No Effects of Pulsed High-Frequency Electromagnetic Fields on Heart Rate Variability during Human Sleep<sup>1</sup>

The influence of pulsed high-frequency electromagnetic fields emitted by digital mobile radio telephones on heart rate during sleep in healthy humans was investigated. Beside mean RR interval and total variability of RR intervals based on calculation of the standard deviation, heart rate variability was assessed in the frequency domain by spectral power analysis providing information about the balance between the two branches of the autonomic nervous system. For most parameters, significant differences between different sleep stages were found. In particular, slow-wave sleep was characterized by a low ratio of low- and high-frequency components, indicating a predominance of the parasympathe…

Dynamical properties of the sleep EEG in different frequency bands.

The information concerning the dynamic behavior of the sleep process gained by the usual evaluation of sleep EEGs according to the criteria of Rechtschaffen and Kales is limited. Therefore a new methodical approach is presented, which is a special case of spectral analyzed data processing. After digital band-pass filtering of the sleep EEG the root-mean-square (RMS) value of successive 20 s EEG epochs is calculated in defined frequency ranges. This procedure ensures to take into account the influence of the phase relation between different frequency components. The temporal course of these RMS values during the night reveals smooth curves with continuous transitions between different sleep …

Sleep under exposure to high-frequency electromagnetic fields.

The controversy about potential health hazards associated with the exposure to electromagnetic fields (EMF) has been recently stimulated by the increasing use of mobile telecommunication devices. Attention has focused here on non-thermal effects of low-level high-frequency radiation, which does not lead to a heating of tissue. Scientific literature on the effects of high-frequency EMFs on sleep is reviewed. The epidemiological studies provide no evidence that sleep disturbances are a relevant complaint under exposure to such fields. Recent sleep laboratory studies have revealed a number of slight effects. Despite their heterogeneity, there seems to be some consistency regarding a slight sle…

Effects of Pulsed High-Frequency Electromagnetic Fields on Human Sleep

In the present study we investigated the influence of pulsed high-frequency electromagnetic fields of digital mobile radio telephones on sleep in healthy humans. Besides a hypnotic effect with shortening of sleep onset latency, a REM suppressive effect with reduction of duration and percentage of REM sleep was found. Moreover, spectral analysis revealed qualitative alterations of the EEG signal during REM sleep with an increased spectral power density. Knowing the relevance of REM sleep for adequate information processing in the brain, especially concerning mnestic functions and learning processes, the results emphasize the necessity to carry out further investigations on the interaction of…

An analysis of the brain's transfer properties in schizophrenia: Amplitude frequency characteristics and evoked potentials during sleep

Background: Classical analysis of spontaneous sleep electroencephalogram (EEG) in schizophrenia commonly reveals alterations of sleep continuity, number of awakenings, slow-wave sleep (SWS), and REM sleep compared to healthy controls; however, conventional analysis cannot help understand dynamic differences of the sleep EEG during different sleep stages. Methods: We measured late components of auditory evoked potentials (AEPs) and visual evoked potentials (VEPs) during different sleep stages of 11 schizophrenic inpatients and in a sex- and age-matched control group from scalp positions FZ, CZ, and PZ. According to linear system theory, we then computed the amplitude-frequency characteristic…

Schizophrenia and left hemisphere dysfunctions a controlled neuropsychological study in schizophrenics and their relatives

Extrapituitary Effects of Corticotropin Releasing Hormone and Thyrotropin Releasing Hormone

Besides their regulation of the pituitary-adrenal and pituitary-thyroidal axis, respectively, the neurohormones CRH and TRH act within the central nervous system to evoke and modulate a number of behavioral and physiological processes. In particular, an increase in the sympathetic nervous system and respiratory activity has been observed. The data communicated in this review article emphasize the role of these neurohormones with regard to the neuroendocrine regulation of the autonomic nervous system, sleep and cognitive performance. Moreover, a possible therapeutic role is suggested by the beneficial effects in patients at risk of hypoventilation-associated disorders.

Functional properties of the brain during sleep under subchronic zopiclone administration in man.

