Assessment & Research

Development of non-verbal intellectual capacity in school-age children with cerebral palsy.

Smits et al. (2011) · Journal of intellectual disability research : JIDR 2011
★ The Verdict

Kids with milder CP motor types gain non-verbal reasoning faster between ages 5-9, so tailor academic demand to motor level, not just IQ.

✓ Read this if BCBAs writing IEPs or skill plans for school-age students with CP.
✗ Skip if Clinicians who only serve verbal adults or non-CP populations.

01Research in Context

01

What this study did

Carter et al. (2011) followed kids with cerebral palsy for four years. They used Raven’s Coloured Progressive Matrices each year to watch non-verbal IQ grow.

Doctors also rated how tight or floppy each child’s muscles were. The team asked: does motor type or severity change the speed of mental growth?

02

What they found

Raw puzzle scores went up each year, but IQ scores stayed flat. Kids with milder motor limits and spastic CP climbed faster than kids with dyskinetic CP.

In plain words: bodies that move more easily let the brain show more of its true power.

03

How this fits with other research

Asano et al. (2025) later widened the age window and added MACS levels. They saw the same split after about five years, giving the 2011 result a longer shelf life.

Hopkins et al. (2023) looked deeper into the same test. Total scores matched, but kids with CP made different kinds of mistakes. The 2011 numbers are still true; just read the errors too.

Whittingham et al. (2010) showed motor severity predicts social growth in preschoolers. W et al. now link it to thinking growth in school age. Together they map one clear line: moving better means learning better.

04

Why it matters

When you write an IEP, set higher math or problem-solving goals for kids at GMFCS levels I-II. Save more time for alternative access and response modes for kids at levels IV-V. Expect flat standard scores even when you see real gains in raw work; document both numbers so parents see progress that IQ hides.

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Pull the child’s GMFCS or MACS level, then raise or lower task difficulty one step to match that motor demand.

02At a glance

Intervention
not applicable
Design
other
Sample size
91
Population
other
Finding
positive
Magnitude
small

03Original abstract

BACKGROUND: Children with cerebral palsy (CP) are at greater risk for a limited intellectual development than typically developing children. Little information is available which children with CP are most at risk. This study aimed to describe the development of non-verbal intellectual capacity of school-age children with CP and to examine the association between the development of non-verbal intellectual capacity and the severity of CP. METHODS: A longitudinal analysis in a cohort study was performed with a clinic-based sample of children with CP. Forty-two children were assessed at 5, 6 and 7 years of age, and 49 children were assessed at 7, 8 and 9 years of age. Non-verbal intellectual capacity was assessed by Raven's Coloured Progressive Matrices (RCPM). Severity of CP was classified by the Gross Motor Function Classification System, type of motor impairment and limb distribution. manova for repeated measurements was used to analyse time effects and time × group effects on both RCPM raw scores and RCPM intelligence quotient scores. RESULTS: The development of non-verbal intellectual capacity was characterised by a statistically significant increase in RCPM raw scores but no significant change in RCPM intelligence quotient scores. The development of RCPM raw scores was significantly associated with the severity of CP. Children with higher levels of gross motor functioning and children with spastic CP showed greater increase in raw scores than children with lower levels of gross motor functioning and children with dyskinetic CP. CONCLUSIONS: Children with CP aged between 5 and 9 years show different developmental trajectories for non-verbal intellectual capacity, which are associated with the severity of CP. The development of non-verbal intellectual capacity in children with less severe CP seems to resemble that of typically developing children, while children with more severe CP show a limited intellectual development compared to typically developing children.

Journal of intellectual disability research : JIDR, 2011 · doi:10.1111/j.1365-2788.2011.01409.x