10-20 system

10-20 System is a standardized method of placing electrodes on the scalp in electroencephalography (EEG), a technique used to record the electrical activity of the brain. The system is based on the relationship between the location of an electrode and the underlying area of cerebral cortex. The "10" and "20" refer to the fact that the actual distances between adjacent electrodes are either 10% or 20% of the total front–back or right–left distance of the skull.

History

The 10-20 system was developed in 1958 by Herbert Jasper, a neurologist and pioneer in the field of neurophysiology. The system has been adopted internationally and is now used in most clinical and research applications of EEG.

Methodology

The 10-20 system involves dividing the scalp into four regions: frontal (F), central (C), parietal (P), and occipital (O). Each region is further divided into left and right hemispheres, denoted by odd and even numbers respectively. The 'z' (zero) line represents the midline of the skull, running from the nasion (bridge of the nose) to the inion (bump at the back of the skull).

Applications

The 10-20 system is used in a variety of clinical and research settings. It is the standard method for electrode placement in routine clinical EEG, as well as in research studies investigating brain function and dysfunction. The system is also used in brain-computer interface technology, where it helps to ensure consistent and accurate recording of brain signals.

Limitations

While the 10-20 system is widely used, it has some limitations. It does not cover all areas of the scalp, and therefore may not capture all brain activity. Additionally, the system assumes that brain activity is related to scalp surface landmarks, which is not always the case.

See also

• Electroencephalography
• Brain-computer interface
• Neurophysiology