Effects of pre-sleep media use on sleep/wake patterns and daytime functioning among adolescents: the moderating role of parental control.

The aim of this cross-sectional study was to investigate the influence of media use in the hour before bedtime on sleep/wake patterns and daytime functioning among adolescents and to examine the moderating role of parental control. A total of 1,926 Belgian students, 55% girls and 45% boys, with a mean age of 16.9 ± 1.5 years, completed a modified version of the School Sleep Habits Survey. Correlational analyses showed that media use, except television viewing, was associated with later bedtimes and longer sleep latencies. Cell phone and computer usage was negatively associated with daytime functioning. On schooldays, parental control had a moderating effect on the relationship between bedtime and computer use (ß = .05; p < .05) and between bedtime and mp3 player use (ß = .08; p < .01). During the weekend, parental control played a moderating role between bedtime and television viewing (ß = .06; p = .01). As media use can influence the sleep of adolescents considerably, parental control is necessary to regulate the exposure of adolescents to media and to moderate the detrimental effect of media use on sleep.

An exploratory study on the effects of tele-neurofeedback and tele-biofeedback on objective and subjective sleep in patients with primary insomnia.

Insomnia is a sleeping disorder, usually studied from a behavioural perspective, with a focus on somatic and cognitive arousal. Recent studies have suggested that an impairment of information processes due to the presence of cortical hyperarousal might interfere with normal sleep onset and/or consolidation. As such, a treatment modality focussing on CNS arousal, and thus influencing information processing, might be of interest. Seventien insomnia patients were randomly assigned to either a tele-neurofeedback (n = 9) or an electromyography tele-biofeedback (n = 8) protocol. Twelve healthy controls were used to compare baseline sleep measures. A polysomnography was performed pre and post treatment. Total Sleep Time (TST), was considered as our primary outcome variable. Sleep latency decreased pre to post treatment in both groups, but a significant improvement in TST was found only after the neurofeedback (NFB) protocol. Furthermore, sleep logs at home showed an overall improvement only in the neurofeedback group, whereas the sleep logs in the lab remained the same pre to post training. Only NFB training resulted in an increase in TST. The mixed results concerning perception of sleep might be related to methodological issues, such as the different locations of the training and sleep measurements.

Defining the occurrence and influence of alpha-delta sleep in chronic fatigue syndrome.

BACKGROUND: Patients with chronic fatigue syndrome (CFS) present a disordered sleep pattern and frequently undergo polysomnography to exclude a primary sleep disorder. Such studies have shown reduced sleep efficiency, a reduction of deep sleep, prolonged sleep initiation, and alpha-wave intrusion during deep sleep. Deregulation of the 2-5A synthetase/RNase L antiviral pathway and a potential acquired channelopathy are also found in a subset of CFS patients and could lead to sleep disturbances. This article compiles a large sleep study database on CFS patients and correlates these data with a limited number of immune parameters as it has been thought that RNase L could be associated with these sleep disturbances. METHODS: Forty-eight patients who fulfilled 1994 Centers for Disease Control and Prevention criteria for CFS underwent extensive medical evaluation, routine laboratory testing, and a structured psychiatric interview. Subjects then completed a complaint checklist and a two-night polysomnographic investigation. RNase L analysis was performed by gel electrophoresis using a radiolabeled 2',5'-oligoadenylate trimer. Basic descriptive statistical parameters were calculated. RESULTS: Patients experienced a prolonged sleep latency, showed a low sleep efficiency index, and had a low percentage of slow wave sleep. The present alpha-delta intrusion correlated with anxiety; no correlations appeared, however, between alpha-delta sleep and immunologic parameters, including RNase L. CONCLUSIONS: The main findings are 1) validation of sleep latency problems and other sleep disturbances as already suggested by several authors; 2) alpha-delta intrusion seems associated with anxiety; and 3) elevated RNase L did not correlate with alpha-delta sleep.

Simulator driving performance, subjective sleepiness and salivary cortisol in a fast-forward versus a slow-backward rotating shift system.

