A rhythm is characterized as a repeatable change in a measurement that occurs over time. Rhythms are classified based on the frequency of the rhythm. The rhythmic nature of seizures can be directly determined by analyzing seizure severity throughout a cycle of interest either under normal living conditions or under controlled living conditions. Besides analyzing the rhythmic nature of seizures, investigators can also examine other well-characterized rhythms and compare these rhythms to the seizure rhythm. Most of the equipment used to study rhythmic seizures in humans is the same as would be used to study any seizure response. Determining the rhythmic components of seizure activity has many advantages. If anticonvulsants are provided at the maximal seizure response, then the compounds can have their greatest effectiveness. Finally, the administration of anticonvulsants at specific times of day can reduce the side effects of the anticonvulsants while maintaining their effectiveness in preventing seizures.