Dear Editor,
I reviewed with great interest the multimedia educational material published by Zhao et al. 1 in Epileptic Disorders, which addresses prolonged ictal and post‐ictal central apnea (ICA and PICA). This study makes an excellent contribution, particularly in terms of visualizing respiratory dysfunction in patients with refractory focal epilepsy. However, correlating the 52‐s ICA and 25‐s PICA durations presented in the case with the “sudden unexpected death in epilepsy (SUDEP) risk thresholds” and localization values in the literature would further underscore the significance of this phenomenon.
A recent study by Lacuey et al. 2 based on intracranial EEG data has demonstrated that the ICA is a highly sensitive and specific predictor of mesial temporal seizure onset. The fact that the case presented by Zhao et al. 1 was characterized by left temporal seizures supports this semiological relationship highlighted by Lacuey. 2 On the other hand, Seyal and Bateman 3 have argued that apnea occurs only when discharges spread to the contralateral temporal lobe. Although bilateral tonic–clonic evolution was not observed in Zhao's case, 1 the extreme apnea durations observed suggest that the “contralateral spread” condition is not limited to interhemispheric transmission alone; it may be related to the extent to which the discharge activates pathways descending from limbic networks to the respiratory centers in the brainstem.
From a clinical perspective, the most critical point is that durations of >17 s for ICA and >14 s for PICA have been identified in the literature as independent risk factors for SUDEP. 4 The fact that the durations in the presented case far exceed these critical thresholds underscores the patient's life‐threatening risk. Meletti et al. 5 have demonstrated the anatomical link between persistent PICA and functional and structural abnormalities in autonomic control centers (particularly the insula and amygdala). Exceeding the 14‐s threshold for PICA indicates a reduced ability of brainstem neurons to recover during the postictal period, a finding prospectively confirmed by Ochoa‐Urrea et al. 4
In conclusion, this valuable material presented by Zhao et al. 1 should not only present clinicians with a case study; it should also serve as a reminder of the vital importance of these critical time thresholds (>17 s for ICA and >14 s for PICA), which are well‐established in the literature. In the epilepsy monitoring unit (EMU), relying solely on EEG monitoring is insufficient; routinely evaluating respiratory plethysmography and peripheral oxygen saturation (SpO2) monitoring against these threshold values will be a vital step in personalized SUDEP risk management.
FUNDING INFORMATION
This research did not receive any specific grant from funding agencies in the public, commercial, or not‐for‐profit sectors.
CONFLICT OF INTEREST STATEMENT
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
DATA AVAILABILITY STATEMENT
Data sharing not applicable to this article as no datasets were generated or analysed during the current study.
REFERENCES
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Data Availability Statement
Data sharing not applicable to this article as no datasets were generated or analysed during the current study.