THE SO-CALLED EPILEPTIC EEG AND ITS CLINICAL CORRELATION A GENERAL SURVEY FROM THE 1,200 AUTO-EXPERIENCED CASES*

Abstract

Summary The results of the findings obtained from EEGs of the 1,200 cases with definite epilepsy were summarized as follows: 1) The synthetic interpretation proved that the approximately normal cases accounted for 4%, the borderline-abnormal for 6% and the definitely abnormal for 90%, thereby seizure discharge was observed in 85% of the total number of cases. 2) Dysrhythmia in respect to the basic activity was observed in half of the cases, which was verified also by the EEG auto-analyser. 3) With regard to the abnormal EEG-findings, the non-focal diffuse findings were perceived in 15% of the cases, the so-called centrencephalic type in 30%; and the focal signs in 55%. Moreover, in 95% of the latter, the existence of either the areal or discrete foci were confirmed in 85%. 4) Concerning seizure discharge, it appeared in 96% of the abnormal EEGs, and the ratio of the focal to the non-focal was 3:2. It also appeared in the following decreasing order: spike-&-wave complexes spikes; the other patterns were very scanty. 5) As for the distributions of the foci, the following numerical order was obtained: the temporal the occipital; only the last two were sparse in number. 6) Abnormal EEG-findings appeared in 50% of the resting record, but were increased to 90% by activations, thus the significance of activating techniques was presumed. 7) In regard to the relations between clinical seizure patterns and EEG-findings, there existed a definitely positive correlation between petit mal absence and/or automatism and rhythmic 3 c/s spike-&-wave complex. And, as for the other patterns, the centrencephalic type was usually observed in cases of both generalized convulsion and the petit mal group, and the focal signs (especially the temporal ones) almost always in both the focal seizure group and the psychomotor seizure group, and the multiple spikes for the most part in cases with both myoclonic seizure and massive myoclonic seizure. However, it seems to be difficult to introduce any definite and uniform relation according to the each seizure type unitarily. 8) In clinical EEG-examination, even in the case of epilepsy, a generalized or multi-dimensional interpretation using systematic procedures, including application of activating techniques, is yet necessary.