Associations Between Child Sleep Problems and Maternal Mental Health in Children with ADHD

ABSTRACT

Objective/Background: Children with attention-deficit/hyperactivity disorder (ADHD) experience more sleep problems than typically developing children. In addition, higher rates of depression are experienced by mothers of children with ADHD compared to mothers of children without ADHD. This study aimed to determine whether particular sleep problems in children with ADHD are associated with specific maternal mental health difficulties.

Participants: Female caregivers of 379 children with ADHD (5–13 years) participated. The child’s ADHD diagnosis was reconfirmed during recruitment by caregivers completing the ADHD Rating Scale-IV.

Method: Caregivers reported on their mental health using the Depression Anxiety Stress Scale and their child’s sleep using the Children’s Sleep Habits Questionnaire. Unadjusted and adjusted regression analyzes were undertaken.

Results: In the adjusted analyzes, there were small significant associations between most aspects of child sleep (i.e. Bedtime Resistance, Night Waking, Parasomnias, Sleep Duration, Daytime Sleepiness and Total Sleep Problems) and maternal Anxiety and Stress, with the exception of Sleep-Onset Delay. Bedtime Resistance, Sleep Duration, Daytime Sleepiness and Total Sleep Problems also had small significant associations with maternal Depression. Sleep Anxiety had a small significant association with maternal Anxiety only.

Conclusions: This study demonstrates important connections between many child sleep problems and particular aspects of maternal mental health, suggesting adaptations to behavioral sleep interventions for children and mental health interventions for parents to take a family approach may be beneficial. Future research should consider the longitudinal associations between child sleep and parent mental health in an effort to inform future intervention approaches.     

Subjective and objective sleepiness in monozygotic twins discordant for chronic fatigue syndrome

STUDY OBJECTIVE: To examine the association of chronic fatigue syndrome (CFS) with measures of objective and subjective sleepiness. DESIGN: Monozygotic co-twin control study. SETTING: Academic medical center. PATIENTS AND PARTICIPANTS: Twenty monozygotic twin pairs discordant for CFS. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: All twins completed an Epworth Sleepiness Scale (ESS), 4 Stanford Sleepiness Scales (SSS), and underwent a standard 4-nap multiple sleep latency test. We compared the ESS scores, average SSS scores, and average sleep latency in CFS and healthy twins. The CFS twins reported more sleepiness as measured by mean scores on the ESS (10.9 vs 8.2; 95% confidence interval [CI] = 0.3-5.5; P = .03) and the SSS (3.4 versus 2.1; 95% CI = 0.7-1.9; P < .001). The mean sleep latency on the Multiple Sleep Latency Test was not significantly different between the CFS and healthy twins (8.9 vs 10.0 minutes; 95% CI -4.4-1.7; P = .33). Mean SSS scores increased among the CFS twins and decreased among healthy twins from nap 1 to nap 4 (P < .001). The individual ESS scores and mean sleep latencies on the Multiple Sleep Latency Test were negatively correlated for all the twins (Pearson's r = - 0.40; P = .01), with a slightly stronger association among the healthy twins (Pearson's r = -0.42, P = .07) than the CFS twins (Pearson's r = -0.36, P = .15). CONCLUSIONS: CFS twins reported significantly more subjective sleepiness than their healthy co-twins despite similar nonpathologic mean sleep latencies on the Multiple Sleep Latency Test. Patients with CFS may mistake their chronic disabling fatigue for sleepiness.     

The cyclic alternating pattern demonstrates increased sleep instability and correlates with fatigue and sleepiness in adults with upper airway resistance syndrome

