APOE and Alzheimer disease: examined neural biomarkers of key‐tapping tests in MCI (n = 27), AD (n = 39), and HC (n = 47) and found hand motor performance associated with hippocampal volume but not with apolipoprotein E (APOE) ɛ4 alleles or global amyloid‐β deposition, leading the authors to conclude that later stage AD pathology is associated with motor changes.34