Dynamics of epileptiform activity, efficacy and tolerability of valproic acid in adults and adolescents with newly-diagnosed epilepsy

Abstract

To evaluate the changes of epileptiform activity index (EAI) as a measure of the efficacy and tolerability of treatment with valproic acid (VA) in patients with newly-diagnosed generalized and focal epilepsy. The study included 93 patients (55 men and 38 women): 27 with focal epilepsy (FE) and 66 with idiopathic generalized epilepsy (IGE). Patients with idiopathic and age-dependent FE were not included in the study. At each visit, video-EEG monitoring with the analysis of focal, diffuse and generalized epileptiform activity during wakefulness before sleep, during sleep, after sleep and during partial awakenings with quantitative EAI assessment at baseline, after 1, 3, 6 and 12 months of therapy was performed. Therapeutic drug monitoring was performed during dose titration 1 month after the start of treatment or in case of treatment change. Treatment efficacy was assessed based on the absence of seizures, decrease of seizure episodes by more than 50% (responders) and <50% (insufficient efficacy). Adverse effects (AE) were assessed using the Assessing SIDe effects in AED treatment scale (SIDAED). Maximal EAI was observed at baseline both in FE and IGE groups. In patients with IGE, the total EAI (52.8±7.8) was significantly higher compared to FE group (27.1±5.5 (p=0,027)). During wakefulness before sleep and during sleep EAI was significantly lower in the IGE group compared to FE patients (3.4±0. vs. 10.5±5.5 (p=0.003) and 4.3±0.8 vs. 8.9±3.7 (p=0.046), respectively). VA demonstrated the high efficacy and good tolerability in IGE and FE patients: after 12 months of treatment remission was achieved in 69 (74.2%) patients, the decrease of seizure frequency by more than 50% was observed in 22 (23,7%) patients, insufficient efficacy only in 2 (2.1%). AEs were registered only sporadically. VA remains one of the drugs of choice in IGE and FE. EAI may become an additional objective test in cases of difficult differential diagnosis in IGE and FE, using total EAI, EAI before sleep, during sleep, during partial awakenings in the first months of treatment (1-3 months). EAI objectively reflects the dynamics of VA treatment efficacy.