Alpha rhythm

Glucocorticoids have important effects on the nervous system. Adrenal insufficiency causes marked slowing of the alpha rhythm of the electroencephalogram and is associated with depression. Increased amounts of glucocorticoids often produce behavioral disturbances in humans initially insomnia and euphoria and subsequently depression. Large doses of glucocorticoids may increase intracranial pressure (pseudotumor cerebri). 

Neuroleptic drugs cause slowing of alpha rhythm and increased synchronization and amplitude with superimposed sharp fast activity. They also induce discharge patterns in the electroencephalogram similar to those associated with epileptic seizures of the tonic-clonic generalized or focal types (SED-11,108 168). 

A current example of such interaction is the finding that in Zen meditation (a highly developed discipline in Japan) there are physiological correlates of meditative experiences, such as decreased frequency of alpha-rhythm, which can also be produced by means of instrumentally aided feedbacklearning techniques (23). This finding may elucidate some of the processes peculiar to each discipline. 

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. 

Cohen, D. 1968. Magnetoencephalography evidence of magnetic fields produced by alpha-rhythm currents. Science 161 784. 

EEG alpha rhythm de-synchronization Sleepiness in pilots during consecutive night Gundel etal. (1995) F... 

When eyes are closed the sine-wave-shaped large-amplitude alpha rhythm appears in the scalp potentials, of which frequency fluctuates within a frequency range 8-13 Hz, and this almost periodic waveform is clearly seen in the spontaneous electroencephalogram. The instantaneous frequency is defined from the interval between consecutive zerocrossing points. Its power spectral density is found to be of 1// in a certain range of the Fourier frequency. It is another example of 1// fluctuations of biological rhythm phenomena. When a subject is in a... 

Changes in electric activity of the brain evidenced by slow alpha rhythm (BLL = 29 pg/dL). 

In adult humans exposed to elevated levels of Pb, EEG recordings have shown a slowing of the alpha rhythm and increases in the amount of slow wave activity in the theta and delta range, diffuse irregular patterns, and focal pairoxysmal discharges. Saito reported increased activity in theta and decreased activity at higher frequences. These EEG abnormalities can be reversed by chelation therapy. ... 

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