Issue 16: A Cautionary Tale of Three Testing Issues | Dr Paul Beljan

In 2024, I will have been testing children for gifted intellect for 30 years. In that time, I have noticed many nuances using the Wechsler Intelligence Scales for Children (WISC) volumes Revised (R) through Five (V). Herein, I endeavor to describe three issues that are problematic with the WISC V and some issues of interpretive value. We all know that children with gifted intelligence express a wide variety of behaviors and ways of being. It is that diversity that can also have a positive or negative impact on testing behavior and results. So, ‘buyer beware’ when it comes to understanding WISC V outcomes.

The first issue is the WISC V Processing Speed Index (PSI). My colleague, Dr Justin Gardner, and I recently submitted an article for publication titled, Processing Speed in Gifted Children: A Clinical Neuropsychological Perspective. The article discusses how the PSI is not a valid measure of cognitive speed, especially in the gifted population. We showed that gifted children often earn lower scores on the PSI than their non-gifted counterparts but do not have a processing speed deficit!

Processing speed is commonly misunderstood by laypersons and is often misinterpreted by clinicians who use the results of the PSI as the basis of clinical diagnostics and educational determinations of need (Hook & Kuentzel, 2022). Identifying any disorder – particularly with regard to an ability as elusive to measure as processing speed – solely based on the results of a single index without considering large-scale brain systems lends to a high degree of misdiagnosis (Koziol & Beljan, 2016). In fact, research consistently indicates that processing speed is a foundational cognitive ability essential to the expression of overall intelligence (Magistro et al., 2015). Processing speed is defined as the velocity with which neurons communicate (Seidl, 2014). Scientists use a magnetoencephalogram to accurately measure processing speed, while your neighborhood psychologist or WISC V administrator uses a stopwatch.

Scientists use a magnetoencephalogram to accurately measure processing speed, while your neighborhood psychologist or WISC V administrator uses a stopwatch.

The PSI is derived by aggregating the Symbol Search (SS) and Coding (Cd) subtests. These are paper-and-pencil tasks that require the examinee to either serially draw a line through various symbols (SS) or to repetitiously pair numbers with abstract and relatively complex symbols using a pencil (Cd), each lasting for two minutes. Children with gifted intellect notoriously dislike and often actively avoid paper-and-pencil tasks despite not having fine motor deficits or dysgraphia. Because the SS and Cd subtests place a large demand on graphomotor speed to infer underlying processing speed, coupled with their common idiosyncratic tendency to avoid paper-and-pencil tasks, gifted children, therefore, perform significantly lower than their non-gifted counterparts on these measures of processing speed. Another reason gifted individuals, in general, earn relatively lower scores on measures on the WISC V PSI is due to the interference effect of perfectionism, which is highly prevalent in gifted populations (Lovecky, 2015; Vaivre-Douret, 2011; Webb et al., 2016). That is, gifted children will earn lower scores if they double check their work on SS or painstakingly form the Coding symbols. This is not a speed issue; it is a behavioral choice.

Now consider the WISC V Block Design (BD) task in regard to speed. The child is instructed to assemble red and white blocks to match a block design drawing on a flipchart. The task is timed, and starting on item #10 the child can earn bonus points for speed. Our research showed that gifted children earn nearly 10 more raw score points and 3 or more scaled score points than non-gifted children on the BD subtest. These numbers are statistically significant.

An old neuropsychological caveat says, “You cannot fake an ability that you do not have.” Therefore, if a gifted child performs poorly on one or both of the PSI subtests but well on BD, then they cannot possibly have a processing speed deficit.

Now onto the working memory index (WMI). Working memory (WM) is a concept that has gotten into the public lexicon and is often misused. WM is the ability to hold two or more bits of information in immediate memory and use that information purposefully. Dr Elkhonon Goldberg (2017) describes WM as “a prospective, future-oriented function.” I have also heard him call it a “future memory,” which is the ability to work towards a goal by maintaining the planning and organization elements to meet that goal across time. Working memory is actually quite complex.

The WISC V WMI muddies the concept. The Digit Span (DS) tasks are part of the WMI along with the Picture Span task. The DS has three elements: Digit Span Forward, Digit Span Backwards, and Digit Span Sequencing. Digits Span Forward is not a WM task; it is an encoding task. The child is read random numbers and prompted to report them back in order. However, the Digit Span Backwards task has the child hear numbers and report them in reverse order. The Digit Span Sequencing task has the child report randomly administered numbers back in the lowest to the highest order. Digit Span Backwards and Sequencing are WM tasks because the digits are encoded, manipulated according to an instruction, and then reported. Unfortunately, the scores from each task are combined to calculate the Digit Span subtest score. One can easily see that the Digit Span Forward task muddies the Digit Span score. As well, Digit Span Sequencing is easier than the Digit Span Backwards task by generally a standard deviation. One must be careful with the WMI due to these issues. It is more clinically sound to score each Digit Span task individually (available in the WISC V Scoring Manual) and report them in regard to their actual function.