OBJECTIVE: To clarify the relationship between sleep instability and subjective complaints in patients with upper airway resistance syndrome (UARS). METHODS: Thirty subjects (15 women) with UARS and 30 age- and sex-matched controls in a prospective, single-blind, case-control study. Blinded cyclic alternating pattern (CAP) electroencephalogram analysis and scales of fatigue and sleepiness were completed. ANALYSIS: Mann-Whitney U tests for independent, nonparametric variables between groups and chi2 tests for nonparametric variables with defined standard values. RESULTS: Patients with UARS had significantly more complaints of fatigue and sleepiness, compared with controls, demonstrated on their Fatigue Severity Scale (P < 0.001) and Epworth Sleepiness Scale (P < 0.001). By design, the mean apnea-hypopnea index was normal in both groups, whereas the respiratory disturbance index was greater in patients with UARS than in those without (14.5 +/- 3.0 vs 9 +/- 5.2, respectively [P < 0.001]). CAP analysis demonstrated abnormal non-rapid eye movement sleep with abnormally increased CAP rate, electroencephalogram arousals, A2 index, and A3 index. Decreased A1 index in controls was consistent with their more normal progression of sleep. CAP rate correlated with both the Epworth Sleepiness Scale (r = 0.38, P < 0.01) and the Fatigue Severity Scale (r = 0.51, P < 0.0001), and there was a positive trend between the Fatigue Severity Scale and phase A2 index (r = 0.29, P < 0.05). CONCLUSION: Compared with age- and sex-matched controls, patients with UARS have higher electroencephalogram arousal indexes and important non-rapid eye movement sleep disturbances that correlate with subjective symptoms of sleepiness and fatigue. These disturbances are identifiable with sensitive measures such as CAP analysis but not with traditional diagnostic scoring systems.     

The clinical predictors of sleepiness correlated with the multiple sleep latency test in an Asian Singapore population

STUDY OBJECTIVES: To explore the clinical predictors of sleepiness as objectively determined by the Multiple Sleep Latency Test with the Epworth Sleepiness Scale, age, body mass index, and overnight polysomnographic parameters at a tertiary referral center Sleep Disorders Unit. DESIGN: Retrospective, consecutive case series review. SETTING: A multidisciplinary sleep disorders unit in Singapore General Hospital, a tertiary-care university-affiliated hospital. PATIENTS: 72 consecutive patients evaluated for sleep disorders with overnight polysomnograms and Multiple Sleep Latency Tests between March 2002 and September 2002. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Mean sleep latency on the Multiple Sleep Latency Test was 9.0 +/- 4.4 minutes, and mean Epworth Sleepiness Scale score was 10.8 +/- 5.8. On univariate analysis, mean sleep latency on the Multiple Sleep Latency Test showed a significant negative correlation with the Epworth Sleepiness Scale score, apnea-hypopnea index, body mass index, arousal index, and time spent below 90% oxygen saturation during overnight polysomnography. After performing multiple linear regression, only Epworth Sleepiness Scale score and apnea-hypopnea index remained significantly correlated (P = .039 and P = .008, respectively). An Epworth Sleepiness Scale score of 8 or above predicted a mean sleep latency on the Multiple Sleep Latency Test of less than 10 minutes with a sensitivity of 73.9% and specificity of 50.0%. CONCLUSIONS: The Epworth Sleepiness Scale and apnea-hypopnea index are useful predictors of sleepiness in our Asian Singapore population.     

Genetic Analyses of Maternal and Teacher Ratings on Attention Problems in 7-year-old Dutch Twins

The goal of the present study is to examine genetic and environmental influences on maternal and teacher ratings of Attention Problems (AP) in 7-year-old children. Teachers completed the Teacher Report Form (N = 2259 pairs), and mothers the Child Behavior Checklist (N = 2057 pairs). Higher correlations were found in twins rated by the same teacher than in twins rated by different teachers. This can be explained by rater bias or by a greater environmental sharing in twins, who are in the same classroom. We further found that 41% of the variation in maternal and teacher ratings is explained by a common factor. The heritability of this common factor is 78%. The heritabilities of the rater specific factors of mothers and teachers are 76% and 39%, respectively. Because Attention Problems that are persistent over situations may indicate more serious behavior problems than context dependent Attention Problems, we believe that gene finding strategies should focus on this common phenotype.Edited by Richard Rose     

A randomized crossover efficacy trial of oral CPAP (Oracle) compared with nasal CPAP in the management of obstructive sleep apnea

