Executive and memory dysfunctions are among the most frequently reported deficits following a ruptured aneurysm of the anterior communicating artery (ACoA). In order to study the impact of the dysexecutive syndrome on episodic and semantic memory, the data obtained from 59 ACoA patients were examined retrospectively. All patients were assessed on a variety of episodic memory tests (Rey Auditory-Verbal Learning Test, Rey Complex Figure Test, Weschler Memory Scale), semantic memory (verbal fluency), and standardized tests of executive functions (Trail Making Test, Maze tests, Wisconsin Card Sorting Test). There was a strong positive correlation between executive dysfunction and retrieval difficulties in episodic and semantic memory tasks. Comparisons of subgroups of patients with high and low frontal lobe functioning on delayed recall and recognition revealed a significant group X condition interaction in addition to significant group and condition main effects. ACoAs patients with low frontal lobe functioning were particularly deficient in free recall (immediate and delayed) while recognition was equally well preserved in the two subgroups. Neither subgroup presented with an abnormal forgetting over time suggesting a retrieval deficit rather than a true retention impairment.
The rupture of a cerebral aneurysm is the most frequent cause of subarachnoid hemorrhage. In 30–40% of the cases, the aneurysm is located in the anterior communicating artery (ACoA) (Beeckmans, Vancoillie, & Michiels, 1998). The two lesion sites most frequently observed after a ruptured aneurysm of the ACoA are the frontal lobes and the basal forebrain (DeLuca, 1993; Parkin & Leng, 1993; Parkin, Yeomans, & Bindschaedler, 1994; Van der Linden, Bruyer, Roland, & Schils, 1993). Consequently, memory and executive dysfunctions are the most consistent cognitive deficits encountered after a ruptured aneurysm of the ACoA.
In general, the neuropsychological evaluation of cognitive outcomes after a ruptured aneurysm of the ACoA reveals impairments in planning, set shifting, and verbal fluency. In a maze task, these patients present difficulties in anticipating dead ends and in completing a planned action. In verbal fluency tasks, their output is often reduced, they have difficulties respecting the rules and they show perseverative tendencies. On the Wisconsin Card Sorting Test (WCST), in addition to an abnormal number of perseverative responses, the patients are easily disturbed by irrelevant stimuli and show poor self-correction of their performance. In a study by Thomas-Anterion et al. (1996) these patients show initial adaptation deficits on tasks of serial reaction time and mirror-reading. These observations suggest the presence of a difficulty initiating a task, which disappears when the task becomes automatic.
At the memory level, retrieval is most consistently affected. On serial learning tasks, such as the Rey Auditory-Verbal Learning Test (RAVLT), free recall rapidly reaches a plateau and both retroactive and proactive interference effects may be observed. Delayed recall is often poorer than immediate recall but performance is improved by recognition. However, it is unclear if the patients lose information over time. Some studies (DeLuca & Diamond, 1995; Rousseaux, Godefroy, & Cabaret, 1998) reveal a loss of information among ACoA subjects, while others do not (Diamond, DeLuca, & Kelley, 1997). Finally, studies by Van der Linden and Bruyer (1992) and Palmer and McDonald (2000) have revealed a deficit of prospective memory in patients after a ruptured aneurysm of the ACoA.
This brief review of neuropsychological sequelae after a ruptured aneurysm of the ACoA highlights the fact that most of the memory impairment exhibited by these patients may be a consequence of their dysexecutive syndrome. They showed an information retrieval deficit, interference effects, poor verbal fluency, initial adaptation difficulties on a procedural memory task, and a prospective memory deficit, which may all be linked to executive dysfunctions such as planning, intention, or inhibition impairments. Their ability to adequately retain the information over time remains debatable. The objective of the present study was to directly assess the role of the dysexecutive syndrome often observed following ACoA aneurysm, on various aspects of memory functions, such as encoding, retention over time, and retrieval. To this end, the neuropsychological tests performances of 59 patients with a ruptured aneurysm of the ACoA were retrospectively examined.
