Variability of cognitive development in children with Down syndrome: relevance of good reasons for using the cluster procedure.
Kids with Down syndrome split into four thinking profiles, so test skills before picking lessons.
01Research in Context
What this study did
Lawer et al. (2009) looked at 88 French kids with Down syndrome. They used cluster math to sort the kids by thinking skills, not age.
The goal was to see if kids with the same label still learn in different ways.
What they found
The numbers made four clear groups. Each group had its own pattern of strengths and needs.
Age did not decide the group. Two kids of the same age could land in different groups.
How this fits with other research
Mélia et al. (2023) did the same cluster math on 194 kids with mixed NDD labels. They also found three clean profiles, showing the idea works past Down syndrome.
Némorin et al. (2025) repeated the plan with 458 newly diagnosed ASD kids and again found four subtypes. DSM-5 labels alone miss this spice.
Dolezal et al. (2010) carved profiles in kids with ID but saw no behavior differences across them. This seems to clash with Lawer et al. (2009), yet the 2010 paper only checked broad behavior checklists, not fine cognitive skills. When you zoom in on thinking tests, the profiles pop out.
Why it matters
Stop using age or the Down syndrome label to pick goals. Run brief tests of memory, language, and problem solving, then match teaching to the child’s cluster. Swap worksheets for visuals for kids in the low-verbal cluster. Push rapid naming games for kids in the strong-rote cluster. One size hurts.
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02At a glance
03Original abstract
The main goal of this cross-sectional study was to demonstrate that, in addition to a main change during childhood, the cognitive development of children with Down syndrome (DS) is characterized by interindividual variability in their cognitive functioning. Eighty-eight French children with DS took part in this experiment. They were divided into six chronological age groups: 6 years (N=9), 7 years (N=19), 8 years (N=18), 9 years (N=19), 10 years (N=14) and 11 years (N=9). They were assessed by means of the Differential Scales of Intellectual Efficiency. This test, composed of six independent scales, measures verbal abilities and nonverbal reasoning abilities. Initial analyses of the verbal and nonverbal subtest scores indicated a main change in cognitive skills. We then used a clustering approach to identify four cognitive profiles that distinguished the children with DS independently of age and gender. The results confirm that there is a growth in the cognitive skills of DS children. They also suggest that the cognitive functioning of DS children is characterized by different individual profiles. Implications for more fine-tuned research and intervention efforts are discussed.
Research in developmental disabilities, 2009 · doi:10.1016/j.ridd.2008.10.009