Abstracts

Rationale: Congenital hemiplegia carries up to a 40% incidence of epilepsy, often intractable, and the benefit of epilepsy surgery (hemispherotomy ) in these children has previously been demonstrated . However, even with well-controlled seizures, many of these children pre-operatively have developmental delay, learning disabilities, and behavioral problems, and the contribution from subclinical seizures or an abnormal interictal EEG to these elements of encephalopathy is difficult to determine. Review of the literature reveals a paucity of data on the effects of hemispherotomy on the epileptic encephalopathy associated with congenital hemiplegia. We report our experience with the effects of hemispherotomy on the encephalopathy in 4 children with congenital hemiplegia, and on an additional 2 children with hemiplegia acquired at an early age from trauma or infection. We conclude that hemispherotomy is a safe and effective approach to epileptic encephalopathy associated with congenital hemiplegia, and that in general the presence of epileptic encephalopathy is an important consideration in the epilepsy surgery decision-making process . Methods: We analyzed a series of 4 patients with congenital hemiplegia and 2 patients with early life acquired hemiplegia for the effects of surgery on the encephalopathy. All patients had a hemispherotomy (anterior temporal resection, hemispheric disconnection including intraventricular corpus callosotomy). All patients had serial developmental evaluations or neuropsychological profiling pre- and post-operatively, serial EEG recordings, and clinical examinations. Encephalopathy was defined as developmental delay, learning disability, or behavioral problems and was identified as a developmental regression or stagnation with or without worsening seizure control, and with a markedly abnormal interictal EEG, often with continuous epileptiform activity during sleep. Results: See Table: Conclusions: Based on our experience, the epileptic encephalopathy associated with congenital hemiplegia responds well to surgery. If the clinical profile suggests epileptic encephalopathy, surgery should be considered, even if seizures are well-controlled . Of additional interest is the degree to which medications appear to play a role in the encephalopathy; although it is harder to determine their contribution, negative medication effects may also be included when considering a surgical approach to epileptic encephalopathy. Our observations support a causative association between interictal EEG abnormalities and encephalopathy in these children. Further studies are needed to determine the degree to which this is true in other forms of epileptic encephalopathy.