Visual Cognitive Processing Deficits in Pediatric Multiple Sclerosis

Visual-Cognitive Processing Deficits in Pediatric Multiple Sclerosis

Multiple Sclerosis (MS) is thought to be an autoimmune disorder which affects the central nervous system. According to the National Pediatric MS Center, in MS, myelin is lost in multiple areas, leaving scar tissue called sclerosis. When myelin or the nerve fiber is destroyed or damaged, the ability of the nerves to conduct electrical impulses to and from the brain is disrupted, and this produces the various symptoms of MS. One of these symptoms is cognitive dysfunction. According to the National Pediatric MS Center, approximately 50% of individuals with MS will develop problems with cognition. While the disorder is typically diagnosed in individuals between the ages of 20 and 30, approximately 5% of the cases diagnosed are children (National Pediatric MS Center). Additionally, the National Multiple Sclerosis Society reports that 2% to 5% of adult patients with MS report having symptoms prior to age 18.

There are several challenges unique to the assessment and treatment of children with MS. First of all, because the symptoms of MS are similar to other childhood disorders, it is difficult to diagnose (National Multiple Sclerosis Society). Additionally, children may experience symptoms such as seizures and mental status changes that are not present in adults with MS (National Multiple Sclerosis Society). Finally, Smerbeck et al. (2011) report that cognitive impairments may be more significant in children than adults with MS because the central nervous system is still developing. Language impairment and verbal intelligence are particular concerns (Smerbeck, et al.). Therefore, valid and reliable assessment tools are crucial for identifying these cognitive impairments in children with MS. This paper will review a study designed to evaluate the validity of two such assessments.

Purpose of Research Study

According to Hubley (2010) the Brief Visuospatial Memory Test-Revised (BVMTR) is designed to measure visuospatial learning and memory in adults. The purpose of the Symbol Digit Modalities Test (SDMT) is to provide a screening tool for detecting patients, children as well as adults, who have disease, damage, or dysfunction implicating the cerebral hemispheres (Reed, 2010). The purpose of the research study conducted by Smerbeck et al. (2011) was to determine the sensitivity and validity of these instruments in assessing cognitive impairments in pediatric Multiple Sclerosis.

Description of Methodology

Smerbeck et al. (2011) conducted a study with 43 children who were diagnosed with MS and 45 who were healthy. The participants with MS were selected from two clinics in the U.S. Pediatric MS Network in New York. The researchers excluded participants who "evidenced poor English proficiency, premorbid developmental delay, substance abuse or dependence, vision worse than 20/70 corrected, or behavioral problems that precluded testing completion" (Smerbeck et al., 2011, p. 450). Healthy participants were recruited from the Buffalo, NY area. Researchers matched a healthy control similar in demographics such as age, sex, handedness, race, and education level of parents to a study participant with MS to compare assessment results (Smerbeck et al.).

Social histories, including demographic information, medical and educational history, and family history were gathered from the parents of the participants. Participants were administered several assessments including: the vocabulary and visual problem solving subtests of the Wechsler Abbreviated Scale of Intelligence (WASI); the Expressive One Word Picture Vocabulary Test (EOWPVT), the Behavior Assessment for Children -- Second Edition, Parent Rating Scales (BASC-2, PRS) Depression subscale; the BVMTR; and the SDMT (Smerbeck, et al., 2011). Assessment results were analyzed using SPSS/PASW version 18 (Smerbeck et al.).

Conclusions of Study

The study found that MS patients performed "significantly worse" than the healthy participants on both the BVMTR and the SDMT (Smerbeck, et al., 2011). Smerbeck et al. report that the MS participants scored almost 1 standard deviation below control participants on the BVMTR and 0.69 of the standard deviation lower on the SDMT. According to Smerbeck et al., these results support their hypothesis that "pediatric MS patients achieve significantly lower scores than typically developing controls on tests of visual processing speed and memory" (p. 453). The researchers concluded that the BVMTR and the SDMT could be used in detecting and monitoring pediatric patients with MS.

Implications of Study

Smerbeck et al. (2011) explain that cognitive impairments are a significant burden for children with MS. In order for teachers and other educational professionals to provide accommodations or remediation to address these impairments, the impairments have to be identified. Smerbeck et al. suggest that due to the ease of administration and scoring as well as the ability to repeat the assessments over time due to multiple forms, the BVMTR and SDMT are effective tools for this purpose. Additionally, the instruments may be used to monitor cognitive performance over time.

Ethical Issues Involved in study

The American Psychological Association's (APA, 2010) Code of Ethics provides several guidelines for use in conducting research and assessment. First of all is the requirement of informed consent. According to the APA, informed consent includes an explanation of the nature and purpose of the assessment, fees, involvement of third parties, and limits of confidentiality and sufficient opportunity for the client/patient to ask questions and receive answers. The second ethical issue is releasing of test data. Researchers are required to maintain confidentiality of individual's test results unless required by law to release the results (APA). Additionally, researchers are required to take into account the purpose of the assessment as well as the various test factors, test-taking abilities, and other characteristics of the person being assessed, such as situational, personal, linguistic, and cultural differences, that might affect psychologists' judgments or reduce the accuracy of their interpretations when interpreting test results (APA). In order to alleviate these differences, the researchers in this study excluded participants who were limited English speakers, or who had other cognitive impairments that would impact their results.

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