Biomedical subjects

Joachim Röschke

Publications and source records attributed to Joachim Röschke.

10 recordsLinked to original sources

PubMed2005

Perception of sleep: subjective versus objective sleep parameters in patients with Parkinson's disease in comparison with healthy elderly controls. Sleep perception in Parkinson's disease and controls.

INTRODUCTION: Subjective sleep perception, as measured against objective parameters such as those obtained by polysomnography, have not been examined thoroughly to date. Little is known about subjective sleep perception in patients with chronic somatic diseases. PATIENTS AND METHODS: Patients with Parkinson's disease (PD) and healthy elderly controls filled in a sleep log over 14 days, which included a self-rating questionnaire concerning sleep and quality of time awake, sleep times and somatic complaints. All participants underwent polysomnography in the sleep lab on nights 7 and 8, and slept all other nights at home. RESULTS: Seventeen patients with PD (64 +/- 6 years, 6 female, Hoehn and Yahr median = 2), and 62 healthy controls of the same age without sleep disturbances (64 +/- 8 years, 36 female) were included. Patients with PD showed reduced subjective sleep (p = 0.001) and quality of time awake (p = 0.02), decreased sleep duration (p = 0.01) and reduced sleep efficiency (p = 0.004) compared with the controls. Subjective sleep efficiency at home was no different from that in the sleep lab for both groups. Patients with PD reported more somatic complaints (p = 0.001) than controls but did not show a firstnight effect. CONCLUSION: In summary, patients with PD have subjectively and objectively disturbed sleep as compared to healthy controls of the same age. However, they may not rate this poor sleep as much changed from their baseline sleep at home, and they have more somatic complaints. Increasing sleep efficiency might be of importance in PD patients, as it shows an association with subjective quality of time awake in the morning.

Aged↗

PubMed2004

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 sleep-promoting effect and an increase of the alpha power of the sleep EEG induced by high-frequency EMFs. However, for both the epidemiological and sleep laboratory studies, the database concerning sleep is up to now very limited. At the present level of knowledge, no final conclusions can be drawn from the available data concerning potential health hazards. Although there seem to be some biological effects, these do not provide evidence for any adverse health consequences. However, further research is needed for a better understanding of the interaction between EMFs and the sleep process.

Cell Membrane↗

PubMed2004

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 with increasing age, whereas the lower frequency components were not affected. These findings indicate that aging processes seem to interact with sleep EEG rhythms in a complex manner, where most conspicuous is a disintegration of the activities in the lower frequency range, both concerning the successive sleep cycles across the night and the micro-structure of NREM sleep.

Adolescent↗

PubMed2003

A confirmatory study on the mechanisms behind reduced P300 waves in depression.

A single-trial analysis of event-related potentials (P300) of 21 depressives was performed in comparison with matched controls. The purpose was to confirm previous results revealing an overall reduction of the single-trial P300 amplitude in depression despite fewer elicited single-trial P300 waves in schizophrenics. The result of the present study is in line with our previous investigation implicating a general reduced P300 amplitude on single trials of depressive patients. Therefore, it appears possible to differentiate depressives and schizophrenics by measuring event-related potentials and applying a single-trial analysis of them.

Adult↗

PubMed2003

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 of erections with regard to sleep regulation, indicating that REM sleep and REM-related erections are not completely interdependent. Beside the possibility of obtaining further insight into the physiological mechanisms underlying erectile function, the consideration of dynamic aspects in the assessment of nocturnal erection measurements might have potential clinical implications regarding both the diagnosis and the evaluation of therapies for erectile dysfunction.

Adult↗

PubMed2002

Is the nonREM-REM sleep cycle reset by forced awakenings from REM sleep?

In selective REM sleep deprivation (SRSD), the occurrence of stage REM is repeatedly interrupted by short awakenings. Typically, the interventions aggregate in clusters resembling the REM episodes in undisturbed sleep. This salient phenomenon can easily be explained if the nonREM-REM sleep process is continued during the periods of forced wakefulness. However, earlier studies have alternatively suggested that awakenings from sleep might rather discontinue and reset the ultradian process. Theoretically, the two explanations predict a different distribution of REM episode duration. We evaluated 117 SRSD treatment nights recorded from 14 depressive inpatients receiving low dosages of Trimipramine. The alarms were triggered by an automatic mechanism for the detection of REM sleep and had to be canceled by the subjects themselves. The REM episodes were determined as in undisturbed sleep-they had to include the remaining REM activity and were separated by 30 min without REM epochs. The frequency histogram of REM episodes declined exponentially with episode duration for each of the first four sleep cycles. The duration of nonREM intervals revealed bimodal distributions. These results were found consistent with the model assuming a reset of the ultradian cycle upon awakening. Whether REM or nonREM activity is resumed on return to sleep can be modeled by a random decision whereby the probability for REM sleep might depend on the momentary REM pressure.