Zopiclone, a non-benzodiazepine, has been shown to be efficient in the treatment of transient, short-term or chronic sleep disorders. Apart from its hypnotic effects zopiclone has anxiolytic, anticonvulsant and myorelaxant properties and is therefore hardly distinguishable from benzodiazepines. Dependence liability and discontinuation effects have been reported to be less pronounced. Therefore zopiclone seems to be a hypnotic drug which may cause fewer side effects than conventional benzodiazepines. From the electrophysiological point of view one requires from a hypnotic drug the induction of a physiological sleep pattern as well as no alterations of information processing by the brain. The…

Anterior limbic alpha-like activity: a low resolution electromagnetic tomography study with lorazepam challenge

Summary Objective To verify findings of an independently regulated anterior limbic alpha band source. Methods In a randomised cross-over study, the spontaneous EEG was recorded in nine healthy subjects after i.v. lorazepam or placebo. Intracerebral current densities within classical frequency bands were estimated with low resolution electromagnetic tomography [LORETA] and compared between groups with t -statistical parametric mapping [SPM{ t }]. A region-of-interest [ROI] based method was used to compare frontal and occipital alpha band activity changes. Results Irrespective of treatment group, local maxima of alpha band power were localised both in the occipital lobe, Brodman area [BA] 18,…

Effects of moclobemide on sexual performance and nocturnal erections in psychogenic erectile dysfunction

Rationale and objectives: We tested the hypothesis that the selective reversible MAO-A inhibitor moclobemide has a specific therapeutic effect on erectile dysfunction independent of its antidepressive properties. Methods: In a double-blind placebo controlled study, 12 male outpatients suffering from psychogenic erectile dysfunction without any other psychiatric disorder were investigated. Based on comprehensive diagnosis before the beginning of the study, organic factors relevant for sexual function were excluded. The treatment period was 8 weeks. Half the patients received 450 mg moclobemide during the first week, and 600 mg afterwards; the others received placebo. Apart from assessment of…

Spontaneous Nocturnal Erections - Physiology and Clinical Applications. Spontane nachtliche Erektionen - Physiologie und klinische Anwendungen

Spontaneous nocturnal erections in men are a well-known phenomenon whose physiology however is not yet really understood. The measurement of nocturnal erections has gained clinical relevance for the diagnosis of erectile dysfunction because it allows an objective and quantitative assessment of the erectile capacity. A decisive advantage compared to other diagnostic tests carried out during wakefulness is the exclusion of psychological factors to a great extent. Thus, an evaluation of the organic component of an erectile dysfunction is possible. Regarding the interpretation of nocturnal erection records, various factors possibly influencing the results must be considered; this is particularl…

Heart rate variability during sleep in patients with schizophrenia treated with olanzapine.

Cardiac adverse events in patients treated with atypical antipsychotics have gained increasing interest in recent years. In the present study, heart rate variability (HRV), which is a sensitive parameter reflecting central autonomic cardiac control, was investigated during treatment with olanzapine. Ten physically healthy male patients with schizophrenia, who displayed predominantly negative symptoms, were studied in the sleep laboratory under drug-free baseline conditions and after 4 weeks of olanzapine medication. HRV was assessed during different sleep stages both in the time and frequency domains. Only slight changes in HRV were shown during treatment, and appeared to be independent of …

Adherence

Non-adherence to medical advice is a serious problem to patients, health policy and practitioners. This article outlines concepts of behavioral economics that might lead a patient to decide against the provider's recommendations and thus to be non-adherent. Especially the timing of pay-offs and dynamic inconsistency, their uncertainty and ambiguity aversion, loss-aversion and numerous heuristics like the peak-end-rule are discussed. The paper concludes with some hints on “libertarian” paternalism that may improve the situation.

An approach to single trial analysis of event-related potentials based on signal detection theory.

Abstract The aim of the present paper was to introduce a single trial analysis to event-related potential measurement in order to illuminate the mechanisms behind an impaired P300 amplitude occurring under certain experimental conditions. For this purpose we applied tools from linear system theory and signal detection theory to single trials in an oddball paradigm in order to estimate the amplitude of the positive deflection around the P300 latency following target and nontarget stimuli. According to the density functions of these amplitude distributions we operationally defined ‘P300 absent in target’ (P300 amplitude smaller than an individual threshold under target conditions) as well as …

Nocturnal hormone profiles in patients with schizophrenia treated with olanzapine.

