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IC‐P‐086: COMPARISON BETWEEN THREE VOLUMETRIC MRI Z‐SCORE NORMING METHODS ACROSS THE ALZHEIMER DISEASE SPECTRUM
Author(s) -
Charil Arnaud,
Risacher Shan L.,
Shcherbinin Sergey,
Saykin Andrew J.,
Schwarz Adam J.
Publication year - 2018
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.2018.06.2150
Subject(s) - percentile , nuclear medicine , confounding , concordance , linear regression , atrophy , dementia , psychology , medicine , mathematics , statistics , pathology , disease
hemispheres. Cognitive phenotypes were assessed using the ADNI memory and executive function composite scores (ADNI-MEM and ADNI-EF), and ADAS-Cog13. Results: There was an 83% agreement in subtype assignments using the two norming approaches. In AD Ab+ subjects, the most represented subtype was Limbic using Potvin norming (43%) and Typical using linear norming (42%). This was driven by Potvin norming identifying fewer cases with abnormal cortical volumes. With increasing disease severity, Npercentages decreased while Limbic, Typical and Cortical percentages increased. The different subtypes were associated with different cognitive profiles. The Cortical subtype was the most impaired on executive function while the Typical subtype performed worse on memory. Profiles with linear and Potvin norming were similar overall, although some differences in the statistical separation between subtypes were observed. Conclusions:This simple method recapitulates features reported using more complex subtyping algorithms, including more impaired executive function in the Cortical subtype. Concordance using the two norming approaches was good overall, but the choice of norming approach did affect the distribution of N+ subtypes, especially in more advanced disease stages. The method is easily implementable, enables vMRI-based stratification in AD trials, and may help as a covariate in models explaining different cognitive presentations.