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P2‐292: Exploring novel cognitive outcomes for clinical trials in MCI and Alzheimer's disease compared with the ADAS‐Cog
Author(s) -
Marsico Mark,
Markwick Arwen,
Chandler Julie,
Zhu Xingshu,
Jager Celeste
Publication year - 2012
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.2012.05.1000
Subject(s) - episodic memory , neurocognitive , cognition , psychology , neuropsychology , cambridge neuropsychological test automated battery , activities of daily living , medicine , working memory , psychiatry , spatial memory
of accurately predicting prodromes of different dementia syndromes, we examined whether empirically-derived cognitive subtypes of MCI were consistent with consensus diagnoses (i.e., amnestic and non-amnestic singleand multi-domain; Winblad et al., 2004) and whether resulting neuropsychological profiles vary based on the criteria used for MCI diagnosis. Methods: 135 participants were diagnosed with MCI using conventional criteria (i.e., 1.5 SDs below normal on one test within a cognitive domain; Petersen & Morris, 2005) and 81 participants were diagnosed with MCI using comprehensive criteria developed to increase diagnostic specificity (i.e., 1 SD below normal on two tests within one domain; Jak et al., 2009). To examine tests and underlying cognitive constructs that constitute subgroup profiles, we conducted a hierarchical cluster analysis using 13 measures of language, memory, executive function, visuospatial function, and attention. Results: The conventional criteria for MCI yielded the following three distinct groups: An Amnestic subgroup (n 1⁄4 57) mildly impaired primarily on memory measures; a Mixed or multi-domain subgroup (n 1⁄4 14) impaired on memory, executive function, language, and visuospatial measures; and a Relatively Normal subgroup (n 1⁄4 64) that performed within normal limits. Of the MCI participants diagnosed via comprehensive criteria, four distinct groups emerged: An Amnestic MCI subgroup (n 1⁄4 30), a Dysexecutive MCI subgroup (n 1⁄4 13), a Mixed MCI subgroup (n1⁄4 19), and a Visuospatial subgroup (n1⁄4 19) impaired on a specific visuospatial measure. Conclusions: Findings revealed that neuropsychological profiles vary depending on classification scheme used to define MCI. The conventional criteria produced subgroups consistent with single and multi-domain amnestic MCI diagnoses. However, one subgroup performed largely within normal limits suggesting that using an isolated poor performance for diagnosis may increase risk for false positives. Comprehensive criteria revealed more nuanced subgroups characterized by memory as well as dysexecutive and visuoconstructional impairments. Both schemes revealed a Mixed subgroup consistent with a prodromal AD profile and more severe impairments that may reflect a later stage of MCI.