STUDY OBJECTIVES: To determine the therapeutic efficacy and viability of a novel oral interface for continuous positive airway pressure (CPAP) compared with conventional nasal interfaces. DESIGN: A randomized single-blind crossover study. SETTING: Hospital-based sleep laboratory. PATIENTS OR PARTICIPANTS: 21 CPAP-na?ve patients with obstructive sleep apnea (baseline apnea-hypopnea index, 85 +/- 36) Interventions: Nasal CPAP and oral CPAP MEASUREMENTS AND RESULTS: Patients were each treated for two 4-week periods using nasal CPAP and oral CPAP. The CPAP titrations were undertaken at the start of each treatment arm. Outcome measures were recorded at baseline and at the end of each treatment arm. These included polysomnography variables, CPAP compliance, subjective sleepiness, obstructive sleep apnea symptom ratings, and adverse effects. There were no significant differences between oral and nasal interfaces for the on-CPAP frequency of apneas and hypopneas (mean difference, nasal-oral [95%CI] = -4.6[-10.1-1.0]/h; P = 0.06) or arousals (-3.0 [-7.8-1.8]/h; P = 0.23). There were also no statistically significant differences between interfaces for scores on the Epworth Sleepiness Scale (-0.7 [-3.1-1.7]; P = 0.20), obstructive sleep apnea symptoms (-7.7 [-17.7-2.4]; P = 0.052), CPAP compliance (0.3 [-0.5-1.1] h/night; P = 0.50), CPAP pressure (0.05 [-0.66-0.76] cmH20; P = 0.73), CPAP side effects scores (-2.0 [-5.3-1.4]; P = 0.23), or mask preference (P = 0.407). In addition, both nasal and oral interfaces significantly improved polysomnographic variables, Epworth Sleepiness Scale scores, obstructive sleep apnea symptoms, and CPAP compliance from baseline (all P < 0.05). CONCLUSIONS: This preliminary study indicates that oral CPAP has similar efficacy to traditionally applied nasal CPAP in treating obstructive sleep apnea. Additional large studies are required to determine the range of clinical situations where oral CPAP is indicated.     

Behavioral Phenotype in Children with Turner Syndrome

Compared Child Behavior Checklist results in 103 girls withTurner syndrome (TS) ages 7 to 13 years and 52 age-matched normalgirls. Subjects with TS were part of a national study in Canadato evaluate growth hormone therapy in TS. Present data wereobtained at baseline. Girls with TS scored below the comparisongroup in Total Social Competence (p < .0001), and above itin Total Behavior Problems (p < .05). Social (p < .0001).and Attention Problems (p < .001) scales. Item analysis revealedthat subjects with TS were more immature, hyperactive, and nervous,and had poorer peer relations, greater difficulty at schooling,and more problems concentrating. In children with TS, heightwas correlated with social competence while karyotypes involvingstructural abnormalities of the X chromosome were associatedwith more behavior problems than a missing X or mosaicism.     

A standard procedure enhances the correlation between subjective and objective measures of sleepiness

OBJECTIVE: The goal of this study was to assess whether instituting a standard procedure to minimize transient activation prior to the subjective rating of sleepiness can improve the predictive value of the rating process. METHODS: Thirty young adults, aged 19 to 26 years, participated in the study. Subsequent to sleeping at home with bedtime restricted to 5 hours, they came to the sleep laboratory. They were instructed to rate their level of sleepiness on the Stanford Sleepiness Scale (SSS) and visual analog scales (VAS). A "calm-down" procedure, sitting quietly with eyes closed for 1 minute, was instituted prior to sleepiness ratings for half of the subjects (experimental group) but not for the other half of the subjects (control group). A nap trial with polysomnographic recording was then conducted, followed by a vigilance test. RESULTS: For the experimental group, VAS results of "sleepiness" and "alertness" both correlated significantly with sleep-onset latency during the nap (SOL: r = -.62 and .64, respectively, P values < .05) and with reaction time (RT) on the vigilance test (r = .56 and -.54, P values < .05). The SSS ratings showed significant correlation with nap SOL (r = -.58, P < .05) but not with RT on the vigilance test (r = .19, p = .52). For the control group, none of the subjective ratings showed significant correlation with objective measures. The differences between the resultant correlations for the 2 groups were statistically significant for 2 sets of correlations: the correlation between VAS of "alertness" and nap SOL and the correlation between VAS of "sleepiness" and RT on the vigilance test. CONCLUSION: The results indicate that the subjective ratings of the sleepiness state for individuals with mild sleep restriction more faithfully reflect a physiologic tendency to fall asleep as well as cognitive attentiveness when the ratings are conducted subsequent to sitting still with eyes closed for a sufficient time to minimize transient activation.     

