Verbal memory function after subarachnoid haemorrhage determined by the localisation of the ruptured aneurysm.

Abstract

A total of 219 patients who had suffered from subarachnoid haemorrhage (SAH) were given a set of memory tests. The tests comprised immediate free recall (indexing long-term memory, LTM, and short-term memory, STM), final free recall (LTM) and final cued recall (LTM) of words as well as a digit-span test (an index of working memory, WM). STM was highly sensitive to brain damage caused by SAH whereas WM was not. Localisation of the ruptured aneurysm, angiographic vasospasm or mass effect did not have any selective influence on the SAH group's STM or WM. The final free recall test was the most sensitive measure of LTM whereas the LTM part of the immediate free recall test was the least sensitive. LTM impairment was most pronounced for patients with ruptured left anterior communicating artery aneurysms or for patients with angiographic vasospasm or mass effect. It is suggested that, in the SAH patients, a passive phonological short-term store is impaired, but the active maintenance rehearsal mechanism is intact. For patients with LTM dysfunction, deeper, more elaborate, active processing is disrupted, hindering efficient long-term storage.