The Origins of the SLI Phenotype in the Early Language Development of Children with ASD

Friday, May 15, 2015: 11:30 AM-1:30 PM
Imperial Ballroom (Grand America Hotel)
L. Naigles1, S. Ozonoff2, S. J. Rogers3 and A. M. Mastergeorge4, (1)University of Connecticut, Storrs, CT, (2)MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis Medical Center, Sacramento, CA, (3)University of California at Davis, Sacramento, CA, (4)Family Studies and Human Development, University of Arizona, Tucson, AZ

Researchers have proposed that a subgroup of children with ASD have a specific language impairment (SLI); that is, their nonverbal functioning is unimpaired but their structural language is below the normal range.1,2 It is unclear how commonly this phenotype is observed in ASD.  Moreover, it is unclear whether indications of SLI can be observed in children younger than 4 years of age. Understanding language profiles of young children with ASD provides important information about stability and variability in language symptomatology and furthers our understanding of emergent language phenotypes.


To examine the prevalence of SLI in a large group of 5-year-olds with ASD, and to investigate behavioral precursors when these children were three years of age.

Methods:   98 families of children with ASD participated in a large-scale study of autism phenotypes at two ages, including three years old (Mage=37.61 months; MMullenVR T-score=30.11 (SD=13.71) and five years old (Mage=68.63 months; MDAS NV SS-score=81.39, SD=27.51).  Three-year-olds were administered the Mullen and Vineland; 70 were also administered the EOWPVT and PPVT. Five-year-olds were administered the ADOS, DAS Verbal Comprehension task,  EOWPVT and PPVT.


The 5-year-olds were divided into four exhaustive subgroups: V/NV<70 (both Verbal and Nonverbal below 70; n=34), V/NV>80 (both Verbal and Nonverbal scores above 80; n=36); V/NVnotdiscrepant (Nonverbal above 70, Verbal lower than Nonverbal BY LESS THAN 10 points; n=19); Possible SLI (Nonverbal above 70, Verbal AT LEAST 15 POINTS BELOW Nonverbal; n=9).  Table 1 shows the mean scores.  One-way ANOVAs revealed that the groups differed significantly on all measures (Fs>35.0, ps<.001). Post-hoc Scheffe tests indicated that on the ADOS and Nonverbal scores, the Possible SLI group differed significantly from the V/NV<70 and V/NV>80 groups, but not from the V/NVnotdiscrepant group.  On the Verbal scores, all groups differed significantly from each other.

The performance of these four subgroups two years earlier (at 3 years of age) was then examined for evidence of behavioral precursors.  One-way ANOVAs revealed significant effects of group for the ADOS, Mullen VR, Mullen RL, and Mullen EL (Fs>35.0, ps<.001).  Post-hoc Scheffe tests indicated that the Possible SLI group differed significantly from the V/NV>80 and V/NVnotdiscrepant  groups on the Mullen EL (p<.01), and from the V/NV>80 group on the Mullen VR (p<.001).  However, the Possible SLI group did not differ from the V/NV<70 group on any score at 3 years of age. None of the groups differed on Vineland Socialization score at 3 years of age.


At five years of age, approximately 10% of the sample met criteria for SLI if language scores on the available standardized tests were considered.  Possible SLI children at age 5 did not differ from V/NVnotdiscrepant children at the same age on their nonverbal or ADOS scores, supporting the argument for an impairment that is language-based.  However, two years earlier, Possible SLI children did not differ from V/NV<70 children on Mullen, Vineland, or ADOS scores.  It remains difficult to predict which children, at diagnosis, will manifest an SLI.  Moreover, language impairment in ASD may encompass both lexical and grammatical functioning.