OBJECTIVES: The objectives of this study were to examine simulator driving and subjective sleepiness after morning, afternoon, and night shifts and to compare these differences, as well as objective stress, between a fast-forward and a slow-backward rotating shift system. METHODS: The participants were male volunteers working in a chemical plant, 18 in a slow-backward rotating system and 18 in a fast-forward rotating system. All of the participants performed a driving simulator test and subjectively estimated sleepiness after a night, afternoon, and morning shift. Salivary cortisol samples, as indicators of the objective stress level, at the beginning of the workweek-after the second morning shift-were compared between the two rotating shift systems. RESULTS: Lane drifting was higher after a night shift than after an afternoon shift. No effect of rotation system on driving performance could be shown. The subjective sleepiness scores were significantly higher in the slow-backward rotating group than in the fast-forward rotating group. A significant effect of shift type was also observed, with lower levels of sleepiness after the afternoon shift than after the morning and night shifts. Salivary cortisol samples taken at the start of the workweek did not significantly differ between the fast-forward and the slow-backward rotation shift systems. CONCLUSIONS: This study indicated that shift type is more important than shift schedule-direction and speed of rotation-in determining driving performance. Performance seemed to be threatened mostly by a night shift and the least by an afternoon shift. In contrast, subjective sleepiness also differed between rotation groups and indicated an advantage of the fast-forward rotation system. The exploratory salivary cortisol measurements suggested that the shift systems studied do not differ in the level of stress they induce, that is to say at the beginning of the workweek.

Dual Orexin Receptor Antagonist, Almorexant, in Elderly Patients With Primary Insomnia: A Randomized, Controlled Study.

Objective: Sleep laboratory study to determine the dose-related efficacy and safety of almorexant in elderly patients with primary chronic insomnia. Methods: Patients aged ≥65 years with primary insomnia were enrolled into a prospective, randomized, double-blind, placebo-controlled, multicenter dose-finding study with a five-period, five-way Latin square cross-over design. Patients were randomized to one of 10 unique sequences of two-night treatment with oral almorexant 25, 50, 100, or 200 mg capsules, or matching placebo. The primary efficacy endpoint was polysomnography (PSG)-determined mean wake time after sleep onset (WASO). Secondary and exploratory efficacy endpoints were also assessed. Results: 112 patients were randomized (mean [SD] age 72.1 [5.0] years; 69.9% female). Significant, dose-related improvements (reductions) in mean WASO were observed with almorexant. Least-squares mean (95% CI) treatment effects in the almorexant 200, 100, 50, and 25 mg dose groups versus placebo were -46.5 minutes (-53.0, -39.9; p < .0001), -31.4 minutes (-38.0, -24.9; p < .0001), -19.2 minutes (-25.7, -12.6; p < .0001), and -10.4 minutes (-17.0, -3.9; p = .0018), respectively. Mean total sleep time was significantly increased with each almorexant dose (mean increases versus placebo ranged 55.1-14.3 minutes; p < .0001 for each dose). Latency to persistent sleep was statistically significantly reduced only with almorexant 200 mg versus placebo (mean [95% CI] treatment effect -10.2 minutes, [-15.4, -5.0]; p = .0001). No unexpected safety concerns were identified. Adverse events were similar between all almorexant dose groups and placebo. Conclusions: Two-night oral administration of almorexant was effective and well tolerated in treating primary insomnia in elderly patients.

Neurophysiological aspects of primary insomnia: implications for its treatment.

Insomnia has usually been studied from a behavioral perspective. Somatic and/or cognitive conditioned arousal was shown to play a central role in sleep complaints becoming chronic, and was used as a starting point for the development of treatment modalities. The introduction of the neurocognitive perspective, with its focus on cortical or CNS arousal, has given rise to a renewed interest in the neurophysiological characteristics of insomnia. Recent research, using quantitative EEG, neuroimaging techniques and the study of the microstructure of sleep, suggests a state of hyperarousal with a biological basis. Furthermore, insomnia might not be restricted to sleep complaints alone because it appears to be a 24-h disorder, affecting several aspects of daytime functioning as well. These new findings have implications for the treatments used and indicate that a focus on cortical or CNS arousal should be pursued. As such, the use of EEG neurofeedback, a self-regulation method based on the paradigm of operant conditioning, might be a promising treatment modality. Preliminary results for insomnia and successful applications for other disorders suggest that this treatment can have the necessary stabilizing effects on the EEG activity, possibly resulting in a normalizing effect on daytime as well as nighttime functioning.

Multidimensional scaling of pediatric sleep breathing problems and bio-behavioral correlates.

