10.4 Electroencephalogram (EEG)

EEG is essential in the work-up of children with CP and suspected seizures. It can lend support to the diagnosis of epilepsy and assist in seizure/epilepsy classification to better guide the choice of antiseizure drugs. However, there is no clinical value of performing EEG testing in children with no suggestion of seizure activity by history, and EEG testing is not useful in establishing the cause of CP.

The rate of EEG abnormalities observed in patients with CP and epilepsy is in the range of 66–92.6% [4, 11, 31].

All of the subgroups of spastic CP had a greater than 70% incidence of abnormal EEGs. Whereas in quadriplegic and diplegic CP, the EEG shows predominant bilateral epileptic activity; about half of children with hemiplegia had focal findings. In a study of children with CP and epilepsy, only 7.9% of children had normal interictal EEGs [Table 4] [4].

There was a correlation between brain CT scan and EEG findings; children with bilateral brain abnormalities on their CT scan imaging often had bilateral and generalized epileptiform abnormalities on their EEGs. However, one-fourth of these children had a focal epileptiform abnormality with rapid bilateral synchrony. On the other hand, 35.3% of children with unilateral structural brain abnormalities on their CT scans had focal epileptiform abnormalities in their EEG recordings; the EEG findings were concordant with the CT scan findings in all patients [11].
