Seizure outcomes after cortical stimulation-induced seizures: A systematic review and meta-analysis

Objective: To perform a systematic review and meta-analysis to evaluate the association between stimulation-induced seizures and favorable surgical outcomes in drug-resistant epilepsy patients. Methods: A search was conducted using PubMed, Cochrane and Embase databases to identify relevant studies. The prevalence of stimulation-induced seizures and the association between them and favorable surgical outcomes were assessed using a random effects model. A narrative review was also performed. If a patient achieved either Engel I or ILAE class 1 or 2 they were considered to have had a favorable surgical outcome. A minimum of 12 months of follow-up time was required. Results: Only three studies met criteria to be included in the meta-analysis and over half the patients came from a single study. The pooled prevalence of stimulation-induced seizures was 59.2% (95% CI, 41.5–74.9). There was a trend towards a significant association between stimulation-induced seizures and favorable surgical outcomes in patients who received resection irrespective of stimulation settings, but it did not reach statistical significance (RR: 1.76, 95% CI 0.96–3.23). The narrative review suggested that low frequency stimulation may be less sensitive but more specific compared to high frequency stimulation for producing typical seizures and may be more predictive of surgical outcomes. Conclusions: Stimulation-induced seizures were not statistically associated with surgical outcomes, but our meta-analysis was limited to a small number of studies and pooled results at both high and low frequency stimulation. Low frequency stimulation induced seizures were more consistently associated with favorable surgical outcomes in patients who had resection compared to high frequency stimulation induced seizures.