Phenomenal Qualities of Nightmare Experience in a Prospective Study of College Students

The present study investigated the relationship between both state and global measures of phenomenal qualities of nightmare experience and nightmare prevalence as measured prospectively by dream logs. Sixty three frequent nightmare individuals and 53 controls completed a retrospective measure of their sleep and dreaming processes and kept a dreaming and nightmare log for 21 consecutive nights. Nightmare prevalence was unrelated to all three state-based rating dimensions including a concurrent rating of how distressing the actual nightmare was but was significantly associated with a global measure of nightmare distress. Similarly, global ratings of dream and nightmare saliency showed greater predictive validity than ratings of the same dimensions rated concurrently. The results suggest that whether a person reports having a nightmare on any given night is more associated with how they view their global dreaming processes than with the phenomenal qualities of the actual nightmare itself.     

Dreamed movement elicits activation in the sensorimotor cortex

Since the discovery of the close association between rapid eye movement (REM) sleep and dreaming, much effort has been devoted to link physiological signatures of REM sleep to the contents of associated dreams [1-4]. Due to the impossibility of experimentally controlling spontaneous dream activity, however, a direct demonstration of dream contents by neuroimaging methods is lacking. By combining brain imaging with polysomnography and exploiting the state of "lucid dreaming," we show here that a predefined motor task performed during dreaming elicits neuronal activation in the sensorimotor cortex. In lucid dreams, the subject is aware of the dreaming state and capable of performing predefined actions while all standard polysomnographic criteria of REM sleep are fulfilled [5, 6]. Using eye signals as temporal markers, neural activity measured by functional magnetic resonance imaging (fMRI) and near-infrared spectroscopy (NIRS) was related to dreamed hand movements during lucid REM sleep. Though preliminary, we provide first evidence that specific contents of REM-associated dreaming can be visualized by neuroimaging.     

Psychophysiological correlates of lucid dreaming.

The main goal of the present study was to explore electrophysiological differences between lucid and nonlucid dreams in REM sleep. Seven men and four women experienced in lucid dreaming underwent polysomnographic recordings in the sleep laboratory on two consecutive nights. EEG signals were subjected to spectral analysis to obtain five different frequency bands between 1 and 20 Hz. Lucidity was determined by both subjective dream reports and eye-movement signals made by the subjects in response to light stimuli indicating a REM period. The main discrimination factor between lucid and nonlucid dreaming was found in the beta-1 frequency band (13-19 Hz), which in lucid dreaming was increased in both parietal regions. The ratio of frontal to parietal beta-1 activity was 1 to 1.16 in nonlucid and 1 to 1.77 in lucid dreaming. A tendency towards the greatest increase was observed in the left parietal lobe (P3), an area of the brain considered to be related to semantic understanding and self-awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trait–state interactions in the etiology of nightmares.

Various personality and psychopathology traits are associated with nightmare frequency. This study investigated whether trait variables might also account for individual differences in the longitudinal relationship between daily mood and nightmare incidence each night. Forty-two participants (35 women, 7 men; mean age = 40.10 years) reported having nightmares at least once per month and completed a 14-day dream and mood (anxiety and depression) log. Within-subject correlations between state anxiety and nightmare incidence or absence the following night and between state depression and nightmare incidence or absence were computed. None of the trait measures had significant correlations with these within-subject correlations. However, when only participants scoring above the group median on Hartman’s thin boundariness were analyzed, thin boundariness, Symptom Checklist—Global Severity, adverse life events, and childhood adversity were associated with the incidence of nightmares as a function of state anxiety or depression on a night-by-night basis, with correlation coefficients between .43 and .52. This supports the hypothesis of trait predispositions for a nightmare reaction to daily state anxiety or depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of dream anxiety and subjective sleep quality between chronotypes

