What does the "10-20 system" relate to in EEG electrode placement?

The "10-20 system" is a standardized method used for placing electrodes on the scalp in order to conduct electroencephalography (EEG). This system ensures consistency and reliability in the placement of electrodes, which is crucial for accurate recording and interpretation of brain wave activity.

In this system, the locations of the electrodes are defined based on the measurement of distances between specific anatomical landmarks on the skull. The notation "10-20" refers to the fact that the distances between the electrodes are either 10% or 20% of the total distance from the nasion (the bridge of the nose) to the inion (the bump at the back of the skull). This standardized approach helps in achieving reproducible results, as the precise placement of electrodes can significantly impact the recorded data.

The other options do not accurately reflect the purpose of the 10-20 system. It does not relate to the frequency of brain waves, the depth of brain activity, or determining patient age for electrode application. The primary focus of the 10-20 system is to provide a consistent framework for electrode placement on the scalp to facilitate effective EEG recordings.