electrodecremental response
A sudden reduction in EEG amplitude and frequency marking seizure onset, distinct from postictal suppression.
Full Definition
An electrodecremental response represents an abrupt decrease in both amplitude and frequency of background EEG activity that characteristically occurs at the onset of certain seizure types, particularly focal seizures arising from the temporal lobe. This pattern differs from postictal suppression in that it occurs at seizure initiation rather than termination. The response reflects widespread cortical inhibition and is often followed by rhythmic epileptiform activity. Recognition of this pattern is crucial for accurate seizure localization in presurgical evaluation.
Usage
Usage note: Often confused with postictal suppression, but occurs at seizure onset, not termination.
In Context
- "The electrodecremental response at seizure onset suggested mesial temporal origin." — EEG report
- "Clear electrodecremental response preceded the rhythmic theta activity." — Clinical neurophysiology consultation