interictal spike
Brief epileptiform discharges recorded between seizures on EEG, serving as markers of epileptic brain tissue.
Full Definition
Interictal spikes are transient, sharp electrical discharges recorded on electroencephalography (EEG) that occur between seizures (interictal period) in patients with epilepsy. These spikes typically last 20-200 milliseconds and represent synchronized depolarization of large populations of neurons. They are considered biomarkers of epileptogenic tissue and help clinicians localize seizure foci. Interictal spikes can be recorded from scalp EEG, intracranial electrodes, or depth electrodes. Their frequency, morphology, and distribution provide important information for epilepsy diagnosis and surgical planning.
Usage
Usage note: Distinguish from ictal (during seizure) activity.
In Context
- "The patient showed frequent interictal spikes in the left temporal region on overnight EEG monitoring." — Clinical EEG report
- "Surgical resection was planned based on the distribution of interictal spikes recorded from depth electrodes." — Epilepsy surgery report