Revisiting the Concept of Vigilance.

Vigilance deficits can be observed after a period of prolonged, continuous wakefulness. In this context there has been extensive research targeting the impact of sleep deficits on different aspects of vigilance, but the underlying concept of vigilance was hardly ever addressed and discussed. One reason for this shortcoming is the unclear and ambiguous definition of the term vigilance, which is commonly used interchangeably with sustained attention and even wakefulness.

Procedural memory consolidation is associated with heart rate variability and sleep spindles.

Sleep and memory studies often focus on overnight rather than long-term memory changes, traditionally associating overnight memory change (OMC) with sleep architecture and sleep patterns such as spindles. In addition, (para-)sympathetic innervation has been associated with OMC after a daytime nap using heart rate variability (HRV). In this study we investigated overnight and long-term performance changes for procedural memory and evaluated associations with sleep architecture, spindle activity (SpA) and HRV measures (R-R interval [RRI], standard deviation of R-R intervals [SDNN], as well as spectral power for low [LF] and high frequencies [HF]).

Oscillatory theta activity during memory formation and its impact on overnight consolidation: a missing link?

Sleep has been shown to promote memory consolidation driven by certain oscillatory patterns, such as sleep spindles. However, sleep does not consolidate all newly encoded information uniformly but rather "selects" certain memories for consolidation. It is assumed that such selection depends on salience tags attached to the new memories before sleep.

Quantitative EEG in Alzheimer's disease: cognitive state, resting state and association with disease severity.

Background: Quantitative electroencephalogram (qEEG) recorded during cognitive tasks has been shown to differentiate between patients with Alzheimer's disease (AD) and healthy individuals. However, the association between various qEEG markers recorded during mnestic paradigms and clinical measures of AD has not been studied in detail.

Objective: To evaluate if 'cognitive' qEEG is a useful diagnostic option, particularly if memory paradigms are used as cognitive stimulators.

Do nocturnal headaches matter? A prospective diary study on subjective sleep parameters in snorers and their bed partners.

Background: The objective of this study was to assess the influence of nocturnal headaches (NH) on subjective sleep parameters prospectively in habitual snorers and their bed partners.

Methods: We recruited habitual snorers and their bed partners via newspaper articles. The participants completed a semistructured interview, filled in questionnaires about quality of sleep (PSQI), daytime sleepiness (ESS), depression (SDS) and anxiety (SAS) and they kept a 90-day headache and sleep diary.

Slow oscillation amplitudes and up-state lengths relate to memory improvement.

There is growing evidence of the active involvement of sleep in memory consolidation. Besides hippocampal sharp wave-ripple complexes and sleep spindles, slow oscillations appear to play a key role in the process of sleep-associated memory consolidation. Furthermore, slow oscillation amplitude and spectral power increase during the night after learning declarative and procedural memory tasks.

The assessment of vigilance: normative data on the Siesta sustained attention test.

Objective: In several modern society duties individuals have to maintain their attention or vigilance over prolonged periods of time, even if the monitoring task is monotonous. The aim of our study was to obtain reference data on the 60-minute monotonous Siesta sustained attention test.

Methods: Normative data were gathered in an age-stratified sample of 234 healthy participants (118 men; 116 women) between the ages of 20 and 79 years.

The Pupillographic SleepinessTest in adults: effect of age, gender, and time of day on pupillometric variables.

Objectives: The Pupillographic Sleepiness Test (PST) measures the level of alertness based on spontaneous oscillations in pupillary size. Reference data are available for male and female adults within the age range 20-60 years. The aim of the present multicenter study was to extend the age range for reference data from 20 to 79 years.

Morning headaches in snorers and their bed partners: a prospective diary study.

Background: The prevalence and characteristics of morning headaches (MH) in habitual snorers are not well known, with only one retrospective study reporting MH in 23.5% of snorers. The role of MH in bed partners of snorers has not yet been examined.

Morning headaches, daytime functioning and sleep problems--a population-based controlled study.

The aim of this paper was to assess the prevalence of morning headaches in the Austrian general population and to analyse their relationship to daytime functioning and quality of sleep. In a nationwide survey, we recruited 1000 adults (478 men, 522 women, age over 14 years). For this study, we selected all subjects with self-reported morning headaches as well as controls matched for age, sex, size of hometown, level of education and marital status.

Computer-assisted sleep classification according to the standard of the American Academy of Sleep Medicine: validation study of the AASM version of the Somnolyzer 24 × 7.

Background: In 2007, the AASM Manual for the Scoring of Sleep and Associated Events was published by the American Academy of Sleep Medicine (AASM). Concerning the visual classification of sleep stages, these new rules are intended to replace the rules by Rechtschaffen and Kales (R&K).

