HAI Book 2025 - Flipbook - Page 646
Thompson, Jackson
156
Amyloid spatial extent captures early tau burden and cognitive
deficits, measured by PACC and digital clock drawing test, in preclinical
Alzheimer9s disease
Jackson Thompson1, Jessie Fanglu Fu1,2, Michelle Farrell1, Emma Thibault1, Elliott Slade1,
Grace Del Carmen Montenegro1, Talia Robinson1, Roosmarijn Jutten1, Randall Davis4, Dana
Penney3, Marina Rodriguez Alonso1, Reisa Sperling1, Dorene Rentz1, Julie Price1,2, Keith
Johnson1
1
Massachusetts General Hospital, Harvard Medical School, Boston, MA, US
Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, US
3
Lahey Hospital and Medical Center, Burlington, MA, US
4
Massachusetts Institute of Technology, Cambridge, MA, US
2
Background: A 2-min digital clock drawing test (DCTclock) was shown to detect early Ab and tau burden in
preclinical AD. Spatial extent (EXT) measures the spread of amyloid-b (Ab) and is potentially more sensitive to
early Ab burden than the traditional measure of neocortical Ab level. We explored the relationship between
DCTclock and PACC5 performance with amyloid-b (Ab) spread using EXT and inferior temporal (IT)/ entorhinal
(ERC) FTP.
Methods: 212 cognitively normal older adults underwent baseline cognitive assessments (DCTclock and PACC5),
[11C]Pittsburgh Compound B (PiB, DVR) PET, and 186 underwent Flortaucipir (FTP, SUVR) PET (Table.1). Ab EXT was
calculated as the percentage of Ab-vulnerable neocortex that is PiB+. Participants were separated into 3 EXT
groups: EXT- (EXT
