Neuropsychological and neurophysiological evaluation after anterior communicating artery (ACoA) aneurysm surgery

Background. We evaluated high cerebral functions 6 months after surgery for bleeding ACoA aneurysms comparing neurophysiological and neuropsycological tests. Methods. Twelve patients were chosen among a series of cases operated on in the first 48 hours after ACoA aneurysm bleeding. All of them were in Hunt-Hess grade I or II. We excluded patients over 65 years, or with intracranial haematomas, intraventricular haemorrhage, hydrocephalus, or with multiple or giant aneurysms. All of them underwent neurophysiological evaluation with recording and mapping of long latency (P300) auditory and visual event-related potentials (ERPs) and a neuropsycological assessment for memory, intelligence, frontal lobe functions and language. Results. Neuropsychological assessment: All patients were severely damaged on phonemic fluency. In a first group (group A: 3 cases) tests were all in a normal range. In a second (group B: 3 cases) the tests showed severe impairment on learning and long term memory. In a third (group C: 6 cases) tests showed memory and 'frontal lobe' deficits. Neurophysiological assessment: The whole group of patients showed significant delay in ERPs recordings compared to controls. ERPs of patients in group A and B showed no significant differences from controls, while being significantly delayed in 5 patients out of 6 of group C. Conclusions. All patients had difficulties in the phonemic task in which a notable cognitive effort is necessary, while intelligence, short term memory, attention and language were within normal limits. Patients in group C showed severe frontal lobe type cognitive impairment. Those ones in groups A and B did not present cognitive derangements (A) or only memory and learning impairment (B). ERPs may be an objective parameter in the follow-up of cases with cognitive impairment, even if neurophysiological tests cannot be replaced.