Distribution and ultrastructure of Alzheimer's neurofibrillary tangles in postencephalitic Parkinsonism of Economo type.

The distribution and ultrastructure of Alzheimer's neurofibrillary tangles (ANT) in the brain stem, hypothalamus, and Ammon's horn were studied in four patients with postencephalitic parkinsonism of Economo type (PEPE). The distribution of ANT was as previously reported; the pattern of distribution resembled to that of amine-containing nerve cells. Ultrastructurally, ANT revealed twisted tubules (TT), but straight tubules (ST) of 150 A width were also found in the locus ceruleus of three cases; sometimes, TT and ST were mixed in a single neuron. Whether the coexistence of TT and ST in the locus ceruleus is a characteristic ultrastructural feature of ANT in PEPE or a regional peculiarity could not be determined. Ultrastructurally, ANT in PEPE were identical to those found in the brains of patients with Alzheimer's disease or senile dementia.