Predictors for cognitive impairment one year after surgery for aneurysmal subarachnoid hemorrhage

OBJECTIVE: To assess predictors for cognitive impairment one year after spontaneous subarachnoid hemorrhage (SAH). Evaluated predictors were the total amount of cisternal blood seen on computed tomography (CT) in the acute phase as measured by the Fisher grade, neurological grade at admission classified according to the Hunt and Hess scale, aneurysm site and patient's age, gender and education level. METHOD: 44 patients were operated by surgical clipping within 72 hours after CT verified aneurysmal SAH. After twelve months the remaining 42 patients were assessed by neuropsychological test, Beck Depression Inventory (BDI), the Glasgow Outcome Scale (GOS) and CT. Multiple regression analysis was conducted where predictor variables were independent factors and a global impairment index calculated for each patient was the dependent factor. RESULTS: The Fisher grade was the only independent predictor for neuropsychological impairment. Most patients had good neurological outcome as measured by the GOS and at the same time suffered from some degree of cognitive impairment at follow-up. Individual analysis of cognitive test scores showed mild to moderate dysfunction across multiple cognitive domains. Most frequent impairments were found in domains of memory, executive function and speed of information processing. Age below 50 years was associated with relatively better outcome. CONCLUSION: The severity of cognitive impairment one year post SAH is predicted by the volume of blood in the subarachnoid space as measured by the Fisher score.