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 ?
Ray WJ, Cole HW EEG alpha activity reflects attentional demands and beta activity reflects emotional and cognitive processes.
A high level of alpha activity counts as a marker of the readiness of the brain to exploit new incoming information.
Crabbe and Dishman (2004) conducted a metaanalysis examining EEG responses during and after exercise and concluded that when compared to pre-exercise, alpha activity (absolute power) was greater both during and following exercise, but there was no differences in relative alpha activity.
One of the general findings from EEG research in this area has been that an increase in alpha activity, commonly seen as skill level increases, is not simply indicative of cortical deactivation, but is indicative of neural reorganization concomitant with the acquisition of more efficient, task-specific cognitive and motor processes (Nunez, 1995; Smith, McEvoy, & Gevins, 1999).
Tenders are invited for Supply of Stainless Steel (SS) Planchet for Alpha activity determination as per annexure
Measurements along the EEG alpha activity scale show the degree of attentiveness in a person, he explained.