Handicaps and the development of skills between childhood and early adolescence in young people with severe intellectual disabilities.
Kids with severe ID keep adding real-life skills, but standard scores will still drop—track age-equivalents to see the growth.
01Research in Context
What this study did
Edgin et al. (2005) followed kids with severe intellectual disability for five years. They tracked communication and daily-living skills from childhood into early teens.
The team used age-equivalent scores and standard scores. This let them see real growth and compare kids to typical peers.
What they found
Kids gained small but real skills. Age-equivalent scores went up in talking and self-care.
Standard scores still dropped. The gap between the kids and typical peers widened each year.
How this fits with other research
Onnivello et al. (2024) saw the same pattern in Down syndrome. Age scores rose while standard scores fell. This shows the trend is not just one group.
Austin et al. (2015) tracked physical fitness in mild ID. Skills improved, but the peer gap stayed. The same "grow yet lag" picture appears across domains.
Sprague et al. (1984) found slow language gains in kids once called "aphasic." O et al. repeat this with a broader severe-ID sample, proving the climb is steady but slow.
Why it matters
Stop waiting for standard scores to rise. Watch age-equivalent charts instead. If a teen now dresses like a six-year-old, celebrate that two-year jump. Use it to set next targets and show families real progress.
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02At a glance
03Original abstract
BACKGROUND: While a number of studies have examined the development of skills in children with intellectual disabilities (ID), most have been cross-sectional, most have been concerned with particular syndromes such as Down's syndrome or autism and few have attempted to identify factors associated with improvements in skills. METHODS: From a sample of 111 children with severe ID who had been identified from the registers of six special schools at 4-11 years of age, 82 were traced and reassessed 5 years later at the age of 11-17 years. On both occasions, information on the children's handicaps and skills was collected by interviewing their main carers using a shortened version of the Vineland Adaptive Behaviour Scales and the Disability Assessment Schedule. RESULTS AND CONCLUSIONS: There were small but statistically significant improvements in Vineland age-equivalent communication and daily living skills scores, but not in Vineland Socialization scores, over the 5-year period of follow-up. This pattern of improvement was observed in most aetiological subgroups. Improvement in skills was greatest in younger children, and was associated with reductions in behaviour problems and in levels of parental stress. In spite of the improvements in age-equivalent scores, Vineland standard scores showed significant declines over the same period of time, indicating that the improvements observed were smaller than would be expected in a general population sample of children of the same age. The dangers of using standard scores or quotients to quantify the level of functioning of children with severe ID are highlighted.
Journal of intellectual disability research : JIDR, 2005 · doi:10.1111/j.1365-2788.2005.00716.x