Amnesic syndromes after surgery of anterior communicating artery aneurysms.

Five patients had severe generalized disorder of memory, which lasted for several months after anterior communicating artery aneurysm surgery. Two of them had no signs of frontal lobe lesions. They were confused for not more than four days after surgery. One of them performed normally on the non-memory tests and short-term memory tests. Cues did not substantially improve his poor memory performance. The other patient had similar test results, but he had poor imagination in an inkblot perception test. Three patients had frontal lobe lesions. Two of them were restless, confused and confabulating, with one showing apathetic and stereotyped behaviour for more than a month after surgery. On the memory tests they showed disinhibition of irrelevant associations or deficient initiative. Cueing markedly improved their poor retrieval. These defects seem to be associated with frontal lobe lesions and can affect memory but are not obligatory features of amnesia.