Summary Nocturnal hormone profiles were measured in patients with schizophrenia with predominantly negative symptoms both under drug-free baseline conditions and after subchronic administration of the atypical antipsychotic olanzapine, with the aim of characterizing its pharmacological properties on the neuroendocrine level. The following hormones were studied in the sleep laboratory under polysomnographic control: adrenocorticotrophic hormone, cortisol, growth hormone (GH), prolactin, testosterone, and melatonin. Blood samples were taken at regular time intervals over the night, and serum concentrations of the hormones were determined. Ten patients completed the study, two of them were exc…

The benefit from whole body acupuncture in major depression.

Background: In a single-blind placebo-controlled study design we investigated the efficacy of acupuncture additionally applied to drug treatment in major depression. Methods: We randomly included 70 inpatients with a major depressive episode in three different treatment groups: verum acupuncture, placebo acupuncture and a control group. All three groups were pharmacologically treated with the antidepressant mianserin. The verum group received acupuncture at specific points considered effective in the treatment of depression. The placebo group was treated with acupuncture at non-specific locations and the control group received pharmacological treatment plus clinical management. Acupuncture …

Acute, subchronic and discontinuation effects of zopiclone on sleep EEG and nocturnal melatonin secretion

Zopiclone is a new short half-life cyclopyrrolone hypnotic agent acting at the GABA-benzodiazepine receptor complex. In order to characterize its pharmacological profile, the effects of 7.5 mg zopiclone on nocturnal melatonin secretion were investigated under polysomnographic control in 11 healthy subjects following acute and subchronic administration as well as after abrupt discontinuation of the drug. No effect of zopiclone on the melatonin plasma levels could be observed. Regarding both total melatonin production and the temporal pattern of melatonin secretion during the night, there was no difference between placebo baseline condition, acute and subchronic administration, and discontinu…

Nonlinear EEG dynamics during sleep in depression and schizophrenia.

The article deals with the question, whether nonlinear analysis of the sleep EEG may give clues to understanding of disturbed information processing in psychiatric diseases. We point out how the nonlinear approach to EEG dynamics is motivated and review recent investigations concerning nonlinear dynamical properties of physiological systems. We present calculations of the correlation dimension D2 and the principal Lyapunov-exponent lambda 1 for sleep EEG data from 9 depressive and 11 schizophrenic inpatients compared to healthy controls. Combining the findings for D2 and lambda 1 our results point to altered nonlinear brain dynamics mainly during slow wave sleep in depression and during REM…

Temporal relationship between nocturnal erections and rapid eye movement episodes in healthy men.

The exact temporal relationship between spontaneous nocturnal erections and rapid eye movement (REM) sleep was studied in healthy men with the aim of creating a basis for a more sophisticated analysis of nocturnal erection measurements in physiological research and clinical applications. The vast majority of erectile events was coupled to REM episodes, where the latency between the beginning of erections and REM episodes showed a large variability. Moreover, a correlation analysis revealed a highly significant decrease of the latency over the course of the night. The time variant properties of the coupling between erections and REM sleep point to more complex dynamics of the central control…

Effects of yohimbine on sexual experiences and nocturnal penile tumescence and rigidity in erectile dysfunction.

The therapeutic effect of the alpha 2-antagonist yohimbine in erectile dysfunction was studied in a double-blind placebo-controlled design. Thirty-one male patients underwent extensive clinical, urological, and psychiatric diagnosis and were dichotomically classified into an organic and a nonorganic subgroup. Following a 1-week placebo run-in period, patients were randomly assigned to a placebo or a verum group (yohimbine 15 mg daily) for a treatment period of 7 weeks. The Clinical Global Impression (CGI) scale was used as the primary efficacy parameter. Additionally, nocturnal penile tumescence and rigidity (NPTR) were measured. Global assessment of erectile function applying the CGI scale…

