Journal of Sleep Research
April 1, 2018
Pilleriin Sikka, Antti Revonsuo, Nils Sandman et al.
The aim of this study was to compare the emotional content of dream reports collected at home upon morning awakenings with those collected in the laboratory upon early and late rapid eye movement (REM) sleep awakenings. Eighteen adults (11 women, seven men; mean age = 25.89 ± 4.85) wrote down their home dreams every morning immediately upon awakening during a 7-day period. Participants also...
The American Journal of Psychology
August 21, 2017
Pilleriin Sikka, Diana Feilhauer, Katja Valli et al.
63 citations
Abstract This study demonstrates that different methods for measuring emotional experiences in dreams—self-ratings of dreams using emotion rating scales versus external ratings in the form of content analysis of narrative dream reports—can lead to strikingly different results and contradicting conclusions about the emotional content of home dreams. During 3 consecutive weeks, every morning upon...
Scientific Reports
March 15, 2017
Nils Sandman, Katja Valli, Erkki Kronholm et al.
Nightmares are intensive dreams with negative emotional tone. Frequent nightmares can pose a serious clinical problem and in 2001, Tanskanen et al. found that nightmares increase the risk of suicide. However, the dataset used by these authors included war veterans in whom nightmare frequency - and possibly also suicide risk - is elevated. Therefore, re-examination of the association between...
Sleep Medicine
January 16, 2015
Katja Valli, Birgit Frauscher, Taina Peltomaa et al.
Objective: Rapid eye movement (REM) sleep behavior disorder (RBD) has been related to altered, action-filled, vivid, and aggressive dream content, but research comparing the possible differences in dreams of Parkinson's disease (PD) patients with and without RBD is scarce. The dream content of PD patients with and without RBD was analyzed with specific focus on action-filledness, vividness,...
Consciousness and Cognition
April 1, 2014
Pilleriin Sikka, Katja Valli, Tiina Virta et al.
We investigated whether inconsistencies in previous studies regarding emotional experiences in dreams derive from whether dream emotions are self-rated or externally evaluated. Seventeen subjects were monitored with polysomnography in the sleep laboratory and awakened from every rapid eye movement (REM) sleep stage 5 min after the onset of the stage. Upon awakening, participants gave an oral...
Sleep
July 1, 2013
Nils Sandman, Katja Valli, Erkki Kronholm et al.
Study objectives: To investigate the prevalence of nightmares among the Finnish general adult population during 1972-2007 and the association between nightmare prevalence and symptoms of insomnia, depression, and anxiety in World War II veterans. Design: Eight independent cross-sectional population surveys of the National FINRISK Study conducted in Finland in 1972, 1977, 1982, 1987, 1992, 1997,...
Brain and Cognition
December 1, 2011
Valdas Noreika, Leila Jylhänkangas, Levente Móró et al.
62 citations
Anesthetic-induced changes in the neural activity of the brain have been recently utilized as a research model to investigate the neural mechanisms of phenomenal consciousness. However, the anesthesiologic definition of consciousness as "responsiveness to the environment" seems to sidestep the possibility that an unresponsive individual may have subjective experiences. The aim of the present...
Journal of Sleep Research
August 4, 2011
Katja Valli, Birgit Frauscher, Viola Gschliesser et al.
58 citations
Motor activity in rapid eye movement (REM) sleep behaviour disorder (RBD) has been linked to dream content. Systematic and controlled sleep laboratory studies directly assessing the relation between RBD behaviours and experienced dream content are, however, largely lacking. We aimed to investigate whether a link can be established between RBD behaviours and dream content when both are...
Advances in Consciousness Research
October 28, 2010
Antti Revonsuo, Katja Valli
Based on biological realism, that is, the philosophical assumption that consciousness is a real natural biological phenomenon in the brain, we argue that dreaming is a pure form of phenomenality, and suggest that the dreaming brain could be used as a model system for consciousness. The dreaming brain offers the most challenging model system that represents all the theoretically and...
Psychiatry Research
May 14, 2010
Valdas Noreika, Katja Valli, Juha Markkula et al.
Dream diaries and reports of daytime waking thought were collected from five schizophrenia patients and matched controls. It was more difficult for blind judges to differentiate the patients' than the controls' dream reports from reports of waking thought, and patients reported shorter but more bizarre dreams than did the controls.
International Journal of Psychophysiology
October 1, 2009
Valdas Noreika, Katja Valli, Hetti Lahtela et al.
A new experimental paradigm called "Early-Night Serial Awakenings" (ENSA) was explored to find out its strengths and weaknesses for psychophysiological studies of NREM sleep dreaming. Five participants spent 20 experimental nights in the sleep laboratory, and were serially awakened with approximately 24-minute intervals during Stages 2 and 3 of NREM sleep. As a total, 164 awakenings were...
The American Journal of Psychology
April 1, 2009
Katja Valli, Antti Revonsuo
132 citations
The recently proposed threat simulation theory (TST) states that dreaming about threatening events has a biological function. In the past few years, the TST has led to several dream content analysis studies that empirically test the theory. The predictions of the TST have been investigated mainly with a new content analysis system, the Dream Threat Scale (DTS), a method developed for...
Epilepsy & Behavior
August 1, 2008
Mirja Johanson, Katja Valli, Antti Revonsuo et al.
19 citations
Epilepsy research suffers from a deficiency of systematic studies concerning the phenomenology of the contents of consciousness during seizures, partially because of the lack of suitable research methods. The Phenomenology of Consciousness Inventory (PCI), a standardized, valid, and reliable questionnaire, was used here to study which dimensions of the contents of consciousness are distorted...
Consciousness and Cognition
March 1, 2005
Katja Valli, Antti Revonsuo, Outi Pälkäs et al.
The threat simulation theory of dreaming (TST) () states that dream consciousness is essentially an ancient biological defence mechanism, evolutionarily selected for its capacity to repeatedly simulate threatening events. Threat simulation during dreaming rehearses the cognitive mechanisms required for efficient threat perception and threat avoidance, leading to increased probability of...