Abstract/Summary

Most individuals with Down syndrome (DS) have some sort of speech and language deficit and this is prominent from an early age. Previous research has identified that various early precursors may be important for language development for typically developing (TD) children including: joint attention and maternal interactive style. However, there is limited research in this area for children with DS. Part 1 of the thesis includes a study looking at whether joint attention and maternal interactive style are important for concurrent language outcomes for a group of children with DS aged 17-23 months and a TD group with comparable non-verbal mental age. The results found that responding to joint attention was a significant predictor of concurrent language scores for infants with DS and maternal positive expressed emotion was a significant predictor for TD children. Part 2 of the thesis was a longitudinal intervention study focusing on improving responding to joint attention for infants with DS at 17-23 months with the view to improving speech and language outcomes at 30-35 months. The results of the intervention found responding to joint attention could be improved through an early intervention and at 30-35 months there was a significant difference for receptive vocabulary with the intervention group being reported to understand more words than the control group. Finally, part 3 investigated which early precursors were associated with concurrent and longitudinal language and vocabulary outcomes at 24-30 months and 30-35 months for children with DS. Non-verbal mental age emerged as an important predictor. The results are discussed in line with previous research. The theoretical and practical implications are discussed as well as ideas for future research.