Practice question

Reproducible comparison of EEG recordings across patients and laboratories requires standardized scalp coordinates independent of head size. Internationally accepted placement positions electrodes at intervals of 10 and 20 percent of total nasion-inion and interaural distances, creating systematic frontal, central, parietal, temporal and occipital sites labeled F, C, P, T, O with odd numbers left hemisphere and even right. This 10-20 montage documented in some textbooks and software as 20-Oct shorthand ensures consistent coverage and reliable localization. Notations like 10-Feb or 20-30 lack anatomical validity entirely.