Intraoperative EEG recording during corpus callosum surgery

The EEG recorded during sectioning of the corpus callosum for intractable epilepsy, especially for atonic-tonic seizures with drop attacks, shows a lateralization of generalized interictal discharges in about 75% of the patients. In a recent study, however, the degree of lateralization did not correlate with the degree of reduction in seizures. Some patients may not exhibit any changes in the generalized activity yet may do very well after surgery. Other determinants of the extent of sectioning of the corpus callosum need to be considered, e.g., the ictal patterns seen in preoperative testing, the neuropsychological testing (IQ), and the number of seizure types.