Effect of topical nasal azelastine on the symptoms of rhinitis, sleep, and daytime somnolence in perennial allergic rhinitis.

BACKGROUND: Recent data suggested that daytime somnolence in patients with allergic rhinitis was secondary to disrupted sleep caused by nasal congestion. Medications, which decreased congestion, would be expected to improve sleep and daytime somnolence. Previously, we demonstrated that nasal steroids improved all three symptoms. The effect of topical nasal antihistamines on these symptoms has yet to be studied. OBJECTIVE: The objective of this 8-week, double-blind, placebo-controlled study was to determine whether topical nasal azelastine was effective at decreasing congestion, daytime somnolence, and improving sleep. METHODS: We recruited 24 subjects with perennial allergic rhinitis and randomized them in a double-blinded, crossover fashion, to receive placebo or azelastine two sprays BID, using Balaam's design. Questionnaires, daily diary, and Epworth Sleepiness Scale were used as tools. The last 2 weeks of each 4-week treatment period were summarized, scored, and compared by PROC MIXED in SAS. RESULTS: The analysis of the Rhinitis Severity Score showed significant improvement only of rhinorrhea in the azelastine group (P = .03). The symptom severity of nasal congestion and daytime somnolence was not significantly different between placebo and azelastine. Subjects considered azelastine effective at improving their sleep (P = .04), but daytime somnolence (P = .06) and congestion (P = .09) were not statistically improved. CONCLUSION: Azelastine is effective in reducing rhinorrhea and improving sleep quality. We were unable to demonstrate that azelastine can significantly reduce the severity of congestion or daytime somnolence.     

Sleepiness and Sleep State on a 90-Min Schedule

The effects of REM and slow wave sleep (SWS) on subjective sleepiness were studied in 10 subjects placed on a 90-min sleep-wakefulness schedule for either 5^1/3 or 6 (24-hr) days. Subjects were permitted to sleep for 30-min periods separated by 60 min of enforced wakefulness. Sleep recordings showed that sleep onset REM periods occurred frequently; REM and SWS appeared during the same sleep period only 27 times; and REM sleep tended to occur on sleep periods that alternated with SWS periods. Sleepiness was measured using the Stanford Sleepiness Scale (SSS) given 15 min before (pre-sleep) and 15 min after (post-sleep) each sleep period. Average SSS ratings showed a 24-hr fluctuation in sleepiness. In addition, negative and positive SSS changes tended to alternate with each 90-min period. Significant correlations were found with post-sleep SSS ratings and SWS and with pre-sleep SSS ratings and REM sleep. Differences between pre- and post-sleep SSS scores were also correlated with the sleep states: increased sleepiness was correlated with SWS and decreased sleepiness with REM sleep.     

Quantification of Sleepiness: A New Approach

The Stanford Sleepiness Scale (SSS) is a self-rating scale which is used to quantify progressive steps in sleepiness. The present study investigated whether the SSS cross-validates with performance on mental tasks and whether the SSS demonstrates changes in sleepiness with sleep loss. Five college student Ss were given a brief test of memory and the Wilkinson Addition Test in 2 test sessions and The Wilkinson Vigilance Test in 2 other sessions spaced throughout a 16-hr day for 6 days. Ss made SSS ratings every 15 min during their waking activities. On night 4, Ss underwent all night sleep deprivation. On all other nights, Ss were allowed only 8 hrs in bed. Mean SSS ratings correlated r= .68 with performance on the Wilkinson Tests. Discrete SSS ratings correlated r= .47 with performance on the memory test. Moreover, mean baseline SSS ratings were found to be significantly lower than corresponding ratings of the deprivation period.     

Normative data on the diurnal pattern of the Karolinska Sleepiness Scale ratings and its relation to age,sex, work,stress, sleep quality and sickness absence/illness in a large sample of daytime workers

