With technological advances, it is now possible to quickly apply an EEG array with 128 or more electrodes to the head of an infant or young child. Researchers who use these dense array techniques typically average across clusters of electrodes to calculate EEG power values (e.g., Grieve, Myers, Stark, Housman, & Fifer, 2005). Researchers who use 32 or fewer electrodes tend to report power values for individual scalp electrodes. The number of scalp electrodes is typically determined by the research question. If information about electrical activity at specific scalp locations is of interest, then the standard 19 electrode montage (i.e., the 10/20 system; Jasper, 1957) may suffice. If information about the source of the electrical signal is of interest, then dense arrays are required.
