Cognitive Detection of Preclinical AD: Validation Using Biomarkers

Biomarkers, such as amyloid deposition, and Hipp volume loss, and low Aβ and high pTau in CSF, are useful for identifying cognitively normal (CN) elderly who are likely have early AD pathology ("preclinical AD"). However, they are invasive and/or expensive. The goal of the current study is to develop and validate cognitive proxies of AD biomarkers by using cognitive tasks that are dependent on brain regions impaired by very early AD pathology. If successful, these tasks will provide a non-invasive and cost-effective way to identify and track change in CN individuals at high risk for progressing to mild cognitive impairment (MCI) and dementia stages of AD and thus will facilitate future prevention trials in pAD.

Subjects will attend three study visits. During the first study visit, subjects will have eligibility criteria confirmed, have a blood sample drawn, and complete about half of the cognitive tasks. The second visit, which will occur within one week of visit one, will involve completion of the remaining cognitive tasks. Subjects will also be asked to have a PET-CT scan during visit three (to occur within 3 months of visits 1 and 2).

Inclusion criteria

• Prior enrollment as a participant in the NYU Alzheimer's Disease Center (ADC) and completion of the ADC Clinical Evaluation within the past year.
• Clinical diagnosis of "cognitively normal" or "amnestic mild cognitive impairment" based on recent (within 1 year) consensus meeting cross-referenced with standard neuropsychological scores.
• Normal or corrected-to-normal vision and hearing (able to see images on computer screen and hear auditory events delivered through the computer speaker).

Exclusion criteria

• Significant history of mental illness, drug or alcohol abuse; severe trauma preventing normal use of dominant hand (needed to move the mouse cursor); clinical depression (unless medically controlled); other neurologic conditions (i.e. stroke), or learning disability; ophthalmologic/visual problems that prevent viewing a computer screen at a normal distance (such as legal blindness, detached retinas, occlusive cataracts).
• Lack of capacity to give informed consent and no legally authorized representative to provide consent.
• Having pacemakers, aneurysm clips, cochlear implants, or metal/foreign objects in body and therefore, unable to receive MRI.
• Pregnancy, breastfeeding or planning to have a baby.