10-20 system (EEG)

10- 20 system is used in the electroencephalography (EEG).

On examination with the EEG, electrodes are attached to certain points of the skull surface to measure the cortical electrical activity. However, since the skull shape and size varies greatly from person to person, had a relative system are defined, which allows comparable results. Herbert Jasper invented such a system, which is used to this day.

The skull bone is measured from the nasion to the inion along the skull. The value of this route takes you to 100 percent. Now you share on this. From the nasion you go 10 percent towards the inion, then four additional 20 -percent steps and at the end again 10 percent. Hence the name 10 -20 system. The same procedure is on the line between the two ( in the ears located ) preauricular points. Based on these coordinates, the electrodes are placed on the scalp.