Frequency of Alzheimer's neurofibrillary tangle in the brains of progressive supranuclear palsy, postencephalitic parkinsonism, Alzheimer's disease, senile dementia and non-demented elderly person.

The frequency and the distribution of Alzheimer's neurofibrillary tangles were examined in those cases of progressive supranuclear palsy (one case), postencephalitic parkinsonism (one case), Alzheimer's disease (two cases), senile dementia (two cases) and non-demented elderly person (three cases). The light microscopic pattern of Alzheimer's neurofibrillary tangles seen in progressive supranuclear palsy was similar to those in postencephalitic parkinsonism, Alzheimer's disease, senile dementia and non-demented elderly person. Some differences in the frequency and the distribution of Alzheimer's neurofibrillary tangles were demonstrated.