Self‐rated sleepiness responds to sleep loss, time of day and work schedules. There is, however, a lack of a normative reference showing the diurnal pattern during a normal working day, compared with a day off, as well as differences depending on stress, sleep quality, sex, age and being sick listed. The present study sought to provide such data for the Karolinska Sleepiness Scale. Participants were 431 individuals working in medium‐sized public service units. Sleepiness (Karolinska Sleepiness Scale, scale 1–9) was rated at six times a day for a working week and 2 days off (>90.000 ratings). The results show a clear circadian pattern, with high values during the morning (4.5 at 07:00 hours) and evening (6.0 at 22:00 hours), and with low values (3–4) during the 10:00–16:00 hours span. Women had significantly higher (0.5 units) Karolinska Sleepiness Scale values than men, as did younger individuals (0.3 units), those with stress (1.3 units above the low‐stress group) and those with poor sleep quality (1.0 units above those with qood sleep quality). Days off showed reduced sleepiness (0.7 units), while being sick listed was associated with an increased sleepiness (0.8 units). Multiple regression analysis of mean sleepiness during the working week yielded mean daytime stress, mean sleep quality, age, and sex as predictors (not sleep duration). Improved sleep quality accounted for the reduced sleepiness during days off, but reduced stress was a second factor. Similar results were obtained in a longitudinal mixed‐model regression analysis across the 7 days of the week. The percentage of ratings at Karolinska Sleepiness Scale risk levels (8 + 9) was 6.6%, but most of these were obtained at 22:00 hours. It was concluded that sleepiness ratings are strongly associated with time of day, sleep quality, stress, work day/day off, being ill, age, and sex.     

Polysomnographic and actigraphic evidence of sleep fragmentation in patients with irritable bowel syndrome

STUDY OBJECTIVE: To characterize the function and quality of sleep in patients with irritable bowel syndrome (IBS). DESIGN: A prospective study with a historic comparison group. SETTING: A regional hospital that also serves as a tertiary referral center. PATIENTS: Eighteen patients with IBS and a comparison group of 20 matched adults with mild benign snoring. INTERVENTIONS: A polysomnography study and a wrist actigraphy study. MEASUREMENTS: All subjects underwent sleep studies and completed self-report questionnaires (IBS severity, psychosocial variables, sleep function, and Epworth Sleepiness Scale). Fourteen IBS and 11 comparison patients underwent actigraphy. RESULTS: The IBS patients had more than 70% less slow-wave stage sleep (4.5 +/- 7.3% vs 19.3 +/- 12.9%; P = 0.006), compensated by increased stage 2 sleep (72.2 +/- 6.6% vs 60.1 +/- 16.8%; P = 0.01). The IBS group had significant sleep fragmentation with a significantly higher arousal and awakening index (P < 0.001), a longer wake period after sleep onset (P = 0.02), and more downward shifts to lighter sleep stages (P = 0.01). The 4-night actigraphy study supported the polysomnography findings. The sleep fragmentation index was significantly higher (P = 0.008) in the IBS group. The IBS patients reported greater daytime sleepiness (9.0 +/- 4.8 vs 6.4 +/- 4.8, Epworth Sleepiness Scale score, P < 0.01) and greater impairment in quality of life, which correlated significantly with the sleep fragmentation indexes. The difference between the groups was not due to differences in baseline anxiety/depression levels. CONCLUSIONS: Patients with IBS have impaired sleep quality, reduced slow-wave sleep activity, and significant sleep fragmentation. The cause-and-effect relationship of these findings with patients' daytime symptoms should be studied further.     

Off-label treatment of severe childhood narcolepsy-cataplexy with sodium oxybate

STUDY OBJECTIVES: To evaluate the efficacy and side-effect profile of off-label sodium oxybate (gamma hydroxy butyrate) therapy in severe childhood narcolepsy-cataplexy. DESIGN: Retrospective; chart review. SETTING: A multidisciplinary tertiary sleep center. PATIENTS: A group of eight children with severe narcolepsy-cataplexy diagnosed on the basis of clinical history, nocturnal polysomnography and the multiple sleep latency test were studied. A modified Epworth Sleepiness Scale and an arbitrary cataplexy severity scale (1 = minimal weakness, 2 = voluntarily preventable falls, 3 = falls to the ground) were utilized. INTERVENTIONS: Sodium oxybate therapy; concurrent medications were maintained. MEASUREMENTS AND RESULTS: Before sodium oxybate therapy, all subjects had suboptimally controlled sleepiness and cataplexy. Following treatment with sodium oxybate, 7/8 subjects (88%) improved. Cataplexy frequency decreased from a median of 38.5 to 4.5/ week (p = 0.0078). Cataplexy severity decreased from 2.75 to 1.75 (p = 0.06). The Epworth Sleepiness Scores improved from a median of 19 to 12.5 (p = 0.02). Suicidal ideation, dissociative episodes, tremor and constipation occurred in one subject each and terminal insomnia in two. Three of the 8 (38%) discontinued therapy. Two stopped the drug owing to side effects and one due to problems with postal delivery of the medication. CONCLUSIONS: This is the first report on sodium oxybate therapy in childhood narcolepsy-cataplexy. Our finding of improvement in cataplexy and sleepiness suggests that this medication is effective in treating severe childhood narcolepsy-cataplexy.     

