[The use of zygomatic electrodes in the assessment of epileptic patients. Presentation of methodology for recording and assessing a digital EEG].

INTRODUCTION AND
OBJECTIVES: Electrographic anomalies of the temporal lobe may be seen in 70% of epileptic patients. Focalization if inter-ictal epileptiform discharges makes a major contribution to clinical diagnosis. Also, it is accepted that the detection and interpretation of such anomalies is influenced by the method of recording. Thus the use of additional extracranial electrodes has been shown to significantly increase the sensitivity of inter-ictal or ictal electroencephalograms (EEG) PATIENTS AND METHODS: We present the results of two years work in the Electroencephalogram Laboratory of the International Centre for Neurological Recovery, La Habana, Cuba (CIREN), using zygomatic electrodes for the standard assessment of epileptic patients. Recordings were made using the FCz position as reference electrode instead of the reference electrode (short-circuited ears) used as pre-programmed in the recording module of the software Track Walker 2 for Medicid 3E (used in the Clinical Neurophysiology Laboratories of the National Network). Epileptiform activity was seen on 196 recordings; in 100 (51%) of these, this activity involved the temporal lobe, with strictly temporal localization shown in 25 patients (25%) and in 7 (28%) we recorded focalization on the medial aspect. We present segments of EEGs with epileptiform discharges focalized in the temporal lobe (medial and lateral aspects) in bipolar systems (zygotemporal-parasagittal) and in reference electrodes.
CONCLUSIONS: Our results support the usefulness of this methodology for the detection and localization of epileptiform activity in the temporal lobe and suggest an alternative which would increase the diagnostic sensitivity of EEG in epilepsies.