Periodic focal epileptiform discharges

Area of Science:

• Neurosurgery
• Neurophysiology
• Epileptology

Background:

• Awake craniotomy is a neurosurgical procedure requiring precise brain mapping.
• Intracranial electroencephalography (EEG) is crucial for monitoring brain activity during surgery.
• Periodic focal epileptiform discharges (PFEDs) are a type of abnormal brain activity.

Purpose of the Study:

• To report the occurrence and characteristics of intraoperative PFEDs during awake craniotomy.
• To evaluate the utility of high-density electrocorticography (HD-ECoG) in detecting these discharges.
• To compare HD-ECoG findings with standard scalp EEG.

Main Methods:

• Retrospective analysis of 81 patients undergoing awake craniotomy.
• Intraoperative HD-ECoG with direct electrocortical stimulation (DECS) for functional mapping.
• Assessment of PFEDs, perioperative seizures, and surgical complications.

Main Results:

• PFEDs were identified in 15.9% of patients (11/69) during awake surgery.
• HD-ECoG detected significantly more epileptiform discharges (EDs) than standard EEG (74.4% vs 28.1%).
• PFEDs were novel, highly focal discharges, often approximating a single gyrus.

Conclusions:

• Intraoperative PFEDs are distinct, focal events observed during awake craniotomy.
• HD-ECoG enhances the detection of epileptiform discharges compared to scalp EEG.
• PFEDs contribute to understanding the interictal-ictal continuum in epilepsy.