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Biomedical subjects

Christine Acebo

Publications and source records attributed to Christine Acebo.

13 recordsLinked to original sources
PubMed2006

Actigraphy.

Actigraphy is a methodology for recording and analyzing activity (movement) from small, computerized devices worn on the body. Published reports on the reliability and validity of actigraph measures, although not comprehensive, generally indicate that sleep estimated by scoring algorithms is relatively consistent with PSG-scored sleep for normal individuals across the lifespan and for some patient groups. Accuracy is often greatly decreased when sleep is disordered or disrupted. Although actigraphy maybe suitable for documenting and evaluating some sleep disorders, its role in clinical diagnosis is limited. Actigraphy is a useful methodology for investigating group differences, sleep-pattern variations over time, and the effects of behavioral or treatment interventions. Controlling artifacts is extremely important, and using some form of daily log is essential for documenting events. The recording period should be long enough to provide reliable measures and to capture important variations across time.

Electrophysiology↗
PubMed2005

Experimental restriction of sleep opportunity in children: effects on teacher ratings.

STUDY OBJECTIVE: To determine the effects of experimental restriction of sleep opportunity on teacher ratings of academic performance and behavior in healthy normal children. DESIGN: Home-based, within-subjects design in which participants followed 3 week-long sleep schedules-Baseline (self-selected), Optimized, and Restricted-while attending school, with order of conditions counter-balanced (Optimized and Restricted). PARTICIPANTS: Seventy-four children (39 boys; aged 6 to 12 years, mean = 10) screened for medical and psychological health. MEASUREMENTS AND RESULTS: Teachers masked to assigned hours of sleep completed paper-and-pencil questionnaires at the end of each study condition. Questionnaire items were selected from several published measures. Summary scores included Academic Problems, Hyperactive-Impulsive Behaviors, Internalizing, Oppositional-Aggressive, Sleepiness, Total Attention Problems, and Mean Severity of Attention Problems. Main effects of sleep condition were found forAcademic Problems, Sleepiness, Total Attention Problems, and Mean Severity of Attention Problems. Restricting sleep increased ratings of Academic Problems (medium effect) relative to both Baseline (P < .01, eta(p)2 = .11) and Optimized (P < .05, eta(p)2 = .10) conditions and increased the Mean Severity of Attention Problems (medium effect) relative to Baseline (P < .01, eta(p)2 = .12). CONCLUSIONS: These findings provide experimental support for widely held beliefs about the importance of sufficient time-in-bed for academic functioning in children. Reducing sleep opportunity had a direct effect on academic performance, as rated by teachers, even among healthy students with no history of behavioral problems or academic difficulty. Findings also support insufficient sleep as a direct source of variability in the manifestation of attention problems but not hyperactivity.

Achievement↗
PubMed2005

Sleep/wake patterns derived from activity monitoring and maternal report for healthy 1- to 5-year-old children.

STUDY OBJECTIVES: To describe behavioral sleep/wake patterns of young children from actigraphy and mothers' reports, assess age-group and sex differences, describe daytime napping, and investigate the impact of family demographic variables on sleep-wake measures. DESIGN: Cross-sectional sample of children wore actigraphs for 1 week; mothers kept concurrent diaries. SETTING: Children studied in their homes. PARTICIPANTS: 169 normal healthy children in 7 age groups (12, 18, 24, 30, 36, 48, and 60 months old); 84 boys and 85 girls. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Nocturnal sleep/wake measures estimated from activity recordings using a validated algorithm; mothers' reports of nocturnal sleep/wake patterns and daytime naps obtained from concurrent diaries. Bedtimes and sleep start times were earliest and time in bed and sleep period times were longest for 12-month-old children. Rise time, sleep end time, and nocturnal sleep minutes did not differ across age groups. Actigraphic estimates indicated that children aged 1 to 5 years slept an average of 8.7 hours at night. Actigraph-based nocturnal wake minutes and wake bouts were higher than maternal diary reports for all age groups. Daytime naps decreased monotonically across age groups and accounted for most of the difference in 24-hour total sleep over age groups. Children in families with lower socioeconomic status had later rise times, longer time in bed, more nocturnal wake minutes and bouts, and more night-to-night variability in bedtime and sleep period time. Children with longer naps slept less at night. CONCLUSIONS: Individual differences in sleep/wake measures reflect characteristics of children, parents, or parent-child interactions.

Age Factors↗
PubMed2005

Sleep tendency during extended wakefulness: insights into adolescent sleep regulation and behavior.

Sleep tendency (latency to sleep onset) was examined during extended waking in prepubertal and mature adolescents to determine whether sleep pressure is lower near bedtime in the latter group. Participants were nine prepubertal (pubertal stage Tanner 1, mean age 11.1 years, SD+/-1.3 years, five males) and 11 pubertally mature adolescents (Tanner 5, 13.9+/-1.2 years, three males). They spent 10 nights at home on an identical fixed 10-h sleep schedule followed by a 36-h constant routine with sleep latency tests at 2-h intervals using standard polysomnography. Saliva was collected to assess dim-light melatonin onset (DLMO) phase. DLMO was earlier in the Tanner 1 (mean clock time=20:33 hours, SD=49 min) than Tanner 5 group (21:29 hours+/-42 min). Sleep latency compared at a 'critical period' spanning 12.5 (20:30 hours clock time) to 18.5 h (02:30 hours) after waking did not differ at 20:30 hours, but was shorter for the Tanner 1 group at 22:30 hours (Tanner 1=9.2+/-6.3 min; Tanner 5=15.7+/-5.8 min), 00:30 hours (Tanner 1=3.6+/-1.7 min; Tanner 5=9.0+/-6.4 min), and 02:30 hours (Tanner 1=2.0+/-1.7 min; Tanner 5=4.3+/-3.2 min; trend). These differences were apparent controlling for circadian phase by partial correlation. Sleep tendency after 14.5, 16.5, and 18.5 h awake was lower in mature versus prepubertal adolescents, supporting our hypothesis that a developmental change of intrinsic sleep-wake regulation may provide physiologically mediated 'permission' for later bedtimes in older adolescents.

