**Study of Donanemab in Participants Who Completed Study AACM** This study is checking if people who took a medicine called *donanemab* before can benefit from taking it once a year. The study will take about 2.5 years and involves 6 visits. *Donanemab* is a drug being studied to see if it helps with brain health. **Key Points:** - **Study Duration:** The study lasts up to 2.5 years. - **Number of Visits:** Participants will have 6 visits in total. - **Eligibility:** Participants should have completed a previous study and have a reliable partner to help with study requirements. Some people might be excluded if they have certain health conditions or metal implants that interfere with MRI scans. Participants need to not be able to have children or should follow local rules for birth control during the study. Some health issues like serious illnesses or specific brain conditions might prevent joining the study. Also, if someone has participated in another conflicting study recently, they might not be able to join.