1. A method, comprising: sensing a time of beat sequence of a patient's heart; processing said time of beat sequence with a medical device to identify a change in heart rate of a patient from a first heart rate to a second heart rate; determining with the medical device at least one of a) a ratio of the second heart rate to the first heart rate and b) a difference between the second heart rate and the first heart rate; determining with the medical device at least one of a) a dynamic ratio threshold for the ratio and b) a dynamic difference threshold for the difference, wherein the at least one threshold is based upon the first heart rate; comparing at least one of a) the ratio to the dynamic ratio threshold and b) the difference to the dynamic difference threshold; and detecting a neurologic event when at least one of a) the ratio exceeds the dynamic ratio threshold and b) the difference exceeds the dynamic difference threshold.