Possibilities of a temporal relationship between the morphology and frequency of parietal somato-sensory evoked spikes and the occurrence of epileptic manifestations.

Abstract

Recently it has been shown that an epileptic form, originating from the characteristic evoked spikes on the parietal regions, develops gradually into the condition of convulsive seizures. Continuing the study of this phenomenon, we have investigated the cases whose status was already in the clinical phase. With these 15 subjects we studied the possibilities of a relationship between the morphology and the maximal frequency of the evoked potentials, and then, the latency between the first occurrence of the above mentioned potentials and the clinical phase. We have also investigated the behavior of the cases, in which, in addition to the presence of evoked parietal spikes, there was evidence of generalized discharges of spikes and waves. The results appear to confirm a temporal relationship between the initial amplitude and the frequency of the above-mentioned evoked potentials and the more or less precocious occurrence of the clinical phase. It also seems that the non-focal patterns arrive in the clinical phase in a shorter time, and are always accompanied by seizures of the tonic-clonic type. In conclusion, the problems that arise from these results are discussed.