It was Hans Berger, the German psychiatrist, that used the term electroencephalogram (EEG) which denotes the potential fluctuations recorded from the brain.
The recordings done by the EEG records the brainwaves, which are generated by a variety of active neuronal current generators.
The brain can be divided into three main parts:
The cerebrum is a paired structure, with left and right hemispheres, each relating to the opposite side of the body.
The brainstem is divided into four regions - the medulla oblongata, the pons, the midbrain and the diencephalon.
The cerebellum receives information from the spinal cord about the position of the the body and limbs in space and can be simplified and called the "feedback" center for the cerebrum.
To measure brainwaves electrodes are placed onto the scalp using the EEG, but recordings can also be taken on the exposed surface of the brain and are known as electrocorticograms (ECoG) while thin needle electrodes can also be placed into the tissue of the brain to make recordings, which is referred to as depth recordings.
Brainwaves can basically be divided into four different types -
Alpha brainwaves occur between 8 - 13 Hz and are normally found when a person is awake in a quiet resting state. These alpha waves disappear totally during sleep.
Beta brainwaves occur between 14 - 30 Hz but during intense mental activity can reach 50 Hz.
Theta brainwaves occur between 4 - 7 Hz and are mostly found in children, but can be found in adults in times of emotional stress, and specifically when disappointed or frustrated.
Delta brainwaves occur below 3.5 Hz and occur in normal deep sleep, during infancy and in serious brain disease and occur only within the cortex.
During an epileptic seizure, the basal level of excitability of all or part of the nervous system rises above a critical threshold.
There are also two types of epilepsy - generalized epilepsy and partial epilepsy where generalized epilepsy involves the entire brain and partial epilepsy just a small or minute spot in the brain.
Generalized epilepsy can further be divided into grand mal and petit mal epilepsy where the former is a far more severe form of seizure.
It is the brainwave patterns that are influenced by the use of essential oils in aromatherapy, and for this reason it is clear to see why people suffering from epilepsy should be careful in the use of essential oils.
Yet, that statement also is an over-simplification, since hedonics also play a part in the triggering mechanism of a seizure precipitated by essential oils, and some essential oils are very successfully used by people like Dr. Tim Betts to control seizures.
But regardless of the scientific proof that essential oils have an influence on brainwaves, the fact of the matter is that essential oils, when used in aromatherapy massage or vapor therapy, can have a beneficial effect on your health due to their therapeutic properties, as well as the calming and de-stressing effect they have on the body and mind.