Examiners must be careful administering the WM tasks to gifted children. These children tend to become frustrated with repetitious work, and the Digit Span tasks are repetitious and boring. The examiner must take care to watch the gifted child’s behavior and approach to these tasks to determine their level of applied effort and interest. Low or variably expressed effort on these tasks invalidate the WMI and can lead to a misdiagnosis from the less savvy evaluator.

Finally, we come to the WISC V Vocabulary and Similarities tasks within the Verbal Comprehension Index (VCI). The WISC V Vocabulary task is simply an expressive language task that directs the child to define words. The Similarities task gets at semantic reasoning (thinking in categories) by having the child report how two words are similar or what they have in common. One caveat to watch for, especially in the gifted population, is that many gifted children are voracious readers. Regular reading significantly increases vocabulary. Therefore, it is common for a gifted child to earn a higher score on the Vocabulary task than on the Similarities task, but it does not mean that Similarities is impaired. Another issue to look into is if the Vocabulary score is lower than the Similarities score. In this case, it may suggest that the child needs to read more often. Finally, it is my experience that many gifted children obfuscate tasks. They might like to impress the examiner by attempting to show how much they know or how creative they can be with a response. This puts their performance on the Similarities task at risk as they may overthink the task and miss the simplicity or over-arching idea of some of the items. Again, it is up to the examiner to identify this issue as it occurs and prompt the child to not overthink the task by giving the best answer and not necessarily the most creative answer. The creative answer is interesting and fun but does not earn points.

What I have discussed here are only three issues from one test, the WISC V, that can lower or increase scores and be misinterpreted among the gifted population. A neuropsychological assessment or school psychology assessment uses a multitude of tests, and each test is vulnerable to the issues described in this text. That is, gifted children, have an idiosyncratic way of being that can have a negative impact on test performance and thus prevent them from being enrolled into a gifted program or cause them to be misdiagnosed with a neuropsychological disorder that is not present. Perhaps in another 30 years of testing gifted children, I will have figured out more nuances that I can share.

Buyer beware: any assessment and data interpretation is only as good as the clinician who is testing and interpreting. Vet any clinician about their understanding of giftedness before letting them work with your possibly gifted child.

References

• Hook, J. N., & Kuentzel, J. G. (2022). Basics of pediatric clinical neuropsychology. In E. K. Hodges, J. G. Kuentzel, & J. N. Hook (Eds.), Pediatric neuropsychology (pp. 1-14). Routledge.
• Koziol, L. F., Beljan, P., Bree, K., Mather, J., & Barker, L. (2016). Large-Scale Brain Systems and Neuropsychological Testing: An Effort to Move Forward. Switzerland: Springer International Publishing.
• Magistro, D., Takeuchi, H., Nejad, K. K., Taki, Y., Sekiguchi, A., Nouchi, R., Kotozaki, Y., Nakagawa, S., Miyauchi, C. M., Iizuka, K., Yokoyama, R., Shinada, T., Yamamoto, Y., Hanawa, S., Araki, T., Hashizume, H., Sassa, Y., & Kawashima, R. (2015). The relationship between processing speed and regional white matter volume in healthy young people. PLOS One, 10(9). [journals.plos.org]
• Seidl, A. H. (2014). Regulation of conduction time along axons. Neuroscience, 276, 126–134. [doi.org]
• Goldberg, Elkhonon (2017). Executive Functions in Health and Disease. London: Elsevier Inc.

Dr Paul Beljan

Dr Paul Beljan is a pediatric neuropsychologist practicing in Scottsdale, AZ. He is a past president of the American Board of Pediatric Neuropsychology (ABPdN) and served on the Arizona Board of Psychology Examiners. He holds child diplomate status with the ABPdN and adult diplomate with the American Board of Professional Neuropsychology (ABN).

Dr Beljan co-authored Misdiagnosis and Dual Diagnosis of Gifted Children and Adults: ADHD, BiPolar, OCD, Depression, and Other Disorders. He also co-authored Large Scale Brain Systems and Neuropsychological Assessment: An Effort to Move Forward. Dr Beljan lectures nationally and internationally about gifted intellect, among other neuropsychological topics. He also is a nationally retained forensic expert.

Extracts from Dystinct Magazine