Sleep duration and mortality – Does weekend sleep matter?

Previous studies have found a U‐shaped relationship between mortality and (weekday) sleep duration. We here address the association of both weekday and weekend sleep duration with overall mortality. A cohort of 43,880 subjects was followed for 13 years through record‐linkages. Cox proportional hazards regression models with attained age as time‐scale were fitted to estimate multivariable‐adjusted hazard ratios and 95% confidence intervals for mortality; stratified analyses on age (<65 years, ≥65 years) were conducted. Among individuals <65 years old, short sleep (≤5 hr) during weekends at baseline was associated with a 52% higher mortality rate (hazard ratios 1.52; 95% confidence intervals 1.15–2.02) compared with the reference group (7 hr), while no association was observed for long (≥9 hr) weekend sleep. When, instead, different combinations of weekday and weekend sleep durations were analysed, we observed a detrimental association with consistently sleeping ≤5 hr (hazard ratios 1.65; 95% confidence intervals 1.22–2.23) or ≥8 hr (hazard ratios 1.25; 95% confidence intervals 1.05–1.50), compared with consistently sleeping 6–7 hr per day (reference). The mortality rate among participants with short sleep during weekdays, but long sleep during weekends, did not differ from the rate of the reference group. Among individuals ≥65 years old, no association between weekend sleep or weekday/weekend sleep durations and mortality was observed. In conclusion, short, but not long, weekend sleep was associated with an increased mortality in subjects < 65 years. In the same age group, short sleep (or long sleep) on both weekdays and weekend showed increased mortality. Possibly, long weekend sleep may compensate for short weekday sleep.     

Subjective fatigue and subjective sleepiness: two independent consequences of sleep disorders?

The objective of this investigation was to evaluate subjective fatigue versus subjective sleepiness as independent consequences of sleep disorders. Furthermore, we tried to explore how these symptoms relate to alertness, depressive symptoms and illness intrusiveness. In a prospective observational study, 283 sleep-disordered patients referred to a hospital-based sleep laboratory for various indications over a 1-year period were evaluated vis-à-vis fatigue and sleepiness. All patients completed five subjective questionnaires, underwent objective sleep recording and attended a clinical interview with a sleep specialist. The subjective questionnaires included the Epworth Sleepiness Scale, the Fatigue Severity Scale, the Toronto Hospital Alertness Test, the Illness Intrusiveness Rating Scale and the Center for Epidemiologic Studies-Depression Scale. Only 4% of the total sample was referred to the sleep clinic due to a complaint of excessive fatigue compared with 17% for excessive daytime sleepiness. However, during the assessment, 64% of referred patients reported pathological fatigue without overlap of sleepiness and only 4% reported pathological sleepiness without overlap of fatigue. Pearson's correlation analysis indicated a weak association (r=0.18) between subjective fatigue and sleepiness in the total sample. Analysis of variance testing showed strong association between those patients with prominent fatigue and depressive symptoms (P<0.01) and illness intrusiveness (P<0.001). The findings support the notion that subjective fatigue and sleepiness can be independent manifestations of sleep disorders. Furthermore, predominantly fatigued individuals with sleep disorders seem vulnerable to additional negative consequences due to possible interplay between amplified fatigue and psychological distress.     

Sleep and interrogation: does losing sleep impact criminal history disclosure?

Study ObjectivesDespite centuries of using sleep deprivation to interrogate, there is virtually no scientific evidence on how sleep shapes behavior within interrogation settings. To evaluate the impact of sleeplessness on participants’ behavior during investigative interviews, an experimental study examined the impact of sleep restriction on disclosure of past illegal behavior.MethodsHealthy participants from a university community (N = 143) either maintained or curbed their sleep (up to 4 h a night) across 2 days with sleep monitored via actigraphy. They were then asked to disclose past illegal acts and interviewed about them. Next, they were reinterviewed following an example of a detailed memory account (model statement). Disclosures were blindly coded for quantity and quality by two independent raters.ResultsSleep-restricted individuals reported similar offenses, but less information during their disclosure with slightly less precision. Model statement increased disclosure but did not reduce the inhibiting impact of sleep loss. Mediation analysis confirmed the causal role of sleep as responsible for experimental differences in amount of information, and participants’ reports suggested impaired motivation to recall information played a role.ConclusionsThe findings suggest that even moderate sleep loss can inhibit criminal disclosure during interviews, point to motivational factors as responsible, and suggest investigators should be cautious when interrogating sleepy participants.     

