Association Between Scalp High-Frequency Oscillations and Burden of Amplitudes and Epileptiform Discharges (BASED) Scores in Infantile Epileptic Spasms Syndrome

Tools for measuring the likelihood of relapse in infantile epileptic spasms syndrome (IESS) treatment could aid clinicians in making critical management decisions. High-frequency oscillations (HFOs), transient bursts of electroencephalography (EEG) activity with frequencies beyond 80 Hz, are a new and promising noninvasive biomarker. The present study aimed to investigate the association between the Burden of Amplitudes and Epileptiform Discharges (BASED) scores, an interictal EEG grading scale for IESS, and scalp HFOs in patients with IESS. The study enrolled 50 patients, 25 with a clinical diagnosis of IESS and 25 without epilepsy. The percentage of patients with at least one scalp HFO detected, stratified by BASED scores, differed significantly: for BASED scores ≤ 2, 7.7%; for 3, 16.7%; for 4, 87.5%; and for 5, 100% (p < 0.001). Compared with BASED scores ≤ 2, the median scalp HFO detection rate was significantly highest for BASED scores of 5 (median [IQR]: 6.24 [2.25-8.32], p < 0.001), followed by BASED scores of 4. The scalp HFO detection rates showed a better performance in estimating patients with BASED scores of 4 and 5. It is hoped that scalp HFOs can be used as an objective indicator to validate the results of BASED scores.