Effects of corpus callosum section on secondary bilaterally synchronous interictal EEG discharges.

We studied the effect of corpus callosum section on secondary bilaterally synchronous interictal EEG discharges in 13 patients with partial and secondarily generalized seizures before and after partial or complete section of the corpus callosum. Bilaterally synchronous discharges were completely eliminated in one patient. In 12 patients, there was a distinct reduction in frequency. Our clinical experience agrees with experimental data to suggest that epileptic discharges follow pathways, both across the corpus callosum and/or down to diencephalic/mesencephalic structures, before there is bilateral spread.