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 focal[1]ization 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
Pacientes y métodos Presentamos los resultados de dos años de trabajo del Laboratorio de Electroencefalograma del Centro Internacional de Restauración Neurológica de La Habana, Cuba, utilizando electrodos cigomáticos en la evaluación ordinaria de pacientes epilépticos. Los registros se realizaron empleando la posición FCz como electrodo de referencia, en sustitución de la referencia (orejas cortocircuitadas) que por defecto se utiliza en el módulo de registro del software Track Walker 2 para Medicid 3E (empleado en los Laboratorios de Neurofisiología Clínica de la Red Nacional). Se comprobó actividad epileptiforme en 196 registros; de éstos, en 100 (51%) dicha actividad involucraba el lóbulo temporal, con localización estrictamente temporal demostrada en 25 pacientes (25%), y en 7 (28%) documentamos focalización en el aspecto mesial. Se presentan segmentos de EEG con descargas epileptiformes focalizadas en el lóbulo temporal (aspecto mesial y lateral) en montajes bipolares (cigotemporoparasagital) así como en referenciales.
Conclusiones Nuestros resultados avalan la utilidad de esta metodología para la detección y localización de actividad epileptiforme en el lóbulo temporal y plantean una alternativa que sensibiliza el valor diagnóstico del EEG en las epilepsias
