The aim of the study was to investigate whether the electromagnetic field (EMF) emitted by digital radiotelephone handsets affects brain physiology. Healthy, young male subjects were exposed for 30 min to EMF (900 MHz; spatial peak specific absorption rate 1 W/kg) during the waking period preceding sleep. Compared with the control condition with sham exposure, spectral power of the EEG in non-rapid eye movement sleep was increased. The maximum rise occurred in the 9.75-11.25 Hz and 12.5-13.25 Hz band during the initial part of sleep. These changes correspond to those obtained in a previous study where EMF was intermittently applied during sleep. Unilateral exposure induced no hemispheric asymmetry of EEG power. The present results demonstrate that exposure during waking modifies the EEG during subsequent sleep. Thus the changes of brain function induced by pulsed high-frequency EMF outlast the exposure period.

The Delphi process allowed a consensus to be achieved in an area where there are limitations to the current evidence.

This consensus paper provides an overview of the state of the art in research on the aetiology and treatment of nightmare disorder and outlines further perspectives on these issues. It presents a definition of nightmares and nightmare disorder followed by epidemiological findings, and then explains existing models of nightmare aetiology in traumatized and non‐traumatized individuals. Chronic nightmares develop through the interaction of elevated hyperarousal and impaired fear extinction. This interplay is assumed to be facilitated by trait affect distress elicited by traumatic experiences, early childhood adversity and trait susceptibility, as well as by elevated thought suppression and potentially sleep‐disordered breathing. Accordingly, different treatment options for nightmares focus on their meaning, on the chronic repetition of the nightmare or on maladaptive beliefs. Clinically, knowledge of healthcare providers about nightmare disorder and the delivery of evidence‐based interventions in the healthcare system is discussed. Based on these findings, we highlight some future perspectives and potential further developments of nightmare treatments and research into nightmare aetiology.

Although the variability of dream content is large, typical dream themes that occur quite often and are reported by many people can be identified (e.g., being chased, falling, flying, failing an examination, being unable to find a toilet or restroom). The present study is an investigation of the stability of the rank order of the dream themes and of gender differences in the content of dreams. The authors administered A. L. Zadra and T. A. Nielsen's (1997) Typical Dream Questionnaire to 444 participants. The findings indicated that most of the 55 dream themes occurred at least once in most of the participants' lifetimes. In addition, the correlation coefficients for the rank order of the themes were very high; that is, the relative frequencies were stable. The gender differences in the present study were in line with content analytic findings; for example, men reported dreams about physical aggression more often than did women. Overall, previous research and the present data indicate that available research results of the measurement of typical dream themes are reliable and valid. The question of the meaning of these themes or the relationship between typical dream contents and waking life experiences, however, has not yet been answered and is open to future research.