Predicting Symptom Onset in Sporadic Alzheimer Disease With Amyloid PET

BACKGROUND AND OBJECTIVES: To predict when cognitively normal individuals with brain amyloidosis will develop symptoms of Alzheimer disease (AD). METHODS: Brain amyloid burden was measured by amyloid PET with Pittsburgh compound B. The mean cortical standardized uptake value ratio (SUVR) was transformed into a timescale with the use of longitudinal data. RESULTS: < 0.0001, RMSE 2.8 years). CONCLUSION: The age at symptom onset in sporadic AD is strongly correlated with the age at which an individual reaches a tipping point in amyloid accumulation.