Do Infants With Down Syndrome Show an Early Receptive Language Advantage?

Purpose The study explored longitudinally the course of vocabulary and general language development in a group of infants with Down syndrome (DS) compared to a group of typically developing (TD) infants matched on nonverbal mental ability (NVMA). Method We compared the vocabulary and general language trajectories of the two groups in two ways: (a) at three time points during a 12-month period and (b) at two time points when the groups had made equal progress in NVMA (a period of 6 months for the TD infants vs. 12 months for the infants with DS). Results The TD group had overtaken the DS group on all general language and vocabulary measures by the end of the 12-month period. However, expressive communication and expressive vocabulary were developing at the same rate and level in the two groups when examined over a period in which the two groups were matched in gains in NVMA. Furthermore, the infants with DS showed a receptive language advantage over the TD group; this group's auditory comprehension and receptive vocabulary scores were superior to those of the TD group at both time points when NVMA was accounted for. Conclusion The results shed light on the widely reported discrepancy between expressive and receptive language in individuals with DS. Although infants with DS appear to be developing language skills more slowly than chronological age TD peers, when NVMA is taken into account, infants with DS do not have expressive language delays, and they seem to show a receptive language advantage.

How do maternal interaction style and joint attention relate to language development in infants with Down syndrome and typically developing infants?

Down syndrome (DS) is more detrimental to language acquisition compared to other forms of learning disability. It has been shown that early social communication skills are important for language acquisition in the typical population; however few studies have examined the relationship between early social communication and language in DS. The aim of the current study is to compare the relationship between joint attention and concurrent language skills, and maternal interactive style and concurrent language skills in infants with DS and in typically developing (TD) infants matched for mental age. We also investigated if these relationships differ between children with DS and TD children. Twenty-five infants with DS (17-23 months) and 30 TD infants (9-11 months) were assessed on measures of joint attention, maternal interactive style and language. The results indicated a significant positive relationship between responding to joint attention (RJA) and concurrent language for the DS group, and a significant positive relationship between maternal positive expressed emotion (PEEM) and concurrent language for the TD group. We hypothesise that different social-communication factors are associated with language skills in DS, at least between 17 and 23 months of age compared to TD infants of similar non-verbal and general language abilities.

Longitudinal predictors of early language in infants with Down syndrome: A preliminary study.

PURPOSE: Children with Down syndrome (DS) typically have marked delays in language development relative to their general cognitive development, with particular difficulties in expressive compared to receptive language. Although early social communication skills, including gestures and joint attention, have been shown to be related to later language outcomes in DS, knowledge is limited as to whether these factors exclusively predict outcomes, or whether other factors (e.g. perceptual and non-verbal skills) are involved. This study addressed this question. METHOD: Longitudinal data for a group of infants with DS (n = 14) and a group of typically-developing (TD) infants (n = 35) were collected on measures that have been shown to predict language in TD infants and/or those with developmental delays. These included: non-verbal mental ability, speech segmentation skills, and early social communication skills (initiating and responding to joint attention, initiating behavioural requests). RESULTS: Linear regression analyses showed that speech segmentation and initiating joint attention were the strongest predictors of later language in the TD group, whereas non-verbal mental ability and responding to joint attention were the strongest predictors of later language for infants with DS. CONCLUSIONS: Speech segmentation ability may not determine language outcomes in DS, and language acquisition may be more constrained by social communication and general cognitive skills.