Bilateral Atrophic Lobar Sclerosis following Thrombosis of the Superior Longitudinal Sinus.

IsN the category of atrophic lobar sclerosis it is customary to group a number of degenerative affections of the cerebral cortex having a differing and often obscure pathogenesis but a comparatively uniform morphology. Macroscopically, the cortex in these cases shows a shrinkage of the gyri with a corresponding widening of the intervening sulci. Apart from the changes produced by these distorting factors, the general convolutional patterning of the hemispheres is normal, so that usually it is possible to distinguish by naked-eye inspection this type of abnormality from true microgyria of developmental origin. The name ' ulegyria ' is often used to describe this condition of atrophy of the convolutions. Microscopically, it is apparent that the neurones of the affected gyri have degenerated to a greater or less degree and that an extravagant proliferation of the fibrous neuroglia is present in those areas where neuronal destruction has been most complete. This gliosis tends to vary according to the time of onset of the primary cortical lesion, being densest and most widespread when the disease has started during foetal or infantile life and being less pronounced in the more mature brains.15 In the latter class of case there is evidence both from the clinical and pathological standpoints that a progressive degeneration of the cortex may occur. In this type of progressive cortical atrophy the lesions are essentially laminar in distribution and affect chiefly the third or pyramidal cell-layer. As Hallevorden 8 has pointed out, the similarity of the histopathological findings in cases of lobar sclerosis is no proof of an uniform aetiology. This observation is particularly pertinent when an attempt is being made to evaluate the part played by birth injury in the actiology of a given case. Although the extensive investigations of Schwartz 13 have shown that atrophic sclerosis may follow multiple small intracerebral haemorrhages or softenings, it is clearly unjustifiable to classify all cases of lobar sclerosis with a clinical history of ' difficult labour 'as the result of vascular lesions sustained during birth. Moreover, the precise mechanism by which these haemorrhages are produced is not yet fully understood. According to Schwartz, they 1 3.1