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IC‐P‐134: Differentiating Preclinical Alzheimer’s Disease from Normal Aging: The Effects of Age and Amyloid on Cognitive Decline Over 3.5 Years
Author(s) -
Farrell Michelle E.,
Kennedy Kristen M.,
Rodrigue Karen M.,
Wig Gagan S.,
Bischof Gérard N.,
Rieck Jennifer R.,
Chen Xi,
Festini Sara B.,
Devous Michael D.,
Park Denise C.
Publication year - 2016
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.2016.06.164
Subject(s) - episodic memory , cognitive decline , amyloid (mycology) , cognition , psychology , medicine , alzheimer's disease , pittsburgh compound b , longitudinal study , gerontology , disease , dementia , pathology , neuroscience
the ADNI1 study with BTB 1.5T MPRAGEMRIs at baseline, year 1 and year 3 were used. The BTB reproducibility of the atrophy rate of both the left and right hippocampus over 1 year and 3 years were compared with a simple statistical test based on the binomial sign test that handled outlying data points robustly. Results: The noise in the atrophy rate, as measured by the reproducibility in units of percentage points, showed no statistical difference between 1 and 3 years in 4 of the 5 methods. FSL/FIRST was slightly noisier in both hippocampi over 1 year than 3 years (p1⁄40.002 & p1⁄40.002). For example, the noise for the left hippocampus for FreeSurfer longitudinal was 2.0% over 1 year and 2.2% over 3 years while the corresponding atrophy rates were 1.9% and 5.2%. Conclusions: The noise of measuring hippocampal atrophy rates over 3 years was no worse than over 1 year for the 5 methods studied. Therefore, if the atrophy rate was stable over the 3 years, the 3 year study would be at least 3 times as sensitive as the 1 year study to changes in atrophy rate.