Relationship between scalp high-frequency oscillations and time since the last seizure in epilepsy

Objective: The accuracy of self-reported seizure-freedom duration are essentially limited. Scalp high-frequency oscillations (HFOs) are more tightly linked to seizures than spikes alone and are a promising new biomarker. The purpose of this study is to determine the relationship between scalp HFO and time since the last reported seizure. Methods: The study population consisted of 169 pediatric epilepsy patients (91 males; age range, 0–20 years). A holdout method was used to develop and validate a predictive model (multivariate HFO model) to estimate the time since the last reported seizure. Results: The multivariate HFO model was created with four variables: scalp HFO detection rate, developmental delay, epilepsy duration, and the use of antiepileptic drugs. The area under the curve (AUC) of the multivariate HFO model was higher than that for the HFO and spike models in all four discriminations for time since the last reported seizure (≥ 2 years: AUC = 0.95, ≥ 1 year: 0.91, ≥ 2 months: 0.82, and ≥ 2 weeks: 0.76). Conclusions: The multivariate HFO model showed higher performance in patients with a longer time since the last reported seizure (≥ 1 year). Significance: This model may help establish a new measure of epilepsy remission.