This is a multi-center, prospective, partially blinded, longitudinal study of the rate of recovery of neuropsychological function after sub-arachnoid hemorrhage (SAH). Patients who have undergone craniotomy for clipping of intra-cranial aneurysms will be studied. Goal of this investigation is to characterize the effects of intra-operative hypothermia and anatomical location of aneurysm on the rate of recovery of neuropsychological function. A secondary goal is to study the relationship between neurological outcome (as determined by GOS) and neuropsychological function. Patients in IHAST are randomized to normothermic (36.5°C) and hypothermic (33°C) groups based on the core body temperature at the time of aneurysm clip application. The patients, neurosurgeons, neurological examiners and study coordinators are blinded to the group assignments. Outcome is assessed (using Glasgow outcome score, NIH Stroke Score (NIHSS), Rankin disability score, Barthel’s Activities of daily living score, Mini Mental State Examination and a 5 test battery of neuropsychological function) 3 months after surgery, which is the end point of IHAST trial. We propose to administer a more comprehensive, 8 -test battery of neuropsychological function, to a subset of English speaking patients enrolled in IHAST, and extend their period of follow up to 15 months. Patients will be recruited for this study, at the time of last visit for IHAST. In consenting patients, an assessment of neuropsychological function will be done at 3, 9 and 15 months after surgery. Neuropsychologists, administering / scoring these tests will be blinded to the group assignment (hypothermia / normothermia) and location of the aneurysm. The effect of hypothermia and location of aneurysm (anterior communicating, anterior cerebral, middle cerebral, posterior communicating and basilar arteries) on performance and rate of change in neuropsychological function will be studied by appropriate statistical analyses.

CFAAST is supported by a grant from the National Institutes of Health.