Practice parameters for behavioral treatment of bedtime problems and night wakings in infants and young children

Bedtime problems and frequent night wakings are highly prevalent in infants, toddlers, and preschoolers. Evidence suggests that sleep disruption and/or insufficient sleep have potential deleterious effects on children's cognitive development, regulation of affect, attention, health outcomes, and overall quality of life, as well as secondary effects on parental and family functioning. Furthermore, longitudinal studies have demonstrated that sleep problems first presenting in infancy may become chronic, persisting into the preschool and school-aged years. A solid body of literature now exists supporting the use of empirically-based behavioral management strategies to treat bedtime problems and night wakings in infants, toddlers, and preschoolers. The following practice parameters present recommendations for the use of behavioral (i.e., non-pharmacological) treatments of bedtime problems and night wakings in young children (aged 0 - 4. years 11 months). A companion review paper on which the recommendations are based was prepared by a taskforce appointed by the Standards of Practice Committee (SPC) of the American Academy of Sleep Medicine (AASM), and summarizes the peer-reviewed scientific literature on this topic. The authors of the review paper evaluated the evidence presented by the reviewed studies according to modified Sackett criteria. Using this information and a grading system described by Eddy (i.e., standard, guideline or option), the Standards of Practice Committee and Board of Directors of the American Academy of Sleep Medicine determined levels of treatment recommendation presented in the practice parameters below. These practice parameters provide 3 types of recommendations. First, recommendations are provided indicating that behavioral interventions are effective in the treatment of bedtime problems and night wakings in young children, producing reliable and significant clinical improvement in sleep parameters. Second, recommendations are made regarding specific behavioral therapies, including: (1) unmodified extinction, extinction with parental presence, and preventive parent education are all rated as individually effective therapies in the treatment of bedtime problems and night wakings (Standards), and (2) graduated extinction, bedtime fading/positive routines and scheduled awakenings are rated as individually effective therapies in the treatment of bedtime problems and night wakings but with less certainty (Guidelines). There was insufficient evidence to recommend standardized bedtime routines and positive reinforcement as single therapies. In addition, although behavioral therapies for bedtime problems and night wakings are often combined, there was insufficient evidence available to recommend one individual therapy over another or to recommend an individual therapy over a combination of therapies. Finally, recommendations are provided regarding the beneficial effects of behavioral treatments on secondary outcomes, including daytime functioning (child) and parental well-being.     

Bedtime activities, sleep environment, and sleep/wake patterns of Japanese elementary school children

Bedtime activities, sleep environment, and their impact on sleep/wake patterns were assessed in 509 elementary school children (6-12 years of age; 252 males and 257 females). Television viewing, playing video games, and surfing the Internet had negative impact on sleep/wake parameters. Moreover, presence of a television set or video game in the child's bedroom increased their activity before bedtime. Time to return home later than 8 p.m. from after-school activity also had a negative impact on sleep/wake patterns. Health care practitioners should be aware of the potential negative impact of television, video games, and the Internet before bedtime, and also the possibility that late after-school activity can disturb sleep/wake patterns.     

Brief report: a "storybook" ending to children's bedtime problems--the use of a rewarding social story to reduce bedtime resistance and frequent night waking

OBJECTIVE: To evaluate the efficacy and acceptability of a social story with tangible rewards to reduce children's disruptive bedtime behavior and frequent night waking. METHOD: Four children (ages 2 to 7), with clinically significant disruptive bedtime behavior, received the intervention, which consisted of a social story (The Sleep Fairy) that sets forth (a) parental expectations for appropriate bedtime behavior and (b) rewards for meeting those expectations. RESULTS: Parent sleep diaries indicated that children had a 78% average decrease in frequency of disruptive bedtime behaviors from baseline to intervention, with another 7% decrease at 3-month follow-up. Night wakings, a problem for 2 children during baseline, were not a problem during intervention and follow-up. Parents reported improved daytime behavior for 3 of the 4 children. Parents gave the intervention high acceptability ratings and maintained a high level of treatment fidelity. CONCLUSIONS: Use of a social story helped parents implement a multicomponent intervention using a familiar bedtime routine, thereby increasing the likelihood that implementation and effects occurred. The book format makes this intervention widely available to parents and professionals, with minimal costs and inconvenience.     

