EEG findings in shunted hydrocephalic patients with epileptic seizures.

The EEG findings in 40 shunted hydrocephalic patients tested after the onset of epileptic seizures are assessed. The salient point to emerge from the study is the higher frequency of anomalies, both specific (spikes, slow spikes, spike and wave complexes) and nonspecific (monomorphic and polymorphic slow waves) on the shunted hemisphere (19 cases) than on the unshunted side (8 cases). The lateralization of EEG anomalies on the shunted side in patients with no neurological deficits and no focal damage to the substance of the brain suggests that the EEG focus is in some way related to the presence of the shunt. Without denying the importance of the hydrocephalus etiology as a cause of epilepsy in shunted patients, we do think that, in some cases at least, epilepsy is to be regarded as a surgical complication.