EEG findings in hydrocephalus and their relation to shunting procedures

Abstract

Thirty-nine patients with hydrocephalus were studied. The EEGs of 26 patients who had an external shunt placed in the lateral ventricle were compared with those of 21 patients who were not shunted. Thirteen patients (62%) in the non-shunted group and 22 subjects (85%) in the shunted group had abnormal EEGs. Focal specific paroxysmal discharges (SPDs) were present in 10 patients (38%) in the shunted group in contrast to only two (10%) in the non-shunted group. Focal SPDs and slow waves were seen most frequently over the shunted hemisphere in the shunted group. The prevalence of seizures was significantly greater in the shunted group (20% in the non-shunted, 48% in the shunted group). It is concluded that the shunt has irritative effects on the cerebral cortex and is responsible for these findings.