Abstracts

Rationale: Deep brain stimulation using different targets has been used to treat distinct epileptic syndromes. We used hippocampal stimulation to treat temporal lobe epilepsy, thalamic anterior nucleus stimulation to treat fronto-temporal epilepsy and thalamic centro-median nucleus to treat generalized epilepsy. Little is known about long-term effects of DBS on epileptogenesis. We studied patients submitted to chronic DBS in whom there was depletion of the generator battery. Methods: Nine patients with refractory epilepsy who were submitted to at least 3 years of DBS and in whom there was at least 6 months of battery depletion were studied. One was submitted to hippocampal (Hip-DBS)l, 2 to centro-median (CM-DBS) and 6 to anterior nucleus stimulation (AN-DBS). Results: The patient with Hip-DBS was seizure-free and re-started having seizures after battery depletion (1 every 3 months). One patient with CM-DBS remained stable after battery depletion; the other had an increase in seizure frequency (from 4/month to daily seizures). Five patients with AN-DBS worsen after battery depletion: 2 were seizure-free and re-started with seizures (daily in one; doubled in frequency in the other); seizure frequency doubled in 1, tripled in one, quadrupled in another. One patient under AN-DBS remained stable after battery depletion. Conclusions: DBS did not show a permanent effect on epileptogenesis in patients with refractory epilepsy. Patients needed continued stimulation to benefit from the seizure frequency reduction induced by DBS.