 One of the most widely used procedures for interim analysis of a clinical trial is the spending function approach of Lan and DeMets. This method uses a function of time to specify the rate at which the total Type I error probability is to be spent during the trial so that this quantity does not exceed the desired alpha level. For this study, the spending function corresponding to an OBrien and Fleming boundary will be used. With this method, the rate at which the type I error is spent is a function of the fraction of total information available at the time of the interim analysis i.e., information time. The information time is determined by the type of statistical test employed. For the analysis of seizure rate, the information time is the proportion of the total patients randomized. The table below provides the Z score at each time point required for considering terminating the study early and for final analysis to show statistical significance at the alpha0.05 level: 