Adolescent↗
PubMed2004

Regulation of adolescent sleep: implications for behavior.

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↗
PubMed2004

Performance on a dual driving simulation and subtraction task following sleep restriction.

A novel task, combining simulated driving with subtraction, was compared in 26 participants ages 18 to 26 years (M=20.6, SD=2.3; 13 men). After two nights of 8.5 hr. in bed, participants performed a 30-min. driving and subtraction task followed by a 10-min. Psychomotor Vigilance Task. These tasks were repeated after two more nights of 8.5 hr. time in bed for the control group and 5 hours and 3 hours time in bed for the restricted group. The sensitivity of the task to moderate sleep loss was supported because impairment was seen on several dual-task variables whereas impairment was not observed on the Psychomotor Vigilance Task.

Adolescent↗
PubMed2003

Evidence for the validity of a sleep habits survey for adolescents.

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.

Adolescent↗
PubMed2003

Effects of menopausal status on sleep in midlife women.

Disturbed sleep is a common complaint of midlife women often attributed to menopause, though few studies have examined direct effects of menopausal status on sleep. Our objective was to assess this issue in healthy midlife women. We examined sleep polysomnographically on 2 consecutive nights in 25 women (ages 45 - 56 yrs) without sleep complaints (13 pre-menopausal; 12 post-menopausal). Groups differed in Stage 1% (lower in post-menopausal) and slow wave sleep latency (shorter in post-menopausal). Subjective sleep reports did not differ. Age correlated negatively with Stage 1% and positively with Stage 4%. These results indicate that menopausal status plays a minimal role in sleep quality and sleep stage distribution in healthy midlife women without sleep complaints.

Female↗
PubMed2002

How well do school-aged children comply with imposed sleep schedules at home?

STUDY OBJECTIVES: To quantitatively assess compliance and experimental success with imposed sleep schedules among healthy children involved in an experimental comparison of optimized and restricted sleep. DESIGN: We asked children to follow assigned sleep schedules at home that created optimized (at least 10 hours time-in-bed per night) and restricted (6.5 to 8 hours time-in-bed per night) sleep conditions across 2 weeks during the school year. Self-report or parent-report of bedtime and risetime was obtained daily and continuous actigraphy was recorded. SETTING: Home. PARTICIPANTS: 78 healthy children (41 boys, 37 girls; mean age, 10.2 years; age range, 6.5 to 12.9 years) INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: We used reported time-in-bed to assess noncompliance with assigned schedules. Experimental failure was assessed with actigraphically based estimates of sleep period (time from sleep onset to sleep offset) and total sleep time (minutes of scored sleep during sleep period). Reported time-in-bed averaged 3.45 hours less per night under restricted versus optimized conditions. Sleep period and total sleep time showed similar differences (2.97 and 2.32 hours less, respectively). Four children met a priori criteria for noncompliance (3 for optimized nights and 1 for restricted). Eight children met a priori criteria for experimental failure within conditions (7 for optimized nights and 1 for restricted), but most achieved a substantial difference in sleep behavior across optimized and restricted weeks. CONCLUSIONS: In general, healthy children as young as 6 years of age can maintain substantial changes in their usual schedules across several nights at home and should be considered for inclusion in experimental studies of sleep extension and restriction. This paper offers a methodologic "road-map" for scientists interested in pursuing this goal.

Child↗
PubMed2002

The role of actigraphy in sleep medicine.

During the last decade actigraphy (activity-based monitoring) has become an essential tool in sleep research and sleep medicine. The validity, reliability and limitations of actigraphy for documenting sleep-wake patterns have been addressed. Normative data on sleep-wake patterns across development have been collected. Multiple studies have documented the adequacy of actigraphy to distinguish between clinical groups and to identify certain sleep-wake disorders. Actigraphy has also been shown to be effective in documenting the effects of various behavioral and medical interventions on sleep-wake patterns. Actigraphy is less useful for documenting sleep-wake in individuals who have long motionless periods of wakefulness (e.g. insomnia patients) or who have disorders that involve altered motility patterns (e.g. sleep apnea). Potential users should be aware of a number of pitfalls of actigraphy: (1) validity has not been established for all scoring algorithms or devices, or for all clinical groups; (2) actigraphy is not sufficient for diagnosis of sleep disorders in individuals with motor disorders or high motility during sleep; (3) the use of computer scoring algorithms without controlling for potential artifacts can lead to inaccurate and misleading results.

Humans↗
PubMedDate not supplied

Marital conflict and disruption of children's sleep.

Marital conflict was examined as a predictor of the quality and quantity of sleep in a sample of healthy 8- to 9-year-olds. Parents and children reported on marital conflict, the quantity and quality of children's sleep were examined through an actigraph worn for 7 consecutive nights, and child sleepiness was derived from child and mother reports. Increased marital conflict was associated with disruptions in the quantity and quality of children's sleep as well as subjective sleepiness, even after controlling for child age, ethnic group membership, socioeconomic status, sex, and body mass index. The results support the sensitization hypothesis in that exposure to marital conflict may influence an important facet of children's biological regulation, namely sleep.

Adult↗