Family Chaos and Child Functioning in Relation to Sleep Problems Among Children at Risk for Obesity

This study evaluated the influence of child and family functioning on child sleep behaviors in low-income minority families who are at risk for obesity. A cross-sectional study was utilized to measure child and family functioning from 2013 to 2014. Participants were recruited from Head Start classrooms while data were collected during home visits. A convenience sample of 72 low-income Hispanic (65%) and African American (32%) families of preschool-aged children were recruited for this study. We assessed the association of child and family functioning with child sleep behaviors using a multivariate multiple linear regression model. Bootstrap mediation analyses examined the effects of family chaos between child functioning and child sleep problems. Poorer child emotional and behavioral functioning related to total sleep behavior problems. Chaos associated with bedtime resistance significantly mediated the relationship between Behavioral and Emotional Screening System (BESS) and Bedtime Resistance. Families at high risk for obesity showed children with poorer emotional and behavioral functioning were at higher risk for problematic sleep behaviors, although we found no link between obesity and child sleep. Family chaos appears to play a significant role in understanding part of these relationships. Future longitudinal studies are necessary to establish causal relationships between child and family functioning and sleep problems to further guide obesity interventions aimed at improving child sleep routines and increasing sleep duration.     

Estimating dim light melatonin onset (DLMO) phase in adolescents using summer or school-year sleep/wake schedules

STUDY OBJECTIVES: This analysis examined associations between the salivary dim light melatonin onset (DLMO) phase and self-selected sleep/ wake schedules in groups of children and adolescents during summer vacation and during the school year to determine the degree to which sleep/wake patterns can estimate salivary DLMO phase. DESIGN AND SETTING: Participants slept at home on self-selected schedules for 5 consecutive nights and reported their bedtime and wake-up time via daily telephone messages. Salivary melatonin was sampled in the laboratory on one evening every 30 minutes in dim light (< 50 lux) to determine DLMO phase. Within group bivariate regressions between sleep pattern measures (bedtime, wake-up time, and midsleep time) and DLMO phase were computed. PARTICIPANTS: One group, ages 9 to 17 years (mean age = 12.5, SD = 2.3 years, 74 males, 75 females) contributed 149 DLMO phase and sleep/wake pattern measures while on a school year schedule ("school group"). A separate group, ages 9 to 16 years (mean age = 13.1, SD = 1.3 years, 30 males, 29 females) contributed 59 DLMO phase and sleep/wake pattern measures while on a summer schedule ("summer group"). RESULTS: Bedtime, midsleep time, and wake-up time were positively correlated with DLMO phase in both groups. Although all correlation coefficients for the summer group were statistically greater compared to the school group, the regression equations predicted DLMO phase within +/- 1 hour of the measured DLMO phase in approximately 80% for both groups. CONCLUSIONS: DLMO phase can be estimated using self-selected sleep/wake patterns during the school year or summer vacation in healthy children and adolescents.     

Parent-reported periodic limb movement, sleep disordered breathing, bedtime resistance behaviors, and ADHD

The purpose of this study was to compare the relative strength of association between symptoms of attention deficit/hyperactivity disorder (ADHD) with sleep disordered breathing (SDB), periodic limb movement disorder (PLMD), and bedtime resistance behaviors (BRBs). The Pediatric Sleep Questionnaire was completed by parents of 283 children. Scales were derived to indicate risk for specific sleep disorders, then correlated with symptoms of ADHD. Strong independent interrelationships between symptoms of PLMD and symptoms of ADHD emerged, with potential additional contributions by bedtime resistance. These interrelationships remained after controlling for age, SDB, sleepiness, or BRBs. These data suggest ADHD symptoms may be especially related to PLMD but that insufficient sleep duration secondary to bedtime resistance and noncompliance may make an independent contribution.     

Parent-Reported Periodic Limb Movement,Sleep Disordered Breathing,Bedtime Resistance Behaviors,and ADHD

The purpose of this study was to compare the relative strength of association between symptoms of attention deficit/hyperactivity disorder (ADHD) with sleep disordered breathing (SDB), periodic limb movement disorder (PLMD), and bedtime resistance behaviors (BRBs). The Pediatric Sleep Questionnaire was completed by parents of 283 children. Scales were derived to indicate risk for specific sleep disorders, then correlated with symptoms of ADHD. Strong independent interrelationships between symptoms of PLMD and symptoms of ADHD emerged, with potential additional contributions by bedtime resistance. These interrelationships remained after controlling for age, SDB, sleepiness, or BRBs. These data suggest ADHD symptoms may be especially related to PLMD but that insufficient sleep duration secondary to bedtime resistance and noncompliance may make an independent contribution.     