STUDY OBJECTIVES: Complex relationships exist between pediatric sleep disorders and daytime behavior. Using a multidimensional scaling model, we investigated these relationships in 126 children with sleep breathing disorders (SBD). METHOD: Validated questionnaires on nighttime behavior, daytime behavior, and respiratory health were administered to a large number of school children in Belgium. Children who met the criterion of having at least one sleep-related breathing problem (three or more times per week during the past six months) were selected for further analyses. A total of 26 indicators were defined and modeled, including sleep problems, sleep efficiency, sleep environment, sleep enuresis, internalised and externalised behavioral problems, respiratory health of the child and relatives, smoking exposure, and caffeine consumption. RESULTS: From 3,045 questionnaire responses 4.1% of the children were reported to have a SBD symptom. SBD children differed on sleep and health domains from non-SBD children. Furthermore, through scaling of the (dis)similarities among the 26 indicators the SBD child was able to be modeled. By way of an internal analysis of the data-matrix the following indicators were eliminated: sleep correlates, health of the family, and behavior rated by teachers, followed by caffeine intake, drugs, and behavior rated by the parents. This revealed a two-dimensional model, consisting of primary SBD and secondary SBD. CONCLUSION: Children with SBD differ on many domains from children without such disorders and an underlying two-fold SBD concept was found. Firstly, the SBD-indicator positioned in between investigated correlates with disorders of initiating and maintaining sleep and sleep hyperhydrosis on one hand and with respiratory-related illnesses on the other; this was labeled primary SBD. Secondly, the SDB-indicator not closely associated with any of the investigated correlates can be interpreted as secondary SBD.

Executive function in sleep apnea: controlling for attentional capacity in assessing executive attention.

STUDY OBJECTIVES: As the effects of general slowness and decreased attentional capacity on higher executive attention have not been fully taken into account in the sleep apnea literature, we statistically controlled for basic attentional performance in evaluating executive attention per se in sleep apnea patients. DESIGN: A case-controlled design was used with comparison of basic and executive attentional tasks. PARTICIPANTS: Thirty-six polysomnographically diagnosed patients (mean apnea-hypopnea index = 60.5 +/- SD 31.6) participated, together with 32 healthy controls. MEASUREMENTS AND RESULTS: Neuropsychological tests included Trail Making part A and B, Symbol Digit Modalities (SDMT), Digit Span forward and backward, Stroop Color-Word, Five-Point design fluency, and an Attentional Flexibility task. Patients' vigilance data indicated time-on-task decrements after 10 minutes. Moreover, their performance was significantly reduced on the SDMT (effect size d = 0.93), the Digit Span forward task (d = 0.44), the number of errors on the basic 2-choice reaction time subtest of the Attentional Flexibility task (d = 0.74) and the mean RT on the actual Attentional Flexibility subtest (d = 0.54). It has been argued that the latter poor performance was probably primarily related to the task's phonologic loop component of working memory rather than to an attentional switching deficit per se. No other performance differences were found between patients and healthy controls. CONCLUSIONS: In addition to vigilance decrements, attentional capacity deficits clearly emerge, ie, slowed information processing and decreased short-term memory span. However, no specific clinical indications for executive attentional deficits--such as disinhibition, distractibility, perseveration, attentional switching dysfunction, decreased design fluency, or an impaired central executive of working memory--are found in patients with severe sleep apnea. Their cognitive performance seems very similar to the cognitive decline found after sleep loss and qualitatively different from patients with chronic obstructive pulmonary disease, suggesting sleepiness as the primary factor in a parsimonious explanation for the attention deficits in sleep apnea, without the need to assume prefrontal brain damage.

Pediatric sleep disorders: exploratory modulation of their relationships.

STUDY OBJECTIVES: This study explores relationships between clinically encountered sleep problems in children. DESIGN: The Sleep Disturbance Scale for Children (SDSC) (Bruni et al 1996), which screens 26 sleep problems and results in 6 sleep disorder-subscales, was used as core in a larger health-behavior questionnaire (HBQ). PARTICIPANTS: Caregivers of 3045 6- to 12-year-olds filled out the HBQ. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: 21 SDSC-items plus 15 new sleep items were selected. Via structural equation modelling we explored (1) relations within and between disorder-subscales, (2) relations between the disorder-subscales with 3 indexes added (i.e., sleep efficiency index, sleep environment index, and sleep enuresis) and (3) relations of the disorder-subscales to their categorization: dyssomnia and parasomnia, without and with the indexes. CONCLUSIONS: The final model had a satisfying fit and approximates the Association of Sleep Disorders Centers' classification. Each disorder-subscale can be applied individually. However, some items are statistically of low value. For that reason, the use as the inference of relations between such items should be cautious. Adding the 3 indexes improved the fit of the model. The complexity of 'sleep enuresis' was especially revealed. For the practicing care provider, as for researchers, the statistical model proposed could be a valuable directive in the diagnostic classification process of pediatric sleep problems.

