Speech Delays and Early Social Communication and Symbolic Functioning in Toddlers with and without Autism

Background: Prelinguistic communication skills such as joint attention, gesture use, and shared positive affect distinguish autism spectrum disorders (ASD) from typical development and nonspectrum developmental delays (DD) in the first few years of life (e.g., Osterling et al., 2002; Wetherby et al., 2004) and predict later language development (e.g., Mundy et al., 1990; Wetherby et al., 2007). In addition, early language functioning is one of the strongest predictors of outcome in ASD (Luyster et al., 2007; Billstedt et al., 2007). Understanding how early expressive speech/language skills relate to social communication skills in children with ASD will expand knowledge of the key factors related to ASD development.

Objectives: The purpose of this study was to examine the concurrent relationship between early expressive speech/language and social communication, expressive speech/language, and symbolic functioning, the three measured components of the Communication and Symbolic Behavior Scales Developmental Profile Behavior Sample (Wetherby & Prizant, 2002) - in a sample of young children evaluated for ASD or DD.

Methods: The Behavior Sample (BS), a face-to-face evaluation of the child interacting with a parent and clinician, was completed with 55 children evaluated for ASD or other DD. Following a research evaluation, 31 children were diagnosed with ASD (mean age=31.7 months, SD=5.2) and 24 comprised a nonspectrum group (mean age=26.0 months, SD=5.8). BS raw scores were computed for the Social (emotion and eye gaze, communication, gestures), Speech (sounds, words), and Symbolic (understanding, play) composites. We examined these composites in relation to parent reports of expressive language, including number of words produced (from the MacArthur-Bates Communicative Development Inventories; Fenson et al., 1993) and age of first words (from the Toddler ADI-R; Lord et al., 2004).

Results: Preliminary findings revealed that 45% (14/31) of children with ASD and 67% (16/24) of children in the nonspectrum group were reported to use words when assessed on the Toddler ADI-R. Using age-matched groups, significant large correlations (spearman’s rho) were found between number of words produced and Social and Speech in children with ASD, with a nonsignificant moderate correlation between words produced and Symbolic. In the nonspectrum group, number of words produced was significantly correlated with Speech, but not Social or Symbolic. Results of Cox Regression survival analyses revealed that the children with ASD attained first words significantly later than children in the nonspectrum group (p=.015). In ASD, age of first words was significantly related to Social (p=.015) and Speech (p=.000), but not Symbolic (p=.097). In the nonspectrum group, age of first words was not significantly related to Social (p=.278), Speech (p=.063), or Symbolic (p=.173).

Conclusions: Preliminary results indicate that social communication skills in a sample of young children with ASD are strongly related to expressive speech/language both in terms of age of first words and current words produced. It is possible that language and social deficits may be more interdependent in young children with ASD but become more independent with age. Further analysis of larger samples and of different ages will be important in clarifying the relationship between language and other deficits in ASD.