Lack of significant correlation between circadian profiles of valproic acid serum levels and epileptiform electroencephalographic activity.

Using mobile long-term electroencephalographic (EEG) monitoring in 7 absence epilepsy patients, the course of spike-wave discharge rate before and during valproate monotherapy was measured and compared to the profile of valproic acid serum level. Correlation analysis was done, taking into account an eventual time delay between drug concentration and effect on EEG. No significant correlation was found when comparing serum levels with the actual discharge profile or with the profile of changes in discharge rate.