alpha activity

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Related to alpha activity: alpha rhythm

alpha rhythm

A type of electrical activity in adults detected by EEG in the posterior brain, which may be abolished with visual stimulation and attenuated by thinking. Alpha rhythm (AR) is seen in relaxed adults with closed eyes; it has a frequency of 8–13 Hz over the occipital lobe and has bihemispheric asynchrony, where the non-dominant hemisphere has a greater wave amplitude. Focal CNS disease is accompanied by focally altered AR, which becomes diffuse in coma. 

AR is the EEG pattern that corresponds to the awake state; it is present in most, but not all, normal individuals, and is most consistent and predominant during relaxed wakefulness, particularly with reduction of visual input. AR has a range in each person: the low end is exhibited in drowsiness or sleep and the upper end with alertness. AR also varies with age: it is slower in children and older age groups relative to young and middle-aged adults.

alpha activity

Sleep disorders The presence of alpha waves or alpha rhythm in an EEG. See Alpha rhythm.
References in periodicals archive ?
Interestingly, Kubitz and colleagues (1996; 1997) observed decreases in alpha activity during exercise, while the present investigation observed increases in alpha activity.
In relation to performance, only right hemispheric alpha activity was significantly associated with accuracy.
In this literature, it is assumed that alpha activity is an inverse index of cortical activity.
Visual dream content, graphical representation and EEG alpha activity in congenitally blind subjects.
Gross alpha and beta activity in muscle: For gross alpha activity in muscle, there was no significant difference between locations (ANOVA, p = 0.
Biomuse's processing circuitry can sift through the continuous and busy EEG signals and detect the onset of alpha activity.
Since alpha activity is associated with both wakefulness and receptiveness to sensory signals, the researchers hypothesized that it also could indicate a sleeper's sensitivity to environmental stimuli.