Brain waves are oscillating electrical voltages in the brain measuring just a few millionths of a volt.
There are five widely recognized brain waves.
Gamma 35 Hz Concentration
Beta (β) 12–35 Hz Anxiety dominant, active, external attention, relaxed
Alpha (α) 8–12 Hz Very relaxed, passive attention
Theta (θ) 4–8 Hz Deeply relaxed, inward focused
Delta (δ) 0.5–4 Hz Sleep
The EEG (electroencephalograph) measures brainwaves of different frequencies within the brain.
Electrodes are placed on specific sites on the scalp to detect and record the electrical impulses within the brain.
A frequency refers to the number of times a wave repeats itself within a second.
Fequency deficiencies, excessivity or difficulty to access may result in mental performance impairment.
Gamma greater than 30(Hz) BETA (13-30Hz), ALPHA (8-12 Hz), THETA (4-8 Hz), and DELTA(less than 4 Hz).
The brain uses 13Hz, high alpha or low beta, for active intelligence.
Individuals who exhibit learning disabilities and attention problems having a deficiency of 13Hz activity in certain brain regions that affects the ability to easily perform sequencing tasks and math calculations.
DELTA (0.1 to 3.5 Hz)
The lowest frequencies are delta waves, which are less than 4 Hz and occur in deep sleep and in some abnormal processes.
Delta waves are the dominant rhythm in infants up to one year of age and it is present in stages 3 and 4 of sleep.
Delta waves tend to be the highest in amplitude and the slowest waves.
Increased Delta EEG waves is associated with decreased awareness of the physical world.
The unconscious access of information occurs through Delta waves.
Decreases in Delta waves occur when high focus and peak performance are required.
However, most patients with Attention Deficit Disorder, naturally increase rather than decrease Delta activity when trying to focus.
This inappropriate Delta response often severely restricts the ability to focus and maintain attention., as if the brain is locked into a perpetual drowsy state.
DELTA waves (0.1-3 Hz)
Distribution: generally broad or diffuse; may be bilateral, widespread
Subjective feeling states: deep, dreamless sleep, non-REM sleep, trance, unconscious
Associated tasks & behaviors: lethargic, not moving, not attentive
Physiological correlates: not moving, low-level of arousal
THETA waves (4-8 Hz)
Theta activity has a frequency of 3.5 to 7.5 Hz and is classed as slow activity.
Theta activity is seen in connection with creativity, intuition, daydreaming, and fantasizing and is a repository for memories, emotions, sensations.
During internal focus, meditation, prayer, and spiritual awareness, theta waves are prominent.
Theta waves reflect the state between wakefulness and sleep and relates to the subconscious mind.
It is abnormal in awake adults but is perfectly normal in children up to 13 years old.
It is also normal during sleep.
Theta is suspected to reflect activity from the limbic system and hippocampal regions.
Theta activity is observed in anxiety, behavioral activation and behavioral inhibition.
When the theta rhythm appears to function normally it mediates and/or promotes adaptive, complex behaviors such as learning and memory.
THETA (3.5-7.5 Hz): Distribution: usually regional, may involve many lobes, can be lateralized or diffuse.
Subjective feeling states with theta: intuitive, creative, recall, fantasy, imagery, creative, dreamlike, switching thoughts, drowsiness.
Alpha waves are those between 8 and 12(Hz).
Alpha waves will peak around 10Hz.
Alpha wave production promotes mental resourcefulness, helps ability mental coordination, enhances overall sense of relaxation and fatigue.
Alpha wave state allows quick and efficient abilities to accomplish tasks.
Alpha wave predominate in most people who are at ease and are calm.
Alpha bridges the conscious rhythm seen in normal relaxed adults.
Alpha bridges are present during most of life especially beyond the thirteenth year when it dominates the resting tracing.
Alpha rhythms are reported to be derived from the white matter of the brain.
The white matter can be considered the part of the brain that connects all parts with each other.
Alpha is a common state for the brain and occurs whenever a person is alert.
Alpha rhythm is a marker for alertness and sleep, but not actively processing information.
Alpha rhythms are strongest over the occipital cortex and also over frontal cortex.
Alpha has been linked to extroversion, creativity and mental work.
Alpha rhythm within normal range tends to be experienced with good moods, seeing the world truthfully, and have a sense of calmness.
Alpha rhythm is one of the brain’s most important frequencies to learn and use information taught in the classroom and on the job.
Alpha rhythm is increased by closing the eyes or deep breathing or decreased alpha by thinking or calculating.
Alpha-Theta training can create increased sensation, abstract thinking and self-control.
Alpha rhythm allows us to shift easily from one task to another.
ALPHA(8-12 Hz): Distribution is regional, usually involves entire lobe.
Alpha occipital waves are strong with eyes closed.
Subjective feeling states with alpha rhythm: relaxed, not agitated, but not drowsy; tranquil and conscious.
Associated with meditation, no action.
Physiologically correlated with relaxed, healing state
BETA (above 12 Hz)
Beta activity is fast activity and has a frequency of 14 and greater Hz.
Beta activity reflects desynchronized active brain tissue.
It is most evident frontally.
It may be absent or reduced in areas of cortical damage.
It is generally regarded as a normal rhythm and is the dominant rhythm in those who are alert or anxious or who have their eyes open.
Beta activity is the state that most of brain is in when eyes open and one is listening and thinking during analytical problem solving, judgment, decision making, processing information about the world around us.
Beta activity can be divided into low, midrange and high levels.
LOW BETA (12-15HZ): lobes frontal, occipital
Subjective feeling states: relaxed yet focused, integrated
Physiological correlates: is inhibited by motion; restraining body may increase sensorimotor rhythm.
Effects of Training: increasing sensorimotor rhythm can produce relaxed focus, improved attentive abilities.
MID BETA (15-18hz):
Subjective feeling states: thinking, aware of self & surroundings
Associated tasks & behaviors: mental activity
Physiological correlates: alert, active, but not agitated
Effects of Training: can increase mental ability, focus, alertness
HIGH BETA (above 18hz):
Subjective feeling states: alertness, agitation
Associated tasks & behaviors: mental activity, e.g. math, planning
Physiological correlates: general activation of mind & body functions.
Effects of Training: can induce alertness, but may also produce agitation
GAMMA (above 30 Hz)
Subjective feeling states: thinking; integrated thoughts
Associated tasks & behaviors: high-level information processing.
Physiological correlates: associated with information-rich task processing
Gamma is measured between 30 and 44 (Hz) and is the only frequency group found in every part of the brain.
A good memory is associated with well-regulated and efficient 40Hz activity, whereas a 40Hz deficiency creates learning disabilities.