Intrahippocampal ripple propagation is proportionally greater in less-irritative non-seizure onset zone tissue than in epileptogenic hippocampus.
In a study of 49 patients with hippocampal contacts, intrahippocampal propagation of ripples on oscillations (RonO, 80-250 Hz) was highest in less-irritative non-SOZ tissue (less than 6 IED/min) compared to more-irritative non-SOZ (p<0.05) and seizure onset zone (p<0.001). This suggests RonO propagation may serve as a metric for hippocampal epileptogenicity along a continuous spectrum.
This article is automatically generated from the structured evidence profile behind the claim above. Scores reflect the quality and quantity of available research, not clinical advice.
Intrahippocampal ripple propagation is proportionally greater in less-irritative non-seizure onset zone tissue than in epileptogenic hippocampus. The current body of evidence comprises 1 study. EvidenceHub rates the overall confidence at 34/100 (low).
The Claim
Intrahippocampal ripple propagation is proportionally greater in less-irritative non-seizure onset zone tissue than in epileptogenic hippocampus.
This conclusion is most relevant to: 49 patients (68 hemispheres) with verified hippocampal contacts undergoing non-REM sleep stereo-EEG..
What the Research Shows
The conclusion draws on 1 linked study. Highlights from the cited literature:
- ▸Epileptogenicity alters intrahippocampal ripple propagation. (medRxiv : the preprint server for health sciences, 2026) —
How It Works
The proposed biological pathway:
- ▸Hippocampal tissue is stratified by epileptogenicity based on IED rate and seizure onset.
- ▸Empirical temporal networks of HFO propagation are constructed with 150 ms maximum latency.
- ▸Significant propagation pathways are validated against 1,000 permutation-generated surrogates.
- ▸Intrahippocampal RonO propagation proportion is highest in less-irritative non-SOZ tissue, indicating a continuous physiological-to-pathological spectrum.
Who Might Benefit
Evidence fit by population:
- ▸49 patients (68 hemispheres) with verified hippocampal contacts undergoing non-REM sleep stereo-EEG.
Recommended Dose
N/A
Limitations & Caveats
Important context when interpreting this evidence:
- ▸The study is based on a preprint and has not undergone peer review.
- ▸Distinguishing physiological from pathological RonO using signal features alone remains challenging, limiting clinical applicability.
Frequently Asked Questions
What are ripples on oscillations (RonO)?▼
RonO are high-frequency oscillations in the 80-250 Hz range that occur on top of slower brain oscillations, often studied in the context of epilepsy and memory.
How was hippocampal epileptogenicity measured in this study?▼
Hippocampi were stratified by excitability into three groups: seizure onset zone (SOZ), more-irritative non-SOZ (>6 interictal epileptiform discharges per minute), and less-irritative non-SOZ (<6 IED/min).
Did the study find differences in fast ripple propagation?▼
No, propagation proportions for fast ripples on oscillations (FRonO, 250-600 Hz) did not differ significantly across the hippocampal epileptogenicity spectrum, even though their rates were higher in SOZ.
What is the clinical implication of this finding?▼
Intrahippocampal RonO propagation may serve as a novel metric to quantify hippocampal epileptogenicity, potentially aiding in surgical planning for epilepsy patients.
References
- 1.Chen Y, Ye H, Ye L, Hu L, Chen C, Staba R, Wang S, Weiss SA. “Epileptogenicity alters intrahippocampal ripple propagation..” medRxiv : the preprint server for health sciences, 2026. PMID: 42369499 DOI: 10.64898/2026.06.13.26355594