Language Disfluency and Cognitive Load in Children with ASD

Background: Higher-functioning children with autism (HFA) may display language on par with typical controls (TD) on standardized measures, yet not use language fluently insocial contexts. Previous observations suggest problems in language fluency may have significant impact on the social communicative interactions of children with HFA.  However, little is known about the extent of language disfluency and its clinical specificity to the syndrome. 

Objectives: A virtual reality public speaking paradigm was used to compare rates of disfluency in children with HFA, children with ADHD, and TD children. In addition, the attention demands were varied to examine the effects of differences in cognitive load on language disfluency.

Methods: Eighty children, divided into younger 8-11 and older 12-16 age groups were assessed.  The sample included four groups of children: 17 HFA with low ADHD symptoms scored on the Conners 3 parent report, 21 with high ADHD symptoms who were called ASD/ADHD comorbid (T-scores > 70), 21 children with ADHD symptoms but no symptoms of ASD, and 21 children with typical development. ASD diagnosis was confirmed with the ADOS. Groups were matched in their Full-scale IQ level with a minimum IQ of 75 necessary to participate in this study. Children viewed a virtual classroom through a head-mounted display. They were asked to answer different questions about their interests and daily activities while viewing 9 targets seated around a large table in a VR classroom. There were three 3-minute conditions: In the Non-Social Attention condition children talked to 9 “lollipop” shaped forms positioned to their left and right at the table; in the Social Attention Condition children talked to avatar “peers”, and in the High-Demand Social Attention Condition they talked to avatars that faded if children did not fixate them every 15 seconds.  . Their speech was audiotaped, transcribed, and then analyzed for seven measures of disfluencies (‘um’, ‘uh’, false starts, repetitions, revision, non-completion of a word, and sighs).  

Results: Analyses revealed a significant interaction between Diagnostic Group, Age Group, and Cognitive Load Condition, F (3, 71) = 2.89, p < .05, eta² = .11. Post hoc analyses revealed that more disfluencies were evident with changes in the cognitive load conditions and that diagnostic group difference were more apparent in the condition with the highest cognitive load in the older age groups, F (3,71) = 3.96 p < .015, eta² = .14. Across diagnostic groups children in ASD/ADHD comorbid group displayed the highest frequency of disfluencies in the most demanding public speaking condition (See Fig. 1).   

Conclusions: The results indicated that as the attention demands of the public speaking task increased the frequency of language disfluency increased. Children in ASD/ADHD comorbid group were especially susceptible to this type of language and communication difficulty as task demands increased. This pattern of results suggests that within ASD the presence of ADHD symptoms may be related to greater risk for social-communication disturbance as the attention demands of social interactions increase.