EEG and clinical predictors of medically intractable childhood epilepsy.

OBJECTIVES: To identify electroencephalographic and clinical factors associated with both seizure control and medical intractability in children with epilepsy.
METHODS: We retrospectively reviewed EEGs and medical records from children with well-controlled epilepsy or medically intractable epilepsy.
SUBJECTS: Features of the initial EEG and clinical findings were compared in 39 children with well controlled seizures and 144 with intractable epilepsy using both univariate and multivariate analyses.
RESULTS: Strong univariate associates were noted between intractability and several EEG factors: abnormal EEG background including diffuse slowing, asymmetry, abnormal amplitude, a high frequency of spikes or sharp waves, and focal spike and wave activity. With multiple logistic regression, independent predictors of intractability were diffuse slowing and focal spike and wave activity. Strong univariate associates of clinical factors with intractability included: an early age of onset, simple partial, tonic, and myoclonic seizures, a history of status epilepticus, a symptomatic etiology of the seizures, and abnormal magnetic resonance imaging of the head. Multivariate analysis detected 4 independent clinical features associated with intractable epilepsy: symptomatic etiology, tonic seizures, simple partial seizures, and an early age of onset.
CONCLUSIONS: There are a number of EEG and clinical features that can be identified early in the course of childhood epilepsy that are predictive of outcome. These findings will need to be verified in a prospective study.