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Detecting cognitive changes in preclinical Alzheimer's disease: A review of its feasibility
Author(s) -
Mortamais Marion,
Ash Jessica A.,
Harrison John,
Kaye Jeffrey,
Kramer Joel,
Randolph Christopher,
Pose Carine,
Albala Bruce,
Ropacki Michael,
Ritchie Craig W.,
Ritchie Karen
Publication year - 2017
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2016.06.2365
Subject(s) - disease , neuroscience , cognition , psychology , alzheimer's disease , cognitive reserve , cognitive decline , medicine , cognitive impairment , dementia
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.