QUANTIFICATION OF BETA-A4 PROTEIN DEPOSITION IN THE MEDIAL TEMPORAL-LOBE - A COMPARISON OF ALZHEIMERS-DISEASE AND SENILE DEMENTIA OF THE LEWY BODY TYPE

The distribution of beta-amyloid protein (beta-A4) was examined in the medial temporal lobes from cases of Alzheimer's disease (AD) (n=13), senile dementia of Lewy body type (SDLT) (n=12) and age matched controls (n=9). Using a previously described image analysis technique the extent of beta-A4 pathology was determined in ten distinct anatomical sites within the medial temporal lobe. AD and SDLT cases contained very similar amounts of beta-A4 in the areas sampled and both contained significantly more beta-A4 than the age matched controls. particularly in the dentate and parahippocampal gyri. The similarity of the beta-A4 load in the two conditions is in contrast to reported differences in the number of neurofibrillary tangles which can be observed. It is suggested that AD and SDLT represent a spectrum of pathology which centres around the aberrant processing of the beta-A4 precursor protein.