Antonio Zadra

The value of sleep deprivation as a diagnostic tool in adult sleepwalkers

ObjectiveAdult somnambulism can result in injury to the sleeper and to others. Attempts to induce sleepwalking episodes in the sleep laboratory have yielded mixed results. 1,2 Having shown that sleepwalkers have lower slow-wave activity power than control subjects, 3 the authors hypothesized that an enhanced pressure of the homeostatic process underlying sleep regulation could affect the disorder’s characteristics even further. Therefore, the effects of 38 hours of sleep deprivation in adult sleepwalkers and control subjects were investigated. MethodsTen adult somnambulistic patients and 10 sex- and age-matched control subjects were studied in the sleep laboratory. After a screening night, participants were monitored during 1) one night of baseline recording, and 2) one recovery night in which subjects slept ad libitum immediately after the sleep deprivation protocol. Behavioral manifestations were assessed for frequency and complexity using a 3-point scale of increasing complexity. ResultsNone of the control subjects had any behavioral manifestations on either of the two nights. Conversely, sleepwalkers showed a significant increase in the frequency and complexity of the somnambulistic episodes during the recovery night compared with baseline. Somnambulistic patients had a greater number of awakenings from slow-wave sleep than control subjects on both nights, but there was no significant increase during the recovery night. ConclusionSleep deprivation can be an effective tool for inducing somnambulistic episodes in the laboratory, thereby facilitating the diagnosis of sleepwalking.

Somnambulism: clinical aspects and pathophysiological hypotheses

Somnambulism, or sleepwalking, can give rise to a wide range of adverse consequences and is one of the leading causes of sleep-related injury. Accurate diagnosis is crucial for proper management and imperative in an ever-increasing number of medicolegal cases implicating sleep-related violence. Unfortunately, several widely held views of sleepwalking are characterised by key misconceptions, and some established diagnostic criteria are inconsistent with research findings. The traditional idea of somnambulism as a disorder of arousal might be too restrictive and a comprehensive view should include the idea of simultaneous interplay between states of sleep and wakefulness. Abnormal sleep physiology, state dissociation, and genetic factors might explain the pathophysiology of the disorder.

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.

Prevalence of Auditory, Olfactory, and Gustatory Experiences in Home Dreams

Although numerous studies have investigated the content of laboratory and home dream reports, surprisingly Little is known about the prevalence of various sensory modes in dreams. 49 men and 115 women completed a battery of questionnaires and kept a home dream diary for two to three consecutive weeks. Retrospective responses to the questionnaire indicate that approximately 33% of men and 40% of women recalled having experienced sensations of smell or taste in their dreams. A total of 3372 dream reports were collected and scored for unambiguous references to auditory, olfactory, and gustatory experiences. Auditory experiences were reported in approximately 53% of all dream reports. Olfactory and gustatory sensations occurred in approximately 1% of all dream reports. A significantly greater percentage of women than men reported one or more dreams containing references to olfactory sensations. The results lend support to previous studies which have shown that a variety of sensory experiences, although relatively rare, can occur in dreams.

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.

Measuring nightmare and bad dream frequency: Impact of retrospective and prospective instruments.

Studies on nightmare frequency have yielded inconsistent results. We compared the frequency of nightmares and bad dreams obtained with retrospective methods (annual and monthly estimates) and with two types of prospective measures (narrative and checklist logs). Four hundred and eleven participants completed retrospective estimates of nightmare and bad dream frequency and recorded their dreams in either narrative or checklist logs for 2–5 weeks. When measured prospectively with narrative logs, nightmare frequency was marginally higher than the 1‐year estimate (P = 0.057) but not significantly different from the 1‐month estimate (P > 0.05). Prospective bad dream frequency was significantly greater than the two retrospective estimates (ps < 0.0005). There were no significant differences in the frequency of nightmares and bad dreams reported prospectively with narrative versus checklist logs (ps > 0.05). However, checklist logs yielded a significantly greater number of everyday dreams per week (P < 0.0001). Taken together, the results provide partial support for the idea that when compared to daily logs, retrospective self‐reports significantly underestimate current nightmare and bad dream frequency. Prospective studies of dream recall and nightmare frequency should take into account the type of log used, its duration, and the participants’ level of motivation over time.

Increased Mastery Elements Associated With Imagery Rehearsal Treatment for Nightmares in Sexual Assault Survivors With PTSD.

Exposure, abreaction, and mastery have been proposed as the therapeutic processes of nightmare (NM) reduction. Imagery rehearsal therapy (IRT) effectively reduces NMs but involves minimal exposure and abreaction. The authors investigated the use of mastery in the scripting of new dreams (NDs) elaborated during IRT. NM an dN D reports were collected from 44 female sexual assault survivors with chronic NMs during their initial application of IRT. Mastery was assessed with a standardized dream coding system and a multidimensional mastery scale. NDs contained significantly fewer negative elements and more occurrences of positive elements and mas

Evolutionary function of dreams: A test of the threat simulation theory in recurrent dreams ☆

proposed an intriguing and detailed evolutionary theory of dreams which stipulates that the biological function of dreaming is to simulate threatening events and to rehearse threat avoidance behaviors. The goal of the present study was to test this theory using a sample of 212 recurrent dreams that was scored using a slightly expanded version of the DreamThreat rating scale. Six of the eight hypotheses tested were supported. Among the positive findings, 66% of the recurrent dream reports contained one or more threats, the threats tended to be dangerous and aimed at the dreamer, and when facing a threat, the dreamer tended to take defensive or evasive actions that were possible and reasonable. However, less than 15% of the recurrent dreams depicted realistic and probable situations critical for ones physical survival or reproductive success and the dreamer rarely succeeded in fleeing the threat despite important and appropriate efforts. The findings thus provide mixed support for the threat simulation theory.

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.

Dream content in chronically-treated persons with schizophrenia.

Many clinical, laboratory and non-laboratory studies have examined dream content reported by patients with schizophrenia but findings have been variable and inconsistent. Using both questionnaire-based measures and laboratory REM sleep awakenings, we investigated dream content in 14 patients with schizophrenia (mean age=25.5+/-3.2 years) under atypical antipsychotic medication and 15 healthy controls (mean age=22.3+/-4.2 years). The relationship between eye movement density during REM sleep and dream content was also explored. Questionnaire data revealed that when compared to controls, patients with schizophrenia report experiencing a greater number of nightmares but no significant differences were found on other measures including overall dream recall, presence of recurrent dreams, and frequency of specific emotions. 39 dream reports were collected from each group following awakenings from REM sleep. Laboratory dream narratives from the patients were shorter and, after controlling for report length, most significant differences in dream content between the two groups disappeared with the exception of a greater proportion of unknown characters in the participant group. Patients with schizophrenia spontaneously rated their dream reports as being less bizarre than did controls, despite a similar density of bizarre elements as scored by external judges. Finally, both groups had a comparable density of rapid eye movements during REM sleep but a significant positive correlation between eye-movement density and dream content variables was only found in controls. Taken together, the findings suggest that dream content characteristics in schizophrenia may reflect neurocognitive processes, including emotional processing, specific to this disorder.