Centrencephalic Epilepsy and Suboccipital Derivations

There is a special group of epilepsies whose primary source lies within so called “centrencephalic” regions and are commonly characterized by loss or impairment of consciousness during the attack and by a characteristic EEG pattern which shows bilaterally synchronous discharges of the spikes and wave complex of various frequency (Penfield-Jasper). Frequently, however, these specific discharges are often overlooked in standard recording performed from the scalp where merely slow activity or biphasic slow waves can be detected. Apart from this, the occurrence of these “centrencephalic” discharges is not always bilaterally synchronous from the very beginning, as was believed earlier (Rovit et al., Hajnsek et al.) (Fig. 1). These facts led us to use suboccipital EEG recordings for epilepsy where the primary source appeared to lie within centrencephalic regions. This approach was used in order to record activities originating in the suboccipital area in the regions termed “centrencephalic”. The technique of needle-electrode application is as follows: The needle is introduced and placed extracranially starting from the back part of the mastoid process of the temporal bone half a centimetre upwards from its crest. The needle is then led vertically to the sagittal plane of the skull and lightly slant-wise upwards terminating at the atlantooccippal joint (Fig. 2). If the needle is introduced at the right point there is no danger of lesion of any structures in these regions.