The present findings provide information on stability and change across development for the P300 component of the ERP. Group based trajectory modeling of approximately annual P300 amplitude measurements obtained for child and adolescent offspring and biennially for young adults with high familial risk for AD revealed heterogeneity of early P300 amplitude development among the subjects. Auditory P300 development for the youngest age group (8–12 year olds) was characterized by two groups of linearly increasing P300 amplitude with slower linear increase in an attenuated P300 group and a faster increase in a higher-level P300 group. For the adolescent subjects (13–18) and the young adult subjects (19–29) three groups with stable P300 levels were found. These findings illustrate the important role that brain development has on the elicited P300.