Executive control of attention in sleep apnea patients: theoretical concepts and methodological considerations.

Sleep apnea patients' nocturnal breathing disturbances cause daytime sleepiness and cognitive impairments. Attentional capacity and vigilance deficits have often been observed. Moreover, some studies have suggested executive dysfunction, usually assumed to be related to (pre)frontal lobe dysfunction caused by intermittent hypoxemia. However, sleep disruption itself has a pervasive influence on cognitive function and affects not only underlying 'lower-level' processes such as arousal and alertness, but also 'higher-level' cognitive processes such as executive attention. This methodological caveat has not been fully taken into account in the sleep apnea literature. In order to be able to disentangle these cognitive processes on different levels, sound theoretical neurocognitive frameworks are needed to attain careful analyses and interpretations of neuropsychological data. Therefore, this paper firstly presents an overview of relevant theoretical concepts and models of arousal, attention, and executive function. Then, it is being argued that these theoretical considerations have important methodological implications. These methodological concerns are being addressed by specific experimental and statistical approaches, illustrated by some well-known neuropsychological tests. It can be concluded that the reported executive deficits in sleep apnea patients should be regarded as tentative, and that more case-controlled studies are needed using fine-grained analyses to parcel complex cognitive abilities into their subcomponents.

Daytime sleepiness and its evaluation.

Basic models of sleepiness, focusing on the homeostatic and circadian components of sleepiness, are able to predict important fluctuations of sleepiness. However, they fail in explaining certain sleepiness phenomena, as for instance in insomnia patients. To meet this shortcoming, modern models incorporate the arousal component of sleepiness, in addition to the sleep drive. While these models mainly concentrate on short-term changes in sleepiness, "state" sleepiness, there are indications that a stable characteristic level of sleepiness, "trait" sleepiness, is also an important determinant of a person's level of sleepiness. This leads to a conceptualization of sleepiness in which situational factors modify a basal level of sleep drive and arousal. It implies that sleepiness is not a unitary concept and can reflect essentially different states. Multiple sleepiness assessment tools have been proposed in the past. The majority of them offer valuable information, but they do not grasp all aspects of sleepiness. We should bear in mind that tools for assessing sleepiness are always operationalizations reflecting the theoretical framework the investigator has on sleepiness. Hence, rather than searching for a gold standard for the measurement of sleepiness, future research effort should be aimed at linking the various measurement techniques with the hypothesized underlying components of sleepiness on a sound empirical basis.

Attentional switching-related human EEG alpha oscillations.

Alpha oscillations during cognitive performance have mostly been studied in memory and/or basic attention tasks. This study investigates task-related alpha power desynchronization during an attentional switching task requiring higher executive attentional control. Low 8-10 Hz and high 10-12 Hz alpha power responses are studied in good versus poor performers based upon normative data. Accurate, fast and stable performers showed significant task-related desynchronization in the 8-10 Hz range during attentional switching, whereas inaccurate performers hypersynchronized in the 10-12 Hz range, and slow and unstable performers did not demonstrate significant alpha reactivity. These preliminary findings indicate, in agreement with previous research, functional differences in these narrow frequency bands. The 8-10 Hz power decrease is likely to be related to phasic arousal or alertness, whereas the 10-12 Hz power increase appears to be associated with inaccurate attentional switching.

Zolpidem 'as needed': methodological issues and clinical findings.

This article introduces 'as needed' hypnotic treatment as a possible option in the psychopharmacological treatment for chronic but non-daily occurring insomnia complaints. This treatment option is a well-structured regimen designed by both patient and treating physician. It aims at providing symptomatic relief for sleepless nights and preventing the development of possible dependence on the hypnotic agent. A significant amount of responsibility regarding the necessary accompanying lifestyle changes remains in the patient's hands. This paper describes three of the early experiments designed as a 'proof of concept'. All three studies demonstrated that zolpidem can be used effectively and safely on a non-daily basis in individuals with chronic insomnia. Although these studies have methodological limitations, they opened doors to well-designed clinical trials in both in and outpatients. The scientific validation of this therapeutic approach is still in progress. In addition to sleep laboratory studies, ecological studies are needed to investigate pill-taking behaviour and the risk of dependence over a long period of time in real life settings.

