Amyloid deposition in younger adults is linked to episodic memory performance.
OBJECTIVE
To examine the relationship of β-amyloid (Aβ) deposition to episodic memory in younger (30-49 years), middle-older (50-69 years), and older adults (70-89 years). We hypothesized that subclinical levels of amyloid would be linked to memory in adults across the lifespan in a dose-dependent fashion. Of great interest was whether, within the younger group, a relationship between amyloid level and memory performance could be established.


METHODS
A total of 147 participants from the Dallas Lifespan Brain Study, aged 30-89, underwent PET imaging with18F-florbetapir and cognitive assessment. We assessed the relationship between age group and amyloid and tested whether Aβ differentially affected memory performance across the 3 age groups.


RESULTS
We report a significant association of age to amyloid burden for younger and middle-older adults (r = 0.57 and 0.28, respectively), but not for the oldest group, although absolute level of amyloid increased across the age groups. Importantly, the youngest group showed a significant decrease in recall (r = -0.47, p = 0.004) and recognition memory (r = -0.48, p = 0.003) as a function of increases in Aβ burden, whereas this relationship was absent in the middle-older and oldest group (all p > 0.23).


CONCLUSIONS
These results indicate that variance in subclinical levels of Aβ in younger adults is meaningful, and suggest that higher SUVRs relative to one's peers at a younger age is not entirely benign.
From the Center for Vital Longevity (G.N.B., K.M.R., K.M.K., D.C.P.), School of Behavioral and Brain Sciences, University of Texas at Dallas; Multimodal Neuroimaging Group (G.N.B.), Department of Nuclear Medicine, University Hospital Cologne; Cognitive Neuroscience (G.N.B.), Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Germany; and Department of Radiology (M.D.D.), University of Texas Southwestern Medical Center, Dallas. gerard.bischof@uk-koeln.de.
Gérard N
GN
Bischof
From the Center for Vital Longevity (G.N.B., K.M.R., K.M.K., D.C.P.), School of Behavioral and Brain Sciences, University of Texas at Dallas; Multimodal Neuroimaging Group (G.N.B.), Department of Nuclear Medicine, University Hospital Cologne; Cognitive Neuroscience (G.N.B.), Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Germany; and Department of Radiology (M.D.D.), University of Texas Southwestern Medical Center, Dallas.
Karen M
KM
Rodrigue
From the Center for Vital Longevity (G.N.B., K.M.R., K.M.K., D.C.P.), School of Behavioral and Brain Sciences, University of Texas at Dallas; Multimodal Neuroimaging Group (G.N.B.), Department of Nuclear Medicine, University Hospital Cologne; Cognitive Neuroscience (G.N.B.), Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Germany; and Department of Radiology (M.D.D.), University of Texas Southwestern Medical Center, Dallas.
Kristen M
KM
Kennedy
From the Center for Vital Longevity (G.N.B., K.M.R., K.M.K., D.C.P.), School of Behavioral and Brain Sciences, University of Texas at Dallas; Multimodal Neuroimaging Group (G.N.B.), Department of Nuclear Medicine, University Hospital Cologne; Cognitive Neuroscience (G.N.B.), Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Germany; and Department of Radiology (M.D.D.), University of Texas Southwestern Medical Center, Dallas.
Michael D
MD
Devous
From the Center for Vital Longevity (G.N.B., K.M.R., K.M.K., D.C.P.), School of Behavioral and Brain Sciences, University of Texas at Dallas; Multimodal Neuroimaging Group (G.N.B.), Department of Nuclear Medicine, University Hospital Cologne; Cognitive Neuroscience (G.N.B.), Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Germany; and Department of Radiology (M.D.D.), University of Texas Southwestern Medical Center, Dallas.
Denise C
DC
Park
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D063506:Ageism; D000544:Alzheimer Disease / Q000175:diagnosis / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D008875:Middle Aged; D009483:Neuropsychological Tests; D019275:Radiopharmaceuticals / Q000378:metabolism
D016229:Amyloid beta-Peptides; D019275:Radiopharmaceuticals