Neurocognitive Assessment
Within one week prior to their operation and on postoperative day four, all patients were administered a Repeatable Battery Assessment of Neuropsychological Status (RBANS) neuropsychological assessment, which has been shown to detect even mild impairment in cognitive function.4 This assessment comes in two forms, with the questions administered before the operation being different than those administered postoperatively but testing the same areas of cognitive function. These include immediate and delayed memory, language, attention, global cognition, and visuospatial function. Each of these cognitive domains were scored to produce both a raw and scaled score that were collectively added for a total score. The mean raw score is 100 with a standard deviation of 15.6 and is the summation of each cognitive domain. The scaled score is produced in reference to a normative sample of healthy individuals and considers age and gender to produce a score with a mean of 10 and a standard deviation of 3. The forms were administered by individuals who were native English speakers and had been trained by a neuropsychologist. The pre and postoperative tests were administered by the same individual for each patient.