Udaya Seneviratne1, Graham Hepworth2, Mark Cook3, Wendyl D'Souza4. 1. Department of Medicine, St. Vincent's Hospital, The University of Melbourne, Melbourne, Australia; Department of Neuroscience, Monash Medical Centre, Melbourne, Australia. Electronic address: Udaya.Seneviratne@svhm.org.au. 2. Statistical Consulting Centre, The University of Melbourne, Melbourne, Australia. Electronic address: hepworth@unimelb.edu.au. 3. Department of Medicine, St. Vincent's Hospital, The University of Melbourne, Melbourne, Australia. Electronic address: markcook@unimelb.edu.au. 4. Department of Medicine, St. Vincent's Hospital, The University of Melbourne, Melbourne, Australia. Electronic address: wendyl@unimelb.edu.au.
Abstract
OBJECTIVE: Bilateral, symmetric and synchronous generalized epileptiform activity is considered to be the typical electroencephalographic (EEG) abnormality in genetic generalized epilepsy (GGE). We sought to study atypical EEG abnormalities in a systematic way based on 24-h ambulatory EEG recordings. METHODS: The diagnosis of GGE was validated and classified into syndromes according to the International League against Epilepsy criteria. All participants underwent 24-h ambulatory EEG recording. Epileptiform discharges were counted and detailed information was entered into an electronic database. Amplitude asymmetry, focal onset/offset of paroxysms, focal discharges, atypical morphology and generalized paroxysmal fast rhythm were defined as atypical abnormalities. RESULTS: Of the total of 120 patients, 107 had abnormal EEGs, of which 66.4% had at least one atypical epileptiform abnormality on EEG. Atypical morphology was the most frequent abnormality in 93.4% of patients, followed by amplitude asymmetry (28.0%), focal discharges (21.5%), focal onset of paroxysms (13.1%), focal offset of paroxysms (8.2%) and generalized paroxysmal fast rhythm (1.9%). The analysis of individual discharges revealed that 76% of paroxysms were of atypical morphology. Significant associations were found between (a) amplitude asymmetry and state of arousal (p<0.001) as well as seizure-free duration (p 0.013); (b) atypical morphology and state of arousal (p<0.001). CONCLUSION: In GGE, there are both common and rare atypical epileptiform EEG abnormalities that may vary according to the state of arousal and seizure-free duration. SIGNIFICANCE: Awareness of these variations is important to avoid misdiagnosis. Crown
OBJECTIVE: Bilateral, symmetric and synchronous generalized epileptiform activity is considered to be the typical electroencephalographic (EEG) abnormality in genetic generalized epilepsy (GGE). We sought to study atypical EEG abnormalities in a systematic way based on 24-h ambulatory EEG recordings. METHODS: The diagnosis of GGE was validated and classified into syndromes according to the International League against Epilepsy criteria. All participants underwent 24-h ambulatory EEG recording. Epileptiform discharges were counted and detailed information was entered into an electronic database. Amplitude asymmetry, focal onset/offset of paroxysms, focal discharges, atypical morphology and generalized paroxysmal fast rhythm were defined as atypical abnormalities. RESULTS: Of the total of 120 patients, 107 had abnormal EEGs, of which 66.4% had at least one atypical epileptiform abnormality on EEG. Atypical morphology was the most frequent abnormality in 93.4% of patients, followed by amplitude asymmetry (28.0%), focal discharges (21.5%), focal onset of paroxysms (13.1%), focal offset of paroxysms (8.2%) and generalized paroxysmal fast rhythm (1.9%). The analysis of individual discharges revealed that 76% of paroxysms were of atypical morphology. Significant associations were found between (a) amplitude asymmetry and state of arousal (p<0.001) as well as seizure-free duration (p 0.013); (b) atypical morphology and state of arousal (p<0.001). CONCLUSION: In GGE, there are both common and rare atypical epileptiform EEG abnormalities that may vary according to the state of arousal and seizure-free duration. SIGNIFICANCE: Awareness of these variations is important to avoid misdiagnosis. Crown
Authors: Susanne Fauser; Thomas Cloppenborg; Tilman Polster; Ulrich Specht; Friedrich G Woermann; Christian G Bien Journal: Epilepsia Open Date: 2020-03-12