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Brain Waves

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As neuronal signals are constantly fired by the brain, they produce rhythmic electrical patterns known as brain waves that can be detected through a monitoring method known as electroencephalography (EEG). Electroencephalography is a noninvasive process during which electrodes (small metal conductors) placed on the scalp detect the brain waves. The EEG machine then amplifies and records the signals in a wave pattern.

The human brain produces four types of brain waves that each create distinguishable shapes on EEG readings: alpha waves, beta waves, theta waves and delta waves.

Alpha and beta waves are produced by the awake brain. Alpha waves, with frequencies of 8 to 13 Hz, originate mainly in the parietal and occipital lobes of the brain when the eyes are closed and the brain is relaxed. Beta waves are faster, with frequencies of 14 to 30 Hz, and originate in the frontal and parietal lobes when you are processing a sensory input or focusing on a task. Theta and delta waves are produced by the sleeping brain. These waves are slower than alpha and beta waves. Theta waves have frequencies of 4 to 7 Hz, and delta waves have frequencies less than 3.5 Hz. Delta waves are produced during deep sleep.

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