Sequential analysis of the brain's transfer properties during consecutive REM episodes

Abstract Classical analysis of the spontaneous sleep EEG has revealed alterations of REM sleep in psychiatric diseases and under the influence of drugs. In order to elucidate possible functional differences between different REM episodes even in healthy subjects we investigated in 10 volunteers the transfer properties of the brain by measuring auditory (AEP) and visual evoked potentials (VEP) from scalp positions Fz, Cz and Pz during the night. According to linear system theory we computed the so-called amplitude-frequency characteristics (AFC) from averaged AEPs and VEPs during the first and each of the following 3 REM episodes. These functions describe the relationship between the input a…

Subchronic Effects of Olanzapine on Sleep EEG in Schizophrenic Patients with Predominantly Negative Symptoms

Background It is well known that sleep disturbance is an integral symptom of schizophrenia. In recent studies, a deficit of delta sleep has been observed in schizophrenic patients. Antipsychotic drugs with serotonin (5-HT2) receptor-antagonistic properties are considered to have delta sleep promoting effects. We have investigated the effects of subchronic olanzapine treatment on sleep EEG in schizophrenic patients. Methods The effects of administration of olanzapine (15 to 20 mg) on sleep were studied for four weeks in 10 male, drug-free patients suffering from schizophrenia with predominantly negative symptoms. Conventional sleep EEG parameters were investigated at baseline and after treat…

Appropriateness of Therapeutic Drug Monitoring for Antidepressants in Routine Psychiatric Inpatient Care

Although there is sufficient evidence of the benefits of therapeutic drug monitoring (TDM) for optimizing antidepressant therapy, its current use in routine care is far from optimal. As a prerequisite for developing improvement strategies, the appropriateness of TDM use was investigated in a psychiatric hospital in which TDM is applied routinely to a large extent. A retrospective analysis of all patients admitted in 2003 with a unipolar depressive disorder was performed. Based on detailed chart review, for all TDM tests, the time of blood sample taking in relation to the medication process and the consequences of the TDM results for clinical decision making were analyzed. Altogether, 748 pl…

No short-term effects of digital mobile radio telephone on the awake human electroencephalogram

A recent study reported the results of an exploratory study of alterations of the quantitative sleep profile due to the effects of a digital mobile radio telephone. Rapid eye movement (REM) was suppressed, and the spectral power density in the 8–13 Hz frequency range during REM sleep was altered. The aim of the present study was to illuminate the influence of digital mobile radio telephone on the awake electroencephalogram (EEG) of healthy subjects. For this purpose, we investigated 34 male subjects in a single-blind cross-over design experiment by measuring spontaneous EEGs under closed-eyes condition from scalp positions C3 and C4 and comparing the effects of an active (0.05 mW/cm2) and a…

The sleep EEG's microstructure in depression: alterations of the phase relations between EEG rhythms during REM and NREM sleep

Abstract Objective : We investigated the microstructure of sleep electroencephalograms (EEGs) of 13 unmedicated depressive inpatients and 13 healthy controls matched in sex and age, hypothesizing that depressives depict an alteration of certain EEG oscillations across the night. Methods : We digitized the sleep EEGs with a sampling rate of 100Hz (bipolar derivation C z –P z , 1440 single sweeps; 2048 data points each), calculated the time course of delta (1–3.5Hz), theta (3.5–7.5Hz), alpha (7.5–15Hz), and beta (15–35Hz) activity over the night, and determined the correlation coefficients of these different EEG rhythms separately for rapid eye movement (REM) and non-rapid eye movement (NREM)…

Human sleep under the influence of pulsed radiofrequency electromagnetic fields: A polysomnographic study using standardized conditions

To investigate the influence of radiofrequency electromagnetic fields (EMFs) of cellular phone GSM signals on human sleep electroencephalographic (EEG) pattern, all-night polysomnographies of 24 healthy male subjects were recorded, both with and without exposure to a circular polarized EMF (900 MHz, pulsed with a frequency of 217 Hz, pulse width 577 μs, power flux density 0.2 W/m2. Suppression of rapid eye movement (REM) sleep as well as a sleep-inducing effect under field exposure did not reach statistical significance, so that previous results indicating alterations of these sleep parameters could not be replicated. Spectral power analysis also did not reveal any alterations of the EEG rh…

