[Diagnosis of Alzheimer's disease in the aged. II. Quantitative aspects].

A quantitative aspect was instrumental in the distinction of late Alzheimer's disease from senile brain lesion in 9 cases from a group of 10. Eight to ten plaques in one microscopical field [magnification 400 X] were a decisive finding in Brodmann's area 10 or 21. Neuronal decrease in nucleus basalis was a less reliable feature [7: 10], neuronal frequency in locus coeruleus was the same as in control group. Another criterion seems to be necessary when border line cases of histological Alzheimer's disease with dementia and without dementia are to be distinguished. Subclinical forms of Alzheimer's disease in old age can be supposed because of the finding of plaques in neocortex and neuronal decrease in nucleus basalis in several cases of the control group.