ACQ Vol 13 No1 2011

Research updates

Spoken and written language development in children with Down syndrome Anne van Bysterveldt

I ndividuals with Down syndrome (DS) have a phenotypic spoken and written language profile which includes elements of both delay and disorder, with considerable variation reported (e.g., Miller & Leddy, 1998). Significant advances have been made in understanding the spoken and written language in this population and the directions interventions might take. However, little is known about the language profiles of these children in the New Zealand (NZ) cultural and educational environment. Over the last 5 years, joint research between the Champion Centre and the University of Canterbury has focused on addressing this gap by investigating spoken and written language development in NZ children with DS. The first sizeable national investigation to be carried out in NZ involved 88 school-aged children, comprising an estimated 15% of children with DS receiving instruction in years 1–8 in NZ schools. Children’s parents and teachers completed comprehensive questionnaires investigating the home and school literacy environment. The majority of homes were rich in literacy resources and children and parents read together on a regular basis. However, parents reported that many children took a very passive role during these interactions, that fewer than one third of the children had complete letter name and sound knowledge, and that only 25% of the children were regular independent readers (van Bysterveldt, Gillon, & Foster-Cohen, 2010b). Teachers reported that nearly all children took part in regular classroom reading instruction, most frequently in small groups or in a one-on-one context. Teachers’ reports of children’s literacy skills were largely in line with those of parents. Far fewer children were reported to take part in regular writing compared to reading activities, both in the classroom and for allocated homework. To investigate the development of phonological awareness, letter knowledge and decoding skills, 77 of these children completed further assessments. Results revealed a wide range of phonological awareness and decoding skills with some children demonstrating mastery of phoneme identity and letter knowledge tasks while others were unable to achieve correct scores on any assessment measure. Twenty-four percent of children were unable to read any words correctly and 6.6% were able to decode at a level expected for 7–8 year old children. Analysis of data by age group (5–8 and 9–14) revealed the development of skills with maturation. As a group, older children achieved significantly higher scores than younger children on all measures (van Bysterveldt, Gillon, & Foster-Cohen, 2008b). The 31 children who could decode 10 or more words on a standardised reading test were invited to complete additional assessments of speech, reading accuracy and comprehension, and personal narrative (PN) production. Twenty-six children completed these assessments and produced analysable PN transcripts that were at least 60% intelligible (van Bysterveldt, Westerveld, Gillon, & Foster- Cohen, submitted). Results revealed considerable variability.

Nearly 90% of children were able to produce 50 utterances; however mean length of utterance in morphemes (MLU-M) was generally low with over one-third of children producing PN samples with MLU-M of < 2. High point analysis revealed that most children produced early developing PN narrative structures, with only 4 children producing a PN with a high point. Overall, the results of these investigations identified widespread and persistent spoken and written language disorder in school-aged children with DS. In addition, while home and school literacy environments were generally positive, and children were receiving regular reading instruction, many children were not equipped with the necessary prerequisite skills to enable them to become independent readers. These findings also highlighted the need for early, focused and integrated intervention to facilitate language development and to better prepare children with DS for the language learning environment at school. To investigate the impact of an early intervention strategy, 10 pre-school children with DS participated in an integrated intervention linking spoken and written language and designed to simultaneously facilitate speech production, letter name and sound knowledge and phonological awareness. The intervention contained three components: a parent-led home-based reading program using print referencing techniques to draw the child’s attention to intervention targets, a computer-based program and an activities-based speech therapy component, all focusing on the same speech, letter name and letter sound targets. All 10 children made statistically significant gains on speech production targets and the majority of children also showed an increase in letter knowledge and phonological awareness skills (van Bysterveldt, Gillon, & Foster-Cohen, 2010a). Follow-up assessments after 2 terms of formal schooling revealed 7 of the 10 children made continued improvements in speech and phonological awareness skills and 5 children demonstrated some generalisation of these skills to real word reading and spelling (van Bysterveldt, Gillon, & Foster-Cohen, 2008a). These results suggest an integrated phonological awareness intervention which simultaneously targets speech, phonological awareness and letter knowledge can be effective in facilitating development in these skills for young children with DS. Findings of these studies have identified the need for longitudinal research into spoken and written language development in children with DS to allow for the evaluation of specific early interventions within a preventative framework. The persistent nature of language difficulties in individuals with DS also suggests the need for sustained interventions. The evaluation of home- and classroom-based activities to promote spoken and written language development in this population is also warranted.

Anne van Bysterveldt

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ACQ Volume 13, Number 1 2011

ACQ uiring knowledge in speech, language and hearing