Which EEG electrode site is half the distance from F8 to Fz?

The correct answer is F4 because it is positioned at exactly half the distance between electrode sites F8 and Fz on the international 10-20 system for EEG electrode placement. In this system, the location of each electrode is based on specific anatomical landmarks on the scalp, and the distances between electrodes are standardized.

When determining the location that is half the distance from F8 to Fz, it is essential to consider the orientation and the established arrangement of electrodes. F8 is located more laterally on the right side of the head, while Fz is positioned centrally. Therefore, the midpoint, which represents half the distance from F8 to Fz, aligns with F4, as it is situated on the right side of the frontal lobe, midway between these two points.

This knowledge of the 10-20 system and the spatial relationships between electrode sites is critical for sleep technicians when setting up EEG recordings and analyzing brain activity during sleep studies.