Accurate differentiation between physiological and pathological ripples recorded with scalp-EEG. (November 2022)

• Record Type: Journal Article
• Authors: Mooij, Anne H.; Huiskamp, Geertjan J.M.; Aarts, Emmeke; Ferrier, Cyrille H.; Braun, Kees P.J.; Zijlmans, Maeike
• Is Part Of: Clinical neurophysiology. Volume 143(2022)
• Page Start: 172
• Page End: 181
• Publication Date: 2022-11
• Subjects: Surface EEG -- Vertex sharp transients -- Interictal epileptiform discharge -- High-frequency oscillations -- HFOs; (IEDs) Interictal Epileptiform Discharges -- (RMS) Root Mean Square; Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2022.08.014
• Languages: English
• ISSNs: 1388-2457

Abstract

Highlights: Physiological ripples start after co-occurring vertex waves, while pathological ripples start around the start of co-occurring IEDs. Scalp-EEG recorded physiological ripples have longer durations, lower frequencies, and lower amplitudes than pathological ripples. Pathological ripples in EEGs of children with idiopathic epilepsy may differ from ripples in EEGs of children with symptomatic epilepsy. Abstract: Objective: To compare scalp-EEG recorded physiological ripples co-occurring with vertex waves to pathological ripples co-occurring with interictal epileptiform discharges (IEDs). Methods: We marked ripples in sleep EEGs of children. We compared the start of ripples to vertex wave- or IED-start, and duration, frequency, and root mean square (RMS) amplitude of physiological and pathological ripples using multilevel modeling. Ripples were classified as physiological or pathological using linear discriminant analysis. Results: We included 40 children with and without epilepsy. Ripples started (χ 2 (1) = 38.59, p < 0.001) later if they co-occurred with vertex waves (108.2 ms after vertex wave-start) than if they co-occurred with IEDs (4.3 ms after IED-start). Physiological ripples had longer durations (75.7 ms vs 53.0 ms), lower frequencies (98.3 Hz vs 130.6 Hz), and lower RMS amplitudes (0.9 μV vs 1.8 μV, all p < 0.001) than pathological ripples. Ripples could be classified as physiological or pathological with 98 % accuracy. Ripples recorded in children with idiopathic or symptomatic epilepsy seemed to form two subgroups of pathological ripples. Conclusions: Ripples co-occurring with vertex waves or IEDs have different characteristics and can be differentiated as physiological or pathological with high accuracy. Significance: This is the first study that compares physiological and pathological ripples recorded with scalp EEG.