Methods: We adapted the automatic R&K sleep scoring system Somnolyzer 24 × 7 to comply with the AASM rules and subsequently performed a validation study based on 72 polysomnographies from the Siesta database (56 healthy subjects, 16 patients, 38 females, 34 males, aged 21-86 years).

Sleep habits and sleep complaints in Austria: current self-reported data on sleep behaviour, sleep disturbances and their treatment.

Objectives: To acquire current information on sleep habits, disturbances and treatment options in the adult population of Austria and compare results with previously collected data.

Materials And Methods: A representative sample of the Austrian population (women: n = 522, men: n = 478).

Results: Seventy-five percent reported daily sleep-duration between 6 and 8 h.

Cyclic alternating pattern and sleep quality in healthy subjects--is there a first-night effect on different approaches of sleep quality?

Objective: Cyclic alternating pattern (CAP) is defined as periodic EEG activity during NREM sleep that reflects unstable sleep and represents a marker of instability of the sleep process. The aim of the present investigation was to analyze sleep quality of 28 healthy subjects (mean age 53.3+/-21.

Modafinil improves information processing speed and increases energetic resources for orientation of attention in narcoleptics: double-blind, placebo-controlled ERP studies with low-resolution brain electromagnetic tomography (LORETA).

Background And Purpose: Recent neuroimaging studies in narcolepsy discovered significant gray matter loss in the right prefrontal and frontomesial cortex, a critical region for executive processing. In the present study, event-related potential (ERP) low-resolution brain electromagnetic tomography (LORETA) was used to investigate cognition before and after modafinil as compared with placebo.

Patients And Methods: In a double-blind, placebo-controlled cross-over design, 15 patients were treated with a 3-week fixed titration scheme of modafinil and placebo.

Interrater reliability for sleep scoring according to the Rechtschaffen & Kales and the new AASM standard.

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.

Sleep classification according to AASM and Rechtschaffen & Kales: effects on sleep scoring parameters.

Study Objective: To investigate differences between visual sleep scoring according to the classification developed by Rechtschaffen and Kales (R&K, 1968) and scoring based on the new guidelines of the American Academy of Sleep Medicine (AASM, 2007).

Design: All-night polysomnographic recordings were scored visually according to the R&K and AASM rules by experienced sleep scorers. Descriptive data analysis was used to compare the resulting sleep parameters.

Actigraphy--a useful tool for motor activity monitoring in stroke patients.

Aim: The aim of the present study was the evaluation of actigraphy as a tool to objectify the recovery process after motor paresis due to stroke.

Methods: The motor activity of both arms of patients suffering from stroke was actigraphically recorded at four different time points during the course of rehabilitation: 24-36 h, 5-7 days, 3 months, and 6 months after stroke.

Results: Motor activity monitored by wrist-worn actigraphs located at the impaired side revealed an increase in activity between the first two time points and the subsequent ones.

Event-related-potential low-resolution brain electromagnetic tomography (ERP-LORETA) suggests decreased energetic resources for cognitive processing in narcolepsy.

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).

Interindividual sleep spindle differences and their relation to learning-related enhancements.

We reported earlier that overnight change in explicit memory is positively related to the change in sleep spindle activity (between a control and a learning night). However, it remained unclear whether this effect was restricted to good memory performers and whether a general association of sleep spindles and a "sleep-related learning trait" may not account for this effect. Here we now present a secondary and more detailed analysis of our randomized multicenter study.

No effect of an UMTS mobile phone-like electromagnetic field of 1.97 GHz on human attention and reaction time.

Several studies in the past reported influences of electromagnetic emissions of GSM phones on reaction time in humans. However, there are currently only a few studies available dealing with possible effects of the electromagnetic fields emitted by UMTS mobile phones. In our study, 40 healthy volunteers (20 female, 20 male), aged 26.

Is excessive daytime sleepiness a predictor of carotid atherosclerosis in sleep apnea?

Objective: To elucidate the relationship between excessive daytime sleepiness (EDS) in obstructive sleep apnea (OSA) and carotid atherosclerosis determined by ultrasonography and serum surrogate markers.

Methods: One hundred and forty-seven patients (102 males) with snoring and sleep-disordered breathing were investigated. Carotid atherosclerosis was evaluated by serum analysis of high-sensitivity C-reactive protein and fibrinogen and four sonographic indices: intima media thickness (IMT) of the common carotid artery (CCA), IMT from the bulb to the internal carotid artery (ICA), combined IMT measurements from all segments and a plaque score.