USEFULNESS OF LATERO-ORBITAL ELECTRODES IN DETECTING INTERICTAL EPILEPTIFORM ACTIVITY - A STUDY OF 60 PATIENTS WITH COMPLEX PARTIAL SEIZURES

Objectives: The use of latero-orbital (Lo) electrodes is a routine pra ctice in any EEG laboratory to evaluate eye motion, but there are no d ata about their usefulness in revealing interictal epileptiform abnorm alities. Methods: In 60 consecutive patients (27 men, 33 women, mean a ge 36 8 years, range 17-72) with complex partial seizures, we prospect ively evaluated the utility of Lo electrodes in comparison with anteri or temporal (AT) electrodes, for the detection of interictal epileptif orm discharges (SW). Results: No epileptic,rm abnormality was seen in 4/60 patients. Both AT and Lo electrodes were significantly superior t o 10-20 electrodes for detection of both patients and foci. Indeed, th e standard 10-20 system alone allowed the detection of only 39 indepen dent epileptiform Foci in 35/56 (63%) patients, while AT and Lo electr odes were necessary for detection of 23 epileptiform foci in the remai ning 21/56 (37%) patients. Importantly, there was no statistically sig nificant difference in detection between AT and Lo electrodes. Conclus ions: Recordings from Lo electrodes are comparable to those from AT el ectrodes and are useful for localizing interictal temporal spiking act ivity. Lo electrodes may be substituted for basal electrodes in the da y-to-day evaluation of patients with complex partial seizures, (C) 199 8 Elsevier Science Ireland Ltd. All rights reserved.