Preliminary evaluation of cerebellar stimulation by double-blind stimulation and biological criteria in the treatment of epilepsy

✓ This series included five patients who had suffered 8 to 23 years of severe, medically intractable seizures without remission, severe socioeconomic handicaps, and an average of over one seizure a day on hospital observation and by history. All had combinations of partial and general seizures with focal and/or bilaterally synchronous epileptiform activity consistently on multiple electroencephalograms (EEG's). One patient had nearly continuous myoclonic activity. Serum levels of phenytoin, primidone, and phenobarbital were adjusted to therapeutic ranges. Three patients had additional medication (diazepam, ethosuximide). Cerebellar biopsy in three patients showed reduction in Purkinje cells. After implantation of cerebellar stimulators, seizure frequency was evaluated in hospital during three or four admissions for 4- to 6-week periods over the ensuing 15 to 21 months. No slow trends toward improvement or deterioration were noted. No significant differences in seizure frequency were found when comparing intervals of about 7 days of on-and-off stimulation both in the double-blind and unblinded conditions. No changes in EEG or Intelligence or Memory Quotients occurred unaccounted for by variations in serum levels of antiepileptic drugs. Despite the lack of objective improvement, patient and family acceptance of cerebellar stimulation was positive to enthusiastic. A rise in CSF norepinephrine and a fall in gamma aminobutyric acid (GABA) accompanied cerebellar stimulation and may be related to the results.