Brain wave

First recordings of electricity in the head

In 1875 the British physician Richard Caton recorded tiny currents from the brain surface of rabbits and monkeys. The human EEG was first recorded in 1924 by Hans Berger, a psychiatrist in Jena, Germany, who was so unsure of his results that he published only in 1929. The rhythm of about 10 cycles per second seen when resting with eyes closed is called the alpha wave or Berger rhythm. Initial scepticism faded when Nobel laureate Edgar Adrian and Bryan Matthews reproduced it in 1934. In 1958 the international 10–20 system standardised electrode positions so recordings could be compared worldwide.

Types of rhythm and their uses

Brain waves are grouped by frequency: delta below 4 Hz in deep sleep, theta at 4–8 Hz in drowsiness and light sleep, alpha at 8–13 Hz in relaxed wakefulness, beta at 13–30 Hz in focus or tension, and faster gamma. They arise when the synaptic potentials of vast numbers of neurons line up, and in Rhythms of the Brain (2006) György Buzsáki argued that these oscillations help coordinate communication and memory between brain areas. In 1935 Frederic Gibbs, Hallowell Davis and William Lennox recorded the characteristic spike-and-wave of epileptic seizures, and EEG remains central to epilepsy diagnosis. In 1937 Alfred Loomis and colleagues showed that EEG changes with sleep depth, and Rechtschaffen and Kales's 1968 manual became the standard for scoring sleep stages including REM sleep. EEG is also used for coma, brain-death assessment, anaesthesia monitoring and evaluating dementia.

Brain–computer interfaces and neurofeedback

In the 2006 BrainGate study a person with paralysis moved a computer cursor using electrodes implanted in the brain, and scalp-EEG spellers have since developed. Neurofeedback — learning to adjust one's own brain waves — is tried for ADHD and other conditions, but a 2017 review argued that much of its effect may be placebo. Claims that "alpha-wave music" or brainwave gadgets boost study also lack solid evidence. An EEG is painless and safe, but have a neurologist interpret results and make any diagnosis, and seek immediate care for seizures or loss of consciousness.

This article is general health information and is not a substitute for diagnosis or treatment. If symptoms persist, see a doctor.

FAQ

Is an EEG painful or risky?

No. Electrodes on the scalp only record the brain's electricity; no current is sent in. Flashing lights or deep breathing may be used during the test to provoke changes.

Will boosting alpha waves make me smarter?

Alpha waves simply mark relaxed wakefulness; there is no evidence that increasing them raises intelligence or grades. Good sleep and exercise help cognition more reliably.

Sources reviewed: 2026-10-26

References

1. Caton, R. (1875). The electric currents of the brain. British Medical Journal, 2, 278.
2. Berger, H. (1929). Über das Elektrenkephalogramm des Menschen. Archiv für Psychiatrie und Nervenkrankheiten, 87, 527–570.
3. Adrian, E. D., & Matthews, B. H. C. (1934). The Berger rhythm: Potential changes from the occipital lobes in man. Brain, 57(4), 355–385.
4. Gibbs, F. A., Davis, H., & Lennox, W. G. (1935). The electro-encephalogram in epilepsy and in conditions of impaired consciousness. Archives of Neurology and Psychiatry, 34(6), 1133–1148.
5. Loomis, A. L., Harvey, E. N., & Hobart, G. A. (1937). Cerebral states during sleep, as studied by human brain potentials. Journal of Experimental Psychology, 21(2), 127–144.
6. Jasper, H. H. (1958). The ten-twenty electrode system of the International Federation. Electroencephalography and Clinical Neurophysiology, 10, 371–375.
7. Rechtschaffen, A., & Kales, A. (1968). A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects. Washington, DC: US Government Printing Office.
8. Buzsáki, G. (2006). Rhythms of the Brain. Oxford: Oxford University Press.
9. Hochberg, L. R., et al. (2006). Neuronal ensemble control of prosthetic devices by a human with tetraplegia. Nature, 442(7099), 164–171.
10. Thibault, R. T., & Raz, A. (2017). The psychology of neurofeedback: Clinical intervention even if applied placebo. American Psychologist, 72(7), 679–688.