Insomnia as a Moderator of Response to Time in Bed Restriction for Augmenting Antidepressant Treatment: A Preliminary Investigation

Background: There are complex, bidirectional associations between major depressive disorder and insomnia. In the present study, we evaluated insomnia as a moderator of response to antidepressant therapy in the context of a sleep manipulation (time in bed restriction) for major depressive disorder. Methods: Fifty-eight adults with major depressive disorder received 8 weeks of fluoxetine 20–40 mgs and were randomized to 8 hr time in bed (8h TIB) or 6 hr time in bed (6h TIB) for the first 2 weeks (participants in the 6h TIB condition were further randomized to a delayed bedtime (Late Bedtime) or advanced rise time (Early Rise Time) group). Insomnia was assessed at baseline using the Insomnia Severity Index. Depression symptom severity was determined by the clinician-rated 17-item Hamilton Rating Scale for Depression (HAMD-17), completed weekly. Results: A group by time interaction was observed whereby HAMD-17 scores were higher for participants assigned to the 6h TIB group (without insomnia, weeks 3 through 7; with insomnia from week 3 through 6, ps < .05) relative to participants without insomnia assigned to the 8h TIB group. There were no differences in HAMD-17 scores for participants with insomnia in the 6h TIB group relative to the 8h TIB group. Conclusion: These preliminary findings suggest that response to fluoxetine may be hindered by TIB restriction in individuals without insomnia. Individuals with insomnia respond similarly to fluoxetine regardless of whether their TIB is restricted. Limitations include exclusive use of self-report measures to categorize insomnia, and small sample sizes in several of the subgroups.     

Cosleeping versus solitary sleeping in children with bedtime problems: child emotional problems and parental distress

This study investigated sleep, behavioral and emotional problems, and parental relationships and psychological distress in a group of school-aged children with bedtime problems and persistent cosleeping, compared to solitary sleepers and controls. Participants were 148 school-aged children with bedtime problems (44 cosleepers, 104 solitary sleepers) and 228 healthy peers. Results suggested that cosleepers have a significantly later bedtime, shorter nighttime sleep duration, higher Children's Sleep Habits Questionnaire (CSHQ) bedtime resistance and sleep anxiety scores, and more behavioral and emotional problems compared to other groups. Parents of cosleepers have a significantly higher level of psychological and couple distress. A past history of sleep problems, couple and maternal distress, CSHQ bedtime resistance, sleep anxiety, and night wakings subscale scores, and nighttime fears were significantly predictive of cosleeping. Thus, when cosleeping is present, the child's emotional adjustment, family relationships, and parental psychological problems should be investigated.     

Efficacy of brief dynamic psychotherapy for children with emotional disorders.

BACKGROUND: Child psychiatry has enjoyed a long tradition of using brief psychotherapy with children, but research on its efficacy and effectiveness in the setting of routine clinical care is remarkably sparse; the aim of this study was to evaluate the efficacy of an original model of brief psychodynamic psychotherapy (BPP) for children with emotional disorders in a clinical outpatient setting. METHODS: A sample of 30 subjects (6.3-10.9 years old) was divided into an experimental BPP group and a control group. Each subject was evaluated at the beginning, after 6 months and at an 18-months follow-up. Outcome measures were Children's Global Assessment Scale and Child Behavior Check-List. Statistical and clinical significance of change were evaluated. RESULTS: At the first evaluation, the experimental group showed a better improvement in global functioning; at follow-up, the two groups improved to a comparable degree, but only the mean of the experimental group moved to a functional range. The experimental group showed a significant reduction in total behavioral problems and externalizing problems at the follow-up. CONCLUSIONS: The better improvement of the experimental group in two outcome measures suggests that BPP is efficient in emotional disorders. The hypothesis that BPP introduces changes at long term (sleeper effects) is suggested. The improvement in global functioning of the two groups is discussed in relation to specific characteristics of emotional disorders. Finally, limitations of the study are discussed and in particular the bias introduced by lack of randomization.     

A Nightly Bedtime Routine: Impact on Sleep in Young Children and Maternal Mood

Background:

Establishment of a consistent bedtime routine is often recommended to parents of young children, especially those with sleep difficulties. However, no studies have investigated the efficacy of such a routine independent of behavioral intervention. Thus, the purpose of this study was to examine the impact of a consistent bedtime routine on infant and toddler sleep, as well as maternal mood.