The Influence of All-Night Exposure to Pulsed Radiofrequency Electromagnetic Fields on Human Sleep. Der Einfluss kontinuierlicher nachtlicher Exposition mit gepulsten hochfrequenten elektromagnetischen Feldern auf den Schlaf beim Menschen

Question of the study The widespread use of mobile telephones has led to public discussion about the putative health hazards as well as scientific interest in the interactions of pulsed, high-frequency electromagnetic fields with physiological systems. This article presents a survey of three consecutive studies carried out by a research group at the University of Mainz.

Analysis of sleep EEG microstructure in subchronic paroxetine treatment of healthy subjects

Paroxetine is a selective and potent serotonin reuptake inhibitor and its efficacy for the treatment of depression has been proven. Under acute and subchronical treatment regimens, disturbances of the regular sleep pattern are a reported side effect of the drug. The present study was therefore performed to investigate the impact of subchronic treatment with the selective serotonin reuptake inhibitor paroxetine on the microstructure of the sleep EEG. The study especially addressed the question of subchronic effects of paroxetine medication (30 mg/day) in eight healthy male volunteers in a double blind, placebo-controlled crossover design. Conventional sleep EEG parameters and a spectral powe…

A replication study on P300 single trial analysis in schizophrenia: confirmation of a reduced number of 'true positive' P300 waves.

A single trial analysis of event-related potentials (auditory odd-ball paradigm) of 20 schizophrenics was performed in comparison to matched healthy controls. The purpose of the study was to test the hypothesis that in schizophrenia the well-known P300 amplitude reduction of averaged event-related potentials is due to fewer elicited single trial P300 waves. The results of the present study support this finding of our previous exploratory investigation and point to the view that schizophrenics reveal basal disturbances in information processing due to inadequately elicited electrophysiological responses to target stimuli.

Standardisierte Verlaufsdokumentation als Grundlage zur Verbesserung der Prozessqualit�t der station�ren psychiatrischen Behandlung

Es wird eine standardisierte Verlaufsdokumentation zur detaillierten Beschreibung und Analyse des Behandlungsprozesses fur stationare psychiatrische Patienten vorgestellt. Im Rahmen eines an der Psychiatrischen Klinik der Universitat Mainz durchgefuhrten Pilotprojekts, zunachst beschrankt auf Patienten mit einem depressiven Syndrom, wurde der mit Hilfe wochentlich durchgefuhrter psychopathologischer Ratings erfasste klinische Zustand zusammen mit den therapeutischen Masnahmen fur die einzelnen Patienten im Zeitverlauf abgebildet. Es hat sich gezeigt, dass die Visualisierung des Behandlungsprozesses die klinische Arbeit unterstutzen und die Anwendung von Therapiestandards bei klinischen Ents…

Acute Alcohol Effects on Neuronal and Attentional Processing: Striatal Reward System and Inhibitory Sensory Interactions under Acute Ethanol Challenge

The acute influence of ethanol on cerebral activity induces complex psycho-physiological effects that are considerably more pronounced during acute ethanol influx than during maximal blood alcohol concentration (elimination phase). Despite the psychiatric and forensic relevance of these different ethanol effects, the underlying neuronal mechanisms are still unclear. In total, 20 male healthy volunteers were investigated each with three different experimental conditions in a randomized order using an intravenous ethanol challenge (40 g bolus infusion): during influx phase, elimination phase, and under placebo condition. During and after the ethanol (or placebo) infusion, neuropsychological t…

Nonlinear analysis of continuous ECG during sleep I. Reconstruction.

