PRECLINICAL PREDICTION OF ALZHEIMERS-DISEASE USING SPECT

Background: Regional cerebral perfusion measured by single photon emis sion computed tomography (SPECT) was examined as a preclinical predict or of the development of Alzheimer's disease (AD). Methods: Singular v alue decomposition was used to produce 20 SPECT factors (known as vect ors) (n = 152). Vector scores were then computed for four groups (n = 136), differing in cognitive status: Group 1-normal controls at both b aseline and follow-up; Group 2-subjects with ''questionable'' AD at bo th baseline and follow-up; Group 3-subjects with questionable AD at ba seline who converted to AD on follow-up (Converters); Group 4-subjects with AD at baseline. All SPECT data in the analyses were gathered at baseline. Results: The four groups could be distinguished on the basis of their baseline SPECT data (p less than or equal to 0.00005; hit ra te = 83%), Regional decreases in perfusion were most prominent among C onverters in the hippocampalamygdaloid complex, the posterior cingulat e, the anterior thalamus, and the anterior cingulate. Inclusion of apo lipoprotein E status did not significantly improve the discrimination. Conclusions: SPECT data gathered and analyzed in this manner may be u seful as one aspect of the preclinical prediction of AD. Three of the four brain regions important for discriminating Converters from normal controls involve a distributed brain network pertaining to memory, su ggesting that this network may be selectively affected in the earliest stages of AD.