Morning and evening-type individuals differ on a number of psychological and biological variables. In this study, we aimed to investigate the relationship between sleep quality, dream anxiety, and chronotypes. A sample of 264 university students, aged between 17 and 26 years, completed the Morningness-Eveningness Questionnaire, the Pittsburgh Sleep Quality Index, and the Van Dream Anxiety Scale for assessing nightmare frequency and the dream anxiety caused by frightening dreams. Main findings indicated that evening-type individuals were significantly more likely to suffer from poor sleep quality, daytime dysfunction, nightmares, and nightmare-related disturbances as compared to either intermediate- or morning-type individuals. Previous studies have pointed out the possible connections of irregular sleep-wake habits and circadian dysregulation with a tendency to reveal eveningness chronotypical characteristics. Current findings suggest that evening-type individuals are more prone to experience psychologically deteriorating nightmares and sleep-related anxiety. Poor sleep quality is also a significant antecedent of dream anxiety after controlling for age and gender.

     

Affective and Personality Characteristics in Function of Nightmare Prevalence, Nightmare Distress, and Interference Due to Nightmares.

This study analyzes the relationships among nightmare frequency, nightmare distress, and interference due to nightmares, sleep quality, psychopathology (anxiety and depression), and personality (neuroticism, psychoticism, and boundaries). The nightmare parameters were evaluated with the Nightmare Frequency Questionnaire (B. Krakow et al., 2000; see also record 2000-16731-002), the Nightmare Distress Questionnaire (K. Belicki, 1992b; see also record 1993-08389-001), and the Nightmare Effects Survey (Krakow et al., 2000). The sample was composed of 147 healthy students. The results demonstrated that the 2 measurements of distress (subjective distress associated with nightmares and, especially, deterioration of psychosocial functioning) were the dimensions that best related to the variables studied, although the relationships were modulated by nightmare frequency. The parameter of nightmare frequency was found to be useful as an indicator of certain personality characteristics rather than psychological perturbation. Having nightmares on a weekly basis was strongly associated with depressed mood. The knowledge about these relations is relevant not only theoretically but also as a practical guide. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Virtual reality training of lucid dreaming

Metacognitive reflections on one''s current state of mind are largely absent during dreaming. Lucid dreaming as the exception to this rule is a rare phenomenon; however, its occurrence can be facilitated through cognitive training. A central idea of respective training strategies is to regularly question one''s phenomenal experience: is the currently experienced world real, or just a dream? Here, we tested if such lucid dreaming training can be enhanced with dream-like virtual reality (VR): over the course of four weeks, volunteers underwent lucid dreaming training in VR scenarios comprising dream-like elements, classical lucid dreaming training or no training. We found that VR-assisted training led to significantly stronger increases in lucid dreaming compared to the no-training condition. Eye signal-verified lucid dreams during polysomnography supported behavioural results. We discuss the potential mechanisms underlying these findings, in particular the role of synthetic dream-like experiences, incorporation of VR content in dream imagery serving as memory cues, and extended dissociative effects of VR session on subsequent experiences that might amplify lucid dreaming training during wakefulness.This article is part of the theme issue ‘Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation''.     

Dreaming correlates of alexithymia among sleep-disordered patients.

Increasing evidence supports the clinical view that alexithymia is associated with disturbed dreaming. However, a consistent, replicable pattern of relationships between alexithymia and different dreaming components has not yet been identified. Groups of sleep-disordered outpatients (N = 580; 46.0 ± 13.2 years) and nonclinical controls (N = 145; 22.9 ± 4.2 years) were administered the Toronto Alexithymia Scale (TAS-20) and a 14-item Dreaming Questionnaire. Sleep diagnoses were assessed from polysomnography and clinical histories following the American Academy of Sleep Medicine classification system. The Dreaming Questionnaire was reduced by principal-components analysis to a 3-factor solution that distinguishes nightmare distress, dream recall, and dream meaning items. Factor coefficients were correlated with TAS total score and TAS subscales while age was controlled as a covariate. TAS total score was found to correlate positively with nightmare distress and negatively with dream recall for both clinical and nonclinical groups and for both men and women considered separately. TAS total score also correlated negatively with dream meaning for nonclinical participants. TAS subscales were differentially correlated with the 3 dream factors: difficulty identifying feelings (DIF) with increased nightmare distress, difficulty describing feelings (DDF) with decreased dream recall and externally oriented thinking (EOT) with decreased dream meaning. With some exceptions, these patterns were obtained independently for clinical and nonclinical groups and for men and women within these groups. Findings suggest a consistent and replicable pattern of relationships between alexithymia and dreaming components that implicates processes regulating emotion during both wakefulness and dreaming, for example, affect distress, expressive anxiety, and openness to experience. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Associations between diurnal preference,impulsivity and substance use in a young-adult student sample

