This exercise summarizes the basic brain processes in sleep and the use of the EEG (electroencephalogram; "brain waves") to measure sleep stages. It includes the following topics: ! sleep as an active process and brain areas that turn it on ! the EEG: how it is recorded and what it shows about brain activity ! the EEG for the two basic kinds of sleep, slow wave sleep (SWS) and rapid eye movemen...

Epileptic activity in the form of spike-wave discharges (SWD) appears in the electroencephalogram (EEG) during absence seizures. A relationship between SWD and normal sleep spindles is often assumed. This study compares time-frequency parameters of SWD and sleep spindles as recorded in the EEG in the WAG/Rij rat model of absence epilepsy. Fast Fourier transformation and continuous wavelet trans...

Patients suffering from sleep disorders, especially respiratory disorders, are often investigated by all-night ambulatory home recordings instead of extended polysomnographic in-laboratory studies. Reasons for this are lower costs and long waiting lists to sleep laboratories. Special ambulatory recording equipment has been developed for these home recordings (1). In some instances sleep electro...

Sleep spindle is the characteristic waveform of electroencephalogram (EEG) which is important for clinical diagnosis. In this study, an automatic sleep spindle detection method was developed. The EEG signals were recorded based on the standard polysomnogram (PSG) measurement. A preprocessing procedure is introduced to exclude the unnecessary data segments and normalized the necessary data segme...

Seizures in Juvenile Myoclonic Epilepsy (JME) are dependent on the sleep-wake cycle and precipitant factors, among which sleep deprivation (SD) is one of the most important. Still an under diagnosed syndrome, misinterpretation of the EEGs contributes to diagnostic delay. Despite this, a quantitative EEG investigation of SD effects has not been performed. We investigated the effect of SD on EEGs...

Electroencephalography (EEG) recordings during sleep are often contaminated by muscle and ocular artefacts, which can affect the results of spectral power analyses significantly. However, the extent to which these artefacts affect EEG spectral power across different sleep states has not been quantified explicitly. Consequently, the effectiveness of automated artefact-rejection algorithms in min...

The discovery that the electrical activity of the brain oscillates during sleep is almost as old as the discovery of the electroencephalogram (EEG). The first human EEG recordings already reported a propensity to show oscillations, of which type, frequency and amplitude highly depend on behavioral state (Berger 1929; see Fig. 4.1). In an alert, awake subject, the EEG is dominated by low-amplitu...

It has been demonstrated in the rodent hippocampus that rhythmic slow activity (theta) predominantly occurs during rapid eye movement (REM) sleep, while sharp waves and associated ripples occur mainly during non-REM sleep. However, evidence is lacking for correlates of sleep stages with electroencephalogram (EEG) in the hippocampus of monkeys. In the present study, we recorded hippocampal EEG f...

Sleep stages are mainly classified via electroencephalogram (EEG) which involves some prominent characters not only in amplitude but also in frequency. What is more, researchers are using computer assisted analysis to acquire the panoramic view of long duration sleep EEG. However, unlike the empirical judgment, it is fairly difficult to decide the specific values of sleep rules for computer bas...

OBJECTIVES A measure to increase the electroencephalogram (EEG) outcome includes a short period of nap sleep during a routine standard EEG with the aim of increasing its sensitivity to interictal abnormalities or provoking seizures. As part of an ongoing auditing of our EEG data, we aimed to investigate the contribution of nap sleep during routine outpatient department based EEGs requested for ...