Deep brain stimulation as an adjunctive in drug resistant therapy: Analysis of success rate and possible predictors of response in a monocentric Swiss patient cohort

Abstract-Text (inklusive Referenzen und Bildunterschriften)

Background: Deep brain stimulation deep brain stimulation (DBS) of the anterior nucleus of the thalamus has recently emerged as an adjunctive therapy for patients suffering from drug-resistant focal epilepsies. Yet the reported success rates varies widely in different studies (Li M; Cook M; Epilepsia 2018;59(2):273-290). In addition, the individual response to this treatment option is hard to predict. Therefore, the question remains which clinical parameters predict a good therapeutic response and accordingly which patients are best suited for this treatment option.

Material and Methods: We included 13 patients with drug resistant focal epilepsy in this retrospective monocentric study, who had undergone DBS between 2011 and 2020 at the University Hospital Zurich. Based on a structured follow-up 6 and 12 months after DBS, seizure frequency and seizure types and severity, side-effects of DBS, pharmacotherapy were documented and compared to the situation during the last three months before DBS as baseline condition. We correlated these clinical parameters as well as stimulation parameters with the response to DBS.

Results: DBS resulted in a significant improvement of seizure frequency in seven (54%) out of 13 patients (ILAE outcome score 1-4), with two of these patients (15%) even becoming temporarily seizure free. The responder and non-responder-group did not differ significantly with respect to age, sex, seizure type, frequency and medication. However, there was a tendency towards early-onset epilepsies and frontal epilepsies responding less to DBS- treatment. Observed side effects were mostly mood changes (observed in five patients; 38%) but occurred exclusively under high amplitude DBS (above 3V).

Conclusion: In at least half of the patients with drug-resistant epilepsy, DBS proved to be a successful third-line therapy. Our data suggest that DBS might be less effective in patients with frontal lobe epilepsies and in patients with early-onset epilepsies. Further multicenter trials will be needed to identify reliable predictors of patient response to deep brain stimulation.