EEG telemetry with closely spaced electrodes in frontal lobe epilepsy

The use of additional electrodes (other than standard 10-20 electrodes) has proved to be extremely useful in the investigation of patients with tempor al lobe epilepsy. The development of 32- and 64-channel EEG machines, along with the reformatting capabilities of digital EEG has greatly increased th e possibilities in the number of electrodes and recording montages. The aut hors wanted to determine whether the use of closely spaced electrodes desig ned to increase the coverage of frontocentral regions is of benefit in the investigation of patients with frontocentral epilepsy. Patients investigate d for frontocentral epilepsy underwent EEG telemetry with closely spaced el ectrodes based on the 10-10 nomenclature. Twenty-three patients were studie d. An additional 30 minutes was required by technicians to create the monta ge. Unilateral frontal or frontocentral epileptic abnormalities were observ ed in 10 patients, independent bifrontal in 5 patients, synchronous bifront al in 4 patients, and no EEG changes in 4 patients. In no patient did the a ddition of closely spaced electrodes lead to a change in the classification of the EEG. Closely spaced electrodes did not reveal focal abnormalities, which were not already apparent with 10-20 electrodes, nor did they demonst rate evidence of laterality in bilaterally synchronous discharges.