Lobar Sclerosis

LOBAR SCLEROSIS (insular), a partial sclerosis of the brain involving some part of it or an entire hemisphere; it represents a characteristic feature of the initial processes in infantile paralysis and is observed only in exceptional cases in focal changes in the brain in adults. Etiology and pathogenesis: it is assumed that lobar sclerosis is predominantly a secondary atrophically-degenerative process in a limited focal disease of the cortex; the primary process can be inflammatory (encephalitis), vascular (thrombosis, embolism), or degenerative. In the surrounding area of the primary focus, secondary degenerative processes develop, which entail degeneration and consecutive atrophy of the white and gray matter of the cortex, hence the atrophy of the convolutions; such processes can spread to entire lobes. The greater prevalence of cortical degenerations in children is explained by the greater instability of their cortical neuron: those atrophic changes which are barely expressed in adults reach their fullest development in the children's brain. A second condition promoting the development of sclerosis is the special tendency of children's neuroglia to proliferate. At autopsy, macroscopic findings include depression and shriveling of the atrophic convolutions, their brownish coloration, and dense consistency. Microscopically, one observes the disappearance of nerve cells and fibers in the atrophied convolution and the appearance of cells with breakdown products (Abbauprodukte), abundant proliferation of glia; degenerated fibers—association, commissural, and projection fibers—extend from the focus in various directions; the topography of degeneration is determined by the localization of the focus: all fibers whose trophic centers are destroyed degenerate; changes are observed at a considerable distance from the focus in the cortical cells and even in the corresponding cells of the opposite hemisphere. The clinical picture depends on the localization and prevalence of the process; physical and psychological symptoms are observed: various developmental anomalies, phenomena of paresis and paralysis (see Infantile paralysis), disorders of fine coordination, tremor phenomena, decreased strength, changes in reflexes, paresis of the ocular muscles, nystagmus, visual, auditory, and speech disorders; epileptic seizures mostly of the Jacksonian type (though generalized ones also occur). Psychological disorders are mainly in intellectual development: varying degrees of dementia depending on the time of the disease's development and the intensity and prevalence of the process; sometimes a change in character is also observed. The course is stationary, with deterioration mainly of the psyche; in mild cases, some undemanding work is possible. Prophylaxis and therapy pertain to the underlying condition (see Infantile paralysis).