Association of Interictal Epileptiform Discharges with Treatment Change in Juvenile Absence Epilepsy
Abstract number :
1.26
Submission category :
3. Neurophysiology / 3C. Other Clinical EEG
Year :
2024
Submission ID :
1146
Source :
www.aesnet.org
Presentation date :
12/7/2024 12:00:00 AM
Published date :
Authors :
Presenting Author: Peter Hingston, MD – St Vincent's Hospital Melbourne
Anita Dharan, MPsych, PhD Candidate – The University of Melbourne
Sara Vogrin, PhD – St Vincent's Hospital Melbourne
Ewan Nurse, PhD – Seer Medical
Udaya Seneviratne, MD – St. Vincent's Hospital
Wendyl D'Souza, MBChB, MPH, FRACP, PhD – St Vincent's Hospital Melbourne
Rationale: There is limited longitudinal data on the association of interictal epileptiform discharges (IEDs) and the effect of treatment with anti-seizure medications (ASM). This study aimed to investigate this relationship in idiopathic generalised epilepsy (IGE), particularly absence epilepsy (Juvenile Absence Epilepsy - JAE, Childhood Absence Epilepsy - CAE) using serial ambulatory 24-hours EEG recordings (aEEG) during ASM intervention.
Methods: Using three serial 24-hour aEEGs recordings during ASM add-on, we prospectively measured IED burden and patient-reported seizure frequency extracted by medical record review at each serial EEG time-point. Measurement of IED burden was estimated with an automated IED detection algorithm1 subsequently confirmed by two independent reviewers, with adjudication by a third reviewer when discordant. IED burden included: 24-hour cumulative IED duration; maximum, mean and median IED duration; IED duration greater than 3 seconds; IED duration greater than 10 seconds; and relationship to daytime versus nocturnal IED frequency.
Results: 20 patients (14 JAE, 1 CAE and 5 IGE with generalised tonic-clonic seizures alone) had 3 serial aEEGs capturing a total of 17,331 IEDs. At baseline the most common ASMs were 85% sodium valproate (VPA, 30% monotherapy), 35% lamotrigine (LTG, 0% monotherapy), with 30% VPA-LTG in polytherapy. At final aEEG the most common ASM add-on was LTG (35% to 65%), in polytherapy with VPA (30% to 60%) with add-on zonisamide (10% to 45%), perampanel (0% to 15%) and add-on VPA (85% to 95%).
Seizure frequency: Reduced seizure frequency at second EEG was associated with: 92% reduction in cumulative IED duration (p=< 0.001), 98% reduction in maximum IED length (p=< 0.001), and 92% reduction in IED frequency (p=< 0.001). This association between reduced seizure frequency and IEDs was also observed between the second and final aEEG but was not statistically significant. Where seizure frequency was unchanged between aEEGs, there was no associated IED change between recordings.
Treatment: ASM addition or dose increase prior to second aEEG was associated with a 7% reduction in IEDs >3 seconds (p=0.008), 62% reduction in cumulative IED duration (p=0.023), 57% reduction in IED frequency (p=0.048), along with reduced IED frequency and mean IED duration during sleep. Addition prior to third aEEG was associated with a 6% reduction in IEDs >3 seconds (p=0.036). Where ASM was unchanged between aEEGs there was no change in IED measures.
Conclusions: The addition of ASM treatment, particularly VPA-LTG combination in JAE is associated with a reduction in longitudinal IED burden. Although the wider clinical and comorbid significance remains uncertain, IED burden represents a useful objective biomarker for ASM trials in absence epilepsy.
1. Clarke S, Karoly PJ, Nurse E, et al. Computer-assisted EEG diagnostic review for idiopathic generalized epilepsy. Epilepsy Behav. 2021;121(Pt B):106556. doi:10.1016/j.yebeh.2019.106556
Funding: None
Neurophysiology