Methods:

405 mothers and their infant or toddler (ages 7-18 months, n = 206; ages 18-36 months, n = 199) participated in 2 age-specific 3-week studies. Families were randomly assigned to a routine or control group. The first week of the study served as a baseline during which the mothers were instructed to follow their child''s usual bedtime routine. In the second and third weeks, mothers in the routine group were instructed to conduct a specific bedtime routine, while the control group continued their child''s usual routine. All mothers completed the Brief Infant Sleep Questionnaire (BISQ) on a weekly basis and a daily sleep diary, as well as completed the Profile of Mood States (POMS).

Results:

The bedtime routine resulted in significant reductions in problematic sleep behaviors for infants and toddlers. Significant improvements were seen in latency to sleep onset and in number/duration of night wakings, P < 0.001. Sleep continuity increased and there was a significant decrease in the number of mothers who rated their child''s sleep as problematic. Maternal mood state also significantly improved. Control group sleep patterns and maternal mood did not significantly change over the 3-week study period.

Conclusion:

These results suggest that instituting a consistent nightly bedtime routine, in and of itself, is beneficial in improving multiple aspects of infant and toddler sleep, especially wakefulness after sleep onset and sleep continuity, as well as maternal mood.

Citation:

Mindell JA; Telofski LS; Wiegand B; Kurtz ES. A nightly bedtime routine: impact on sleep in young children and maternal mood. SLEEP 2009;32(5):599–606.     

The influence of acute exercise on sleep following high caffeine intake

The purpose of this study was to examine the influence of vigorous acute exercise on nocturnal sleep that had been disrupted by high doses (1200 mg) of caffeine throughout the daytime. Eight moderately fit, young males with a history of moderate caffeine use completed four conditions in a within-subjects, counterbalanced design: 60 min of (i) cycling at 60% VO(2peak) or (ii) quiet rest following placebo consumption, (iii) cycling, or (iv) quiet rest following the consumption of a high dose of caffeine. Each condition was performed twice from 1615-1715 h and followed by all-night polysomnographic recording. Subjects consumed two blinded 200-mg capsules of either lactose placebo or caffeine upon awakening, at 1600 h, and 2 h before bedtime. State anxiety was assessed at bedtime. Criterion scores consisted of the mean data across the two days in each condition. Sleep data were analyzed using a condition (exercise versus quiet rest) by drug (caffeine versus placebo) repeated-measures ANOVA. Caffeine-elicited sleep disturbance that was less than previously reported. Exercise attenuated selected sleep disturbances to a small degree. In general, the effects of exercise on sleep were not greater following caffeine compared to placebo. Indeed, increases in slow-wave sleep after exercise were approximately 1/3 smaller following caffeine treatment compared to placebo.     

Behavioral treatment of bedtime problems and night wakings in infants and young children

This paper reviews the evidence regarding the efficacy of behavioral treatments for bedtime problems and night wakings in young children. It is based on a review of 52 treatment studies by a task force appointed by the American Academy of Sleep Medicine to develop practice parameters on behavioral treatments for the clinical management of bedtime problems and night wakings in young children. The findings indicate that behavioral therapies produce reliable and durable changes. Across all studies, 94% report that behavioral interventions were efficacious, with over 80% of children treated demonstrating clinically significant improvement that was maintained for 3 to 6 months. In particular, empirical evidence from controlled group studies utilizing Sackett criteria for evidence-based treatment provides strong support for unmodified extinction and preventive parent education. In addition, support is provided for graduated extinction, bedtime fading/positive routines, and scheduled awakenings. Additional research is needed to examine delivery methods of treatment, longer-term efficacy, and the role of pharmacological agents. Furthermore, pediatric sleep researchers are strongly encouraged to develop standardized diagnostic criteria and more objective measures, and to come to a consensus on critical outcome variables.     

Children with cystic fibrosis benefit from massage therapy.

OBJECTIVE: To measure the effects of parents giving massage therapy to their children with cystic fibrosis to reduce anxiety in parents and their children and to improve the children's mood and peak air flow readings. METHODS: Twenty children (5-12 years old) with cystic fibrosis and their parents were randomly assigned to a massage therapy or a reading control group. Parents in the treatment group were instructed and asked to conduct a 20-minute child massage every night at bedtime for one month. Parents in the reading control group were instructed to read for 20 minutes a night with their child for one month. On days 1 and 30, parents and children answered questions relating to present anxiety levels and children answered questions relating to mood, and their peak air flow was measured. RESULTS: Following the first and last massage session, children and parents reported reduced anxiety. Mood and peak air flow readings also improved for children in the massage therapy group. CONCLUSIONS: These findings suggest that parents may reduce anxiety levels by massaging their children with cystic fibrosis and their children may benefit from receiving massage by having less anxiety and improved mood, which in turn may facilitate breathing.     

