Beta wave

As we relax in preparation for and pass into sleep, the active desynchronised awake EEG characterised by the low-amplitude (5-10 pV) high-frequency (10-30 Hz) beta waves becomes progressively more synchronised giving larger (20-30 pV) and slower (8-12 Hz) alpha waves, and then even slower (1-4 Hz) and bigger (30-150 pV) delta waves. This so-called slow-wave sleep is interrupted at intervals of some 1-2h by the break-up and desynchronisation of the EEG into an awake-like pattern. Since this is accompanied by rapid eye movements, even though sleep persists and can be deeper, the phase is known as rapid eye movement, REM or paradoxical, sleep. It is a time when dreaming occurs and when memory may be secured. 

Sleepiness, light sleep in young children also during wakefulness. Mostly in combinations with superimposed beta waves... 

Headache, drowsiness, and dizziness are common with niridazole (2,4,5). More severe neuropsychiatric symptoms are more frequent in patients with liver disease, especially those with portosystemic shunts, in whom the drug bypasses the liver (6). Symptoms in these cases include insomnia, anxiety, depression, confusion, hallucinations, and convulsions the reactions may prove fatal. The electroencephalogram can show slowed alpha rhythms, beta waves, and theta waves, as well as sharp wave and spike forms with niridazole (7). A single case of acute cortical necrosis was recorded in the much older literature, but was probably coincidental (SED-8, 691) (8). Agitation can occur in patients with abnormal liver function. 

This experiment was performed with a view to proving the effect of linalool enantiomers on the level of beta wave. The authors arrived at a conclusion that (-)-linalool influences the decrease of beta wave in contrast with (+)-linalool. 

A wake-low voltage-random fast- Beta waves... 

Recording electrical activity with electrodes surrounding the head made it possible to try to relate the mind to the brain. Slow electrical brain waves, called theta waves, were observed during states of low mental activity. At high degrees of arousal, fester beta waves were recorded. Alpha waves were recorded at medium levels of arousal. The greater the state of arousal, the greater the number of alpha and beta waves. 

From wakefulness to deep sleep, there is a progression of EEG activity, slowing from beta wave activity (about 18 Hz) to theta-delta wave activity (3.5 to 8 Hz). Figure 17.43 shows the appearances of the major brain wave frequencies. The delta waves occur in deep sleep or coma. Theta waves are... 

Reducing radiation levels with shielding is another form of protection. Shielding effectiveness, the ability of a specific material to attenuate radiation, varies with different forms of radiation. For example, to some extent, air attenuates low energy beta waves, but it has little effect on other forms of radiation. 

Figure 11.3 Typical samples of human EEG brainwaves (a) Delta wave, (b) Theta wave, (c) Alpha wave and (d) Beta wave, (e) Blocking of the Alpha wave by eye opening, (f) 1 s time marker [34],...

Alpha, Beta and Gamma waves. Each of them has a specific frequency and amplitude. Typical samples of human EEG signals are shown in Fig. 11.3. The Delta wave is the largest wave with amplitude between 20 and 200 pV, but has the lowest occurring fi-e-quency at less than 4 Hz. The amplitude of the Theta wave is between 20 and 1(X) pV and its frequency between 4 and 7 Hz. The Alpha wave is the most commonly recorded wave, at a frequency between 8 and 13 Hz and amplitude at about 20—60 pV. The Beta wave is relatively faster, occurring at 14—30 Hz frequency with amplitude at around 2—20 pV. Finally, the Gamma wave is the smallest and fastest wave, which occurs over 30 Hz, and its amplitude is between 5 and 10 pV. 

Beta waves (13-25 Hz) - are common in alert condition, when performing a cognitive or physical task. 

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