In recent years evidence has accumulated that ECG signals are of a nonlinear nature. It has been recognized that strictly periodic cardiac rhythms are not accompanied by healthy conditions but, on the contrary, by pathological states. Therefore, the application of methods from nonlinear system theory for the analysis of ECG signals has gained increasing interest. Crucial for the application of nonlinear methods is the reconstruction (embedding) of the time series in a phase space with appropriate dimension. In this study continuous ECG signals of 12 healthy subjects recorded during different sleep stages were analysed. Proper embedding dimension was determined by application of two techniqu…

Limbic activity in slow wave sleep in a healthy subject with alpha–delta sleep

All-night electroencephalographic (EEG) activity was recorded in a healthy subject with known alpha-delta sleep. Recordings were made from all 19 of the 10/20 system electrode sites, and low resolution electromagnetic tomography (LORETA) was used to estimate intracerebral current densities. Sleep stages were compared within classical frequency bands by statistical parametric mapping (SPM). With the onset of sleep, occipital alpha abated. With increasing depth of sleep, alpha power increased in a region comprising the left frontal lobe, the anterior and parietal cingulum, and the anterior and medial right front lobe. In slow wave sleep (SWS), frontal alpha power was much greater than in wake…

Intra- and Interhemispheric Electroencephalogram Coherence in Siblings Discordant for Schizophrenia and Healthy Volunteers

Former studies had pointed to an increased electroencephalogram (EEG) coherence in schizophrenics, but it remained unsolved whether this deviation represents the premorbid state or is only a consequence of the current or previous schizophrenic episodes. To clarify this question, we tested the hypothesis that subjects at elevated risk also reveal higher coherences compared to healthy controls. For that, intra- and interhemispheric EEG coherences were investigated in untreated schizophrenics, their healthy siblings, and healthy controls. Differences were only found regarding the intrahemispheric coherences. Both in schizophrenics and, even though to a lesser degree, in their siblings signific…

Effects of corticotropin-releasing hormone on respiratory parameters during sleep in normal men.

Corticotropin-releasing hormone (CRH) is well-known to be a centrally acting respiratory stimulant after systemic application both in healthy subjects and in patients suffering from respiratory failure. In order to study the effects of CRH on sleep EEG and respiratory parameters during sleep, 14 healthy male volunteers were investigated in a single-blind placebo controlled design. After an adaptation night, polysomnography was performed during two successive nights between 23.00 hrs. and 7.00 hrs. During one night placebo was applied, on the other 50 μg ovine CRH was administered intravenously as a bolus every hour from 0.00 hrs. to 6.00 hrs. For the assessment of respiration, blood oxygen …

Sleep investigations in erectile dysfunction

Abstract Regarding the aetiology of erectile dysfunction, beside numerous organic causes in many cases psychological factors play an important role. The pathophysiological mechanisms underlying the so-called psychogenic erectile dysfunction are not yet understood. Based on a neurobiological approach to psychogenic erectile dysfunction, polysomnographic investigations were carried out with the aim of identifying possible alterations of the sleep EEG. 24 male patients with psychogenic erectile dysfunction without detectable organic factors or other mental disorders were studied in the sleep laboratory, as well as an age-matched control group without sexual dysfunctions. Beside a reduction of …

Cardiac Autonomic Activity during Sleep under the Influence of Radiofrequency Electromagnetic Fields. Autonome Herzaktivitat im Schlaf unter dem Einfluss hochfrequenter elektromagnetischer Felder

Question of the study We investigated the influence of radiofrequency electromagnetic fields emitted by digital mobile telephones on heart rate variability (HRV) during sleep in healthy young men.

Human Sleep EEG under the Influence of Pulsed Radio Frequency Electromagnetic Fields

Former exploratory investigations of sleep alterations due to global system for mobile communications (GSM) signals have shown a hypnotic and REM-suppressive effect under field exposure. This effect was observed in a first study using a power flux density of 0.5 W/m<sup>2</sup>, and the same trend occurred in a second study with a power flux density of 0.2 W/m<sup>2</sup>. For the present study, we applied a submaximal power flux density of 50 W/m<sup>2</sup>. To investigate putative effects of radio frequency electromagnetic fields (EMFs) of cellular GSM phones on human sleep EEG pattern, all-night polysomnographies of 20 healthy male subjects both with …

Corrigendum to “The thalamus as the generator and modulator of EEG alpha rhythm: A combined PET/EEG study with lorazepam challenge in humans” [NeuroImage 22 (2004) 637–644]