ABSTRACT

A diurnal preference for eveningness is common in young adulthood and previous research has associated eveningness with anxiety symptoms as well as increased smoking and alcohol use behaviors. There is some evidence that impulsivity might be an important explanatory variable in these associations, but this has not been comprehensively researched. Here we used both subjective and objective measures of impulsivity to characterize impulsive tendencies in young adults and investigated whether trait impulsivity or trait anxiety could mediate the link between eveningness and substance use. A total of 191 university students (169 females), age range 18–25 y, completed the study. Diurnal preference, sleep quality, anxiety, impulsivity, and substance use were assessed by questionnaire. Impulsivity was also measured using a delay discounting task. Eveningness correlated with trait anxiety and trait impulsivity, and these associations were still significant after controlling for sleep quality. On the delayed discounting task, eveningness correlated with a tendency to prefer smaller immediate rewards over delayed, larger ones. Evening types also reported higher levels of alcohol and cigarette use even after controlling for sleep quality. These associations were found to be completely mediated by self-reported impulsivity; anxiety did not contribute. The current results could help inform interventions aiming to reduce substance use in young adult populations.     

Correlation of sleep disturbances, anxiety and depression in Croatian war veterans with posttraumatic stress disorder

The aim of the study was to examine the relationships between global sleep quality and its specific components and Posttraumatic Stress Disorder (PTSD) symptom severity questionnaire. We also researched whether sleep quality and sleep disturbances differed among groups of PTSD based on symptom severity categories. This study was conducted on the sample of 120 Croatian war veterans with PTSD. The following self-report instruments were used: Pittsburgh Sleep Quality Index, the Pittsburgh Sleep Quality Index Addendum for PTSD, the Mississippi Scale for Combat-Related PTSD, the Spielberger State and Trait Anxiety Inventory and the Beck Depression Inventory. There were statistically significant differences between the three PTSD severity groups on general nervousness (PSQI-A variable), where patients with extremely severe PTSD have more symptoms of general nervousness than groups with severe or moderate PTSD. Differences were found between PTSD severity groups in episodes of terror and acting-out dreams, where patients with extremely severe PTSD have more symptoms of episodes of terror and acting-out dreams than groups with severe or moderate PTSD. Sleep quality was significantly correlated with state anxiety, trait anxiety, and depression, indicating that with decrease of anxiety and depression, sleep quality improves. Sleep latency was positively correlated with both state and trait anxiety. There wasn't any significant correlation between sleep latency and depression. Study suggests that sleep disturbances are equally severe across groups of veterans based on PTSD severity and that the severity of sleep disturbances is significantly related to severity of anxiety and depression symptoms.     

Effects of essential oil inhalation on objective and subjective sleep quality in healthy university students

Aromatherapy with essential oils is one of the most popular complementary medical tools for improving sleep quality. However, only a few reports have objectively measured the effects of essential oils on sleep. Here, we used objective and subjective measures to analyze the effects of the essential oils of lavender (Lavandula angustifolia) and sweet orange (Citrus sinensis) on the sleep quality of healthy university students. The participants were monitored for 15 consecutive nights as they inhaled lavender oil and sweet orange oil, in a crossover design. Their sleep was monitored objectively by actigraphy, and total sleep time (TST), sleep efficiency, sleep latency, and wake after sleep onset (WASO) were analyzed. Their sleep was analyzed subjectively using Oguri–Shirakawa–Azumi (OSA) sleep inventory scores. Inhalation of an essential oil improved sleep measures only in participant whose sleep quality was poor in the control condition. Lavender seemed more effective than sweet orange in objective measures, especially in improving sleep latency. In the subjective sleep analysis, the essential oils improved sleep maintenance, dreaming, and sleep length in subjects who had poor sleep quality. Sweet orange seemed more effective than lavender in the subjective sleep measures. The difference between the two oils suggests that expectancy bias had little effect on the hypnotic effect of lavender on objective sleep. Although no obvious effect was observed in good sleepers, the inhalation of lavender oil could be effective for helping poor sleepers improve objective sleep quality.

