diaschisis

Diaschisis (from Greek διάσχισις meaning "shocked throughout") is a sudden change of function in a portion of the brain connected to a distant, but damaged, brain area. The site of the originally damaged area and of the diaschisis are connected to each other by neurons. The loss of the damaged structure disrupts the function of the remaining intact systems and causes a physiological imbalance. This can lead both to restitution as well as disruption of distal brain areas. The injury is produced by an acute focal disturbance in an area of the brain, from traumatic brain injury or stroke, for example. Regarding dysfunctional diaschisis, some function may be restored with gradual readjustment of the intact but suppressed areas through intervention and the brain's natural neuroplasticity.

The term diaschisis was coined by Constantin von Monakow in 1914. Von Monakow's concept of neurophysical changes in distant brain tissue to the focal lesion led to a widespread clinical interest. Doctors were interested in how diaschisis could describe the signs and symptoms of brain lesions that could not be explained.