Diagnostic Significance of Scalp-recorded Direct Current Shifts During Generalized Spike-and-wave Complexes in Idiopathic Generalized Epilepsy
Abstract number :
3.474
Submission category :
3. Neurophysiology / 3C. Other Clinical EEG
Year :
2024
Submission ID :
1386
Source :
www.aesnet.org
Presentation date :
12/9/2024 12:00:00 AM
Published date :
Authors :
Presenting Author: Masako Kinoshita, MD, PhD – National Hospital Organization Utano National Hospital
Ai Demura, BSc – Sakurai Clinic
Hiroya Ohara, MD – Minaminara General Medical Center
Ryota Sasaki, MD, PhD – Nara Medical University
Kentaro Tamura, MD, PhD – National Hospital Organization Nara Medical Center
Rationale: Updated diagnostic criteria for the idiopathic generalized epilepsies (IGE) delineate four syndromes including childhood absence epilepsy, juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), and epilepsy generalized tonic-clonic seizures alone. However, role of EEG to differentiate these syndromes has not been established. Direct current (DC) shifts, EEG components slower than delta waves, are associated with epileptogenic zone in focal epilepsy. Here we investigated diagnostic significance of DC shifts during generalized spike-and-wave complexes (SWC) in adult patients with IGE.
Methods: Four patients with IGE (1 JAE and 3 JME) according to the recent diagnostic criteria (Hirsch et al. 2022), who underwent annual evaluation for more than 6 years, were included. Conventional scalp EEG was recorded for around 30 minutes, using Ag/AgCl electrodes set according to international 10-20 system, with sampling frequency of 500 Hz. In total, 32 EEG records (mean: 8.0 records per patient) were analyzed. All records were reviewed offline under the condition of TC 0.3 sec, 15 sec/screen, and HF 60 in various montages, and SWC were marked. Then the reviewing condition was changed into the average reference montage excluding frontopolar and earlobe electrodes, TC 2.0 sec and HF15. DC shifts were defined as negative slow deflections in < 2Hz frequency with peak-peak amplitude >10 μV and better recognized with TC 2.0 sec than 0.3 sec.
Results: 170 DC shifts were found (duration 1.0 ± 0.5 sec, amplitude 65.6 ± 30.9 μV). DC shifts were maximum in frontopolar electrodes whereas spike peak of SWC maximized in frontal electrodes. Amplitude and duration of DC shifts showed significant positive linear correlation (r=0.54). Slope of regression line was significantly steeper in JAE than JME (p< 0.05).
Neurophysiology