The preclinical diagnosis of AD
The accurate preclinical diagnosis of late-onset Alzheimer's disease is a necessary goal. Studies have shown that damage to the hippocampus and entorhinal cortex, the major memory processing center of the brain, occur early in the course of AD. Imaging studies have shown that reduction in the size of the hippocampus can assist in predicting the decline from mild cognitive impairment (MCI) to AD. In addition, the tau protein and amyloid beta peptide levels can also serve as early diagnostic markers of AD. These markers are potentially useful for the identification of early AD pathology; however, there remains considerable uncertainty regarding their predictive value or their capacity to monitor the course of AD. Dr. de Leon is conducting a longitudinal study of normal and MCI individuals to demonstrate that combining information from imaging studies and biochemical markers improves both sensitivity and specificity for the prediction of cognitive decline and helps characterize early brain changes observed in AD. His ultimate goal is to identify different markers and characterize their relationships in order to improve the early diagnosis of AD.