HAI Book 2025 - Flipbook - Page 640
Bourgeat, Pierrick
154
Identifying an optimal aβ cutoff point for progression from mild
cognitive impairment to Alzheimer9s disease: comparing cognitive
performance and aβ pet insights
Rosita Shishegar1,2, Pierrick Bourgeat3, Vincent Dore1, Simon M. Laws6, Tenielle Porter6,
Michael Weiner4, Colin L. Masters5, Paul Maruff8, Hamid R. Sohrabi9, Jurgen Fripp3, Victor L.
Villemagne7, Christopher Rowe10
1
The Australian e-Health Research Centre, CSIRO, Melbourne, Australia, Melbourne, AU
School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne,
Australia, Melbourne, AU
3
The Australian e-Health Research Centre, CSIRO, Brisbane, Australia, Brisbane, AU
4
Center for Imaging of Neurodegenerative Diseases, University of California-San Francisco, San Francisco, CA, USA;,
San Francisco, CA, US
5
Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia, Melbourne,
AU
6
Centre for Precision Health, Edith Cowan University, Joondalup, Western Australia;, Joondalup, AU
7
Department of Psychiatry, University of Pittsburgh, Pittsburgh, USA, Pittsburgh, PA, US
8
Cogstate Ltd, Melbourne, VIC, Australia, Melbourne, AU
9
Centre for Healthy Ageing, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia,
Murdoch, AU
10
Department of Medicine, Austin Health, Heidelberg, VIC, Australia, Heidelberg, AU
2
Objectives: To identify the optimal A´ PET threshold for distinguishing fast progressors to Alzheimer's disease
(AD) in individuals with mild cognitive impairment (MCI) and assess whether a cutoff based on Mini-Mental State
Examination (MMSE) performance can improve or substitute for the A´ PET cutoff. This research will refine risk
stratification in MCI and guide clinical decision-making regarding early therapeutic interventions.
Methods: We included 690 MCI participants with CDR 0.5 from two cohorts, followed for up to 7 years. Data from
AIBL (N=167) and ADNI (N=523) were analyzed using Cox proportional-hazards models, adjusted for age, sex, years
of education, and APOE-ɛ4 status, with the event of interest being progression to CDR 1 (plus ´-amyloid positivity,
A´>20 CL). Optimal thresholds for MMSE (27) and A´ (44 CL) were selected to maximize hazard ratios (HR) at 3
years, categorizing participants into low-risk and high-risk groups based on cognitive performance (188
participants, 27%, MMSE
