at this time exactly what makes up the preclinical phase of alzheimer's is still being researched, such as why some people with go on to develop alzheimer's and others do not. so the term "preclinical phase" is being used for research only. there is a worldwide effort in various countries doing research in this area known as the world wide alzheimer's disease neuroimaging initiative (ww-adni) which is the umbrella organization for neuroimaging studies being carried out through the north american adni, european adni (e-adni), japan adni, australian adni (aibl), taiwan adni, korea adni, china adni and argentina adni.