Focal prefrontal seizures induced by bilateral ECT

Introduction: It has been proposed that the greater efficacy of bilateral ( BL) over right unilateral (RUL) electroconvulsive therapy (ECT) at low stim ulus intensity is due to differences in site of seizure initiation. We hypo thesized that focal prefrontal seizures are more common with BL than RUL ad ministration. Method: Records were reviewed of the 1,007 ECT treatments of 84 consecutive patients randomized to RUL or BL electrode placement. Result s: Eight events were identified in which there was an electroencephalograph ic seizure without motor manifestation. All of these events occurred at tit ration sessions and with BL stimuli (p = 0.002). These events were more lik ely to occur later in the course of treatment. Discussion: We suggest that BL ECT may induce focal seizures in prefrontal areas and that these seizure s are more likely to occur later in the treatment course.