- Subjects will be followed up for 36 months from the baseline visit. All assessments are to be performed every year from baseline(0, 12, 24, 36 months), except; 1) FDG-PET and amyloid-PET will be performed every two years, i.e., on baseline and at 24 month visit. 2) CSF collection will also be performed on baseline and at 24 months visit. 3) Clinical/cognitive assessment and MRI evaluation will additionally be done at 6 months from baseline to determine short term change.