Recovery of brain function after ischaemia.

Experimental evidence has recently suggested that early reperfusion following at least focal cerebral ischaemia is accompanied by a return of function which has apparently been suspended during the ischaemic period. The experimental evidence for this is presented. Clinical correlates of this reversible ischaemia sometimes referred to as "penumbral ischaemia" are well known in relation to aneurysm surgery. Several examples are presented in this paper. It is also clear that less easily documented and verifiable recovery from long-term ischaemia may occur in neurosurgery and in interesting case suggestive of this is presented. It involved a middle cerebral occlusion which occurred during the excision of a large meningioma.