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- Module Fields:
- Affective Disorders
- Modul Schizophrenie
- Psychiatrie des Alterns
- Personality Disorders and PTSD
- Integrative Psychiatry
Prof. Heidi Danker-Hopfe, PhD
Marie-Luise Hansen, MD, sleep expert
Hans Dorn, PhD, Engineer
Anita Peter, MD, Resident Psychiatry
Cornelia Sauter, PhD, Psychology
The sleep laboratory of the Department of Psychiatry and Psychotherapy (Head: Prof. Isabella Heuser, MD. PhD) of the Charité - Campus Benjamin Franklin was founded in 1992. In 1994 the Department was accredited to the German Society of Sleep Research and Sleep Medicine (DGSM). The sleep laboratory has two polysomnographic units. For research purposes, the capacity of the lab can be extended to four units. Since the introduction of quality management asssurance procedures by the DGSM our lab regularly participates in these activities.
For more details concerning sleep medicine (diagnostics and therapy) see the Sleep Medicine page of this Web site.
The head of the sleep laboratory is a member of a task force of the German Sleep Medicine and Sleep Research Society, which aims at an improvement of the reliability of sleep stage scorings (Rodenbeck et al. 2006). Related to this topic is a publication on the interrater reliability of scorings between experts (Danker-Hopfe et al. 2004). A task force of the American Association of Sleep Medicine (AASM), which recently performed a literature review on inter- and intra-rater reliability of visual sleep stage scorings (Silber et al. 2007) graded this study as evidence level 1. This methodological expertise is reflected by the fact that our lab is the central scoring center in a big multi-center clinical trial in patients with insomnia.
Sleep stage scoring is the fundamental basis of polysomnographically related diagnostics in sleep medicine. Hence, interrater reliabilty is an important factor. The interrater reliabilty between human expert ratings and automatic sleep stage classification systems is analysed. Another task force of the AASM reviewed the literature on this topic (Penzel et al. 2007). One of the two papers which were graded as level 1 evidence (Anderer et al 2005) is co-authored by the head of our sleep laboratory.
A variety of electrophysiological and psychological test (Multiple Sleep Latency Test - MSLT, Maintenance of Wakefulness Test - MWT, Pupillographic Sleepiness Test - PST, computerized test batteries from the Wiener Testsystem and the Test Battery to Test Attention - TAP) including various psychological Scales, e.g. Epworth Sleepiness Scale (ESS) and Stanford Sleepiness Scale (SSS) are used to test different aspects of attention and their interrelations. Our lab is involved in multi-center study on the validation of a monotonous sustained attention test.
Aging is accompanied by changes in sleep and memory. In comparison to young subjects, middle aged and elderly subjects show reduced total sleep time, increased number of awakenings, decreased sleep efficiency, increased amount of wake during the last two hours of sleep, and reduced time (minutes and %) spent in slow wave sleep and REM sleep. With regard to non-REM sleep stages 1 and 2 (NREM1 and NREM2) the results are inconsistent. While some studies report an increase in the amount (%) of NREM1 and NREM2 with increasing age others found no statistically significant variation.
Declarative and procedural memory are negatively affected by aging. In light of recent findings which underline the importance of REM-sleep for memory consolidation in young adults, memory promoting effects of REM-sleep in older adults are of particular interest. The relation between REM sleep and memory is investigated in a study, which was initially funded by the Deutsche Forschungsgemeinschaft. 120 elderly subjects (60-85 years: 51% females) participated in the study. The research question was approached from two different angles, i.e. the deprivation of REM-sleep (by awakenings whenever REM sleep occurred) and the augmentation of REM-sleep (physiologically by rebound and pharmacologically by administration of a single dose of an acetylcholine esterase inhibitor (AchE-I)). Two groups served as control groups, one placebo-group, where participants received a placebo instead of the AchE-I and one group in which participants were woken up in NREM sleep. Performance in a procedural (mirror-tracing) and declarative task (paired-associate-list), was investigated before and after the study night. Meanwhile research was extended to analyze sleep and memory in patients with Affective and Personality Disorders, mainly Borderline Personality Disorder.
