1. Clinical head nodding episodes with or without other types of seizure activity with a frequency of at least 1 per day (7 episodes per week). [The seizures must be frequent enough so that a change/decrease in that frequency is measurable.] Children will be stratified into those with high frequency or observed nodding (with 3 or more episodes daily), and lower frequency events (more than one but fewer than 3 episodes per day reported).