THE MEAN A-BETA LOAD IN THE HIPPOCAMPUS CORRELATES WITH DURATION AND SEVERITY OF DEMENTIA IN SUBGROUPS OF ALZHEIMER-DISEASE

Using image analysis techniques to quantify the percentage area covere d by the immunopositive marker for amyloid beta-peptide (A beta), we e xamined subjects with combinations of either early-onset or late-onset Alzheimer disease (AD) and either familial Alzheimer disease (FAD) or sporadic Alzheimer disease (SAD). We measured the mean and maximum A beta loads, in the hippocampus of each subject. There were no statisti cally significant differences in the mean A beta load between familial and sporadic AD subjects. Although sample sizes were too small for st atistical testing, subjects with the epsilon 4/epsilon 4 allele of the apolipoprotein E (ApoE) gene had higher mean A beta loads than those with the epsilon 3/epsilon 3 or epsilon 3/epsilon 4 alleles. Members o f the Volga German families (recently linked to chromosome 1) all had high mean A beta loads, and one of the chromosome 14-linked subjects h ad the highest mean A beta load while the other had a relatively small load, but the sample was too small for statistical comparisons. The d uration of dementia and neuropsychological test scores showed a statis tically significant correlation with the mean A beta load in the hippo campus, but not with the maximum A beta load. This difference indicate s that the mean A beta load may be a more useful feature than the maxi mum A beta load as an objective neuropathological measure for cognitiv e status. This finding may help to improve the established methods for quantitative assessment of the neuropathological changes in AD.