Progressive Subcortical Vascular Encephalopathy of the Binswanger Type (PSVE)

Abstract

Histopathological diffuse pallor of the cerebral white matter on myelin staining is a characteristic feature of progressive subcortical vascular encephalopathy of the Binswanger type (PSVE). However, the reason for the diffuse pallor was unclear. In a previous electron microscopic study the author reported that the number of nerve fibers per unit area of the frontal white matter was significantly less in PSVE than in the controls. The white matter pallor in PSVE is mainly related to the loss of nerve fibers there. Dementia in PSVE is probably related to the loss of nerve fibers in the cerebral white matter. The sum of the number of oligodendrocytes and astrocytes in the deep white matter in PSVE was approximately half of that in age-matched controls. The number of oligodendrocytes, which were defined as cells with small, round and solid nuclei, also decreased in PSVE being half of that in the deep white matter of the controls. These data suggest that the loss of oligodendrocytes and astrocytes plays a role in the process of nerve fibers loss in PSVE. Diffuse atherosclerotic lesions in the main stem of cerebral arteries and severe hyalinotic changes in the white matter arterioles are characteristic arterial lesions of PSVE. On the basis of severe arteriosclerosis in the cerebral arteries, it was speculated that repeated hypotension or greater variability of casual blood pressure could induce PSVE in the elderly hypertensives. To confirm the hypothesis, casual blood pressure in PSVE was retrospectively studied. During the last 7 years prior to death, neither the annual variability nor the annual mean value of systolic or of mean arterial blood pressure in PSVE was different from that in cases of atherothrombotic cerebral infarction or of hypertensive cerebral hemorrhage. The retrospective study did not support the hypothesis.