The concurrent and predictive validity of the Dutch version of the Communicative Development Inventory in children with Down Syndrome for the assessment of expressive vocabulary in verbal and signed modalities

Developing a screening instrument for underlying core domains of communicative competence in children with communication support needs

A socio-neurocognitive approach to augmentative and alternative communication (AAC) shows several underlying domains of communicative competence: Attention, perception, cognition, memory, orientation, socio-emotional development, motor skills, and language. To determine developmental markers of these underlying core domains of communicative competence in children with communication support needs, we developed a new screening instrument. The present article consists of three consecutive studies. In study 1, we constructed the first version of the screening instrument based on a sample of both children without disabilities and children with Down syndrome. In study 2, we confirmed the reliability (i.e., internal consistency) of the screening instrument in a new group of young children with typical development and established concurrent validity with the Early Language Scale. In study 3, we established concurrent validity with the Communication Matrix in a clinical sample of children with communication support needs. The screening instrument can be used in clinical practice as part of AAC assessment to provide comprehensive insights into strengths and weaknesses in the underlying core domains of communicative competence of children with communication support needs.

Word type and modality in the emerging expressive vocabularies of preschool children with Down syndrome

BACKGROUND

Previous studies have explored the size and word type composition (nouns, predicates, etc.) of expressive vocabularies of preschool children with Down syndrome, both spoken and signed. Separately, overall preferences for modality of expression have also been explored.

AIMS

To extend previous findings by describing the relationships between expressive vocabulary size and both word type and modality of expression in the preschool period including changes to modality preference over time.

METHODS & PROCEDURES

Mothers of 35 children with Down syndrome, aged 36-66 months and attending the same early intervention programme, completed a version - with both spoken word and sign options - of the New Zealand MacArthur-Bates Communicative Development Inventory (CDI): Words and Sentences. Most mothers completed the CDI on multiple occasions across the duration of the study. Completions (n = 114) were analysed cross-sectionally and longitudinally in terms of (1) word type relative to vocabulary size, (2) modality of expression relative to word type and vocabulary size, and (3) individual trajectories in vocabulary size and modality of expression.

OUTCOMES & RESULTS

(1) Word type relative to vocabulary size was similar to previous studies with a greater proportion of the SOCIAL words being present in the children's vocabularies throughout, followed by NOUNS, PREDICATES and CLOSED class words, with proportions converging as vocabulary sizes increase. (2) An initial spoken word preference for SOCIAL and CLOSED class words and sign preference for NOUNS and PREDICATES was found, with more spoken words in larger vocabularies overall. (3) Individual trajectories were highly variable and also revealed temporary points of regression in overall expressive vocabulary size in some children. Children who shifted from reliance on sign to predominantly spoken word expression did so at different ages and at different vocabulary sizes. At school entry, while most of the children used both modalities, some children continued to rely on sign for most vocabulary items whereas others used only spoken words.

CONCLUSIONS & IMPLICATIONS

An appreciation of both the general trends and potential for individual variation in vocabulary structure, modality of expression and change over time will better position clinicians and education specialists to provide individually tailored support to both preschool and school-aged children with Down syndrome.

WHAT THIS STUDY ADDS

What is already known on this subject Preschool children with Down syndrome have been shown to demonstrate developmental patterns in overall conceptual vocabulary size and word type development broadly similar to typical development. The use of signed vocabulary has also been explored, but independently from word type development and with less attention to individual trajectories in either vocabulary size development or modality preferences throughout the preschool period than is necessary for clinical use. What this paper adds to existing knowledge This study found interactions between word type and modality of expression in relation to vocabulary size as well as a few temporary vocabulary size regressions similar to those found in much younger typically developing children. An initial spoken word preference for social and closed class words, and sign preference for nouns and predicates, was followed by a general trend towards spoken words for all word types as vocabulary (with some fluctuations) increased over time. Children demonstrated considerable individual variation in size of vocabulary and age at which they pivoted from a signed to a spoken word preference. Moreover, while most children used both modalities at school entry, a few retained a sign-only vocabulary and others had moved fully onto spoken word-only expression. What are the potential or actual clinical implications of this work? An understanding of both the general trends and individual variation in vocabulary structure and modality of expression development will better position clinicians and educational specialists to provide individually tailored support to children with Down syndrome.

The Italian Words and Sentences MB-CDI: normative data and concordance between complete and short forms

One of the most popular and widely used parent report instruments for assessing early language acquisition is the MacArthur-Bates Communicative Development Inventories (MB-CDI). This study compares normative data of the Italian Words and Sentences complete form (WS-CF) and short form (WS-SF). The samples included 752 children for the WS-CF and 816 children for the WS-SF designed for children aged 18-36 months. The concordance between WS-SF and WS-CF is analyzed in a subgroup of 65 children. The results revealed strong correlations between WS-CF and WS-SF in both lexical and grammar skills as well as strong relationship between lexical and grammar skills. There was a high percentage agreement (97%) between the two forms for scores below the 10th percentile, suggesting that the two forms may be used interchangeably in order to describe vocabulary and grammatical development.

Predictors of receptive and expressive vocabulary development in children with Down syndrome

PURPOSE

There is a lack of longitudinal data on predictors of vocabulary development in children with Down syndrome (DS). In typically developing children, many internal and external predictors of vocabulary development have been determined before. The purpose of the present study was to investigate the role of these variables in the receptive and expressive vocabulary development of children with DS.

METHOD

The present study used a longitudinal design in young children with DS to study the vocabulary development over a period of 1.6 years and investigated the possible predictive role of child-related and environmental variables.

RESULT

Receptive vocabulary development was best predicted by the adaptive level of functioning and early receptive vocabulary skills. Expressive vocabulary development was best predicted by the adaptive level of functioning, receptive vocabulary, maternal educational level, level of communicative intent of the child, attention skills and phonological/phonemic awareness.

CONCLUSION

A wide range of internal and external predictors for vocabulary development of children with DS was found. Predictors resemble those predicting vocabulary development in peers with typical development between 1 and 6 years of age, as identified in other studies.

Core vocabulary of young children with Down syndrome

The aim of this study was to develop a core vocabulary list for young children with intellectual disabilities between 2 and 7 years of age because data from this population are lacking in core vocabulary literature. Children with Down syndrome are considered one of the most valid reference groups for researching developmental patterns in children with intellectual disabilities; therefore, spontaneous language samples of 30 Dutch children with Down syndrome were collected during three different activities with multiple communication partners (free play with parents, lunch- or snack-time at home or at school, and speech therapy sessions). Of these children, 19 used multimodal communication, primarily manual signs and speech. Functional word use in both modalities was transcribed. The 50 most frequently used core words accounted for 67.2% of total word use; 16 words comprised core vocabulary, based on commonality. These data are consistent with similar studies related to the core vocabularies of preschoolers and toddlers with typical development, although the number of nouns present on the core vocabulary list was higher for the children in the present study. This finding can be explained by manual sign use of the children with Down syndrome and is reflective of their expressive vocabulary ages.