Chapter 40: Cognitive Deficits in Children with Epilepsy

INTRODUCTION

Cognitive problems among children with epilepsy are of paramount concern. Cognition includes a variety of skills such as intelligence, attention, learning, remembering, reasoning, judging, planning, and expressing and understanding language. One's proficiency in these processes can influence other aspects of function such as behavior and social skills. During development, the maturation of cognitive processes is protracted, extending from infancy though to adolescence, and for more complex aspects of cognition such as executive function, even into young adulthood. Thus, in youth with epilepsy, seizures occur during a long window of time that is essential for the development of basic and complex cognitive skills that form the core foundation for long-term educational, vocational, and interpersonal adaptation.¹

Deficits in cognition are identified by children with epilepsy and their parents as a significant comorbidity. For example, in a study by Arunkumar et al,² parents of 80 children and adolescents with epilepsy were asked to list in order of importance their concerns about living with or caring for their children with epilepsy; children who were old enough to be interviewed were asked to express (independently of their parents) their own concerns about having epilepsy. For both parents and children, the second most common item identified was that of the cognitive effects of epilepsy. Their worries included learning disabilities, academic difficulties, poor attention and concentration, and impoverished memory.

ONSET OF DEFICITS

Cognitive deficits appear to be present early on in the course of epilepsy and may even predate the onset of seizures. A study of children with idiopathic localization-related or primary generalized epilepsy approximately 10 months after seizure onset revealed a pattern of mild generalized cognitive difficulties.³ It is thought that these deficits are related to structural brain anomalies. For example, in children evaluated soon after they experienced their first seizure, those with an abnormality detected on MRI performed more poorly on cognitive tasks than children without a significant brain abnormality.⁴ These differences were widespread, and were found in the areas of intelligence, memory, language, processing speed, verbal learning and memory, and executive functions, with all these domains affected relatively equally. Cognitive deficits early in the course of epilepsy are especially pronounced in children with neurobehavioral comorbidities.⁵

The severity and duration of epilepsy are also important in determining the incidence and magnitude of cognitive deficits in children. There is evidence that childhood onset temporal lobe epilepsy is associated with adverse neurodevelopmental impact on both brain structure and function.⁶ Patients with childhood onset seizures exhibited greater compromise across domains of cognitive performance and showed a substantial reduction in brain tissue volumes in extratemporal regions compared with patients with late onset temporal lobe seizures. Those patients with structural abnormalities at onset may be especially vulnerable to the long-term adverse effects of epilepsy.⁴ Scores on neuropsychological tests were not related to EEG activity in children with recent onset epilepsy; ...