A neuropathologic study of long-term, Economo-type postencephalitic parkinsonism with a prolonged clinical course.

In this report, the neuropathologic features of five autopsied cases of postencephalitic parkinsonism of the Economo-type (PEPE) with a mean age of 66.6 years and a mean duration of the illness of 53.6 years are described. All five patients had presented with personality changes and severe parkinsonism. In addition, four patients had also had ocular symptoms. A pronounced chronic progression of the symptoms characterized all five cases. Active degenerating lesions were found in the substantia nigra (patients 3, 4 and 5) and the oculomotor nucleus (patient 5) which might explain the clinical observation of chronic active disease in these patients. We found that the intraneuronal neurofibrillary tangles (NFT) were immunoreactive to paired helical filaments (PHF), tau and ubiquitin; but ghost tangles demonstrated immunoreactivity only to glial fibrillary acid protein (GFAP). The ghost tangles consisted of dispersed bundles of abnormal tubules, and electron-dense glial filaments would surround and occasionally invade the ghost tangles. The present study suggests that NFT in PEPE are similar in their immunohistochemistry and ultrastructure to those observed in the case of Alzheimer-type dementia.