Pattern of electroencephalographic abnormalities in children with hydrocephalus: a study of 68 patients.

The pattern of electroencephalographic (EEG) abnormalities was studied in 68 patients (41 male, 27 female, age range 1 month to 17 years) with hydrocephalus. They all had standardized EEG recordings, which were read by the same electroencephalographer. In 48 children the EEG was performed after ventriculo-peritoneal shunting. The EEG abnormalities in the shunted group included slow waves in 26 patients [focal 2 (4.2%), generalized asynchronous 22 (45.8%), generalized synchronous 2 (4.2%)]; amplitude abnormalities in 2 (focal 1, generalized 1); epileptiform activity in 26 [partial 11 (22.9%), generalized 15 (31.3%)] and hypsarrhythmia in 4 (8.3%). Only 4 (8.3%) traces were normal, giving an overall percentage abnormality of 92%. In the unshunted group generalized asynchronous slow waves were found in 12 patients (60%), generalized amplitude abnormality in 1, focal epileptiform activity in 3 (15%), and generalized epileptiform activity in 6 (30%); 2 tracings in this group were normal, giving an overall percentage abnormality of 90%. Hydrocephalus in children, regardless of the cause, may be associated with generalized or focal EEG abnormalities. This may reflect the heterogeneity of the neural generator in the underlying disease process.