Countering the claim among researchers that language learning in children with Down syndrome ends during the teen-age years, a new study from the University of Wisconsin-Madison suggests that individuals with Down syndrome can benefit from language intervention programs during adolescence.
Down syndrome is a developmental disability resulting from an extra copy of chromosome 21, and it affects about 5,000 newborns in the United States every year. A century ago, most children with this disability reached the age of only 9; today, they live well beyond their 50s.
Most children begin learning language skills, such as grammar and speaking, at rapid rates early in their lives. Children with Down syndrome, however, typically experience delays in language development, learning more slowly and at varying rates.
"There's a fanning out of skills in individuals that isn't seen in normally developing children," explains Robin Chapman, the study's primary investigator and a professor emeritus of communicative disorders at UW-Madison's Waisman Center, a facility dedicated to advancing the understanding of developmental disabilities. For example, vocabulary learning may progress much more rapidly than the learning of sentence structure, she says.
Though all these skills continue to improve throughout childhood, Chapman says that some researchers have claimed that the skills begin to plateau as a child with Down syndrome reaches adolescence. As a result of this claim, she notes, educational opportunities for teen-agers with this disability generally shift away from language learning.
Chapman's study, on other hand, shows that certain language skills continue to improve well beyond the teen-age years, suggesting that adolescents with Down syndrome should continue programs for language learning.
For the last six years, Chapman and her colleagues have charted the trajectory of learning skills and memory abilities in 31 individuals with Down syndrome who were ages 5-20 at the study's start. Through comprehension tests and storytelling tasks, they measured each person's ability to understand complex grammar (language comprehension) and his or her ability to speak it (language expression).
While Chapman found that some language skills may stop developing as these children reach late adolescence, she also found that language expression skills continue to improve well into young adulthood - and that their development depends on the development of language comprehension skills, which do tend to plateau.
The longitudinal pattern of language learning in individuals with Down syndrome, says Chapman, shows that language comprehension skills quickly develop during childhood, but that development slows down as the child reaches the teen-age years. Language expression skills run a different course. "The biggest gap in language learning occurs between language comprehension and expression," she says. But, unlike the other set, expression skills continue to improve throughout adolescence.
Chapman found, however, that the continued development of language expression depends on at least maintaining comprehension skills.
"The rate of change in expressive learning skills," she says, "is predicted by the rate of change in language comprehension skills." For example, if an adolescent acquires the ability to understand complex grammar more slowly, he will also acquire the ability to speak that grammar more slowly.
These findings, says Chapman, point to the importance of continuing language intervention during the teen-age years: "The study's findings suggest that there should continue to be language work in both comprehension and expression throughout teen-age and young adult years."
Furthermore, Chapman suggests that, because of the gap in the development of the two skill sets, language instruction should alternate its emphasis between them.
"Kids with Down syndrome can accomplish a lot," Chapman says. "Think of Chris Burke who starred in the television show, 'Life Goes On.' We need to maximize the opportunities so they can accomplish even more."
The study was funded by the National Institutes of Health and the National Down Syndrome Society.
The findings are published in the October issue of the Journal of Speech, Language and Hearing Research.
Emily Carlson 608-262-9772, firstname.lastname@example.org