The progression of Alzheimer's disease from limbic regions to the neocortex: Clinical, radiological and pathological relationships

Alzheimer's disease (AD) is characterised by the gradual accumulation of ne urofibrillary pathology in selected regions of the brain. Earlier studies i ndicate that the accumulation of neurofibrillary tangles is associated both with decline in patient's cognitive performance as well as with medial tem poral robe atrophy on CT scans. There are also indications that progression through the pathological stages of AD is associated with decline in cognit ive functions. The results of this study indicate that progression of disea se, especially beyond the boundaries of the limbic regions, is associated w ith marked decline in the cognitive performance of patients suffering from AD, However the clinical manifestations of early pathological stages are no t so well defined. We also found that the atrophy of the medial temporal lo be on CT scans is related to the progression of pathology. Atrophy is most apparent when the disease reaches its isocortical stages and is not marked in the limbic stages of the disease. The additive effect of pathologies co- existing with AD is apparent in reduced cognitive scores, while the atrophy of limbic structures, as measured on CT scans, seems to be mainly attribut able to AD-related pathology.