There are many active research projects accessing and applying shared ADNI data. Use the search above to find specific research focuses on the active ADNI investigations. This information is requested annually as a requirement for data access.
| Principal Investigator | |
| Principal Investigator's Name: | Zhefeng Guo |
| Institution: | University of California, Los Angeles |
| Department: | Neurology |
| Country: | |
| Proposed Analysis: | There is a wide inter-individual variation in Aβ concentrations in all the cohort studies where cerebral spinal fluid (CSF) or plasma Aβ levels have been measured. In addition to genetic mutations such as those associated with familial Alzheimer’s disease or Down’s syndrome, the single most important factor affecting Aβ levels is Aβ amyloid pathology. Even when comparing individuals with the same Aβ amyloid PET (positron emission tomography) status, the difference in Aβ levels at the high and low ends of the range is generally several-fold. When comparing Aβ PET-positive and PET-negative groups, the Aβ amyloid PET positivity leads to only 40-60% decrease in CSF Aβ42, and 10-20% in plasma Aβ42. As a result, there is a huge overlap in Aβ42 concentrations or Aβ42/Aβ40 ratios when comparing PET-positive and PET-negative groups. This limits the use of Aβ as a biomarker for Alzheimer’s diagnosis in clinics. We hypothesize that Aβ42 concentrations or Aβ42/Aβ40 ratios at individual-level are much more sensitive in predicting changes in Aβ amyloid pathology. As a result, same-individual longitudinal changes in Aβ42 concentrations or Aβ42/Aβ40 ratios are a better diagnostic biomarker than a threshold of Aβ42 concentrations or Aβ42/Aβ40 ratios. To test our hypothesis, we propose to screen for longitudinal data on CSF and plasma Aβ42 concentrations or Aβ42/Aβ40 ratios from the same individual in ADNI. We will look for changes in Aβ42 concentrations or Aβ42/Aβ40 ratios as the individual develops Aβ amyloid pathology (PET-positive). We will compare the plasma Aβ42 concentrations or Aβ42/Aβ40 ratios before and after each individual’s change in PET positivity. We will compare the predictive power of the individual-level changes in CSF and/or plasma Aβ42 concentrations or Aβ42/Aβ40 ratios with the predictive power of the cohort-level changes in the same biomarker. |
| Additional Investigators | |
| Investigator's Name: | Caitlin Tang |
| Proposed Analysis: | Same as principal investigator. |
