Electroencephalographic and Clinico-pathological Observations in Hydrocephalic Children

Abstract

The EEG features seem to be type, time and distribution of the lesions responsible for the development of hydrocephalus, rather than to the presence or severity of hydrocephaly. Neither slow nor rapid changes in the intraventricular pressure appeared to alter substantially the EEG features in selected patients. There was no evidence that spreading depression phenomena might be started by a simple puncture of the brain and its covering, nor by the presence of two stainless steel needles in the lateral ventricles for periods of over half an hour, nor by the insertion of a Spitz -Holter valve. Sharp waves at the vertex, considered as an important EEG feature in hydrocephalus by other workers, were in fact uncommon in our material. The presence of well-formed EEG responses to photic stimulation suggested that vision was not totally lost in doubtful cases. After some operations on one lateral ventricle (Forrest disc), the presence of a unilateral flattening of the EEG was related either to the presence of a large local collection of fluid between the brain and the dura mater, or to an extensive neuronal loss. In general either single or serial EEG investigations were of value in those differential diagnostic problems where information about the functional state of the brain would be unobtainable with other means. Serial EEG studies in our cases did not appear to help in the general prognostic outlook of selected cases. As in other groups of patients, particularly children, the occurrence of discharges in the EEG (focal spikes and sharp waves) was not limited to patients known to suffer from seizures.