Differentiating ASD from DLD in Toddlers

Abstract

Until recently children with autism spectrum disorders (ASD) were rarely diagnosed before the age of 3 to 4 years. But a major thrust of current research has been to lower the age of identification, due in part to evidence supporting the effectiveness of early intervention. Late talkers -- toddlers who appear to be developing normally but do not begin speaking, acquire words very slowly, and do not begin combining words at the typical ages --are also typically seen in their second year or early in the third year of life. This report presents the findings of a comparison of toddlers who received clinical diagnoses of ASD and those who were clinically diagnosed as DLD in order to examine the patterns of behavior in the second and third years of life in these two groups. Findings suggest that, when matched on expressive language level, toddlers with ASD and DLD are similar, and less skilled than toddlers with TD, in their use of gaze to regulate interactions, their ability to share emotions with others, to engage in back-and-forth interactions, their rate of communication, and the range of sounds and words produced. The children with DLD were similar to those with TD, and higher than those with ASD, in terms of their nonverbal cognitive skills, use of gestures to communicate, use of pretend play, and ability to respond to language. Children with DLD did show some weaknesses in interpersonal skills -- such as sharing affect, using gaze, and initiating communication. However, their ability to engage in pretend play, use gestures to communicate and respond to language are sufficient to differentiate them from age-mates with ASD. The clinical implications of these findings are discussed.

Figure 1

Scores for Three Groups on Mullen Scales of Early Learning (Mullen, 1995) Key: VR: Visual reception FM: Fine motor EL: Expressive language RL: Receptive language ASD: Autism spectrum disorder DD: Developmental language delay TD: Typical development

Figure 2

Scores for Three Groups on Communication and Symbolic Behavior Scales (Wetherby & Prizant, 2003). Key: Emot: Emotion, Gaze, and Reciprocity Comm: Communication Gest: Gesture use Sound: Sounds produced Word: Words used Under: Understanding of single words Object: Use of objects in play schemes ASD: Autism spectrum disorder DD: Developmental language delay TD: Typical development