Electroencephalographic recording from the temporal lobes: a comparison of ear, anterior temporal, and nasopharyngeal electrodes.

A prospective study was performed to evaluate the usefulness of ear, anterior temporal, and nasopharyngeal electrodes for recognizing temporal lobe epileptic electroencephalographic (EEG) foci. One hundred and three EEGs were performed on patients suspected of having epilepsy who had a previous normal record. Nasopharyngeal electrodes were simultaneously compared with ear and anterior temporal electrodes to determine their relative abilities to detect pathological epileptiform transients from the temporal region. Epileptic discharges were detected in 22% of the recordings. Pathological discharges seen in nasopharyngeal electrode derivations invariably were seen in ear and anterior temporal electrode derivations using carefully designed montages, and EEG diagnosis was not altered by use of nasopharyngeal electrodes. We conclude that EEG recording with ear and anterior temporal electrodes is sufficient to detect pathological temporal epileptiform transients, and that the use of nasopharyngeal electrodes as a routine procedure offers no added benefit.