The human brain emits electrical activity – waves that can be measured by a device called an electroencephalogram (EEG). When analysing the results of an EEG, scientists identify certain patterns or frequencies of brain waves. When we are awake we produce alpha waves of medium speed; These waves are clearly seen when a person is in a relaxed state; Beta waves, faster than alpha waves, are present during states of concentration or mental work. Theta waves, slower than alpha waves, are seen during moments of drowsiness, reverie or light sleep. A fourth type of brain wave, called delta, the slowest, occurs during deep sleep.
When neuroplasticity does not work well, these waves show irregular patterns. This can manifest as inattention, impulsivity, stress, depression, anxiety, lack of self-control, insomnia, chronic pain and other conditions. Anxious and stressed people have few alpha and theta waves, while children with attention deficit tend to have a lot of slow waves and do not have much faster waves like beta, which are necessary for concentration.