Intrahippocampal ripple on oscillation (RonO) propagation is proportionally greater in less-irritative non-seizure onset zone tissue than in epileptogenic hippocampus
In 49 patients with hippocampal contacts, intrahippocampal RonO (80-250 Hz) propagation proportion was highest in less-irritative non-SOZ (low interictal epileptiform discharge rate) compared to more-irritative non-SOZ (p<0.05) and SOZ (p<0.001). This suggests RonO propagation may serve as a metric to quantify hippocampal epileptogenicity along a continuous spectrum.
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Intrahippocampal ripple on oscillation (RonO) 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 on oscillation (RonO) 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 stereo-EEG during non-REM sleep.
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 from stereo-EEG data
- ▸Significant propagation pathways are validated against 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 stereo-EEG during non-REM sleep
Recommended Dose
N/A
Limitations & Caveats
Important context when interpreting this evidence:
- ▸Abstract does not report effect sizes or confidence intervals for the propagation differences
- ▸Study uses a preprint (medRxiv) and has not undergone peer review
- ▸The distinction between physiological and pathological RonO remains challenging using signal features alone
Frequently Asked Questions
What are ripples on oscillation (RonO)?▼
RonO are high-frequency oscillations in the 80-250 Hz range that occur on top of slower oscillations, measured in hippocampal EEG.
How was hippocampal epileptogenicity measured?▼
Hippocampi were stratified 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 (FRonO) propagation?▼
No, FRonO (250-600 Hz) propagation proportions did not differ significantly across the hippocampal epileptogenicity spectrum, even though FRonO rates were higher in SOZ.
What is the clinical implication of this finding?▼
RonO propagation may serve as a novel metric to quantify hippocampal epileptogenicity, potentially aiding in surgical planning for epilepsy.
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