DOD ADNI

DOD ADNI, also called the Study of Brain Aging in Vietnam War Veterans, is a US Department of Defense funded offshoot of the Alzheimer's Disease Neuroimaging Initiative led by Michael Weiner. It asks whether a history of traumatic brain injury (TBI) or posttraumatic stress disorder (PTSD) raises the risk of Alzheimer's disease, measured with imaging and fluid biomarkers, using the ADNI sites and methods.

Composition

Veterans who served in Vietnam, aged 60 to 80 at entry, were found through VA compensation records and sorted into groups with TBI, PTSD, both, or neither. The first grant planned 65 per group and excluded MCI; a second grant added veterans with MCI, and the 2017 report gives an overall target of about 400. That interim report describes 180 baseline participants: 63 controls without TBI or PTSD, 63 with PTSD only, 22 with TBI only and 32 with both. All but one were men. MRI volumetrics were available for 120 of them and florbetapir PET for 146. Final enrollment numbers were not found in a public source.

Acquisition

Participants were seen at 19 ADNI clinic sites. MRI is done at 3 T; the grant protocol lists a 3D T1-weighted IR-SPGR, FLAIR, a T2* gradient echo for hemosiderin, DTI and resting-state BOLD fMRI, within about 35 minutes. The grant planned to use GE systems only so that DTI stays consistent across sites; which scanners were finally used was not checked. Amyloid PET uses florbetapir, and tau PET is acquired at baseline and after one year. Clinical and cognitive testing and MRI are repeated after one year, and CSF and blood are collected for biomarkers and genetics.

Annotations

No voxel-level labels. The grant plans release of the full clinical database and all scans, along with FreeSurfer volumes, white matter hyperintensity volumes, expert reads of infarcts and head-injury findings on FLAIR and T2*, DTI measures and amyloid PET SUVRs from the ADNI analysis groups. Participants also have structured psychiatric interviews (SCID, CAPS) and the ADNI cognitive battery.

Known limitations

• The TBI groups are small: many veterans with TBI were excluded, often because of metal in the body that ruled out MRI, and the study later waived MRI for some TBI participants.
• Almost all participants are men, and those enrolled differ in ethnicity from the veterans first contacted.
• Published group sizes come from an interim report while enrollment was ongoing.