Potential DIAN participants will be contacted by telephone to
review the study’s inclusion and exclusion criteria. Those who
are willing to participate and who meet all study criteria will
come to the study site with a collateral source (someone who
knows the participant well and has regular contact) to sign
informed consent forms and provide a medical and family history.
Enrolled individuals will participate in the following
procedures:  Clinical assessment  This interview-based
assessment, performed by a physician or nurse clinician, focuses
on memory and physical health concerns and requires the
participation of both the participant and the collateral source
(someone who knows the volunteer well). Both are interviewed
about the participant’s memory and health, and there is a
neurological examination of the participant. The interviews and
examination together usually require about 2 hours. The
collateral source may be interviewed by telephone if unable to
come to the study site.  Memory and thinking tests