Constantin von Economo's contribution to the understanding of movement disorders.

Constantin von Economo's (CvE) main scientific achievements were his studies on the cytoarchitectonics of the cerebral cortex, sleep, and encephalitis lethargica (EL). He found a close relationship between motor symptoms and psychiatric and behavioral disorders in EL and postencephalitic Parkinsonism and identified the underlying neuropathology in the diencephalon and the brainstem. In agreement with Tretiakoff's findings in Parkinson's disease, CvE related postencephalitic Parkinsonism to neuronal loss in the substantia nigra. Several of CvE's early, less well-known publications also deal with the basal ganglia and movement disorders. He demonstrated in rabbits that the substantia nigra modulates automatization, coordination, and succession of masticatory movements and swallowing. In a study on the effects of experimental lesions of the cerebral peduncle in cats and monkeys, CvE hypothesized a corticotegmental pathway that maintains motor functions after pyramidal tract lesions. Recent studies have identified this pathway, which ends in the pedunculopontine nucleus. In a study on posthemiplegic chorea, CvE discussed various pathophysiological hypotheses that partly resemble modern concepts of chorea. In a clinicopathological study on Wilson's disease, CvE traced the striofugal fibers and visualized the basal ganglia outflow pathways. CvE was an outstanding multidisciplinary movement disorder specialist who contributed substantially to modern basal ganglia research.

An autopsy case of postencephalitic parkinsonism of von Economo type: some new observations concerning neurofibrillary tangles and astrocytic tangles.

An autopsied case of postencephalitic parkinsonism of von Economo type with a 71-year duration is reported. Several cases of postencephalitic parkinsonism of von Economo type have been reported in Japan but this is the first reported case from western Japan. The patient was a Japanese man who was 74 years of age at the time of death. He developed encephalitis of unknown etiology at the age of 3 years. The first symptom was antisocial behavior, which developed at 30 years of age. At the age of 40 years, the patient showed progressive parkinsonism. Neuropathological findings disclosed marked neuronal loss with gliosis in the substantia nigra, locus ceruleus, and raphe nuclei, as well as the appearance of neurofibrillary tangles in the aforementioned areas. There were also widespread tuft-shaped astrocytes (Tu-SA) in the central nervous system, including the thalamus. Tuft-shaped astrocytes are considered to represent non-reactive astrocytes because the distributions of neurofibrillary tangles (NFT) and Tu-SA are clearly different. Therefore, the primary astrocytic lesions in postencephalitic parkinsonism of von Economo type may be more widespread. Ultrastructurally, the Tu-SA consisted of straight filaments, 15 nm in width, which formed tight bundles. Ultrastructurally, NFF in this case revealed paired helical filaments but straight filaments, 15 nm in width, which were also found in the neurons of the substantia nigra.

Anti-tau-positive glial fibrillary tangles in the brain of postencephalitic parkinsonism of Economo type.

Tau-immunoreactive astrocytes have been reported in the brain of progressive supranuclear palsy (PSP) and are referred to as glial fibrillary tangles (GFTs). We found a number of GFTs in the heavily degenerated brain region in four cases of postencephalitic parkinsonism of Economo (PPE) with a clinical history of over a half-century. GFTs had the appearance of tufts of spider-like radiating fibers or small thorn-like feature by Gallyas-Braak method and also by anti-tau immunostaining.

Astrogliosis in von Economo's and postencephalitic Parkinson's diseases supports probable viral etiology.

A marked generalized astrogliosis was observed in the frontal and temporal white matter from a case of von Economo's disease and another of postencephalitic Parkinson's disease, which areas were otherwise devoid of any other demonstrable microscopic lesions. No similar astrocytic reaction of any severity was observed in the same areas in a number of other brain diseases or controls, except when other kinds of lesions were present in the same section, with reactive astrocytes being present within the primary or defining lesion or immediately close by. The marked astrogliosis in von Economo's and postencephalitic Parkinson's diseases in areas "distant" from the primary lesions seeming to indicate extensive pathological involvement, added to the strong qualitative and quantitative similarity of this reaction to that observed in concurrently studied cases of encephalitides caused by the human immunodeficiency virus, lend further factual support to the hypothesis of a viral etiology, albeit unspecified, in both von Economo's and postencephalitic Parkinson's diseases.

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.