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 temporal lobe epilepsy. The development of 32- and 64-channel EEG machines, along with the reformatting capabilities of digital EEG has greatly increased the possibilities in the number of electrodes and recording montages. The authors wanted to determine whether the use of closely spaced electrodes designed to increase the coverage of frontocentral regions is of benefit in the investigation of patients with frontocentral epilepsy. Patients investigated for frontocentral epilepsy underwent EEG telemetry with closely spaced electrodes based on the 10-10 nomenclature. Twenty-three patients were studied. An additional 30 minutes was required by technicians to create the montage. Unilateral frontal or frontocentral epileptic abnormalities were observed in 10 patients, independent bifrontal in 5 patients, synchronous bifrontal in 4 patients, and no EEG changes in 4 patients. In no patient did the addition 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 demonstrate evidence of laterality in bilaterally synchronous discharges.