Actigraphy and parental ratings of sleep in children with attention-deficit/hyperactivity disorder (ADHD)

STUDY OBJECTIVES: To assess various sleep parameters in latency-aged children with ADHD and their normally developing peers through the use of multiple sleep measures. DESIGN: Six sleep parameters were evaluated for two groups of children, ADHD and normal comparison. Each group consisted of 25 children (20 males, 5 females) who ranged in age from 7 to 11 years. All children underwent rigorous diagnostic procedures and the ADHD subjects were selected only if they displayed pervasiveness in their symptomatology and were medication naive. Parents completed a retrospective questionnaire which evaluated sleep problems over the past six months. Additionally, each child wore an actigraph for seven consecutive nights, and the child's parents completed a sleep diary during this time period. SETTING: N/A. PATIENTS or PARTICIPANTS: N/A. INTERVENTIONS: N/A. RESULTS: Based on the findings from the questionnaire, parents of children with ADHD reported significantly more sleep problems than parents of normally developing children. However, the majority of these sleep differences were not verified through actigraphy or sleep diary data, with the exception of longer sleep duration for children with ADHD and parent reports that describe increased bedtime resistence. It was also found that child-parent interactions during bedtime routines were more challenging in the ADHD group. CONCLUSIONS: Despite the possibility of intrinsic sleep problems such as longer sleep duration, results indicate that many of the sleep problems of children with ADHD may be due to challenging behaviours during bedtime routines. The reason for discrepancies among sleep studies employing objective measures as well as between retrospective and prospective measures are discussed.     

The impact of media use on sleep patterns and sleep disorders among school-aged children in China

STUDY OBJECTIVES: To determine the amount of television viewing and computer use in urban school-aged Chinese children, and to examine their associations with sleep/wake patterns, duration of sleep, and sleep disorders. DESIGN AND SETTING: Students representing 8 Chinese cities were studied during November and December 2005. PARTICIPANTS: A total of 19,299 elementary-school children, 49.7% boys and 50.3% girls, with a mean age of 9.00 years, participated in the survey. MEASUREMENTS: A parent-administered questionnaire and the Chinese version of the Children's Sleep Habits Questionnaire were completed to quantify media use and to characterize sleep patterns and sleep disturbances. RESULTS: A television or computer was present in the bedroom of 18.5% and 18.3% of Chinese school-aged children, respectively. Media presence in the bedroom and media use were positively correlated with later bedtimes, later awakening times, and a shorter duration of sleep during weekdays and weekends. They were also significantly associated with at least 2 types of sleep disturbances. Overall, the most affected sleep behaviors were bedtime and awakening time on the weekends, the duration of sleep during the weekdays, and sleep disorders of bedtime resistance and sleep anxiety. Television viewing > or = 2 hours/day on weekends, with a prevalence of 48.8%, was the predominant risk factor for all sleep disorders with the exception of the sleep duration disorder. Computer use, however, had no correlation with any sleep disorder. CONCLUSION: The presence of media in a child's bedroom and media use had a negative effect on children's sleep/wake patterns, duration of sleep, and sleep disorders.     

Short- and Long-Term Effects of CBT-I in Groups for School-Age Children Suffering From Chronic Insomnia: The KiSS-Program

Objective/Background: This intervention study evaluates the short- and long-term effects of cognitive behavior therapy for insomnia (CBT-I) in groups for school-age children and their parents, named the KiSS-program. CBT-I was implemented in three sessions for children and three sessions for parents. Participants and Methods: All in all, 112 children with chronic childhood insomnia were randomly assigned to a wait-list (WL) control or treatment condition. Results: According to subjective measures as well as objective wrist actigraphy, children in the CBT-I condition reported greater improvements in sleep behavior immediately after the treatment compared to the WL group. Improvements in sleep behavior after CBT-I persisted over the 3-, 6-, and 12-month follow-up assessments. Conclusions: The present study is the first randomized controlled trial that provides evidence for the long-term effectiveness of CBT-I in treating school-age children with chronic insomnia.     

