Atrophy of the medial occipitotemporal, inferior, and middle temporal gyriin non-demented elderly predict decline to Alzheimer's disease

Our goal was to ascertain, among normal elderly and individuals with mild c ognitive impairment, which temporal lobe neocortical regions predicted decl ine to dementia of the Alzheimer's type (DAT). Individuals received an MRI at baseline and a clinical and cognitive evaluation at baseline and follow- up. By using the baseline MRI we assessed the anatomical subdivisions of th e temporal lobe: anteromedial temporal lobe (hippocampus and parahippocampa l gyrus), medial occipitotemporal (fusiform) gyrus, middle and inferior tem poral gyri, and superior temporal gyrus, We studied two groups of carefully screened age- and education-matched elderly individuals: 26 normal elderly (NL) and 20 individuals with mild cognitive impairment (MCI). Fourteen ind ividuals (12 from the MCI group and two from the NL group) declined to DAT within the 3.2-year follow-up interval. We used logistic regression analyse s to ascertain whether the baseline brain volumes were useful predictors of decline to DAT at follow-up after accounting for age, gender, individual d ifferences in brain size, and other variables known to predict DAT. After a ccounting for age, gender, and head size, adding the volume of the anterome dial temporal lobe (the aggregate of hippocampus and parahippocampal gyrus) and an index of global atrophy raised the accuracy of overall classificati on to 80.4%. However, the ability to detect those individuals who declined (sensitivity) was low at 57%. When baseline medial occipitotemporal and the combined middle and inferior temporal gyri were added to the logistic mode l, the overall classification accuracy reached 95.6% and, most importantly, the sensitivity rose to 92.8%. These data indicate that the medial occipit otemporal and the combined middle and inferior temporal gyri may be the fir st temporal lobe neocortical sites affected in AD; atrophy in these areas m ay herald the presence of future AD among nondemented individuals. No other clinical baseline variables examined predicted decline with sensitivities above 71%. The apolipoprotein APOE epsilon 4 genotype was not associated wi th decline. (C) 2000 Elsevier Science Inc. All rights reserved.