Sequential EEG findings and symptoms in partial seizures of temporal lobe origin

45 cases of partial seizures of temporal lobe origin undergoing sequential EEG investigation first with routine and then methohexitone activated EEG, 31 supplemented by sphenoidal electrodes, are reported. Methohexitone activated foci from temporal lobes which had previously not displayed temporal spike or sharp wave discharges in 15 (33.3%) cases. In 11 (24.4%) this was the first evidence of the focus in 15 (33.3%) cases. In 11 (24.8%) this was the first evidence of the focus in either temporal lobe and in 4 (8.9%) the focus was contralateral to one already seen in routine EEG. In 3 (6.7%) cases the sphenoidal electrodes were essential for demonstrating the focus. Methohexitone evoked temporal spikes or sharp waves irrespective of the nature of the initial routine EEG which was either normal, had non "epileptic" temporal abnormalities or abnormalities outside the temporal region. 2 X 2 chi 2 tests, comparing the frequency with which a particular symptom was accompanied by an EEG in a sequence with temporal discharges, showed that only in the case of evolution to generalised tonic/clonic seizures (secondary generalization) was the association statistically significant: chi 2 4.28, P less than 0.025. Similar testing of length of history and frequency of attacks against the frequency with which temporal discharges occurred failed to establish a statistically significant association.