Developmental Trajectories in Siblings of Children with Autism: Cognition and Language from 4 Months to 7 Years

We compared the cognitive and language development at 4, 14, 24, 36, 54 months, and 7 years of siblings of children with autism (SIBS-A) to that of siblings of children with typical development (SIBS-TD) using growth curve analyses. At 7 years, 40% of the SIBS-A, compared to 16% of SIBS-TD, were identified with cognitive, language and/or academic difficulties, identified using direct tests and/or parental reports. This sub-group was identified as SIBS-A-broad phenotype (BP). Results indicated that early language scores (14–54 months), but not cognitive scores of SIBS-A-BP and SIBS-A-nonBP were significantly lower compared to the language scores of SIBS-TD, and that the rate of development was also significantly different, thus pinpointing language as a major area of difficulty for SIBS-A during the preschool years

Pragmatic Language and School Related Linguistic Abilities in Siblings of Children with Autism

Siblings of probands with autism spectrum disorders are at higher risk for developing the broad autism phenotype (BAP). We compared the linguistic abilities (i.e., pragmatic language, school achievements, and underling reading processes) of 35 school-age siblings of children with autism (SIBS-A) to those of 42 siblings of children with typical development. Results indicated lower pragmatic abilities in a subgroup of SIBS-A identified with BAP related difficulties (SIBS-A-BAP) whereas school achievements and reading processes were intact. Furthermore, among SIBS-A-BAP, significant negative correlations emerged between the severity scores on the Autism Diagnostic Observation Schedule and full and verbal IQ scores. These results are discussed in the context of the developmental trajectories of SIBS-A and in relation to the BAP