Cerebellar stimulation for seizure control: 17-year study.

Since 1974, 32 seizure patients have undergone chronic cerebellar stimulation (CCS); 27 have been contacted with 9 (7 spastic, 2 epileptic) continuing to use CCS for an average of 14.3 years (10-17 years). 6 (67%) are seizure-free and 3 (33%) have a reduction of seizure frequency. In the last 2 years, 2 other patients with spastic seizures, who were using CCS for 13 years, died of respiratory illness; 1 had been seizure-free and the other had a reduction. Of the remaining 16 patients (12 spastic, 4 epileptic) who did use CCS for an average of 8.3 years (2-14 years) and now have nonfunctioning stimulators, 5 (31%) continue to be seizure-free, 7 (44%) have a reduction and 4 (25%) have no change or a slight increase. Overall, 23 (85%) patients have benefitted from CCS. Stimulation charge densities were 0.9-2.5 microC/cm2/phase delivered at 10-180 pulses/sec to bilateral electrode pads on the superomedial cerebellar cortex. CCS is relatively safe and nonablative, and could be offered for patients with intractable seizures originating from bilateral or extratemporal foci.