Rhythmic and periodic patterns

Much time is spent identifying and classifying rhythmic and periodic patterns (RPPs). Many of these patterns are associated with seizures and can sometimes themselves be considered ictal. RPPs are described by combining a localization descriptor from ‘Main term 1’ and a pattern type descriptor from ‘Main term 2’. These main terms combined provide a framework for a wide variety of patterns and these can be further refined by applying ‘major’ and ‘minor’ modifiers. Major modifiers provide the bulk of description for RPPs, such as how often they occur, how long they last, the typical frequency, or their sharpness. Plus modifiers describe activity superimposed on RPPs that result in them appearing more ‘ictal’. Brief potentially Ictal Rhythmic Discharges represents a group of highly epileptic patterns with a strong association with subsequent seizures.