Prediction from early development to later achievement has the potential to improve clinical and educational service delivery as well as to inform developmental theory. In this longitudinal study, we asked how well can educational achievement measured in the final year (Grade 9, age 15) of compulsory education--both overall and for outcomes in the…

Forty-two adolescents with Down syndrome (DS) ages 10 to 21 years completed a battery of language and phonological memory measures twice, 2 years apart. Individual differences were highly stable across two years. Receptive vocabulary scores improved, there was no change in receptive or expressive grammar scores, and nonword repetition scores…

We analyzed several studies of non-verbal communication (prosody and facial expressions) completed in our lab and conducted a secondary analysis to compare performance on receptive vs. expressive tasks by adolescents with ASD and their typically developing peers. Results show a significant between-group difference for the aggregate score of…

Purpose: In this study, the authors examined the expressive language abilities of a subset of highly verbally expressive adolescents and young adults with Down syndrome (DS) and those with fragile X syndrome (FXS) for evidence of syndrome-related differences. FXS gender differences were also examined in an exploratory fashion. Method: The authors…

The spontaneous expressive language abilities of 9 severely brain-injured children/adolescents and age- matched normal controls were examined over a 12-month period following injury. Subjects demonstrated improvement on the majority of measures, but only a few reached the level of their control subjects. Interindividual variability was…

Sign language production of 14 low-functioning students (ages 9 to 20) with autistic disorder were examined. The location aspect of signs was produced more accurately by subjects than either the handshape or movement aspects. Wide individual differences were observed. Sign vocabulary size and accuracy was correlated with performance on two…

Children and adolescents with Down syndrome show an emerging profile of speech and language characteristics that is typical of the syndrome (Chapman & Hesketh, 2000; Chapman, 2003; Abbeduto & Chapman, 2005) and different from typically developing children matched for nonverbal mental age, including expressive language deficits relative to…