Subjective ratings of the characteristics and sequelae of good and poor sleep in normals

Forty normal subjects completed a general screening inventory and two post-sleep questionnaires (PSQs). One PSQ was self-administered after a good night of sleep and one after a poor night of sleep. Responses to a subset of items from both nights were factor-analyzed. Varimax rotation yielded four factors that were interpreted as (a) Dysphoria (b) Cognitive Inefficiency and Sleepiness (c) Motor Impairment and (d) Social Discomfort. Night-to-night comparisons of subjects' estimates of sleep parameters reveal that poor sleep is associated with longer sleep latency, a greater number of awakenings, less total sleep time, and more difficulty initiating and maintaining sleep than good sleep. Mean scores for each generated factor of the PSQ also differed significantly between nights, suggesting that a greater degree of disturbance is associated with poor sleep. The implications of these data as well as the reliability of subjective ratings of sleep quality and post-sleep experiences are discussed.     

大学生学业自我概念、学习动机与学习成绩的关系

目的:探讨大学生学业自我概念与学习动机、学习成绩的关系。方法:采用青少年一般学业自我问卷和学习动机问卷,对哈尔滨两所高校238名本科大学生进行了考察。结果:大学生学习动机和学业自我概念对学习成绩均有显著的影响(β=0.284,0.775;P0.01);学业自我概念在学习动机对学习成绩作用过程上具有完全中介作用(β=0.020,P=0.838;β=0.392,P0.01)。结论:学习动机通过学业自我概念对学习成绩有显著的正面影响。     

Thermal Comfort Intervention for Hot-flash Related Insomnia Symptoms in Perimenopausal and Postmenopausal-aged Women: An Exploratory Study

ABSTRACT

Objective/Background: To examine a novel intervention for nighttime thermal comfort and sleep of perimenopausal- and postmenopausal-aged women who experience hot flashes and insomnia symptoms.

Participants: Thirty-nine women (ages 45–58, M = 52.1 years) with sleep-disrupting hot flashes and insomnia symptoms.

Methods: This was a 4-week randomized cross-over study. The intervention included 2 weeks of nighttime use of a warming/cooling device worn on the wrist and was compared to a 2-week baseline period (no device). All participants completed questionnaires at the end of each 2-week period, including the Insomnia Severity Index, the PROMIS Sleep Disturbance and Sleep-Related Impairment scales, Epworth Sleepiness Scale, and the Hot Flash Related Daily Interference Scale.

Results: The intervention resulted in a reduction in sleep onset latency, as well as an increase in nighttime sleep. There was a significant improvement of scores on the Insomnia Severity Index, PROMIS Sleep Disturbance and Sleep-Related Impairment scales, and the Epworth Sleepiness Scale. Significantly fewer women reported that hot flashes interfered with their sleep (90% vs 70%) and more perceived control over the degree of sleep disruption due to nighttime hot flashes while using the device (5% vs 49%). The majority reported a positive experience, with two-thirds reporting that the device improved their thermal comfort and ability to return to sleep after a night waking.

Conclusions: Overall, a thermal comfort intervention may offer sleep benefits for women who experience disruptive nighttime hot flashes, particularly in terms of falling asleep at bedtime and subjective perception of control over nighttime hot flash sleep interference.     

