Neuropsychological Assessment of Children

Various approaches to pediatric neuropsychological assessment are applied to the pediatric population; some involve cognition as the core unit of analysis with developmental considerations playing a supplementary role, whereas others place greater importance on development in a broader sense, along with the environmental and contextual influences on brain—behavior relationships.1 A developmental neuropsychological approach involves assessment of current cognitive skills and abilities within the context of environmental and developmental influences to construct a model of not only how but also why a child functions in his or her world. The latter model allows for hypotheses to be generated about future function in light of ongoing development and potential disruptions to development. This approach is particularly applicable in the assessment of children with epilepsy before surgical intervention. Understanding the developmental trajectory of a child and the various factors that serve to support as well as threaten developmental progress are necessary in predicting outcomes.

The tools of the trade for the developmental neuropsychologist include trained observation skills, developmental history gathering, psychological tests to assess cognitive abilities, and integrative analysis and interpretation of findings.

Neuropsychological assessment of the child is not merely a collection of results from various cognitive tests. Although important, quantitative test results alone are not sufficient to assess an individual child’s cognitive function. Careful observation of how a child uses his or her skills to arrive at conclusions, solve problems, and provide answers is crucial for interpretation of findings. Furthermore, a child’s individual skills do not operate in isolation but in a context of other neurobehavioral functions. Thus, a neuropsychological profile is carefully interpreted rather than simply providing a list of test scores.

Standardized Psychological Tests

Psychological tests to assess cognitive abilities are most often standardized, norm-referenced tools. This means that the administration directions are specific and that children should be presented materials and questions in a structured way so that responses can be compared with a sample of typically developing children in the same age range (normative reference sample). Choosing tests that are appropriate to the child’s developmental level is necessary for the assessment to be valid. Current normative data are also important, as is information regarding the reliability and validity of the measure for specific purposes. Psychological tests are designed to measure specific constructs; however, it is impossible to completely isolate neurobehavioral constructs, particularly in children. As such, knowledge of the natural development of cognitive functions and well-honed observation skills are essential in interpreting psychological test scores and integrating these findings in the context of the child’s social, developmental, and neurological histories.

Domains of Neuropsychological Assessment

Neuropsychological assessment of children can take on different forms, depending on the theoretical approach taken by the neuropsychologist and the specific goals of the evaluation. The majority of neuropsychological evaluations involve gathering information from several domains of function including general cognitive ability (a.k.a. intelligence), language, visual—perceptual, motor, sensory, memory, attention, and executive functions (executive functions typically include regulation of behavior as well as planning, organization, and integrative problem-solving skills) as well as assessment of emotional, social, and adaptive function.

Epilepsy in Children and Its Effect on Neuropsychological function

The developmental impact of epilepsy in childhood is highly diverse, which is not surprising given that the etiologies of pediatric epilepsy are numerous and often unknown. Moreover, the clinical presentations of patients with seizure disorders are wide ranging. As a group, children with epilepsy are vulnerable to neurodevelopmental dysfunction; however, various developmental trajectories occur in this population, and it is not possible to make broad generalizations. Specific and well-characterized epileptic syndromes are associated with relatively specific neuropsychological profiles. For example, children with Lennox-Gastaut syndrome almost invariably function within the range of moderate to severe mental retardation, whereas children with benign rolandic epilepsy most often have cognitive strengths and weaknesses that do not fall far outside normal limits for age.3 However, most children with epilepsy do not have clearly defined syndromes such as these, and often the cause of seizures is unknown.

Significant limitations in cognitive development resulting in mental retardation occur in approximately 15 to 30% of patients with epilepsy and autism spectrum disorders occur in 20 to 30% of this population.4 That said, the majority of children with epilepsy will have good seizure control on antiepileptic drugs and do not demonstrate substantial intellectual impairment.5

The specific cause of epilepsy often places the child at risk for neuropsychological dysfunction. Earlier onset of seizures has been associated with poorer cognitive outcome; however, this may be because of the likelihood of early onset epilepsy to occur when cortical malformations are present or in the setting of catastrophic epilepsy syndromes that present early in life, such as West syndrome.5 Risk for declines in intellectual function is of concern in children with epilepsy and varies as a function of many factors, not all of which are well understood.6 The primary risks to overall cognitive development in children with epilepsy appear to be the presence of status epilepticus, early onset of seizures in the setting of malformations of brain development, intractable seizures, and drug toxicity.5

Specific patterns of neuropsychological strength and weakness may be related to the neuroanatomical focality of localization-related epilepsy.

The same contributing factors that lead to cognitive limitations, such as neurodevelopment, seizure-related factors (age of onset, syndrome, seizure severity), and medication side effects also place children at risk for academic under-achievement. Specific neuropsychological impairments of skills, such as attention or memory, have substantial contributions to school performance as well. The role of psychosocial influences on academic achievement is very important to consider, including self-esteem, sense of personal effectiveness, and socioeconomic status.5

Children with epilepsy are three to nine times more likely to experience psychiatric disturbance than children without neurological conditions.4 Approximately one third of pediatric epilepsy patients have affective or anxiety disorders.7 Given the morbidity associated with depression, it is not surprising that it is a significant predictor of quality of life even when controlling for seizure frequency.8 Risk is great for increase in mood disturbance after surgery, particularly with temporal lobe resections; however, patients with extratemporal resection and past history of mood problems are at risk of reoccurrence as well.9