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Sleep Episodes (sleep + episode)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Rhythmic hippocampal slow oscillation characterizes REM sleep in humans

HIPPOCAMPUS, Issue 6 2001
Róbert Bódizs
Abstract Hippocampal rhythmic slow activity (RSA) is a well-known electrophysiological feature of exploratory behavior, spatial cognition, and rapid eye movement (REM) sleep in several mammalian species. Recently, RSA in humans during spatial navigation was reported, but systematic data regarding human REM sleep are lacking. Using mesio-temporal corticography with foramen ovale electrodes in epileptic patients, we report the presence of a 1.5,3-Hz synchronous rhythmic hippocampal oscillation seemingly specific to REM sleep. This oscillation is continuous during whole REM periods, is clearly observable by visual inspection, and appears in tonic and phasic REM sleep episodes equally. Quantitative analysis proved that this 1.5,3-Hz frequency band significantly differentiates REM sleep from waking and slow-wake sleep (SWS). No other frequency band proved to be significant or showed this high rhythmicity. Even in temporo-lateral surface recordings, although visually much less striking, the relative power of the 1.5,3-Hz frequency band differentiates REM sleep from other states with statistical significance. This could mean that the 1.5,3-Hz hippocampal RSA spreads over other cortical areas in humans as in other mammals. We suggest that this oscillation is the counterpart of the hippocampal theta of mammalian REM sleep, and that the 1.5,3-Hz delta EEG activity is a basic neurophysiological feature of human REM sleep. Hippocampus 2001;11:747,753. © 2001 Wiley-Liss, Inc. [source]

Increased daytime sleepiness in Parkinson's disease: A questionnaire survey

MOVEMENT DISORDERS, Issue 3 2003
Birgit Högl MD
Abstract We evaluated the frequency and severity of excessive daytime sleepiness in an outpatient population with Parkinson's disease in comparison to age-matched controls and examined its relationship with antiparkinsonian drug therapy and sleep history. Increased daytime sleepiness and involuntary sleep episodes have been described in Parkinson's disease, but the etiology is not completely understood. The Epworth Sleepiness Scale (ESS), a validated questionnaire for daytime sleepiness, was prospectively administered to 99 consecutive outpatients with Parkinson's disease and 44 age-matched controls. In addition, a short sleep-screening questionnaire was used. The ESS revealed significantly increased daytime sleepiness in PD patients compared to controls (7.5 ± 4.6 vs. 5.8 ± 3.0, P = 0.013). The ESS score was abnormally high (10 or more) in 33 % of PD patients and 11.4% of controls (P = 0.001). ESS was not different between PD patients on levodopa monotherapy and those on levodopa and dopamine agonists, or between patients taking ergoline or non-ergoline dopamine agonists. In PD patients and in controls, sleepiness was significantly associated with reported heavy snoring. Increased daytime sleepiness is more frequent in patients with PD than in elderly controls. Similar to controls, increased daytime sleepiness in PD patients is correlated with heavy snoring. © 2002 Movement Disorder Society [source]

Fatigue at sea in Swedish shipping,a field study,

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 7 2010
Margareta Lützhöft PhD
Abstract Background Today many merchant ships sail with only two nautical officers, working a shift schedule of 6,hr on and 6,hr off. There are concerns that such a shift schedule is related to fatigue. However, little data exist from onboard studies of seafarers. Methods Data were collected on board 13 ships. Fifteen participants worked on a 6-on, 6-off watch system and another 15 on a 4-on, 8-off watch system. Electrooculography, actigraphy, diaries, and reaction time tests were used to measure the effects of shift system on fatigue and sleep. Results and Conclusions Sleepiness was higher during the night shift in the 6-on, 6-off system. Moreover, sleepiness increased more during the watch in the 6-on, 6-off system compared to the 4-on, 8-off system. There was a trend toward shorter sleep episodes in the 6-on, 6-off system and sleep was more often split into two episodes. Am. J. Ind. Med. 53:733,740, 2010. © 2010 Wiley-Liss, Inc. [source]

Sleep induced by stimulation in the human pedunculopontine nucleus area

ANNALS OF NEUROLOGY, Issue 4 2010
Isabelle Arnulf MD
The pedunculopontine nucleus is part of the reticular ascending arousal system and is involved in locomotion and sleep. Two patients with Parkinson disease received electrodes that stimulated the pedunculopontine nucleus area to alleviate their severe gait impairment. Instead, we found that low-frequency stimulation of the pedunculopontine nucleus area increased alertness, whereas high-frequency stimulation induced non-rapid eye movement sleep. In addition, the sudden withdrawal of the low-frequency stimulation was consistently followed by rapid eye movement sleep episodes in 1 patient. These data have the potential to benefit patients who suffer from sleep disorders. ANN NEUROL 2010;67:546,549 [source]