Abstracts

Rationale: Vagus nerve stimulation and callosal section are the available palliative surgical options in patients with secondary generalized epilepsy. DBS has been increasingly used in the treatment of refractory epilepsy over the last decade. We report on the outcome after CM-DBS in patients with generalized epilepsy who had been previously treated with extended callosal section. Methods: Six consecutive patients with generalized epilepsy who were previously submitted to callosal section and had at least 1 year of follow-up after deep brain implantation were studied. Age ranged from 10 to 44 years. All patients were submitted to bilateral CM thalamic DBS. Post-operative CT scans documented the electrode position in all patients. All patients had pre- and post-stimulation prolonged interictal scalp EEG recordings, including spike counts. Attention level was evaluated by means of the SNAP-IV questionnaire. The pre-implantation anti-epileptic drug regimen was maintained post-operatively in all patients. Continuous stimulation was carried out using 300usec, 130Hz, 4-6V pulses. Results: Post-operative CT documented that all electrodes were correctly located. There was no morbidity or mortality. Seizure frequency reduction ranging from 55 to 95% and increased attention level was seen in all patients. Interictal spiking frequency was reduced from 25 to 95%, but their morphology remained the same. There was re-synchronization of interictal discharges during slow-wave sleep in 3 patients. Conclusions: All patients benefit from the procedure. The CM seems to play a role in modulating the epileptic discharges and attention in these patients. On the other hand, it is not the generator of the epileptic abnormality and appeared not to be involved in non-REM sleep-related interictal spiking modulation.