The increasing use of mobile communication lead to concerns – at least in a part of the population – about possible health effects due to this technology. In Germany the concerns as well as subjectively experienced impairments of health are documented by telephone surveys conducted annually by the Infas Institute since 2003. This research is funded within the German Telecommunication Research Program by the Federal Office of Radiation Protection. Among complaints of persons who subjectively suffer from the respective electromagnetic fields an impairment of sleep is the most prominent. Almost 1% of the population claims to suffer from sleep problems which they relate causally to electromagnetic fields. Looking at this percentage from the perspective of a causal relationship it has to be kept in mind, that sleep problems are very common in the general population (10-20%). Meaningful results can only be obtained from studies in which exposition (emitted by a cell phone or a base station) varies experimentally. The design of such studies has to be sham-controlled, double-blind and cross-over. Sleep quality should be assessed not only subjectively, but also objectively by “measuring” sleep. Our lab conducted two studies funded by the Federal Office of Radiation Protection which relate to sleep and mobile communication.
Several reviews and meta analyses of studies on biological effects of electromagnetic fields reveal that sleep is an interesting end-point, reflecting an impairment of well-being. Disturbances of sleep and daytime sleepiness are two of the most common complaints expressed by residents living close to cell towers. A main problem in field studies is to disentangle the psychological effects of antennas from possible physiological effects of electromagnetic fields. We separated these effects by implementing an experimental protocol conducted in the domestic setting. Due to the significant technical effort to realize the study design a feasibility study concerning the assessment of subjective and objective sleep parameters was conducted. In the present study subjective sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI), objective sleep parameters were derived from a one-channel frontopolar sleep-EEG, recorded in the home environment with QUISI®. The sleep stage classification algorithm (version 2.0) implemented in QUISI® is based on neural network technologies. The study was performed in Flachsmeer/Westoverledingen, a village in Ostfriesland. The results are based on data from n=105 subjects (47 males and 58 females, mean age males: 43.0 ± 14.8 years; mean age females: 43.4 ± 13.0 years). The number of nights recorded with QUISI® is 1260, for every subject in the study 12 nights have been recorded (two times six consecutive nights with one week interval between the recording periods).
The drop out rate was only 2.8% representing a high level of adherence to the protocol. The amount of missing values in the sleep questionnaires was very low and the data correspond very well to reference values. After exclusion of three adaptation nights and recordings with technical problems, the data of more than 91% of the subjects - at least six nights - were suitable for further analyses. Four out of 11 EEG-based sleep parameters showed a statistically significant difference between "good" and "bad" sleepers as assessed subjectively by the PSQI (sleep efficiency index, sleep onset latency, percentages of NREM1 and wake after sleep onset).
Since the sleep efficiency index is a summary parameter which reflects disturbances of sleep onset as well as problems of maintaining sleep, we suggested this index as primary end-point and the same assessment instruments for a follow-up study which additionally takes into account an experimental variation of the exposition.
The study was funded by the "Niedersächsisches Ministerium für Frauen, Arbeit und Soziales".
The follow-up study "Sleep quality in subjects living in the vicinity of mobilephone base stations - experimental study on psychological and physiological effects performed in the home environment" is funded by the Federal Office for Radiation Protection (Bundesamt für Strahlenschutz, BfS; www.emf-forschungsprogramm.de/forschung/biologie/biologie_gepl).
The aim of this study was to investigate whether electromagnetic fields emitted by mobile phones have an effect on brain activity. From experimental studies in humans there are some results which might point to possible biological effects, however, until now there are no conclusive reports on health effects. 30 healthy young men participate in the study with a randomised, double blind, sham-controlled crossover design, in which the effect of GSM- and UMTS- like signals is analysed with regard to the effect of exposition on sleep, electrophysiological measures during daytime (e.g. waking EEG, evoked potentials, contingent negative variation) and cognitive functioning.
The project, which is funded by the Federal Office for Radiation Protection (Bundesamt für Strahlenschutz, BfS; www.emf-forschungsprogramm.de /forschung/biologie/biologie_verg), started in October 2003 and lasted until the end of September 2006. The exposition equipment was set up, and the literature on the effects of high frequency electromagnetic fields on the activity of the waking and sleeping brain was reviewed. This review can be downloaded as PDF-file from www.emf-forschungsprogramm.de/forschung/biologie/biologie_verg.
Our sleep lab initiates and participates in clinical trials of patients with different sleep disorders (RLS, PLMS, primary insomnia and narcolepsy).
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