     

Cardiovascular responses to dreamed physical exercise during REM lucid dreaming.

Previous studies have demonstrated intriguing psychophysiological correspondences when lucid dreamers carried out specific tasks during lucid dreams (e.g., eye movements and EMG activities). But only a few studies have investigated cardiovascular changes during dreamed physical activities. This study tests the hypothesis that physical activity (performing squats) carried out in a lucid dream increases cardiovascular parameters in the sleeping body. Therefore, 5 proficient lucid dreamers experienced with the eye-signaling method during lucidity spent 2 to 4 nonconsecutive nights in a sleep laboratory. Instructed to carry out specific tasks (counting and performing squats) while lucid dreaming, the participants reported becoming lucid and signaling in 11 REM periods recorded. Fourteen complete lucid dream tasks were verified by eye signaling. The results showed a statistically significant increase of heart rate between the preexercise and exercise periods and the postexercise period. The results for respiration rate were less clear. Even though respiration rate during the exercise period was higher than during the pre- and postexercise period, statistical significance was only found for the second comparison. Overall, the results support the hypothesis that lucidly dreamed motor action causes increases at the level of peripheral effectors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sleep phenotyping in a mouse model of extreme trait anxiety

Background

There is accumulating evidence that anxiety impairs sleep. However, due to high sleep variability in anxiety disorders, it has been difficult to state particular changes in sleep parameters caused by anxiety. Sleep profiling in an animal model with extremely high vs. low levels of trait anxiety might serve to further define sleep patterns associated with this psychopathology.

Methodology/Principal Findings

Sleep-wake behavior in mouse lines with high (HAB), low (LAB) and normal (NAB) anxiety-related behaviors was monitored for 24 h during baseline and recovery after 6 h sleep deprivation (SD). The amounts of each vigilance state, sleep architecture, and EEG spectral variations were compared between the mouse lines. In comparison to NAB mice, HAB mice slept more and exhibited consistently increased delta power during non-rapid eye movement (NREM) sleep. Their sleep patterns were characterized by heavy fragmentation, reduced maintenance of wakefulness, and frequent intrusions of rapid eye movement (REM) sleep. In contrast, LAB mice showed a robust sleep-wake rhythm with remarkably prolonged sleep latency and a long, persistent period of wakefulness. In addition, the accumulation of delta power after SD was impaired in the LAB line, as compared to HAB mice.

Conclusions/Significance

Sleep-wake patterns were significantly different between HAB and LAB mice, indicating that the genetic predisposition to extremes in trait anxiety leaves a biological scar on sleep quality. The enhanced sleep demand observed in HAB mice, with a strong drive toward REM sleep, may resemble a unique phenotype reflecting not only elevated anxiety but also a depression-like attribute.     

Emotions before, during, and after dreaming sleep.

The aim of this study was to provide a preliminary overview of the emotions before, during, and after dreaming sleep in Chinese people. One hundred Chinese participants were included in the study. Cheerful emotions, including interest, exhilaration, and enjoyment, were pervasive in the collected dreams, although anxiety was also a common type of emotion. Positive correlations were found between the intensities of dream, presleep, and postsleep emotions. Significant reductions in intensity were noted in the analyses of emotions preceding dreaming sleep versus emotions following dreaming sleep. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lucid Art and Hyperspace Lucidity

This article explores nonrepresentational, multidimensional lucid dreaming and its parallel imagery in modern art paintings. Developed from a series of successive qualitative experiments on art and lucid dreaming, the study brings together phenomenological and narrative approaches to reveal a relationship between imagery in a particular lucid dream experience (Hyperspace Lucidity) and a particular type of modern art painting (Lucid Art). This article attempts to open new dialogues for investigation of the interconnection between the dreaming mind and art.     

