Neuropsychology and Learning Problems Associated With Spina Bifida
Spina bifida has long been associated with specific neuropsychological characteristics marked by deficits in nonverbal learning abilities, including math concepts, visual-spatial perception, spatial reasoning, and time concepts (159).
Recent studies have revealed specific weaknesses in processing speed, organization, and personality traits. In addition, verbal skills— once thought to be a strength due to the precocious development of conversational speech in young children with spina bifida—are now known to be weak in complexity, organization, and abstract content (160). Recently, neuropsychological studies have investigated the development of executive control processes in individuals who have spina bifida. This line of study has proven beneficial in understanding the essential underlying neuropsychological characteristics associated with this syndrome.Children with spina bifida can manifest several types of complex learning disorders and neuropsychological sequelae. Intellectual function is historically defined as the intelligence quotient, or IQ. When individuals with meningomyelocele have been compared to typically developing peers, a shift to the left is present. Although most fall in the average range, the level of the lesion appears to have some impact on this parameter. Thoracic-level lesions trend toward a lower average IQ, while sacral levels cluster in the opposite direction and tend to have higher IQs.
The development of hydrocephalus is a key component in the spectrum of cognitive impairment. A recent study by Lindquist compared children with hydrocephalus to those with hydrocephalus and spina bifida. Both groups had impaired learning, memory, and executive function, suggesting that hydrocephalus is a major factor in these deficits (161). When individuals with spina bifida were stratified to those with and without hydrocephalus, those without hydrocephalus had relatively normal neuropsychological testing scores, while those with hydrocephalus showed impairments, especially in executive functioning (162).
The combination of spina bifida and hydrocephalus has also been implicated in deficits of working memory and processing speed, along with retrieval problems (163,164). The level of the spina bifida in association with hydrocephalus has been implicated in additional difficulties with learning. Higher-level lesions above T12 with hydrocephalus showed more severe structural brain anomalies and a poorer cognitive outcome (165). The structural abnormalities were noted in the midbrain, tectum, pons, and splenium; the cerebellum was not noted to be involved. Most recently, newer imaging technology has been better at defining structural differences in the brains of individuals with spina bifida and hydrocephalus, implicating myelinization impairments and abnormal white matter tracts along with a decrease in the grey matter and caudate nucleus structure (166). The clinical implications are emphasized in a recent study done by Matson, which tracked individuals through multiple shunt revisions with neuropsychological testing. The testing revealed lasting cognitive effects after hydrocephalus in verbal IQ, processing speed, organization, and response inhibition (167). Recently the Chiari II malformation has been implicated as affecting specifically verbal memory and fluency (168).When looking at the trends in testing those with spina bifida, there is a discrepancy between verbal and performance IQ scores. Verbal scores tend to be higher, and the classic “cocktail party syndrome” is frequently encountered in this population. The cocktail party syndrome describes a speech pattern characterized by repeating phrases, using common phrases, and talking about unrelated topics. This pattern creates the impression of high intellectual functioning to the untrained observer.
One of the most common identified educational issues is a nonverbal learning disorder (NVLD). There are three areas of difficulty in those with NVLD: motoric, visual-spatial organization, and social (169).
Neuropsychology testing identifies problem areas to be impulsivity, difficulty with staying on task, memory, sequencing, organization, higher reasoning, mental flexibility, and visual perceptual skills. A typical child with spina bifida may have early success in preschool because of verbal skills, but begin to have difficulties once the academic demands become more challenging. In areas of self-care, they often are not at the level of their peers. These children and adults have problems with developing and maintaining bowel and bladder programs. The difficulties are not only in the sequencing, but also in realizing the social implications. NVLD has consequences in school, such as problems with cognitive and educational goals. These individuals have problems with sequencing and memory, along with special visual problems. This can eventually lead to problems with homework and school performance. Social skills acquisition can be affected by such simple things as understanding complex conversations, plots of books, and social jokes.Selective memory disorders have been identified. This is the ability to sort out information and prioritize it in higher ranking order. This is important in the classroom to sort out irrelevant material from extraneous information. If you cannot select information, you can get lost in the details (170). Adolescent studies have shown impairments in attention and executive function (171). There is evidence that attention deficit problems are more common in children with spina bifida and that it tends to be more related to inattention as opposed to hyperactivity (172). These problems tend to persist into adulthood, and testing shows persistent deficits in the areas of reading and writing. This continues to have an impact on employability and selfcare skills as one ages with spina bifida (173).
The learning disorders that influence executive control have a great impact on education and social interactions. Executive control processes are closely associated with the development and functioning of the frontal lobes.
Studies of fetal neurological development indicate elementary differentiation of neural cells and migration to the anterior region of developing brain structures as early as 24 days after conception. During development after birth, executive control processes become differentiated and refined in tandem with progressive myelination of the developing brain.Studies of adolescents who have spina bifida have revealed generalized difficulties with all of these abilities, highlighting significant deficits in initiation, mental flexibility, and organization (174). This same constellation of weaknesses in executive control processes has been discovered in preschool-age children with spina bifida. Abnormal executive control functions may be one of the major factors, explaining the surprising failure of children who have spina bifida to achieve the typical functional adaptive competencies of their same-age peers, despite adequate intellectual abilities.
Deficits in executive control processes—especially initiation, organization, and mental flexibility—are highly likely to be associated with reduced acquisition of social competencies (dating, living independently, “motivation” for independence, employment). It is also plausible that these neuropsychological challenges contribute to reduced acquisition of functional daily living skills (self-catheterization, independent care of personal hygiene, execution of household chores, making and keeping appointments). Weak executive control capacities may also underlie the mental health problems so often seen in adolescents and young adults with spina bifida. Despite the availability of psychotherapy, they often have difficulty putting talk- ed-about goals and plans into action.
So what is the bottom line with regard to cognition in children and adults with spina bifida? We can assume that most will have some type of learning problem. Those who have hydrocephalus and multiple shunt revisions may have more impairments than those who do not.
We know that deficits can be in multiple domains and include visual-spatial, perceptual motor, organization, executive function, sequencing, memory, attention, or just about any other type of learning problem. We feel that early identification and intervention programs are important in this population.There are some basic principles in treating individuals with a nonverbal learning disorder that apply to this population:
■ Identification of the learning disorder is critical. Testing should be done prior to entrance into school.
■ Modified program to address these specific needs. Some children will need 504 and Individualized Education Plans (IEP), which are individualized school plans for children with special needs.
■ Providing structure and direction for education. Be specific and repetitive.
■ Teach step-wise and sequentially (baby steps).
■ Make sure to teach social education, as these children may not pick up social cues.
■ Use multiple sources available on NVLD for guide in education, self-skills training, and social integration.