Before revision:  We modified ApEn and SampEn by redefining the distance function used originally in their definitions. We then evaluated the new entropy measures, called range entropies (RangeEn) using different random processes and nonlinear deterministic signals. We further applied the proposed entropies to normal and epileptic electroencephalographic (EEG) signals under different states. Our results suggest that, unlike ApEn and SampEn , RangeEnmeasures are robust to stationary and nonstationary signal amplitude variations and that their trajectories in the tolerance r-plane are constrained between 0 (maximum entropy) and 1 (minimum entropy)  .
After revision:  We modified ApEn and SampEn are related to the Hurst exponent through their tolerance and embedding dimension parameters. We then propose a modification to ApEn and SampEn , RangeEnmeasures are robust to stationary and nonstationary signal amplitude variations and that their trajectories in the tolerance r-plane are constrained between 0 (maximum entropy) and 1 (minimum entropy) .