Influence of exclusive resistance training on body composition and cardiovascular risk factors in overweight or obese children: a systematic review

Objective: Since the last decade, a significant increase in the prevalence of overweight and obesity among children has been reported. Low aerobic fitness and a low compliance with endurance sports in such children are theoretical reasons to favor the use of resistance training in intervention studies, even though positive effects of resistance training on morbidity without accompanying dietary modifications are a matter of debate. In this review we summarize the studies that have shown the isolated effect of resistance training on body composition and cardiovascular risk factors in overweight and obese children. Method: We systematically reviewed interventional studies that exclusively applied resistance training to overweight and obese 3- to 18-year-old children. Outcome measurements were body composition or cardiovascular risk factors. Results: Only six studies passed the inclusion criteria. All studies preferred an individually planned and supervised whole-body resistance training of moderate to submaximal intensity during treatment. The mean compliance was 84%. Four studies reported significant changes in body composition, with an increase in fat free mass and BMI, along with a decrease in fat mass. Three studies analyzed the effect of resistance training on cardiovascular risk factors, and only one study reported a significant decrease in systolic blood pressure. Conclusion: An individually planned and supervised whole-body resistance training of moderate to submaximal intensity in children seems to be safe and tends to show positive effects on body composition. Similar to interventions based on endurance exercise alone or in combination with dietary modifications, the effects on cardiovascular risk factors cannot be substantiated. In consequence, we suggest to substantiate the effect of resistance training on cardiovascular risk factors in overweight and obese children in upcoming randomized controlled trials with high case numbers, applying both resistance training only and resistance training in combination with dietary intervention to get knowledge about whether resistance training alone is effectual in the treatment of overweight and obesity in youth or if a combination of resistance training and dietary interventions is actually needed. Copyright ? 2012 S. Karger GmbH, Freiburg.     

Intraindividual variability in sleep schedule: effects of an internet-based cognitive-behavioral therapy for insomnia program and its relation with symptom remission

Study ObjectivesSleep schedule consistency is fundamental to cognitive-behavioral therapy for insomnia (CBT-I), although there is limited evidence suggesting whether it predicts treatment response. This analysis tested whether: (1) an Internet-based CBT-I program affects intraindividual variability (IIV) in sleep schedule and (2) sleep schedule IIV predicts insomnia symptom remission.MethodsThis secondary analysis compares participants (N = 303) randomized to an Internet-based CBT-I program (SHUTi—Sleep Healthy Using the Internet) or Internet-based patient education (PE). Participants reported daily bedtimes and rising times on 10 online sleep diaries collected over 2 weeks at baseline and 9-week post-intervention assessment. Participants completed the Insomnia Severity Index (ISI) at post-assessment and 6-month follow-up; symptom remission was defined by ISI < 8. Mixed effects location scale modeling was used to examine the effect of SHUTi on bedtime and rising time IIV; a novel two-staged analysis examined the effect of bedtime and rising time IIV on insomnia symptom remission.ResultsAt post-assessment, SHUTi participants reported about 30% less bedtime and 32% less rising time variability compared to PE (ps < 0.03). Bedtime and rising time IIV was not independently associated with likelihood of insomnia symptom remission at the subsequent time point (ps > 0.18), nor did sleep schedule IIV moderate treatment response (ps > 0.12).ConclusionsFindings demonstrate that an Internet-delivered CBT-I program can effectively increase users’ sleep schedule consistency relative to an educational control. This consistency, however, was not related to treatment outcome when defined by insomnia symptom remission, suggesting that enforcing rigid sleep schedules for patients may not be necessary for treatment success.Clinical Trial Registration{"type":"clinical-trial","attrs":{"text":"NCT00328250","term_id":"NCT00328250"}}NCT00328250     

The Timing of Bedtime and Waketime Decisions in Free-Running Subjects

Twelve "free-running" temporal isolation studies were performed using healthy human subjects aged 20-81 years (4 males, 8 females). Circadian rhythms were measured in subjective alertness (using a visual analogue scale technique) and rectal temperature. In all 12 subjects best fitting rhythm period were found to be shorter for rectal temperature (mean = 24.3 hours) than for subjective alertness (mean = 24.8 hours). Both rhythms were predictive of bedtime and waketime decisions. Bedtime decisions tended to cluster on the falling arm of the temperature and alertness cycles (modal times = 120 degrees (temperature) and 140 degrees (alertness) after acrophase); waketime decisions on the rising arm (modal times = 240 degrees (temperature) and 300 degrees (alertness) after acrophase). When this pattern was violated, sleep episodes were significantly more variable in length and disturbed by intruding wakefulness.