Responsible: Dr. Ion Álvarez
Technological development and new scientific knowledge have led to the introduction of new techniques based on the EEG and are today a field of medicine in continuous evolution and innovation.
Baseline EEG: The electroencephalogram (EEG) is the graphical representation of brain electrical activity. By placing electrodes on the scalp, the difference in the electrical potential of a group of neurons between different areas of the cerebral cortex is recorded. The electrical activity of the brain is dynamic and varies according to the activities performed by the person. Thus, during EEG recording, the subject is asked to open and close the eyes, breathe faster and deeper (hyperventilation) and expose him to intermittent light at variable frequency (photo stimulation).
EEG with sleep deprivation: Sometimes the EEG is performed after sleep deprivation, usually rising at 4 o'clock in the morning and sleeping approximately 4 hours. It facilitates the appearance of epileptiform elements on basal activity and is also used to perform a longer EEG that includes sleep phases. Changes from wake to sleep and vice versa facilitate the appearance of some types of epileptic seizures.
Video-PSG with montage 10-20: A variation of the EEG technique is video-polysomnography, which records the EEG activity of specific brain areas and other physiological variables such as mouth-to-nose airflow, thoraco-abdominal breathing movements, limb movements, electrocardiogram, etc. during a whole period of nocturnal sleep. It is used for the study of different sleep pathologies and can be performed in different modalities to assess sleep in specific diseases.
Transcranial Magnetic Stimulation: A non-invasive way to stimulate the cerebral cortex is through transcranial magnetic stimulation (TMS). EMTs generate magnetic fields that reach the surface of the brain causing the electrical activation of the neural tissue. In this way, diagnostic techniques such as the location of the motor area can be performed, while a number of pathologies like depression may benefit from its therapeutic use.
