episodic aggressive outbursts. The need to consider sleep schedule disorders as a primary process underlying some psychopathological disorders, and the related risks of misdiagnosis and mistreatment, are highlighted.

Adolescent↗
PubMed1993

A self-administered rating scale for pubertal development.

The purpose of this study was to assess the reliability and validity of a new self-rating scale to measure children's pubertal status without pictorial representations or interviews. The scale is an adaptation of an interview-based puberty-rating scale by Petersen, and included scores for each of five items rating physical development, an overall maturation measure, and a categorical maturation score designed to be similar to Tanner staging categories. Each measure was obtained from independent ratings by students and parents, and a 3-point categorical scale was also obtained from teachers. Subjects included 698 5th- and 6th-grade students (323 boys and 375 girls) from 61 schools and their parents and teachers. Fifth-grade students rated themselves and were rated by parents as less mature than 6th graders; 6th-grade girls were consistently rated more mature than boys of the same age. Significant correlations were found between parents and students for all of the measures for 6th-graders and 5th-grade girls and several measures for 5th-grade boys. This new scale is a useful tool for assessing pubertal status in settings that require noninvasive measures.

Adolescent↗
PubMed1993

Association between puberty and delayed phase preference.

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.

Adolescent↗
PubMed1993

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.

Age Factors↗
PubMed1993

Parental reports of seasonal mood and behavior changes in children.

OBJECTIVE: The chief purpose of this study was to investigate the nature and prevalence of children's seasonal symptoms. METHOD: Parental reports of seasonal changes in six mood or behavioral symptoms (sleeping, eating, irritability, energy, withdrawal, and sadness) were surveyed for children living across the United States. The sample included 892 girls (mean age = 10.5 +/- 1.0 years) and 788 boys (mean age = 10.6 +/- 0.9 years), with a response rate of 46% for girls' parents and 39% for boys' parents. RESULTS: At least one winter recurring symptom was reported in 48.5% of children, as compared with 9.1% in fall and 10.8% in spring. Winter symptoms were reported equally in girls and boys with one exception ("is tired"); age effects were found for three symptoms only in girls ("sleep more," "is tired," and "withdraws"). Regional effects showed more winter symptoms reports in northern zones than in southern zones. CONCLUSIONS: Given the potential therapeutic benefit of light therapy in children with such seasonal patterns, careful assessment of seasonality is merited for children with winter mood and behavior problems.

Age Factors↗