Purpose: In a double-blind crossover study with lamotrigine (LTG), we investigated a possible relationship between the clinical responses and changes of the amount of epileptiform activity in EEG.
Methods: Twelve patients, aged 4-21 years, with generalized drug-resistant epilepsy who had responded to LTG, completed the study. Twenty-four-hour video-EEGs were taken during control, placebo, and drug phases. The amounts of epileptiform discharges were estimated and compared with the clinical effects.
Results: The duration of periods of repeated epileptiform discharges was significantly reduced during the LTG phase compared with the placebo phase (n = 12, p = 0.04). Ten patients showed a reduction of the amount of epileptiform discharges in the LTG phase by a mean of 81% (range, 17-100%). Periods of repeated epileptiform discharges with duration longer than 30 s were significantly reduced in length (p = 0.03) and number (p = 0.04) during the LTG phase compared with the placebo phase. Shorter periods of epileptiform discharges and the numbers of single epileptiform discharges were not affected. In five patients there was a seizure reduction (>/=50%) concomitant with the reduction of epileptiform discharges in the EEG. The behavior improved during LTG treatment in all patients. The patients became more alert, and their concentration and performance improved, according to their parents and the medical personnel.
Conclusions: LTG in dosages of 1-8 mg/kg body weight was found to depress relatively long episodes of interictal, repetitive, epileptiform activity in young patients with drug-resistant epilepsy, whereas short episodes were not affected. It depressed seizures in about half of the patients studied but gave improvements of behavior in all patients.