APOE and early-onset autosomal dominant Alzheimer disease: Linear mixed-effects models with random intercepts and slopes per subject estimated cognitive trajectories across the Mini-Mental State Examination (MMSE), Clinical Dementia Rating Sum of Boxes (CDR-SB), and Alzheimer's Disease Assessment Scale Cognitive Subscale 13 (ADAS-Cog13) as a function of time, APOE ε4 dose, and ICV-adjusted hippocampal volume, including their three-way interaction and adjusting for age, sex, education, baseline diagnosis, and depression.