Defining neuropsychological deterioration after cardiac surgery: reply

We thank Bruggemans and colleagues for their comments on our paper on the analysis of individual change on neuropsychological tests after coronary artery bypass graft surgery [1]. We concur that the Reliable Change Index (RCI) we have used to define postsurgical change has two theoretic shortcomings [2]. First, test reliability is not dealt with at both pretest and posttest. Second, by incorporating the mean change score of the control group to correct for practice effects, individual differences in the magnitude of practice effects are obscured. We note that Bruggemans and colleagues [3] have adopted a statistical approach that attempts to overcome these problems. We have at tempted to reanalyze our data using their approach and encountered a number of problems.