Diurnal variations in alpha power density and subjective sleepiness while performing repeated vigilance tasks

Higuchi, Shigekazu; Liu, Yang; Yuasa, Takao; Maeda, Akira; Motohashi, Yutaka

doi:10.1016/s1388-2457(01)00527-2

Cited by 23 publications

(14 citation statements)

References 17 publications

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“…In another study, during performance of vigilance tasks significant diurnal variations were found in theta, alpha and beta bands [11] similarly to earlier studies where no-task situations were analyzed [1,12].…”

Section: Introductionsupporting

confidence: 80%

Diurnal Alterations of Brain Electrical Activity in Healthy Adults: A LORETA Study

et al. 2007

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EEG background activity was investigated by low resolution brain electromagnetic tomography (LORETA) to test the diurnal alterations of brain electrical activity in healthy adults. Fourteen right-handed healthy male postgraduate medical students were examined four times (8 a.m., 2 p.m., 8 p.m. and next day 2 p.m.). LORETA was computed to localize generators of EEG frequency components. Comparing the EEG activity between 2 p.m. and 8 a.m., increased activity was seen (1) in theta band (6.5-8 Hz) in the left prefrontal, bilateral mesial frontal and anterior cingulate cortex; (2) in alpha2 band (10.5-12 Hz) in the bilateral precuneus and posterior parietal cortex as well as in the right temporo-occipital cortex; (3) in beta1-2-3 band (12.5-30 Hz) in the right hippocampus and parieto-occipital cortex, left frontal and bilateral cingulate cortex. Comparing the brain activity between 8 p.m. and 8 a.m., (1) midline theta activity disappeared; (2) increased alpha2 band activity was seen in the left hemisphere (including the left hippocampus); and (3) increased beta bands activity was found over almost the whole cortex (including both of hippocampi) with the exception of left temporo-occipital region. There were no significant changes between the background activities of 2 p.m. and next day 2 p.m. Characteristic distribution of increased activity of cortex (no change in delta band, and massive changes in the upper frequency bands) may mirror increasing activation of reticular formation and thus evoked thalamocortical feedback mechanisms as a sign of maintenance of arousal.

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Section: Introductionsupporting

confidence: 80%

Diurnal Alterations of Brain Electrical Activity in Healthy Adults: A LORETA Study

et al. 2007

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“…As shown in figure 2, no differences between snorers and OSA patients were present, suggesting that the absence of controls would not have introduced a systematic bias into the results. Moreover, the diurnal trend in EEG waking measures was not different from that reported in controls [27,28], confirming that the diurnal variation in alpha and theta powers did not correspond to that in subjective [23] and objective sleepiness [22].…”

Section: Discussionsupporting

confidence: 51%

“…Second, while theta and slow alpha activity have consistently been shown to increase linearly in shiftworkers [13] and in sleep deprivation conditions [20], their changes in healthy subjects and in sleep disorder patients have not been examined. The only apparent studies in nonsleep-deprived subjects [22,23] showed that EEG frequency bands did not follow variations in subjective and objective scores, and the relationship between theta and alpha activity and subjective alertness was lost in the whole group of subjects. These findings are consistent with these latter studies.…”

Section: Discussionmentioning

confidence: 97%

Is waking electroencephalographic activity a predictor of daytime sleepiness in sleep-related breathing disorders?

Sforza¹,

Grandin²,

Jouny³

et al. 2002

Eur Respir J

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No data are available in the literature assessing the potential use of waking electroencephalographic (EEG) activity in the detection of excessive daytime sleepiness (EDS) in patients with sleep-related breathing disorders (SRBD). The aim of this study was to evaluate whether waking EEG spectral power reflects the level of EDS in SRBD patients.The study was performed in 48 patients in whom quantitative EEG analysis, including the alpha attenuation coefficient (AAC), was performed. Sleepiness was assessed by the Epworth Sleepiness Scale, the Stanford Sleepiness Scale, the Visual Analogue Scale and the maintenance of wakefulness test.Although AAC and EEG spectral power tended to vary throughout the day, none of these variations correlated with EDS measures. Waking EEG measures were not different between snorers and apnoeic patients. Compared to nonsleepy patients, sleepy patients had greater theta and slow alpha powers, but the differences did not reach statistical significance. The EEG slowing was independent of hypoxaemia, severity of SRBD, or degree of sleep disruption.The authors conclude that waking electroencephalographic measures are not sensitive enough to predict variation in alertness or to differentiate sleepy from nonsleepy sleeprelated breathing disorders patients. The degree of electrocephalographic slowing was related neither to sleep disruption nor to severity of sleep-related breathing disorders. [5,6] may not adequately reveal diurnal impairment in sleepy patients and they do not strongly correlate with the subjective estimation [7]. Second, a decrease in mean sleep latency in the MSLT may occur even when the subjects rated themselves as alert, suggesting that subjective estimation measures different aspects of sleepiness. Thus, neither objective nor subjective measures of alertness currently characterize the phenomenon of sleepiness with complete accuracy.Some recent studies suggest that various components of the spectral electroencephalographic (EEG) activity during wakefulness may help to detect changes in alertness. The awake alpha power with eyes-open increases when performance and alertness decrease [8], and the ratio of alpha power during eyes-closed versus eyes-open, i.e. the alpha attenuation coefficient (AAC) [9], falls in sleep-deprived subjects [10] and in narcoleptics [11]. Furthermore, awake alpha and theta powers are accurate indicators of sleep propensity, enhanced theta activity and decreased alpha activity [12,13] found when sleepiness becomes manifest.Therefore, it is reasonable to suggest that changes in waking alpha and theta EEG power, similar to those described earlier, could be expected in SRBD patients. If so, the degree of waking EEG changes would be an important predictor of reduced alertness and a useful measure of sleepiness. The main aim of the current study was to investigate the relationship between waking EEG activity and daytime sleepiness in a SRBD population. The prediction was that the alpha power and the AAC would be reduced, and that the theta pow...

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“…This procedure was adopted to minimize the influence of circadian fluctuations in arousal and theta band activity (e.g Higuchi et al, 2001;Aeschbach et al, 1999)…”

mentioning

confidence: 99%

Theta power is reduced in healthy cognitive aging

Cummins¹,

Finnigan²

2007

International Journal of Psychophysiology

134

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Diurnal variations in alpha power density and subjective sleepiness while performing repeated vigilance tasks

Cited by 23 publications

References 17 publications

Diurnal Alterations of Brain Electrical Activity in Healthy Adults: A LORETA Study

Diurnal Alterations of Brain Electrical Activity in Healthy Adults: A LORETA Study

Is waking electroencephalographic activity a predictor of daytime sleepiness in sleep-related breathing disorders?

Theta power is reduced in healthy cognitive aging

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