Effects of nightmares on the cortisol awakening response: An ambulatory assessment pilot study.

Previous studies have reported an association between sleep-related factors such as sleep duration, sleep quality and time of awakening with the cortisol awakening response (CAR). Preliminary evidence suggests that frequent nightmares are associated with a blunted CAR. In the present pilot study we investigated the effect of acute nightmares on the CAR and the cortisol profile of the subsequent day using a within-subject ambulatory assessment study design. Thirty healthy volunteers who reported frequent nightmares enrolled in the study. Over a period of 14 days, salivary samples in addition to sleep-related and state variables were collected at home over the day. Salivary profiles of free cortisol and alpha amylase for up to two days following a nightmare were compared to those following a neutral dream. Overall, mood and health were decreased and the CAR was elevated following nightmares compared to neutral dreams. No differences were found for alpha amylase and for all variables over the remaining part of the day. Results suggest that sleep-related factors such as the occurrence of nightmares account for a certain amount of variance observed in the CAR. This has important methodological implications for CAR studies in general and might have even more relevance for studies in clinical populations suffering from chronic sleep disturbances.

Nightmares do result in psychophysiological arousal: A multimeasure ambulatory assessment study.

Individuals who frequently experience nightmares report compromised sleep quality, poor daytime mood, and functioning. Previous research has aimed at linking these impairments with altered sleep architecture, but results were inconclusive. One plausible explanation is that only a few studies recorded markers of autonomic nervous system activity. For the first time, this study collected such markers under ecologically valid conditions with ambulatory assessment. In 19 individuals with frequent nightmares (≥1 nightmare/week) and 19 healthy control participants (<1 nightmare/month), measures indicating autonomic activation (heart rate, heart rate variability, respiration cycle length, electrodermal fluctuations, EEG arousals, saliva cortisol, REM density) were collected while applying ambulatory polysomnographic assessment during 3 consecutive nights. When nightmare participants reported a nightmare, we analyzed the last 5 min of REM sleep before awakening and compared these data to their non-nightmares as well as to the dream episodes of control participants. Overall, there were no general differences in autonomic activation of nightmare sufferers compared to control participants. However, when nightmare participants experienced nightmares, autonomic activation was markedly increased compared to their own non-nightmares and, to some extent, to control participant's dreams. Significant intraindividual differences were found for all autonomic measures except in participant's EEG arousals and cortisol levels. Group differences were found in EEG arousals and heart rate. In conclusion, ambulatory polysomnography demonstrates that nightmares are accompanied by increased autonomic activation. Results support the notion of impaired self-reported sleep quality caused by one's autonomic response rather than altered sleep pattern.

Lifestyle and oral facial disorders associated with sleep bruxism in children.

OBJECTIVE: The aim of the study was to investigate the routine, sleep history, and orofacial disorders associated with children aged 3-7 years with nocturnal bruxism. METHODS: Children (n = 66) were divided into groups of parent reported nocturnal bruxism (n = 34) and those without the disorder (n = 32). Data about the child's routine during the day, during sleep and awakening, headache frequency, temporomandibular joint (TMJ), and hearing impairments were obtained through interviews with parents/caregivers. Electromyography examination was used to assess the activity of facial muscles. Multiple logistic regression (MLR), chi-square test, and t-test analyses were performed. RESULTS: MLR revealed association of nightmares (p = 0.002; OR = 18.09) and snoring (p = 0.013; OR = 0.14) with bruxism. Variables related to awakening revealed an association with bruxism (p < 0.05). Parents of the main group (children with nocturnal bruxism) reported more complaints of orofacial pain, facial appearance, and headache occurrence (p < 0.05). Auditory and muscle disorders were not significant variables (p > 0.05). CONCLUSION: Nightmares and snoring are associated with nocturnal bruxism in children. Bruxism in children elicits consequences such as headache, orofacial pain, and pain related to awakening.

Frequent nightmares are associated with blunted cortisol awakening response in women.

Nightmares are relatively common sleep complaints that seem to be associated with affective distress. To date, few attempts have been made to link nightmares to the biological markers of the stress response, and the HPA response in particular. The present study examined the relationship between frequent nightmares and the cortisol awakening response (CAR) in a cross-sectional study of working women (N=188). Analysis revealed that those who reported frequent nightmares (N=13) showed a blunted CAR on a working day, compared to those who did not report nightmares. This result was independent of psychiatric symptoms, demographic variables, and lifestyle. Our preliminary findings suggest that decreased HPA reactivity might be a trait-like feature of women with frequent nightmares.

Dreaming during non-rapid eye movement sleep in the absence of prior rapid eye movement sleep.

STUDY OBJECTIVES: There is a long-standing controversy surrounding the existence of dream experiences during non-rapid eye movement (NREM) sleep. Previous studies have not answered the question whether this "NREM dream" originates from the NREM sleep mechanism because the subject might simply be recalling experiences from the preceding rapid eye movement (REM) sleep. METHODS: We scheduled 11 healthy men to repeat 20-minute nap trials separated by 40-minute periods of enforced wakefulness across a period of 3 days. At the end of the nap trial, each participant answered questions regarding the formal aspects of his dream experiences during the nap trial, using the structured interviews. RESULTS: We obtained a total of 172 dream reports after naps containing REM sleep (REM naps) and 563 after naps consisting of only NREM sleep (NREM naps). Dream reports from NREM naps were less remarkable in quantity, vividness, and emotion than those from REM naps and were obtained more frequently during the morning hours when the occurrences of REM sleep were highest. CONCLUSIONS: These results suggest that the polysomnographic manifestations of REM sleep are not required for dream experiences but that the mechanisms driving REM sleep alter experiences during NREM sleep in the morning. A subcortical activation similar to REM sleep may occur in human NREM sleep during the morning when REM sleep is most likely to occur, resulting in dream experiences during NREM sleep.

[Parasomnia]. / Les parasomnies.

The parasomnias comprises a group of disorders that intrude into the sleep process and are not primarily disorders of sleep and wake states per se. These disorders are manifestations of central nervous system activation usually transmitted through skeletal muscle or autonomic nervous system channels (ICSD 1990). The parasomnias are divided into four groups: Arousal disorders (sleepwalking, night terrors, and confusionnal arousal), sleep-wake transition disorders (rhythmic movement disorder, sleep starts), REM sleep parasomnias (nightmares, sleep paralysis, hallucinations, and REM sleep behavior disorders), and other parasomnias (sleeptalking, nocturnal enuresis, and nocturnal bruxism.