NEUROFIBRILLARY TANGLE DENSITIES IN THE HIPPOCAMPAL-FORMATION IN A NONDEMENTED POPULATION DEFINE SUBGROUPS OF PATIENTS WITH DIFFERENTIAL EARLY PATHOLOGICAL-CHANGES

Detailed analyses of the neuropathologic changes in the cerebral corte x of elderly individuals and Alzheimer's disease patients have demonst rated that certain components of the neocortical and hippocampal circu its are likely to be selectively vulnerable. In order to investigate t he distribution of lesions associated with aging as well as with the e arliest symptoms of Alzheimer's disease, we performed a quantitative n europathological evaluation of sixty-one non-demented patients from a geriatric hospital. All of the cases had neurofibrillary tangles in la yer II of the entorhinal cortex, and many cases had an involvement of the CA1 field of the hippocampus and the inferior temporal cor-tex. In all of the cases, amyloid deposition was not correlated with age or w ith the number of neurofibrillary tangles. In addition, eight cases sh owed much higher neurofibrillary tangle counts than the remainder of t he cases. It is proposed that these cases may represent the neuropatho logical correlate of the earliest stage of Alzheimer's disease that co uld antedate the appearance of clinical signs of cognitive decline and memory impairment.