Detecting cognitive changes in preclinical Alzheimer's disease: A review of its feasibility

Marion Mortamais, Jessica A. Ash, John Harrison, Jeffrey Kaye, Joel Kramer, Christopher Randolph, Carine Pose, Bruce Albala, Michael Ropacki, Craig W. Ritchie, Karen Ritchie*

*Corresponding author for this work

Research output: Contribution to journalReview articleAcademicpeer-review


Significant progress has been made in characterizing the biological changes occurring in preclinical Alzheimer's disease (AD). Cognitive dysfunction has been viewed, however, as a late-stage phenomenon, despite increasing evidence that changes may be detected in the decades preceding dementia. In the absence of comprehensive evidence-based guidelines for preclinical cognitive assessment, longitudinal cohort and neuroimaging studies have been reviewed to determine the temporal order and brain biomarker correlates of specific cognitive functions. Episodic memory decline was observed to be the most salient cognitive function, correlating with high levels of amyloid deposition and hypoconnectivity across large-scale brain networks. Prospective studies point to early decline in both episodic and semantic memory processing as well as executive functions in the predementia period. The cognitive tests have, however, been principally those used to diagnose dementia. New procedures are required which target more finely the medial temporal lobe subregions first affected by clinically silent AD pathology.

Original languageEnglish
Pages (from-to)468-492
Number of pages25
JournalAlzheimer's and Dementia
Issue number4
Publication statusPublished - 1 Apr 2017

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