Sleep onset rapid-eye-movement episodes in narcolepsy: REM sleep pressure or nonREM-REM sleep dysregulation?

SUMMARY  Thirty-two narcoleptic subjects with excessive daytime sleepiness and cataplexy were recorded for 33 continuous hours. The continuous polysomnographic recording (CPSG) was followed by a standard MSLT at 2-h intervals. There were 64 sleep onset REM episodes (SOREMs) vs 64 sleep onset nonREM episodes (SONREMs) during the CPSG, and 102 SOREMs vs 50 SONREMS during the MSLT. Both sleep onset types peaked at 13–15 h during the CPSG while sleep onsets were evenly distributed during the MSLT. In the latter procedure, the mean sleep latency was significantly shorter with SOREMs occurrence than with SONREMs occurrence. Two factors were extracted in each procedure by means of a Varimax Rotated Factor Analysis. During the CPSG, SOREMs were related to the preceding nocturnal sleep parameters in the first factor, and to the daytime total sleep time and the total number of sleep onsets in the second factor. During the MSLT, SOREMs were related only to the mean sleep latency and the total number of sleep onsets. It was concluded that the occurrence of SOREMs is primarily due to the residual somnolence in narcoleptic subjects. However, their occurrence during the MSLT is largely independent of the prior history of sleep and waking. Thus, we propose a nonREM-REM sleep dysregulation hypothesis to account for the appearance of SOREMs in narcolepsy.     

The impact of sleep duration and subject intelligence on declarative and motor memory performance: how much is enough?

Recent findings clearly demonstrate that daytime naps impart substantial memory benefits compared with equivalent periods of wakefulness. Using a declarative paired associates task and a procedural motor sequence task, this study examined the effect of two lengthier durations of nocturnal sleep [either a half night (3.5 h) or a full night (7.5 h) of sleep] on over-sleep changes in memory performance. We also assessed whether subject intelligence is associated with heightened task acquisition and, more importantly, whether greater intelligence translates to greater over-sleep declarative and procedural memory enhancement. Across both tasks, we demonstrate that postsleep performance gains are nearly equivalent, regardless of whether subjects obtain a half night or a full night of sleep. Remarkably, the over-sleep memory changes observed on both tasks are very similar to findings from studies examining performance following a daytime nap. Consistent with previous research, we also observed a strong positive correlation between amount of Stage 2 sleep and motor skill performance in the full-night sleep group. This finding contrasts with a highly significant correlation between spectral power in the spindle frequency band (12–15 Hz) and motor skill enhancement only in the half-night group, suggesting that sigma power and amount of Stage 2 sleep are both important for optimal motor memory processing. While subject intelligence correlated positively with acquisition and retest performance on both tasks, it did not correlate with over-sleep changes in performance on either task, suggesting that intelligence may not be a powerful modulator of sleep's effect on memory performance.     

Sleep duration in Mexican American children: Do mothers’ and fathers’ parenting and family practices play a role?

