PER resulted in some benefit in 40% of those exposed. Adverse effects on mental health and on balance were common and should be discussed with people before initiating PER.

Objective This study was undertaken to determine reasons for adults with drug‐resistant focal epilepsy who undergo presurgical evaluation not proceeding with surgery, and to identify predictors of this course. Methods We retrospectively analyzed data on 617 consecutive individuals evaluated for epilepsy surgery at a tertiary referral center between January 2015 and December 2019. We compared the characteristics of those in whom a decision not to proceed with surgical treatment was made with those who underwent definitive surgery in the same period. Multivariate logistic regression was performed to identify predictors of not proceeding with surgery. Results A decision not to proceed with surgery was reached in 315 (51%) of 617 individuals evaluated. Common reasons for this were an inability to localize the epileptogenic zone (n = 104) and the presence of multifocal epilepsy (n = 74). An individual choice not to proceed with intracranial electroencephalography (icEEG; n = 50) or surgery (n = 39), risk of significant deficit (n = 33), declining noninvasive investigation (n = 12), and coexisting neurological comorbidity (n = 3) accounted for the remainder. Compared to 166 surgically treated patients, those who did not proceed to surgery were more likely to have a learning disability (odds ratio [OR] = 2.35, 95% confidence interval [CI] = 1.07‒5.16), normal magnetic resonance imaging (OR = 4.48, 95% CI = 1.68–11.94), extratemporal epilepsy (OR = 2.93, 95% CI = 1.82‒4.71), bilateral seizure onset zones (OR = 3.05, 95% CI = 1.41‒6.61) and to live in more deprived socioeconomic areas (median deprivation decile = 40%–50% vs. 50%–60%, p < .05). Significance Approximately half of those evaluated for surgical treatment of drug‐resistant focal epilepsy do not proceed to surgery. Early consideration and discussion of the likelihood of surgical suitability or need for icEEG may help direct referral for presurgical evaluation.

Adverse event rates are similar to other series. Epilepsy surgery carries well defined surgical and neurological risks. The risks of somatic adverse events, in addition to neuropsychiatric and neuropsychological complications need to be made clear to individuals considering this treatment option.