Measuring intellectual ability in children with cerebral palsy: can we do better?
Motor-free IQ short forms raise scores five points in kids with cerebral palsy by removing block design and writing tasks.
01Research in Context
What this study did
The team gave preschool kids with cerebral palsy two kinds of IQ tests. One was the regular WPPSI-III. The other was a short form that cut out the motor-heavy parts.
They wanted to see if taking away pointing, building, and writing tasks changed scores.
What they found
Kids finished more items on the motor-free short form. Their IQ scores also rose about five points.
The regular test made many kids quit early because they could not move the blocks or pencil fast enough.
How this fits with other research
Wormald et al. (2019) saw the same five-point gap in autistic children. Their WISC-IV scores were lower than Leiter-3 scores, echoing the motor problem.
Nader et al. (2016) added Raven’s Matrices and found the same lift, showing the issue crosses diagnoses.
Lough et al. (2016) looked at kids with Developmental Coordination Disorder. Their WISC-IV Processing Speed scores were low for the same reason: the test timed hand movements.
Together, these papers say timed or motor-loaded subtests can hide real ability in any child who moves or writes slowly.
Why it matters
If you test a child with motor delays, swap motor-heavy subtests for motor-free ones. You will get a fuller picture and avoid an underestimation label. A five-point bump can move a child from borderline to low-average, opening doors to less-restrictive classrooms.
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02At a glance
03Original abstract
Standard intelligence tests such as the WPPSI-III have limitations when testing children with motor impairment. This study aimed to determine the proportion of children with cerebral palsy with sufficient verbal and motor skills to complete the WPPSI-III, to determine their comparative ability to complete tasks with and without a significant motor component, and to investigate short forms of the WPPSI-III as alternatives. Participants were 78 of 235 eligible 4-5 year old children with cerebral palsy resident in the Australian state of Victoria. Verbal IQ (VIQ), Performance IQ (PIQ), and Full-scale IQ (FSIQ) were determined using the WPPSI-III. Initial screening for pointing and verbal abilities determined which tests were attempted. The impact of speed was investigated by comparing scores on the Block Design subtest with and without an imposed time limit. FSIQ scores were calculated from two short forms of the WPPSI-III and compared to the full form. On screening, 16 children had inadequate pointing (14) and verbal abilities (2). FSIQ was obtained in 62 (82%) children. Strong associations were seen between completion of the entire test battery and topographical pattern, level of manual ability and level of gross motor function. Scores on subtests requiring manual ability were depressed relative to other scores. Children performed better using short forms of the WPPSI-III and, for a minority, when time limits were disregarded. In summary, children with cerebral palsy often lack the fine and gross motor skills necessary to complete the WPPSI-III, scoring relatively poorly on tasks requiring a fine motor response. Using short-form estimations of FSIQ comprised of subtests without a significant fine motor component has the potential to increase a child's FSIQ by approximately 5 points. These findings have important clinical implications when assessing a child with both motor and cognitive limitations.
Research in developmental disabilities, 2014 · doi:10.1016/j.ridd.2014.06.019