Biomarkers for SUDEP: Are We There Yet?

Area of Science:

• Neurology
• Epileptology
• Critical Care Medicine

Background:

• Sudden unexpected death in epilepsy (SUDEP) is a major concern in epilepsy management.
• Understanding peri-ictal events, such as apnea and hypoxemia, is crucial for identifying SUDEP risk factors.
• Generalized convulsive seizures (GCS) are associated with significant autonomic and respiratory disturbances.

Purpose of the Study:

• To characterize postconvulsive central apnea (PCCA) and its association with SUDEP.
• To investigate risk factors for postictal hypoxemia following GCS.
• To evaluate the effect of early oxygen therapy on postictal oxygen saturation levels.

Main Methods:

• Prospective, multicenter epilepsy monitoring study analyzing video-EEG, respiratory, and ECG data in patients with intractable epilepsy.
• Retrospective analysis of video-EEG and pulse oximetry data in patients experiencing GCS.
• Cox proportional hazards models were used to identify factors associated with SpO2 recovery.

Main Results:

• Postconvulsive central apnea (PCCA) occurred in 22.1% of GCS and was observed in near-SUDEP and probable SUDEP cases.
• Ictal central apnea (ICA) preceded GCS in 40.4% of seizures, exclusively in focal epilepsy.
• Postictal hypoxemia was observed in 86% of GCS; early oxygen administration reduced severe hypoxemia and improved recovery.
• Extratemporal lobe epilepsy, absence of postictal generalized EEG suppression (PGES), and early oxygen were associated with faster SpO2 recovery.

Conclusions:

• Postconvulsive central apnea (PCCA) may serve as a clinical biomarker for SUDEP.
• Postictal hypoxemia is nearly universal after GCS, but its severity can be mitigated by early oxygen administration.
• Factors influencing hypoxemia severity include epilepsy type, PGES, and timing of oxygen therapy.