Psychopathology, psychosocial functioning, and IQ before and after epilepsy surgery in children with drug-resistant epilepsy

Abstract

This is a prospective study of a consecutive series of children undergoing epilepsy surgery. The main aims were to evaluate the heterogeneity with respect to psychopathology and IQ, and to use a global assessment scale (Children’s Global Assessment Scale [CGAS]) to evaluate psychosocial functioning. Clinical neuropsychiatric and neuropsychological assessments were made at baseline and at the 2-year follow-up in 24 patients, and changes were analyzed at an individual level. Psychiatric disorders (mainly attention deficit hyperactivity disorder and/or autism spectrum disorders) were found in 17 of 24 at some point. All except one child with psychiatric diagnoses before surgery still had at least one diagnosis at follow-up. Intellectual ability remained stable in the majority of cases, both in individuals with and in individuals without mental retardation. The CGAS illustrated the consequences of the extensive comorbidity in this cohort. The behavioral problems had been undiagnosed despite parental concern in many cases, indicating an unrecognized need for services for children with drug-resistant epilepsy.

Introduction

Medically intractable epilepsy is a neurological condition with a significant impact on the affected child and her or his family. The aim of epilepsy surgery is usually to cure the patient of drug-resistant seizures, but in children with catastrophic epilepsy, the aim may also be to reduce seizure frequency or seizure severity to prevent cognitive and behavioral deterioration [1]. Outcome with respect to seizure control after epilepsy surgery is well documented, as are cognitive effects. The general cognitive level often remains stable at a group level [2], [3], [4]. The histopathological diagnoses, the localization of the lesion, and the surgical procedure have implications for outcome. Better seizure outcome after surgery is reported in patients with vascular malformations and tumors, and worse outcome is reported in patients with malformations of cortical development (MCDs) and gliosis [5]. Hemispherectomies carry the best prognosis, followed by temporal lobe resections (60–80% seizure free) [6].

Outcome with respect to psychopathology and behavior in children has received more attention only recently. Reports of behavioral outcome after surgery have often relied on anecdotal information or retrospective analyses of medical data [7]. Neuropsychological assessment before and after surgery is an accepted tool for quality and outcome control, but is not equivalent to neuropsychiatric assessment, and the two complement each other. There are positive reports on postsurgical developmental and behavioral outcome in children with drug-resistant epilepsy [1], [8], [9], but there are also less favorable reports [10].

Children with severe epilepsy who are candidates for epilepsy surgery constitute a heterogeneous group. Neurodevelopmental disorders such as mental retardation (MR), pervasive developmental disorders (PDDs)—including autistic disorder, Asperger syndrome, and PDD not otherwise specified (NOS)—and attention deficit hyperactivity disorder (ADHD) are common [11]. Intellectual functioning may range from superior to profound MR.

The PDDs, which occur in 0.5–1% of children in the general population, are characterized by severe reciprocal social and communication difficulties in combination with repetitive behavior, and are documented in 19–38% of pediatric candidates for resective surgery [10], [12]. There are some follow-up studies on the outcome of epilepsy surgery in children with PDD, and in most cases, there appear to be no or minor effects concerning the core deficits in social interaction, communication, and rigid or repetitive behaviors, but in some cases associated behavioral problems improve [10], [13], [14].

ADHD, one of the disruptive behavior disorders, is the most common behavioral disorder of childhood. It affects 3–5% of school-aged children [15], [16] and is four to five times more frequent in children with epilepsy [17], [18]. In McLellan and colleagues’ study [10] on children undergoing temporal lobe resections, 27% had ADHD. Oppositional defiant disorder (ODD), another disruptive behavior disorder, often comorbid with ADHD, consists of repetitive and persistent oppositional and disobedient behaviors directed toward authority figures. The prevalence of ODD is less well established.

The efficacy of an intervention can be established on the basis of symptomatic improvement, but this is not always the same as functional improvement. Global assessment of psychosocial functioning has been used in intervention studies as a clinically meaningful measure incorporating several aspects of functioning [19]. Global assessment scales, such as the Children’s Global Assessment Scale (CGAS), have been used in studies not only of psychiatric disorders, but also of physical disorders [20], [21], [22], [23].

The main aims of this prospective 2-year follow-up study were (1) to evaluate the complexity and heterogeneity with respect to psychopathology and IQ in a pediatric epilepsy surgery series, and (2) to use a global assessment scale for the evaluation of psychosocial functioning. We wanted to examine the spectrum of clinical neuropsychiatric disorders (including their degree of overlap and comorbidity) and establish the rate of psychiatric disorders before and after surgery. A secondary aim was to examine whether questionnaires given to parents could identify the psychiatric disorders in children with drug-resistant epilepsy.