[The phenomenon of diaschisis in cerebral vascular disease]

Diaschisis is a physiological phenomenon based on reversible depression of functions anatomically or functionally connected to the damaged area. Its study has become more interesting over the past twenty years, due to the advances made in functional neuroimaging techniques and their possible participation in the recovery of function. Our objective is to review the main types of diaschisis and their clinical contribution.

At present it has mainly been described in cerebrovascular pathology, and been classified according to the connecting fibres involved. When the connecting fibres are intra-hemispheric, the phenomenon of ipsilateral thalamic or subcortical-cortical diaschisis may be seen; when they are interhemispheric, there is transcallosal diaschisis, and if they are cerebellar, the diaschisis is of the contralateral cerebellum or crossed cerebellar diaschisis. Ipsilateral thalamic and crossed cerebellar diaschisis are phenomena which are frequently observed, but have no clinical significance. Regression of the subcortical-cortical and transcallosal diaschisis might explain the neuropsychological and functional neuroimaging changes observed over the first few months after the vascular incident.

Study of the different types of diaschisis should be considered in patients with cerebrovascular disease since it is potentially reversible, and to differentiate it from focalization due to the lesion.