Effects of slow-release caffeine and a nap on driving simulator performance after partial sleep deprivation.

A driving simulator was used to evaluate the effectiveness of a 30-min. nap and 300-mg slow-release caffeine as countermeasures to drivers' sleepiness induced by partial sleep deprivation. 12 participants were allowed 45 hr. time in bed at the laboratory. Driving performance then was measured twice--at 9 a.m. and at 1 p.m.--by a 45-min. driving task on a simulator. Subjective sleepiness/alertness and mood were assessed four times on the Stanford Sleepiness Scale and the Profile of Mood States. Driving performance was assessed as Lane Drifting, Speed Deviation, and Accident Liability. A 30-min. nap opportunity and 300 mg of slow-release caffeine both were successful in counteracting drivers' sleepiness. The remedial effect of slow-release caffeine lasted longer than that of the nap, that is, it was also effective in the afternoon session. This suggests that slow-release caffeine represents a valuable countermeasure that, in the case of partial sleep deprivation, is preferred to a nap when sleepiness has to be counteracted for a longer time.

Field study on the impact of nocturnal road traffic noise on sleep: the importance of in- and outdoor noise assessment, the bedroom location and nighttime noise disturbances.

The aim of this field study is to gain more insight into the way nocturnal road traffic noise impacts the sleep of inhabitants living in noisy regions, by taking into account several modifying variables. Participants were tested during five consecutive nights in their homes and comparisons between effective indoor and outdoor noise levels (LAeq, LAmax, number of noise events), sleep (actigraphy and sleep logs) and aspects of well-being (questionnaires) were made. Also, we investigated into what extent nocturnal noise exposure - objectively measured as well as perceived - directly relates to sleep outcomes and how the bedroom location influenced our measurements. We found that subjects living and sleeping in noisy regions correctly perceive their environment in terms of noise exposure and reported an overall discomfort due to traffic noise. In the evaluation of the objective noise levels, the inside noise levels did not follow the outside noise levels, though the different noise patterns could be described as characteristic for a noise and quiet environment. The impact on sleep, however, was only modest and we did not find any influence of noise intrusion on mood or pre-sleep arousal levels. Concerning the subjectively reported noise disturbances during the night, a clear relationship between noise and sleep outcomes could be established; with sleep onset latencies and judged sleep quality being particularly affected. The importance of inside and outside noise assessment as well as the use of multiple noise indicators in a home environment is further described. Additional emphasis is put on the determination of quiet control regions and the bedroom location, as this can alter noise levels and sleep outcomes. Also, including subjective noise evaluations during the night might not only provide crucial information on how participants experience the noise, but also allows for a more qualitative interpretation of the actual noise situation.

Excitatory versus inhibitory impairments in insomnia patients: an ERP study.

According to the neurocognitive perspective on insomnia, conditioned arousal results in impairment of information processing, as such interfering with normal sleep processes. In the present study, evening event-related potentials N100 and P200 were evaluated to assess hyperarousal in patients with insomnia and controls. 13 patients (mean age = 40.8) with polysomnographically verified sleep disruptions and 11 good sleepers (mean age = 45.4) were included. An auditory oddball paradigm was administered the evening of the polysomnography. N100 and P200 mean amplitudes and peak latencies at Fz and Cz were analyzed as a measure of respectively general arousability and inhibition of information processing. Patients experiencing insomnia were characterized by decreased P200 amplitudes compared to good sleepers. No significant differences were found for N100 amplitudes and latencies of both ERP waves. These results suggest that this group of patients with objectified insomnia is characterized by an arousal impairment. However, there was no evidence of hyperarousal, considering the normal N100 amplitudes. On the other hand, the inhibition of information processing was distorted. As such, the impairment of de-arousal or de-activation in insomnia is put forward as an additional factor within the arousal model.

Sleepiness phenomics: modeling individual differences in subjective sleepiness profiles.

