TY - JOUR
T1 - Episodic memory of odors stratifies Alzheimer biomarkers in normal elderly
AU - Dhilla Albers, Alefiya
AU - Asafu-Adjei, Josephine
AU - Delaney, Mary K.
AU - Kelly, Kathleen E.
AU - Gomez-Isla, Teresa
AU - Blacker, Deborah
AU - Johnson, Keith A.
AU - Sperling, Reisa A.
AU - Hyman, Bradley T.
AU - Betensky, Rebecca A.
AU - Hastings, Lloyd
AU - Albers, Mark W.
N1 - Funding Information:
Supported by NIH DP2-OD000662 (awarded to M.W.A), P30-AG036449 (awarded to R.A.S.), P50-AG005134 (awarded to B.T.H.), and T32NS048005 (awarded to R.A.B.), the Wilkens Foundation (awarded to M.W.A), MGH ECOR grant (awarded to M.W.A), and the Harvard NeuroDiscovery Center. We thank the participants and their families for their time and efforts. We thank Jeanette Gunther for coordinating the ADRC longitudinal cohort and Kyleen Swords, Stephanie Camhi, Amy Zoller, Frances Hatling, Larissa Collins, and Sandra Yan for testing participants. We thank Matthew Growdon, MD, and Gad Marshal, MD, for providing constructive comments.
Publisher Copyright:
© 2016 American Neurological Association
PY - 2016/12/1
Y1 - 2016/12/1
N2 - Objective: The objective of this study was to relate a novel test of identifying and recalling odor percepts to biomarkers of Alzheimer's disease (AD) in well-characterized elderly individuals, ranging from cognitively normal to demented. Methods: One hundred eighty-three participants (cognitively normal: n = 70; subjective cognitive concerns: n = 74; mild cognitive impairment [MCI]: n = 29, AD dementia: n = 10) were administered novel olfactory tests: the Odor Percept IDentification (OPID) and the Percepts of Odor Episodic Memory (POEM) tests. Univariate cross-sectional analyses of performance across diagnoses; logistic regression modeling, including covariates of age, sex, education, APOE genotype, and neuropsychological test scores; and linear mixed modeling of longitudinal cognitive scores were performed. Amyloid deposition and MRI volumetrics were analyzed in a subset of participants. Results: Accuracy of identification and episodic memory of odor percepts differed significantly across diagnosis and age, with progressively worse performance across degrees of impairment. Among the participants who were cognitively normal or had subjective cognitive concerns, poorer than expected performance on the POEM test (based on the same individual's performance on the OPID and odor discrimination tests) was associated with higher frequencies of the APOE ε4 allele, thinner entorhinal cortices, and worse longitudinal trajectory of Logical Memory scores. Interpretation: Selective impairment of episodic memory of odor percepts, relative to identification and discrimination of odor percepts revealed by this novel POEM battery, is associated with biomarkers of AD in a well-characterized pre-MCI population. These affordable, noninvasive olfactory tests offer potential to identify clinically normal individuals who have greater likelihood of future cognitive decline. Ann Neurol 2016;80:846–857.
AB - Objective: The objective of this study was to relate a novel test of identifying and recalling odor percepts to biomarkers of Alzheimer's disease (AD) in well-characterized elderly individuals, ranging from cognitively normal to demented. Methods: One hundred eighty-three participants (cognitively normal: n = 70; subjective cognitive concerns: n = 74; mild cognitive impairment [MCI]: n = 29, AD dementia: n = 10) were administered novel olfactory tests: the Odor Percept IDentification (OPID) and the Percepts of Odor Episodic Memory (POEM) tests. Univariate cross-sectional analyses of performance across diagnoses; logistic regression modeling, including covariates of age, sex, education, APOE genotype, and neuropsychological test scores; and linear mixed modeling of longitudinal cognitive scores were performed. Amyloid deposition and MRI volumetrics were analyzed in a subset of participants. Results: Accuracy of identification and episodic memory of odor percepts differed significantly across diagnosis and age, with progressively worse performance across degrees of impairment. Among the participants who were cognitively normal or had subjective cognitive concerns, poorer than expected performance on the POEM test (based on the same individual's performance on the OPID and odor discrimination tests) was associated with higher frequencies of the APOE ε4 allele, thinner entorhinal cortices, and worse longitudinal trajectory of Logical Memory scores. Interpretation: Selective impairment of episodic memory of odor percepts, relative to identification and discrimination of odor percepts revealed by this novel POEM battery, is associated with biomarkers of AD in a well-characterized pre-MCI population. These affordable, noninvasive olfactory tests offer potential to identify clinically normal individuals who have greater likelihood of future cognitive decline. Ann Neurol 2016;80:846–857.
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U2 - 10.1002/ana.24792
DO - 10.1002/ana.24792
M3 - Article
C2 - 27696605
AN - SCOPUS:85005999180
SN - 0364-5134
VL - 80
SP - 846
EP - 857
JO - Annals of Neurology
JF - Annals of Neurology
IS - 6
ER -