This study examined parenting styles, parenting practices and family practices that may be associated with weeknight sleep duration among 8‐ to 10‐year‐old Mexican American (MA) children. This cross‐sectional study of MA children used baseline data from a 2‐year cohort study of mother–child pairs (n = 308) with additional data on fathers (n = 166). Children's weeknight sleep duration was accelerometer estimated and averaged for 2 weeknights. Parents reported on their parenting styles and practices regarding food and family food‐related practices. Multivariable linear regression analysis was used to examine sleep duration with parenting styles and practices, and family practices, and adjusting for child gender and body mass index. Model 1 included mothers’ parenting styles and practices; Model 2 included both mothers’ and fathers’ parenting styles and practices. Children's average sleep duration was 9.5 (SD = 0.8) hr. Mothers who used pressure to encourage their children to eat and those who used food to control behavior had children with longer sleep duration (β = 0.21, p < 0.01; β = 0.15, p = 0.03, respectively). Mothers who reported their children ate dinner with the TV on and those who valued eating dinner as a family had children with shorter sleep duration (β = ?0.16, p = 0.01; β = ?0.18, p = 0.01, respectively). Fathers who restricted the amount of food their children ate had children with shorter sleep duration (β = ?0.27, p = 0.01). Mothers’ and fathers’ feeding practices, the child's eating dinner with the TV on, and valuing family dinners, played a role in children's weeknight sleep duration among Mexican American families. Parental feeding practices and family mealtime contexts may have an effect on children's weeknight sleep duration.     

Sleep and sex: what can go wrong? A review of the literature on sleep related disorders and abnormal sexual behaviors and experiences

STUDY OBJECTIVES: To formulate the first classification of sleep related disorders and abnormal sexual behaviors and experiences. DESIGN: A computerized literature search was conducted, and other sources, such as textbooks, were searched. RESULTS: Many categories of sleep related disorders were represented in the classification: parasomnias (confusional arousals/sleepwalking, with or without obstructive sleep apnea; REM sleep behavior disorder); sleep related seizures; Kleine-Levin syndrome (KLS); severe chronic insomnia; restless legs syndrome; narcolepsy; sleep exacerbation of persistent sexual arousal syndrome; sleep related painful erections; sleep related dissociative disorders; nocturnal psychotic disorders; miscellaneous states. Kleine-Levin syndrome (78 cases) and parasomnias (31 cases) were most frequently reported. Parasomnias and sleep related seizures had overlapping and divergent clinical features. Thirty-one cases of parasomnias (25 males; mean age, 32 years) and 7 cases of sleep related seizures (4 males; mean age, 38 years) were identified. A full range of sleep related sexual behaviors with self and/or bed partners or others were reported, including masturbation, sexual vocalizations, fondling, sexual intercourse with climax, sexual assault/rape, ictal sexual hyperarousal, ictal orgasm, and ictal automatism. Adverse physical and/or psychosocial effects from the sleepsex were present in all parasomnia and sleep related seizure cases, but pleasurable effects were reported by 5 bed partners and by 3 patients with sleep related seizures. Forensic consequences were common, occurring in 35.5% (11/31) of parasomnia cases, with most (9/11) involving minors. All parasomnias cases reported amnesia for the sleep-sex, in contrast to 28.6% (2/7) of sleep related seizure cases. Polysomnography (without penile tumescence monitoring), performed in 26 of 31 parasomnia cases, documented sexual moaning from slow wave sleep in 3 cases and sexual intercourse during stage 1 sleep/wakefulness in one case (with sex provoked by the bed partner). Confusional arousals (CAs) were diagnosed as the cause of "sleepsex" ("sexsomnia") in 26 cases (with obstructive sleep apnea [OSA] comorbidity in 4 cases), and sleepwalking in 2 cases, totaling 90.3% (28/31) of cases being NREM sleep parasomnias. REM behavior disorder was the presumed cause in the other 3 cases. Bedtime clonazepam therapy was effective in 90% (9/10) of treated parasomnia cases; nasal continuous positive airway pressure therapy was effective in controlling comorbid OSA and CAs in both treated cases. All five treated patients with sleep related sexual seizures responded to anticonvulsant therapy. The hypersexuality in KLS, which was twice as common in males compared to females, had no reported effective therapy. CONCLUSIONS: A broad range of sleep related disorders associated with abnormal sexual behaviors and experiences exists, with major clinical and forensic consequences.