Sporadic epileptiform discharge morphology

Criteria & assessment

• Spike: pointed transient distinct from background, duration >=20 ms and <70 ms at EEG baseline.
• Sharp wave: same definition, duration >=70 ms and <=200 ms (source states 70–200 ms).
• Polyspike: >=2 consecutive spikes with no interdischarge interval, total duration <0.5 s.
• Typical, not required: diphasic/triphasic, apiculate, asymmetric slope, followed by slow wave or other background disruption.