Sharp Wave

Transients and bursts are paroxysmal activities that appear and disappear suddenly and are clearly distinguishable from the ongoing and sustained EEG activities. A transient is a single wave consisting of a brief mono-, bi-, or triphasic waveform. Examples of transients are spikes or sharp discharges, which are defined as sharply contoured waves (distinguishable from the background activity) with waveform duration of less than 70ms for spike and 70 to 200ms for sharp waves. The spike discharge has a higher correlation with seizure diagnosis than the sharp discharge. Some sharp discharges show a waveform having a steep declining phase, which are considered to be “spike-equivalent” potentials and have equal clinical significance as spike discharge.