Birgit Frauscher1, Nicolás von Ellenrieder2, François Dubeau3, Jean Gotman4. 1. Montreal Neurological Institute and Hospital, McGill University, 3801 University Street, Montreal H3A 2B4, Quebec, Canada; Department of Medicine and Center for Neuroscience Studies, Queen's University, 18 Stuart Street, Kingston K7L 3N6, Ontario, Canada. Electronic address: birgit.frauscher@queensu.ca. 2. Montreal Neurological Institute and Hospital, McGill University, 3801 University Street, Montreal H3A 2B4, Quebec, Canada. Electronic address: nicolas.vonellenrieder@mcgill.ca. 3. Montreal Neurological Institute and Hospital, McGill University, 3801 University Street, Montreal H3A 2B4, Quebec, Canada. Electronic address: francois.dubeau@mcgill.ca. 4. Montreal Neurological Institute and Hospital, McGill University, 3801 University Street, Montreal H3A 2B4, Quebec, Canada. Electronic address: jean.gotman@mcgill.ca.
Abstract
OBJECTIVE: Experimental research demonstrated that distinct underlying mechanisms go along with different seizure-onset patterns on EEG. These different mechanisms may reflect different tissue abnormalities which, we hypothesize, could also be reflected in morphological differences in the interictal epileptic and background EEG activity. METHODS: We searched our database of intracranial EEG recordings for mesiotemporal lobe epilepsy patients with either predominant low-voltage fast activity (LVF) or periodic spiking (PS). Interictal epileptiform discharges (IEDs) were characterized by the spike/polyspike amplitude, the amplitude of the post-spike slow wave, and the associated low-frequency and high-frequency power increases. The EEG background was assessed with the root mean square amplitude, the distribution of the instantaneous amplitude relative to the root mean square value, and the power spectral density. RESULTS: We identified 18 patients with predominant LVF or PS. IEDs in PS were 1.7-times sharper as determined by the high-frequency power increase than IEDs in LVF. In contrast, IEDs in LVF had a 1.2-times higher post-spike slow wave amplitude, and a 1.5-times larger low-frequency power content than IEDs in PS. There was no difference in rates of IEDs/HFOs, spike amplitude, HFO co-occurrence, and EEG background. CONCLUSIONS: We demonstrated an association between the morphology of IEDs and the type of the seizure-onset pattern in mesiotemporal lobe epilepsy. SIGNIFICANCE: Our findings therefore suggest that IED morphology is a marker of the underlying mechanisms of seizure generation.
OBJECTIVE: Experimental research demonstrated that distinct underlying mechanisms go along with different seizure-onset patterns on EEG. These different mechanisms may reflect different tissue abnormalities which, we hypothesize, could also be reflected in morphological differences in the interictal epileptic and background EEG activity. METHODS: We searched our database of intracranial EEG recordings for mesiotemporal lobe epilepsypatients with either predominant low-voltage fast activity (LVF) or periodic spiking (PS). Interictal epileptiform discharges (IEDs) were characterized by the spike/polyspike amplitude, the amplitude of the post-spike slow wave, and the associated low-frequency and high-frequency power increases. The EEG background was assessed with the root mean square amplitude, the distribution of the instantaneous amplitude relative to the root mean square value, and the power spectral density. RESULTS: We identified 18 patients with predominant LVF or PS. IEDs in PS were 1.7-times sharper as determined by the high-frequency power increase than IEDs in LVF. In contrast, IEDs in LVF had a 1.2-times higher post-spike slow wave amplitude, and a 1.5-times larger low-frequency power content than IEDs in PS. There was no difference in rates of IEDs/HFOs, spike amplitude, HFO co-occurrence, and EEG background. CONCLUSIONS: We demonstrated an association between the morphology of IEDs and the type of the seizure-onset pattern in mesiotemporal lobe epilepsy. SIGNIFICANCE: Our findings therefore suggest that IED morphology is a marker of the underlying mechanisms of seizure generation.
Authors: Pariya Salami; Noam Peled; Jessica K Nadalin; Louis-Emmanuel Martinet; Mark A Kramer; Jong W Lee; Sydney S Cash Journal: Clin Neurophysiol Date: 2020-05-29 Impact factor: 3.708
Authors: Daniel J L L Pinheiro; Leandro F Oliveira; Isis N O Souza; João A Ferres Brogin; Douglas D Bueno; Iranaia Assunção Miranda; Andrea T Da Poian; Sergio T Ferreira; Claudia P Figueiredo; Julia R Clarke; Esper A Cavalheiro; Jean Faber Journal: Sci Rep Date: 2020-04-21 Impact factor: 4.379