Mathieu Pilon

Polysomnographic diagnosis of sleepwalking: Effects of sleep deprivation

Somnambulism affects up to 4% of adults and constitutes one of the leading causes of sleep‐related violence and self‐injury. Diagnosing somnambulism with objective instruments is often difficult because episodes rarely occur in the laboratory. Because sleep deprivation can precipitate sleepwalking, we aimed to determine the effects of 25 hours of sleep deprivation on the frequency and complexity of somnambulistic episodes recorded in the laboratory.

Variety and Intensity of Emotions in Nightmares and Bad Dreams

Nightmares are usually defined as frightening dreams that awaken the sleeper. This study uses the waking criterion to distinguish between nightmares and bad dreams and investigated the variety and intensity of emotions reported in each form of disturbing dream. Ninety participants recorded their dreams for 4 consecutive weeks and, for each dream recalled, noted the emotions present and their intensities on a 9-point scale. Thirty-six participants reported at least one nightmare and one bad dream over the 4 weeks covered by the log, while 29 reported having had at least one bad dream but no nightmares. Nightmares were rated as being significantly (p < 0.001) more intense than bad dreams. Thirty percent of nightmares and 51% of bad dreams contained primary emotions other than fear. The findings support the claim that awakening can serve as an indirect measure of nightmare intensity and raise important implications for the operational definition of nightmares.

Analysis of postarousal EEG activity during somnambulistic episodes.

Early studies found that electroencephalographic (EEG) recordings during somnambulistic episodes were characterized by a combination of alpha, theta, and delta frequencies, without evidence of clear wakefulness. Three postarousal EEG patterns associated with slow‐wave sleep (SWS) arousals were recently identified in adults with sleepwalking and sleep terrors. The goal of the present study was to evaluate the distribution of these postarousal EEG patterns in 10 somnambulistic patients (three males, seven females, mean age: 25.1, SD: 4.1) evaluated at baseline and following 38 h of sleep deprivation. A total of 44 behavioral arousals were recorded in the laboratory; seven episodes at baseline (five from SWS, two from stage 2 sleep) and 37 episodes during recovery sleep (30 from SWS, seven from stage 2 sleep). There was no significant difference in the distribution of postarousal EEG patterns identified during baseline and recovery sleep. One pattern, comprised of diffuse rhythmic and synchronous delta activity, was preferentially associated with relatively simple behavioral episodes but did not occur during episodes from stage 2 sleep. Overall, delta activity was detected in 48% of the behavioral episodes from SWS and in 22% of those from stage 2. There was no evidence of complete awakening during any of the episodes. The results support the view of somnambulism as a disorder of arousal and suggest that sleepwalkers’ atypical arousal reactions can manifest themselves in stage 2 sleep in addition to SWS.

Chapter 52 – NREM parasomnias

Considerable progress has been made in the systematic study of nonrapid eye movement (NREM) sleep parasomnias. This chapter focuses on the clinical features, prevalence, pathophysiology, associated sleep parameters, and clinical variants of the prototypic NREM sleep parasomnias, namely confusional arousals, sleepwalking, and sleep terrors. Whereas the occurrence of NREM parasomnias in children is frequently viewed as relatively benign, these disorders often pose greater problems, including sleep-related injuries, in affected adults. Most episodes arise from sudden but incomplete arousal from slow-wave sleep and sometimes from stage 2 sleep. Factors that deepen or fragment sleep can facilitate or precipitate NREM parasomnias in predisposed individuals. NREM parasomnias can be associated with various primary sleep disorders or with medical conditions. Diagnosis of NREM parasomnias can often be made based on a detailed history, although some patients may require more extensive evaluations, including polysomnographic study with an expanded EEG montage. Sleep deprivation and the presentation of auditory stimuli during slow-wave sleep are two techniques that can increase the occurrence of behavioral manifestations under laboratory conditions. A variety of nonpharmacological treatments have been recommended for long-term management of NREM parasomnias, whereas pharmacological agents should be considered only if the behaviors are hazardous or extremely disruptive.