The present study investigates individual differences in subjective sleepiness profiles during 36 h of sustained wakefulness in a modified constant routine protocol. Twenty-three volunteers (11 females), aged between 18 and 47 yrs (M age = 30.41, SD = 10.26) enrolled in the study. Subjective sleepiness ratings were collected every 2 h by means of visual analogue scales. Circadian rhythmicity was assessed by means of salivary cortisol. Subjective sleepiness data were analyzed using functional principal component analysis (fPCA). Our results show that approximately 80% of the variance is accounted for by three functional components. The first component explains 50.28% of the variance and is characterized by a profile of exclusively positive loadings, representing vertical shifts from the mean sleepiness profile. Scores on this component are positively related to self-reported habitual sleep times and mean slow wave activity (SWA) during wake. Positive scores on the second component (18.40% of the variance) are characterized by a higher than average peak-to-trough amplitude in subjective sleepiness profiles. Participants with higher than average scores on this component show a significantly higher amplitude in salivary cortisol profiles as opposed to participants with lower than average scores. Participants with positive scores on the third component (10.09% of the variance) show higher than average levels of subjective sleepiness during morning hours, a buildup of wake effort occurring later and more afternoon sleepiness after sleep deprivation than negative scorers. Peak levels of salivary cortisol occur significantly later in these participants. Taken together, our results suggest that component 1 represents tonic differences in sleepiness profiles primarily related to mechanisms of sleep homeostasis, component 2 to circadian amplitude differences and component 3 to diurnal preference. However, since the components are additions to a mean profile, each of the three components is likely to correspond to a mixture of multiple physiological parameters, rather than to a single process. The approach shows interesting potential for (1) revealing unidentified physiological processes, (2) testing existing assumptions about regulatory mechanisms at the basis of interindividual variability in sleepiness profiles and (3) the specification of sleepiness phenotypes on a quantitative basis.

The influence of pre-sleep cognitive arousal on sleep onset processes.

Cognitive hyperarousal, resulting in enhanced cognitive activation, has been cited as an important contributor to the development and preservation of insomnia. To further understand this process, our study examined the effects of acutely-induced pre-sleep cognitive hyperarousal on sleep onset processes in healthy volunteers. Following an adaptation night, 15 subjects slept two nights in our sleep laboratory: one reference night and another one with cognitive arousal induction, in a counterbalanced order. In the cognitive arousal condition, subjects worked through half an hour of cognitive tasks without interference of an emotional component prior to retiring to bed. Objective sleep onset latency was significantly prolonged in the cognitive arousal condition compared to the reference condition. Significantly more high frequency activity was recorded during the first and second deep-sleep period. Moreover, differences in heart rate and proximal temperature during and after sleep onset were observed in the nights after the cognitive induction. Pre-sleep cognitive activation successfully induced a significant cognitive load and activation in our subjects to influence subsequent sleep (onset) processes.

Effects of pre-sleep simulated on-call instructions on subsequent sleep.

Nightly interventions, prevalent to on-call situations, can have negative consequences for those involved. We investigated if intervention-free-on-call-nights would also mean disturbance-free-sleep for people on-call. 16 healthy sleepers spent three nights in the laboratory: after a habituation night, reference and on-call night were counterbalanced. Subjects were instructed to react to a sound, presented at unpredictable moments during the night. Participants were unaware of the fact that the sound would never be presented. These vigilance instructions resulted in more subjective wake after sleep onset (WASO), lower subjective sleep efficiency and significantly lower experienced sleep quality. Objectively, a longer sleep onset, an increased amount of WASO and significantly lower sleep efficiency were observed. During deep sleep, significantly more beta activity was recorded. Apart from real nightly interventions increased vigilance during the night causes sleep to be less efficient and less qualitative as shown by an increase in wake-activity and a distorted sleep perception.

The emotional brain and sleep: an intimate relationship.

Research findings confirm our own experiences in life where daytime events and especially emotionally stressful events have an impact on sleep quality and well-being. Obviously, daytime emotional stress may have a differentiated effect on sleep by influencing sleep physiology and dream patterns, dream content and the emotion within a dream, although its exact role is still unclear. Other effects that have been found are the exaggerated startle response, decreased dream recall and elevated awakening thresholds from rapid eye movement (REM)-sleep, increased or decreased latency to REM-sleep, increased REM-density, REM-sleep duration and the occurrence of arousals in sleep as a marker of sleep disruption. However, not only do daytime events affect sleep, also the quality and amount of sleep influences the way we react to these events and may be an important determinant in general well-being. Sleep seems restorative in daily functioning, whereas deprivation of sleep makes us more sensitive to emotional and stressful stimuli and events in particular. The way sleep impacts next day mood/emotion is thought to be affected particularly via REM-sleep, where we observe a hyperlimbic and hypoactive dorsolateral prefrontal functioning in combination with a normal functioning of the medial prefrontal cortex, probably adaptive in coping with the continuous stream of emotional events we experience.