Activity Cycles↗

PubMed2002

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

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 100 Hz (bipolar derivation C(z)-P(z), 1440 single sweeps; 2048 data points each), calculated the time course of delta (1-3.5 Hz), theta (3.5-7.5 Hz), alpha (7.5-15 Hz), and beta (15-35 Hz) 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) sleep. RESULTS: For both groups we detected a clear difference between REM and NREM sleep cycles at certain frequency bands. The most impressive changes occurred for the delta/beta and theta/beta correlations, which change their signs between NREM (negatively correlated) and REM (positively correlated) sleep cycles. Following an analysis of variance model with repeated measurement design, a statistically significant group effect (P=0.024) between depressives and controls was observable during NREM sleep for the delta/beta (P=0.010) and theta/beta (P=0.018) interactions. CONCLUSION: We detected alterations of certain sleep EEG oscillations during the NREM sleep cycle, where the delta/beta as well as the theta/beta activities were higher (negatively) compared to healthy controls. Together with previous investigations on the influence of antidepressants on the microstructure of sleep EEGs, this is another hint that the NREM sleep cycle plays a major role in depression.

Journal Article↗

PubMed2002

Human scalp recorded sigma activity is modulated by slow EEG oscillations during deep sleep.

The EEG during deep sleep exhibits a distinct cortically generated slow oscillation of around and below 1 Hz which can be distinguished from other delta (0.5-3.5 Hz) activity. Intracranial studies showed that this slow oscillation triggers and groups cortical network firing. In the present study, we examined whether the phases of the slow oscillation during sleep stage 4 are correlated with the magnitude of sigma (12-16 Hz) and gamma (> 20 Hz) scalp activity. For this purpose, 10-min segments of uninterrupted stage 4 sleep EEG from 9 subjects were analyzed by applying wavelet techniques. We found that scalp recorded sigma, but not gamma, activity is modulated by the phases of the slow oscillation during deep sleep. Enhancement of sigma activity was observed to be triggered by the peak of the surface positive slow wave component, whereas reduction of sigma activity started around the peak of the negative component.

Adult↗

PubMed2002

Covariation of spectral and nonlinear EEG measures with alpha biofeedback.

This study investigated how different spectral and nonlinear EEG measures covaried with alpha power during auditory alpha biofeedback training, performed by 13 healthy subjects. We found a significant positive correlation of alpha power with the largest Lyapunov-exponent, pointing to an increased dynamical instability of the EEG accompanying alpha enhancement. Alpha power amplification, moreover, was significantly correlated with a decrease of spectral entropy within the alpha range. This outcome reflects a sharpening of the alpha peak during biofeedback training. The fact that the sharpening effect clearly preceded the increase of alpha amplitude could be exploited in future biofeedback settings.

Adult↗

PubMedDate not supplied

Effects of REM sleep awakenings and related wakening paradigms on the ultradian sleep cycle and the symptoms in depression.

In 1975 Vogel and coworkers published their classical study where they compared selective rapid eye movement (REM) sleep deprivation by brief awakenings to a control intervention paradigm in depressed patients. The superior antidepressive impact of the first procedure was attributed to the REM pressure accumulating during the treatment period. The laborious procedure and the considerable effort necessary to evaluate the sleep profiles in real time have prevented similar experiments so far. Based on artificial neural networks we developed a software for the real time detection of REM sleep. In combination with an alarm system the algorithm allowed us to wake up subjects automatically and to reduce REM sleep by about 50%. The procedure was then compared to a modified nonREM intervention paradigm for a treatment period of ten consecutive nights in depressed patients (n(1)=14, n(2)=13). These simultaneously received moderate dosages of Trimipramine. We found a strong and robust but not significantly different reduction of the average Hamilton rating scores (33 and 41% of baseline levels). While the REM sleep awakenings shortened the sleep cycle duration considerably, our nonREM intervention paradigm lengthened the ultradian alternations. Both effects might be interpreted as a challenge imposed on the nonREM-REM alternating mechanism possibly responsible for the antidepressive impact. A different timing of the control interventions might have caused the discrepancy between our findings and those of Vogel and coworkers.

Adult↗