A Controlled Clinical Trial of Cathodal DC Polarization in Patients with Refractory Epilepsy


Address correspondence and reprint requests to Dr. F. Fregni at Harvard Center for Noninvasive Brain Stimulation, Harvard Medical School, 330 Brookline Ave., KS 452, Boston, MA 02215, U.S.A. E-mail: ffregni@bidmc.harvard.edu


Summary: Purpose: To study the effects of cathodal DC polarization in patients with refractory epilepsy and malformations of cortical development (MCDs) as indexed by seizure frequency and epileptiform EEG discharges.

Methods: Nineteen patients with MCDs and refractory epilepsy underwent one session of DC polarization (20 min, 1 mA) targeting the epileptogenic focus. The number of epileptiform discharges (EDs) in the EEG and seizures were measured before (baseline), immediately after, and 15 and 30 days after either sham or active DC polarization. Seizure frequency after the treatment was compared with baseline.

Results: Active compared with sham DC polarization was associated with a significant reduction in the number of epileptiform discharges [mean ED reduction of −64.3% (95% CI, −122.5% to −6.0%) for the active treatment group and −5.8% (95% CI, −26.8% to 15.2%) for the sham treatment group]. A trend (p = 0.06) was noted for decrease in seizure frequency after active compared with sham treatment [mean seizure frequency decrease of −44.0% (95% CI, −95.0% to 7.1%) for the active treatment group and −11.1% (95% CI, −22.2% to 44.4%) for the sham treatment group].

Conclusions: This randomized, controlled study shows that cathodal DC polarization does not induce seizures and is well tolerated in patients with refractory epilepsy and MCDs. Furthermore, the results suggest that this technique might have an antiepileptic effect based on clinical and electrophysiological criteria.