Valproate in adolescents with photosensitive epilepsy with generalized tonic-clonic seizures only

To assess the effects of valproate (VPA) on seizure response/control and photosensitivity (PS) in adolescents suffering from photosensitive epilepsy with generalized tonic-clonic seizures only (EGTCS).

We prospectively evaluated 55 adolescents with newly diagnosed EGTCS and PS at presentation, who received VPA monotherapy. Two phases of the study were defined and analysed separately. In the phase I, the electroclinical data of patients were compared over three time points: T1 (at 6 months of treatment); T2 (at 12 months of treatment); and T3 (at 36 months of treatment). In the phase II, only patients who stopped VPA were evaluated over a period of 12 months.

At both T2 and T3 there was a significant great percentage of seizure-free patients compared with that at T1 (78.2% vs 69.1%, p < 0.01; and 85.5% vs 69.1%, p < 0.001) and a similar trend was also noted according to PS-free patients (70.9% vs 52.7%, p < 0.01; 80.0% vs 52.7% p < 0.001). At the end of the phase II, 46.5% and 32.6% out of 43 patients who stopped VPA had seizure relapses and reappearance of PS, respectively. In particular, 78.6% of the 14 patients with PS reappearance presented the same type of EEG response showed at study entry.

VPA monotherapy is very effective for both seizure outcome control and PS reduction in adolescents with EGTCS. Treatment discontinuation induces relapse of seizures and PS in a certain number of patients. PS reappearance presented the same type of EEG response showed before VPA treatment.