Search results for "Stages"
showing 10 items of 217 documents
Nonlinear analysis of sleep eeg in depression: Calculation of the largest lyapunov exponent
1995
Conventional sleep analysis according to Rechtschaffen and Kales (1968) has provided meaningful contributions to the understanding of disturbed sleep architecture in depression. However, there is no characteristic alteration of the sleep cycle, which could serve as a highly specific feature for depressive illness. Therefore, we started to investigate nonlinear properties of sleep electroencephalographic (EEG) data in order to elucidate functional alterations other than those obtained from classical sleep analysis. The application of methods from nonlinear dynamical system theory to EEG data has led to the assumption that the EEG can be treated as a deterministic chaotic process. Chaotic sys…
The influence of lorazepam medication upon the transfer properties of the brain during sleep in man
1993
In order to get better insight into the principles of information processing by the brain during sleep and its alterations under the influence of drugs we applied some tools from linear system theory to sleep EEG data. We investigated late components of auditory and visually evoked potentials (AEPs and VEPs) during different sleep stages and calculated from these the so-called amplitude-frequency characteristics (AFC). The main advantage of this analysis is that it enables one to detect functional differences during different sleep stages. This information can hardly be obtained by conventional spectral analysis. The result of our investigation was that the transfer properties of the brain …
Examination and treatment of sleep-related painful erections--a case report.
1989
The case of a patient with sleep-related painful erections is described. Insomnia and a slight depressive syndrome occurred along with a long history of this disorder. No physical abnormality was found. At a baseline recording of sleep electroencephalography (EEG) and nocturnal penile tumescence (NPT), a disturbed sleep pattern and impaired NPT were recorded. Attempts to treat the disorder with diazepam, amitriptyline, trimipramine, and biperidene did not prompt a stable improvement of the disorder, but a dosage of 25 mg clozapine was sufficient to achieve normalized sleep architecture, remission of the depressive symptomatology, and normalization of NPT. It is likely that marked sedation i…
A breathing-retraining procedure in treatment of sleep-onset insomnia: theoretical basis and experimental findings.
1995
Increase in CO2 has a sedative effect upon the central nervous system, and the beginning of sleep coincides with modifications in breathing, decrease in ventilation, and in pCO2 increase. In this paper is described a technique of breathing that is useful in producing drowsiness in a very short time. 46 insomniacs were randomly allocated to either a treatment or control condition. In the former, patients were trained in the breathing process. The control group was taught no breathing process. Latencies to sleep for the insomniacs confirmed that the breathing process was useful in producing drowsiness. Theoretical bases are discussed.
Automatic SCSB analysis of motor and autonomic nervous functions compared with sleep stages
1996
All-night recordings of respiration, ballistocardiogram, and body movements were obtained using the static charge-sensitive bed (SCSB) and automatically analysed data were compared with sleep stages. The mean sum of eight SCSB variability parameters was lowest in slow wave sleep (SWS), higher during stage 2 (S2), and highest in REM sleep. The sum scores of the parameters with the highest correlations with the EEG data were classified into quiet (QS), intermediate (IS) and active (AS) states. SCSB signals during wakefulness, stage 1 and REM sleep were mostly scored as AS, whereas in S2 and especially in SWS they were scored as QS or IS. The SCSB is an easy and inexpensive tool for conducting…
Sleep-electroencephalography and the secretion of cortisol and growth hormone in normal controls.
1987
Abstract. Sleep-electroencephalography, and the nocturnal secretion of cortisol and GH were investigated simultaneously in a sample of 25 male normal controls (27.1 ± 1.3 years) in order further to examine interaction between sleep structure and concurrent endocrine activity. Slow wave sleep activity was increased during the first part of the night, whereas cortisol concentration was low and GH output reached maximal levels. The second half of the night was characterized by a relative preponderance of REM-sleep, low GH-concentration, and an increase in cortisol. However, no distinct reciprocal interaction between cortisol and GH concentration was noted. In all subjects, a pronounced GH surg…
Precursors of the evoked K-complex in event-related brain potentials in stage 2 sleep.
1997
The aim of the study was to examine precursors of the evoked K-complex as manifested in event-related brain potentials (ERPs) during stage 2 sleep. ERPs to infrequent deviant tones of 1100 and 2000 Hz and immediately preceding frequent standard tones of 1000 Hz were compared between trials containing and trials not containing a K-complex (KC trials, NO KC trials, respectively) to the deviant tones. The N350 wave to the deviant tones was markedly larger during the KC than during the NO KC trials. Also the P210 wave to the 2000 Hz deviant tone showed the same phenomenon. No definite evidence was found for the mismatch negativity-like deflection during the KC trials. ERPs to the standard tones…
Portable PSG for sleep stage monitoring in sports: Assessment of SOMNOwatch plus EEG.
2019
Current sport-scientific studies mostly neglect the assessment of sleep architecture, although the distribution of different sleep stages is considered an essential component influencing an athlete's recovery and performance capabilities. A mobile, self-applied tool like the SOMNOwatch plus EEG might serve as an economical and time-friendly alternative to activity-based devices. However, self-application of SOMNOwatch plus EEG has not been validated against conventional polysomnography (PSG) yet. For evaluation purposes, 25 participants (15 female, 10 male;
The Influence of Lorazepam upon Pre- and Poststimulus EEG during Sleep in Man
1997
Enhancement of beta power in the spontaneous EEG under the influence of benzodiazepine medication is a well known phenomenon under waking conditions as well as during sleep. On the other hand, in certain frequency bands EEG activity following external stimulation is also enhanced. Therefore, the question arises what relationship exists between pre- and poststimulus EEG under the influence of benzodiazepines. Is an augmentation of beta activity during benzodiazepine medication further enhanced when external stimulation is applied? In order to address this question we compared the spectral power of pre- and poststimulus EEG under 2.5 mg lorazepam during sleep with placebo conditions. The hypo…
Behavioural adaptations of argulid parasites (Crustacea: Branchiura) to major challenges in their life cycle.
2015
Fish lice (Argulus spp.) are obligate ectoparasites, which contrary to most aquatic parasites, retain the ability to swim freely throughout the whole of their life. In fish farms, they can quickly increase in numbers and without effective control cause argulosis, which results in the reduced growth and survival of their fish hosts. The morphology of Argulus spp, including their sensory organs, is suitable for both parasitism and free-swimming. By spending a considerable amount of time away from their host, these parasites risk being excessively dispersed, which could endanger mating success. Here we present a review of recent studies on the behaviour of Argulus spp, especially the aggregati…