Clinical and electroencephalographic studies were made on 16 infants and children in the age range of 23 days old to 3 years old with subdural hematoma verified surgically for the purpose to elucidate the etiology, symptomatology and prognosis, with a special emphasis on the significance and usefulness of electroencephalography in early diagnosis.
The results are briefly summarized as follows.
Their EEG revealed abnormalities in everyone of the cases, especially in 15 cases (93. 8%) out of the 16 there was observed localized suppression of the electrical activity (focal low voltage), indicating that it is very important for the diagnosis.
In infancy the important points to be noted are that most of the symptoms at the acute stage may disappear gradually while the EEG abnormalities mentioned above persist and aggravate. Therefore, these EEG findings are valuable for the clinical diagnosis.
The facts that localized spikes can be observed in 68. 8% of the cases in the acute stage and also even after removal of the hematoma often there appear epileptic discharge, suggest the coexistence of parenchymal cerebral damage. Hence it is essential to follow up the patient electroencephalographically for the purpose to predict the onset of clinical epilepsy.
In addition, it is rare to observe such a localized suppression of the electrical activity in infancy, but in Hemiconvulsion-hemiplegia syndrome it is characteristic to see unilateral hemispheric suppression of the EEG. For this reason, we measured the mean visual evoked potential (MVEP) of the cases with subdural hematoma and that of the cases of Hemiconvulsion-hemiplegia syndrome, and found there can be observed asymmetry in MVEP in the two groups, but no change can be seen in the peak latency of MVEP of the former group while a prolongation of the peak latency in the latter.
The EEG is of aid in establishing the diagnosis of subdural hematoma in infancy and early childhood.
