The goal of the Alzheimer Prevention Trials (APT) Webstudy is to accelerate enrollment for Alzheimer's disease (AD) clinical trials by identifying and tracking individuals who may be at higher risk for developing AD dementia.

The APT Webstudy will use web-based cognitive testing and questionnaires to generate a risk score which will be used to identify individuals who may be at an increased risk for developing AD dementia.

Individuals who join the APT Webstudy will register at https://www.aptwebstudy.org/, sign an electronic informed consent form (ICF), provide basic demographic information and participate in web-based cognitive testing. Participants will return the APT Webstudy quarterly (every 3 months) to complete the cognitive testing again.

Based on the risk score and changes identified in the cognitive testing results, participants will be invited to visit a partnering clinical trial site for an in-person visit with biomarker testing and clinical assessment.

The combined results of the web-based assessments, with the biomarker and clinical assessments, will allow an adaptive statistical algorithm to improve the selection of those at highest risk for developing AD.

To Join the APT Webstudy, please visit https://www.aptwebstudy.org/.

Inclusion Criteria:

• male or female at least 50 years of age
• no evidence of dementia
• willing to participate in remote longitudinal cognitive testing and possible referral for biomarker assessment based on risk

Exclusion Criteria:

• N/A. Anyone can register for the APT Webstudy, however, only individuals identified using the risk algorithm will be referred for in-person biomarker assessments.

Anyone who meets entry criteria is eligible to join the Webstudy. We anticipate 200,000 individuals will join.