Search

Copyright of Somnologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Interrater variability of sleep stage scorings has an essential impact not only on the reading of polysomnographic sleep studies (PSGs) for clinical trials but also on the evaluation of patients’ sleep. With the introduction of a new standard for sleep stage scorings (AASM standard) there is a need for studies on interrater reliability (IRR). The SIESTA database resulting from an EU-funded project provides a large number of studies ( n = 72; 56 healthy controls and 16 subjects with different sleep disorders, mean age ± SD: 57.7 ± 18.7, 34 females) for which scorings according to both standards (AASM and R&K) were done. Differences in IRR were analysed at two levels: (1) based on quantitative sleep parameter by means of intraclass correlations; and (2) based on an epoch-by-epoch comparison by means of Cohen’s kappa and Fleiss’ kappa. The overall agreement was for the AASM standard 82.0% (Cohen’s kappa = 0.76) and for the R&K standard 80.6% (Cohen’s kappa = 0.68). Agreements increased from R&K to AASM for all sleep stages, except N2. The results of this study underline that the modification of the scoring rules improve IRR as a result of the integration of occipital, central and frontal leads on the one hand, but decline IRR on the other hand specifically for N2, due to the new rule that cortical arousals with or without concurrent increase in submental electromyogram are critical events for the end of N2. [ABSTRACT FROM AUTHOR]

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 first-night 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. [ABSTRACT FROM AUTHOR]

The precise etiology of the restless legs syndrome (RLS) is unknown. Sensory and motor symptoms of RLS worsen during evening/night, coincident with the physiological peak of pineal melatonin excretion. Decreased melatonin levels have been reported in insomnia, which is an associated feature of RLS. Melatonin substitution improved insomnia. A potential association between the idiopathic RLS (iRLS) and alterations in melatonin excretion was therefore explored. Daytime (7:00–22:00 hr) and night-time (22:00–7:00 hr) urinary excretion of 6-OH-melatonin-sulfate (aMLTs) was measured in 15 patients with iRLS and 11 controls by a radioimmunoassay. There was no significant difference between daytime and night-time urinary aMLTs excretion in iRLS as compared with controls (daytime: 6.14 ± 5.20 ng versus 5.02 ± 5.11 ng, NS; night-time: 21.07 ± 17.05 ng versus 22.92 ± 16.52 ng, NS). Our data do not provide evidence for a decrease of cumulative melatonin production in iRLS. Insomnia in RLS does not seem to be correlated with a deficit of melatonin. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Event-related potentials (ERPs) are sensitive measures of both perceptual and cognitive processes. The aim of the present study was to identify brain regions involved in the processes of cognitive dysfunction in narcolepsy by means of ERP tomography. Methods: In 17 drug-free patients with narcolepsy and 17 controls, ERPs were recorded (auditory odd-ball paradigm). Latencies, amplitudes and LORETA sources were determined for standard (N1 and P2) and target (N2 and P300) ERP components. Psychometry included measures of mental performance, affect and critical flicker fusion frequency (CFF). Results: In the ERPs patients demonstrated delayed cognitive N2 and P300 components and reduced amplitudes in midline regions, while N1 and P2 components did not differ from controls. LORETA suggested reduced P300 sources bilaterally in the precuneus, the anterior and posterior cingulate gyri, the ventrolateral prefrontal cortex and the parahippocampal gyrus. In psychometry, patients demonstrated deteriorated mood, increased trait anxiety, decreased CFF and a trend toward reduced general verbal memory and psychomotor activity. Conclusions: Narcoleptic patients showed prolonged information processing, as indexed by N2 and P300 latencies and decreased energetic resources for cognitive processing. Significance: Electrophysiological aberrations in brain areas related to the ‘executive attention network’ and the ‘limbic system’ may contribute to a deterioration in mental performance and mood at the behavioral level. [Copyright &y& Elsevier]

Abstract: Low-resolution brain electromagnetic tomography (LORETA) showed a functional deterioration of the fronto-temporo-parietal network of the right hemispheric vigilance system in narcolepsy and a therapeutic effect of modafinil. The aim of this study was to determine the effects of modafinil on cognitive and thymopsychic variables in patients with narcolepsy and investigate whether neurophysiological vigilance changes correlate with cognitive and subjective vigilance alterations at the behavioral level. In a double-blind, placebo-controlled crossover design, EEG-LORETA and psychometric data were obtained during midmorning hours in 15 narcoleptics before and after 3 weeks of placebo or 400 mg modafinil. Cognitive investigations included the Pauli Test and complex reaction time. Thymopsychic/psychophysiological evaluation comprised drive, mood, affectivity, wakefulness, depression, anxiety, the Symptom Checklist 90 and critical flicker frequency. The Multiple Sleep Latency Test (MSLT) and the Epworth Sleepiness Scale (ESS) were performed too. Cognitive performance (Pauli Test) was significantly better after modafinil than after placebo. Concerning reaction time and thymopsychic variables, no significant differences were observed. Correlation analyses revealed that a decrease in prefrontal delta, theta and alpha-1 power correlated with an improvement in cognitive performance. Moreover, drowsiness was positively correlated with theta power in parietal and medial prefrontal regions and beta-1 and beta-2 power in occipital regions. A less significant correlation was observed between midmorning EEG LORETA and the MSLT; between EEG LORETA and the ESS, the correlation was even weaker. In conclusion, modafinil did not influence thymopsychic variables in narcolepsy, but it significantly improved cognitive performance, which may be related to medial prefrontal activity processes identified by LORETA. [Copyright &y& Elsevier]