The influence of cognitive reserve on seizure-induced injury

Status epilepticus (SE) is associated with a significant risk of cognitive impairment. While many factors likely determine cognitive outcome following SE, there is evidence that cognitive ability prior to a neurological insult may be an important determinant of outcome. Patients with greater cognitive abilities or so-called cognitive reserve may be less vulnerable to injury than patients with limited cognitive ability. Here we tested the hypothesis that cognitive abilities prior to SE would be predictive of cognitive outcome. Immature rats were tested in the water maze, a test of visual-spatial memory, and divided into fast and slow learners. Animals were then subjected to SE and retested in the water maze 23 days later. Control rats were tested in the same manner but not subjected to SE. SE resulted in marked impairment in water maze performance. However, no statistical difference was noted in performance between slow and fast learners in either the SE or control group. Likewise, no differences were seen in the histopathology of the slow and fast learners. This study demonstrates that SE adversely effects visual-spatial memory equally in both fast and slow learners and does not support the theory that cerebral reserve plays a major role in cognitive function following a cerebral insult.