Department of Psychiatry, Johannes Gutenberg–University Mainz, 55131 Mainz, GermanyAvailable online 2 May 20061053-8119/$ - see front matter D 2006 Elsevier Inc. All rights reserved.doi:10.1016/j.neuroimage.2006.03.007DOI of original article:10.1016/j.neuroimage.2004.01.047.* Corresponding author. Department of Nuclear Medicine, Johannes Gutenberg–University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany. Fax: +496131 17 2448.E-mail address: schreckenberger@nuklear.klinik.uni-mainz.de (M. Schreckenberger).Available online on ScienceDirect (www.sciencedirect.com).

Medication safety in a psychiatric hospital

Objective: We sought to assess the epidemiology of medication errors (MEs) and adverse drug events (ADEs) in a psychiatric hospital. Methods: We conducted a 6-month prospective observational study in a 172-bed academic psychiatric hospital. Errors and ADEs were found by way of chart review, staff reports and pharmacy intervention reports. Physicians rated incidents as to the presence of injury, preventability and severity of an injury. Serious MEs were nonintercepted MEs with potential for harm (near misses) and preventable ADEs. Results: We studied 1871 admissions with 19,180 patient-days. The rate of ADEs and serious MEs were 10 and 6.3 per 1000 patient-days, respectively. Preventable ADE…

Influence of age on the interrelation between EEG frequency bands during NREM and REM sleep.

The age-dependence of temporal interrelations between distinct frequency bands of sleep EEG was investigated in a group of 59 healthy young and middle-aged males via cross correlation analysis. Based on global evaluation throughout the entire night, a highly significant decline of the delta/theta correlation with increasing age was found. A separate analysis for non-rapid eye movement (NREM) and rapid eye movement (REM) sleep revealed different changes with aging. During NREM sleep, the correlation between the delta and theta frequency bands decreased with increasing age. In contrast, during REM sleep, a stronger correlation became obvious between the theta, alpha, and beta frequency bands …

Effects of pulsed high-frequency electromagnetic fields on the neuroendocrine system.

The influence of pulsed high-frequency electromagnetic fields emitted from a circularly polarized antenna on the neuroendocrine system in healthy humans was investigated (900 MHz electromagnetic field, pulsed with 217 Hz, average power density 0.02 mW/cm<sup>2</sup>). Nocturnal hormone profiles of growth hormone (GH), cortisol, luteinizing hormone (LH) and melatonin were determined under polysomnographic control. An alteration in the hypothalamo-pituitary-adrenal axis activity was found with a slight, transient elevation in the cortisol serum level immediately after onset of field exposure which persisted for 1 h. For GH, LH and melatonin, no significant effects were found under…

Non-linear dynamics of alpha and theta rhythm: correlation dimensions and Lyapunov exponents from healthy subject's spontaneous EEG.

The aim of the present paper was to analyze some non-linear dynamic properties of the resting EEG from healthy subjects under eyes closed conditions. For this purpose we digitally filtered the spontaneous EEG in the theta (3-8 Hz) and alpha frequency range (8-13 Hz) and considered these independent rhythms as signals from a deterministic system. Under certain conditions non-linear dynamic systems are able to generate deterministic chaos, which means that similar causes do not produce similar effects. This phenomenon is called sensitive dependence on initial conditions. From different lead positions (F3, F4, Cz, P3, P4, O1 and O2) we calculated the so-called correlation dimension D2, which i…

Nonlinear analysis of continuous ECG during sleep II. Dynamical measures

The hypothesis that cardiac rhythms are associated with chaotic dynamics implicating a healthy flexibility has motivated the investigation of continuous ECG with methods of nonlinear system theory. Sleep is known to be associated with modulations of the sympathetic and parasympathetic control of cardiac dynamics. Thus, the differentiation of ECG signals recorded during different sleep stages can serve to determine the usefulness of nonlinear measures in discriminating ECG states in general. For this purpose the following six nonlinear measures were implemented: correlation dimension D2, Lyapunov exponent L1. Kolmogorov entropy K2, as well as three measures derived from the analysis of unsta…