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IC‐P2‐093: Differential FDDNP‐PET patterns identify subgroups of middle‐aged and older adults
Author(s) -
Ercoli Linda M.,
Siddarth Prabha,
Kepe Vladimir,
Miller Karen J.,
Huang S.-C.,
Lavretsky Helen,
Bookheimer Susan Y.,
Phelps Michael E.,
Barrio Jorge R.,
Small Gary W.
Publication year - 2008
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.2008.05.086
Subject(s) - posterior cingulate , cognitive impairment , cognition , alzheimer's disease , statistical parametric mapping , psychology , medicine , audiology , neuroscience , disease , magnetic resonance imaging , radiology
Background: We explored whether positron emission tomography (PET) with 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl) amino]-2-naphthyl} ethylidene)malononitrile (FDDNP), a molecule that binds to plaques and tangles in vitro, might identify homogeneous subgroups of persons according to FDDNP signal in middle-aged and older persons with mild cognitive impairment (MCI) or normal cognition. Methods: Sixty-one older adults (MCI, N 34; normal cognition (NC, N 27) received FDDNP-PET scans and cognitive testing. MCI patients included amnestic, (N 13); multiple domains impaired (N 16); and non-amnestic (N 5) subtypes. Logan parametric images were produced using cerebellum as a reference region, and relative distribution volumes were obtained for regions of interest (ROIs) known to accumulate plaques and tangles in Alzheimer’s disease (AD). Cluster analysis was performed to identify subgroups of subjects according to FDDNP signal distribution. Results: The analysis identified three FDDNP signal clusters: high signal in all (temporal, parietal, frontal and posterior cingulate) ROIs (high global cluster, HG); low signal in all ROIs (low global cluster, LG); high frontal and parietal signal with intermediate temporal and posterior cingulate signal (HF/PA). Most MCI subjects were in the HG and HF/PA clusters, but MCI subtypes were not differentiated according to cluster membership. Most cognitively normal subjects were in LG. On cognitive tests, the HG and HF/PA clusters performed significantly worse than LG; but did not significantly differ from each other. Repeat cognitive evaluations (over a average of 3.2 years) were available for 16 subjects (8 MCI; 8 CN). Half from each group declined, and the two subjects with MCI who developed dementia were from HF/PA. Conclusions: These initial analyses suggest that the HG FDDNP signal pattern may represent high AD risk. The FDDNP signal pattern of HF/PA was not characteristic of AD, but initial findings suggest HF/PA is a high dementia risk group. The HF/PA cluster may represent a combination of etiologies, variants, or severities related to underlying amyloid or tau. Longitudinal follow-up continues, and will determine the association of these subgroups with outcome.