Subarachnoid blood on CT and memory dysfunctions in aneurysmal subarachnoid hemorrhage.

Ninety patients with a previous subarachnoid haemorrhage (SAH) were given a set of memory tests comprising immediate free recall of words (indexing long-term memory, LTM, and short-term memory, STM), final free recall of words (indexing LTM), final cued recall of words (indexing LTM), and a digit span test (indexing working memory, WM). Patients with a large amount of blood on CT, carried out within 72 h of the bleed, showed LTM as well as STM dysfunction, whereas patients with a small amount of subarachnoid blood evidenced only STM dysfunction. Patients with the ruptured aneurysm located on the anterior cerebral artery, however, constituted an exception with dysfunction of both LTM and STM together with intact WM, independent of the amount of subarachnoid blood. Also, patients with internal carotid artery or middle cerebral artery aneurysms and large volume SAH displayed LTM dysfunction, but differed concerning STM, the former showing intact STM and the latter showing STM dysfunction. Thus, it appears, that the combined information from factors such as the amount of subarachnoid blood and the location of the ruptured aneurysm is of vital importance for explaining the different patterns of memory dysfunctions after SAH.