EEG & EDA Essential Oils Research

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:

• cerebrum


• brainstem


• cerebellum

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.

Brainwaves

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


• beta


• theta


• delta

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.

When measuring brainwaves  by means of an EEG it has been noted that there was an increase of alpha waves when smelling lavender oil, which is assumed to be a relaxant fragrance. These test results did however vary when test subjects were in different states of arousal or relaxation.

When using alerting odors, such as jasmine, an increase in brain activity was noted. Certain odors again reduced systolic blood pressure and reduced stress such as nutmeg, mace extract and valerian oil.

During testing another interesting fact came to light – an odor need not be very strong to have an effect on the body.

With electro-dermal activity (EDA) testing (where the electrical current between two points of the skin is measured) it was also found that slower currents occurred with relaxing odors such as  bergamot and lavender.

EEG & EDA Essential Oils Research