Effectiveness of the Kaufman Brief Intelligence Test in people with Prader-Willi syndrome.
K-BIT is a valid 30-minute IQ screener for Prader-Willi syndrome, but bump adult scores up about 5–7 points.
01Research in Context
What this study did
Researchers checked if the 30-minute Kaufman Brief Intelligence Test (K-BIT) gives the same IQ numbers as the full Wechsler scales in people with Prader-Willi syndrome (PWS).
They tested the kids and the adults with PWS. Each person took both the K-BIT and the Wechsler test on the same day.
What they found
For kids, the two tests matched well. The K-BIT score was within a few points of the Wechsler score.
For adults, the K-BIT usually came out 5–7 points lower. It still tracked ability order, but it slightly underestimated adult IQ.
How this fits with other research
Sajith et al. (2008) also tweaked an IQ tool for a genetic syndrome. They cut language and motor items from the Bayley to get a “cleaner” cognitive score for infants with Down syndrome. Both studies show that small test changes can make scores more fair for specific syndromes.
Colbert et al. (2020) built the 15-minute RAI+ as another quick IQ proxy. Like the K-BIT, it saved time and still tracked well with longer tests. Together, these papers give you a menu of brief screeners when a full IQ battery is too much.
Ohan et al. (2015) followed kids with autism and saw IQ scores climb over time. Their work reminds us that any single test, K-BIT included, is just a snapshot. Re-test yearly if you need to track real growth in PWS.
Why it matters
If you need a fast IQ estimate for school placement or service eligibility, the K-BIT works for kids with PWS and is “good enough” for adults—just add 5–7 points to the adult score before you write the report. Always note the slight underestimate so teams do not under-set expectations.
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02At a glance
03Original abstract
BACKGROUND: Evaluating intelligence using conventional tools is very complex in patients with Prader-Willi Syndrome (PWS), as it is time consuming and requires levels of care that are difficult to sustain for this population. Therefore, we explore the ability of a brief test to assess intelligence in these patients. METHODS: This study included individuals with a genetically confirmed diagnosis of PWS, with regular attendance at transdisciplinary treatment in an institution dedicated to the care of rare diseases in Argentina. The Wechsler Intelligence Scale for Children (WISC-IV), the Wechsler Adult Intelligence Scale (WAIS-III) and the Kaufman Brief Intelligence Test (K-BIT) were used. RESULTS: Correlation was obtained between the scales in paediatric and adult populations. Within the paediatric population, no significant differences were identified between the WISC-IV scale (Wechsler for paediatrics) and the K-BIT (56.4 ± 8.6, vs. 53.4 ± 10.1, P = 0.28), with a good agreement between the methods {intraclass correlation 0.79 [95% confidence interval (CI) 0.15-0.95]}. Regarding the adult population, the discrimination of the WAIS-III scale (Wechsler for adults) and the K-BIT of adults (16 years and over) presented an acceptable concordance [0.77 (95% CI -0.09; 0.93)], although also underestimating the results (58.3 ± 7.2 vs. 51.1 ± 11.2, P < 0.0001). CONCLUSIONS: We observed the feasibility and potential usefulness of a brief intelligence test (K-BIT) in patients with PWS with an acceptable agreement with conventional tools.
Journal of intellectual disability research : JIDR, 2024 · doi:10.1111/jir.13090