Short sleep duration in middle childhood: risk factors and consequences

STUDY OBJECTIVES: To measure sleep duration in 7-year-old children; identify the determinants of sleep duration; and assess the association between short sleep duration and obesity, cognitive functioning, and behaviour. DESIGN: Longitudinal study with disproportionate sampling of the participants. SETTING: Community. PARTICIPANTS: 591 seven-year-old children, of whom 519 had complete sleep data. INTERVENTIONS: Not applicable. MEASUREMENTS: Sleep duration was assessed by actigraphy. Other measurements included height, weight, BMI, percentage body fat as assessed by bioimpedance assay, intelligence (WISC-III) and behaviour (Strengths & Difficulties questionnaire, parent and teachers Conners Rating Scales). RESULTS: Mean time in bed according to parental report was 10.9 hours (SD 0.8). Mean sleep duration by actigraphy was 10.1 (SD 0.8) hours. In multivariable analysis, sleep duration was longer on weekdays vs. weekend nights (31.5 min, P = 0.002), in winter (40.5 min), autumn (31.1 min), and spring (14.8 min) compared with summer (P <0.0001), and in those with younger siblings (11.7 min, P = 0.03). Sleep duration was shorter when bedtime was after 21:00 (-41.1 min, P <0.0001). In multivariable analysis, sleep duration <9 hours was associated with being overweight/ obese (BMI: OR = 3.32; 95% CI = 1.40, 7.87) with an increase of 3.34% body fat (P = 0.03), and this was not explained by physical activity or television watching. Short sleep duration was also associated with higher emotional lability scores (Conners Rating Scale Parent Form; P = 0.03). IQ (WISC-III) and attention deficit / hyperactivity disorder scores (both parent and teachers Conners Rating Scales) did not differ with sleep duration. CONCLUSIONS: Sleep duration in 7-year-old children varies considerably among individuals. The duration is affected by weekday, season, and having younger siblings. Importantly, short sleep duration was shown to be an independent risk factor for obesity/overweight.     

Relationship between sleep inertia and sleepiness: cumulative effects of four nights of sleep disruption/restriction on performance following abrupt nocturnal awakenings

Performance deficits are usually evident following both extended wakefulness (sleep deprivation effects) and immediately upon awakening from sleep (sleep inertia effects). In order to determine whether sleep inertia effects are qualitatively different from sleep deprivation effects, performance on addition tests, Stanford Sleepiness Scale (SSS) ratings, and return-to-sleep latencies (RSLs) were assessed during four nights of sleep disruption/restriction. Eight subjects were polygraphically monitored in the sleep laboratory for five consecutive nights, from 2400 to 0700. On the last four nights (after an adaptation night) subjects were awakened at 0040, 0140, 0240, 0340, 0440, and 0540 for a 20-min test session. Sleepiness ratings and performance on 5-min addition tests were measured at 1.5, 7.5, and 13.5 min post-awakening, and RSL was measured at the end of each test session. Analysis of addition test performance across nights revealed that both speed and accuracy of calculations were adversely affected by the sleep disruption/restriction procedure, indicating that increasing sleepiness exacerbates sleep performance deficits upon awakening. Although divergence of SSS ratings and addition test performance across nights was suggestive, there was no conclusive evidence that sleep inertia is qualitatively different from "typical" sleepiness.     

Sleep habits and accident risk among truck drivers: a cross-sectional study in Argentina

Road accidents are a major cause of death, and sleep deprivation affects driving skills. We conducted a cross-sectional study to evaluate sleep habits and accident risk in long-haul truck drivers in Buenos Aires, Argentina. Questionnaires regarding sleep habits, snoring, and daytime sleepiness were administered, and a limited physical examination was performed. We obtained 738 complete answers (response rate 85%). Mean sleep hours during working days was 3.76 (SD 2.40). Mean driving hours was 15.9 (SD 5.60) per day. Frequent sleepiness while driving was reported by 43.7% of responders. Sleepiness while driving was associated with Epworth Sleepiness Scale values >10 (odds ratio 1.85, 95% confidence interval = 1.20-2.85). Snoring was reportea by 71% of drivers and was frequent in 43.8%. Snoring more than 3 times a week (odds ratio 1.73, 95% confidence interval = 1.23-2.44), sleepiness while driving (OR 1.92, 95% confidence interval = 1.08-1.96), and Epworth Sleepiness Scale score > 10 (odds ratio 2.53, 95% confidence interval = 1.61-3.97) were independently associated with reporting of accidents or near accidents. Sleep deprivation and long driving shifts were prevalent in our study. Accident risk was associated with frequent snoring, daytime sleepiness, and reporting of sleepiness at the wheel. This study highlights the need of improving working conditions in this highly exposed population.