Intractable Epilepsy in a Population‐Based Series of Mentally Retarded Children

Abstract

Summary: Purpose:The characteristics of intractable epilepsy were analyzed in a population-based study of active epilepsy in mentally retarded children aged 6-13 years.Methods: Diagnostic registers, EEG laboratory registers, and registers for the Education of the Subnormal were searched. Medical files were scrutinized. Clinical examinations and interviews with parents and caregivers or both were performed. EEG recordings, computed tomography (CT) and magnetic resonance imaging (MRI) of the CNS were reevaluated.Results: Forty-five percent (44 of 98) of the children with mental retardation (MR) and active epilepsy had intractable seizures, defined as one or more seizures every day or week. The median age at onset was 0.8 years, as compared with 3.0 years for those with controlled epilepsy. Predictive factors for frequent seizures were the number of seizure types, severe MR, status epilepticus (SE) and tonic seizures. Epileptiform EEG activity was present in 91%, and focal activity in 65%. Brain lesions were detected on CT and MRI in 70%, with generalized lesions in 60%. Concurrent focal epileptiform activity and focal brain lesions on CTIMRI were detected in 26%. The percentages and prevalence rates for infantile spasms (IS) and LennoxGastaut syndrome (LGS) were 18% (0.25 in 1,OOO) and 7% (0.06 in 1,000), respectively. One of 8 children with IS had had previous neonatal seizures, 3 had SE and 1 later developedLGS . Conclusions:Children with MR and intractable epilepsy have a high frequency of severe MR and additional major neuroimpairments. EEG recordings frequently showed focal changes despite generalized lesions in neuroradiology.

Features of a Subset of Children With Complex Partial Epilepsy Requiring Combination Therapy for Effective Seizure Control

“…18 Another study looked at intractability in children with mental retardation and epilepsy and found a higher rate of severe mental retardation in the intractable group. 20 This study also found that children with mental retardation and intractable epilepsy had more frequent status epilepticus and were more likely to have 2 seizure types, which is consistent with our findings. The explanation as to why these seizures seem harder to treat than those in children without coexisting neurodevelopmental disability may lie in that MR and epilepsy are often an indication of widespread cortical damage, 19 and this widespread brain damage underlies an epilepsy that is difficult to control.…”

Antiepileptic Drug Selection in Pediatric Epilepsy

“…46 The concept of intractability is difficult because there is no one accepted definition for this. 49 The duration of epilepsy before intractability is called is variable from one treating physician to the next. In children with mental retardation, there is a greater incidence of intractability.…”

Clinical Features of a Series of Non-Surgical Patients with Focal Cortical Dysplasia and Epilepsy

“…Most of them have FCD in the frontal lobe. As mentioned by other authors [5,6,22,26], FCD is associated with a wide range of clinical presentations. There is no particular seizure semiology that characterizes patients with FCD compared with other surgical series of epilepsy patients [16][17][18].…”

“…MCD are considered the second most common cause of medically resistant focal epilepsy in adults after hippocampal sclerosis [3]. In patients with resistant epilepsy, the MCD have been observed in 8-12% of cases [4] and in up to 14% of children with resistant epilepsy and mental retardation [5,6].…”