Austrian Dream Behavior: Results of a Representative Population Survey

This study was based on a survey of a representative sample of 1000 Austrians who were questioned about their sleep and dream behavior. About two-thirds of the respondents reported that they generally recalled at least one dream per month. Dream recall frequency decreased with advancing age, but did not differ between men and women. Fifty-five percent of the respondents characterized the affective content of their dreams: 29% reported neutral, 20% positive, and 6% negative dreams. Four percent of the sample reported suffering from nightmares. These respondents more frequently reported snoring, interrupted sleep, daytime somnolence, anxiety and nervousness, depression, high dream recall, recurrent dreams, and dreaming in color. Twenty-six percent of the total sample reported that sometimes they realized during their dreams that they were dreaming. These respondents more frequently reported family problems, high dream recall, positive dream content, recurrent dreams, dreaming in color, and nightmares.     

Association of lucid dreaming frequency with Stroop task performance.

Lucid dreaming involves the attentional skill of having metacognition about the dreamer's state of consciousness at the same time as being engaged in the dream scenario. A combination of two levels of cognition also occurs in the incongruent condition of the Stroop task, where there is interference between the attentional demands of a relatively difficult (color naming) and an easy (reading) task. It was thus hypothesized that frequent lucid dreamers would perform better on the Stroop task than would nonlucid dreamers. Individuals who reported having lucid dreams more than once per month (n = 15) were found to be significantly faster on the incongruent condition of the Stroop task than were occasional lucid dreamers (n = 15) or nonlucid dreamers (n = 15). The groups did not differ on the standard colored nonword control condition. Continuity in attentional ability between waking and dreaming cognition was thus found. This continuity may counteract the psychophysiologically dominant and possibly evolutionarily selected lack of self-awareness in dreams. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cerebral specialization during lucid dreaming: A right hemisphere hypothesis.

Research has shown that certain individuals are able to carry out prearranged tasks while lucid dreaming, and that these tasks produce physiological effects on the body similar to what is observed during waking. It was hypothesized that the difficulty of performing cerebrally lateralized tasks during a lucid dream would vary with the dominant hemisphere for that task, with less difficulty for right hemisphere tasks. Twenty-seven participants rated the difficulty of performing three matched pairs of left hemisphere and right hemisphere tasks, first in a lucid dream, and later in their waking imagination. Results indicated right hemisphere dominance during lucid dreaming, especially among right-handed participants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dreaming and insomnia: Polysomnographic correlates of reported dream recall frequency.

This study assesses which polysomnographic variables are associated with changes in reported dream recall frequency in patients meeting diagnostic criteria for primary insomnia. Data analyzed included sleep latency, total sleep time, sleep efficiency, time in REM, time in sleep stages (1&2 vs. 3&4), and periodic limb movement. For the grouping meeting ICD-10 diagnostic criteria for primary insomnia, a significant decrease in dream recall was found compared to the noninsomniac group. A decline in polysomnographic sleep quality was associated with a decline in reported dream or nightmare recall frequency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review of The Mind at Night: The New Science of How and Why We Dream.

In this article I review "The Mind at Night: The New Science of How and Why We Dream," written by Andrea Rock. To begin with this book is an exciting journey through modern dream research. Scientific facts, which are skillfully explained, are complemented by personal accounts of well-known researchers in the field obtained through interviews. The diversity of the themes addressed in the book (e.g., sleep and memory, animal research, imaging studies, dream content analysis, consciousness research, creativity, and lucid dreaming) clearly shows the extensive "detective work" the author has accomplished. The major problem I had--as a researcher in this field--was the structure, or the lack of structure, within the book. Because of the way the book is organized, I decided to structure this review along the following themes: REM sleep, REM sleep and dreaming, biology of dreaming, dream content findings, and the integration of dream research into cognitive neuroscience in general. Despite the lack of structure of the book, Andrea Rock has written a wonderful book about modern dream research that is stimulating for researchers as well as for interested lay persons. I recommend it to everyone who is interested in dream research, the old question of the mind-body relationship, or understanding consciousness in general. (PsycINFO Database Record (c) 2010 APA, all rights reserved)