Objective measure of treatment outcome in epilepsy.

Treatment outcome in epilepsy is too often a vague, ill-defined subjective measure. Based on a proposal of Shoffer and Temkin (1987) of "time to kth seizure" as a measure of seizure frequency, we devised the formula: % improvement = 100 - [time to X seizure (i*) x 100]/ [time to X seizure (f*)]. This formula provides an objective measure of treatment outcome and should prove useful in clinical settings and research. We offer examples of practical applications of the formula.